Fingermark Visualisation Manual [1 ed.] 9781782462347

Citation preview

i

Fingermark Visualisation Manual

Go to Contents

ii

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Thank you to the following organisations for supporting the production of this Manual:

ISBN: 978-1-78246-234-7 © Crown Copyright 2014. All rights reserved. Issued by Home Office Centre for Applied Science and Technology (CAST). First Edition. Home Office January 2014

ii

iii

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Production of this Manual would not have been possible without the support, hard

Police Forces

page contains details of those who have made a significant contribution towards its

Derbyshire Constabulary

work, endeavours and encouragement of many individuals and organisations. This

publication. The Editor would particularly like to thank Dr Val Bowman who had the

original vision and foresight to see what could be achieved with this Manual and was inspirational during her efforts whilst ‘retired’ from the Home Office. In addition, the Editor would like to acknowledge all those who have contributed to the robustness

of the information within the Manual. This includes all previous CAST fingerprint staff

Cheshire Constabulary

Scottish Police Authority

Gloucestershire Constabulary

Thames Valley Police

Gwent Police

Hertfordshire Constabulary Metropolitan Police

Fingermark Visualisation Manual

Acknowledgements

South Wales Police

West Midlands Police West Yorkshire Police

members, students and contributors to this Manual’s predecessor (Manual of Fingerprint

Special thanks to: K D Ambrose (Hertfordshire Constabulary); D J Auld (Gloucestershire

Home Office

Lewis (Metropolitan Police); N Marsh (Metropolitan Police); J H O’Hara (West Yorkshire

Development Techniques 1st and 2nd Edition). Editor

Dr H L Bandey

Centre for Applied Science and Technology



Dr S M Bleay

Centre for Applied Science and Technology

Main Authors

Project Manager

Dr H L Bandey Dr V J Bowman* R P Downham V G Sears

Dr H L Turner

Additional Support L A Fitzgerald

A P Gibson



J Ramadani



Proofreader

S Mehmet** S R Slater A Praill

Text preparation

P King

and layout

Government Organisations

Centre for Applied Science and Technology

National Crime Agency (NCA)

Centre for Applied Science and Technology Centre for Applied Science and Technology Centre for Applied Science and Technology

Centre for Applied Science and Technology Centre for Applied Science and Technology Centre for Applied Science and Technology

Forensic Science Regulation Unit (FSRU) College of Policing (CoP)

Academia

Dr R S Croxton, University of Lincoln

Prof. A R Hillman, University of Leicester

Contracts

Communications Development Section,

P Denly, DenlyPraill Editorial & Design

Centre for Applied Science and Technology Home Office Science Shared Support

Communications Development Section, Home Office Science Shared Support

Health and Safety Executive

Special thanks to: K Lever, J Fish (NCA); J Guiness OBE (FSRU)

Centre for Applied Science and Technology

**Not currently employed by the Home Office Home Office January 2014

Police); A A York (South Wales Police).

Centre for Applied Science and Technology

* Originally employed by the Home Office and then contracted to the Home Office postretirement

Constabulary); M J Cox (Thames Valley Police); K J Laing (Scottish Police Authority); J

Dr M Bernstein, ChemLaw UK R Ellis, Indexellis

Dr K Manlove, J R A Smith, Dr M Barber, Manlove Forensics Limited Dr K M Stow, L McGarr, Forensic Focus Limited J O’Hagan, Public Health England

Special thanks to: P Denly (DenlyPraill Editorial & Design)

iii

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

iv

Contents

Appendices

Glossary

Index

With thanks to the following for the use of their photos.

Chapter 6

Chapter 2

6.1.13

(both photos)

Denise Harman, Wiltshire Police

Tom Patrick, College of Policing

6.1.24

(all photos)

Monika Hilgert, BKA

Martin Cox, Thames Valley Police

6.1.45

(all photos)

Monika Hilgert, BKA

2.1.4

(top)

2.5.5 Chapter 3

6.1.48

Dr Geraint Williams, Swansea University

3.2.2

Debbie Auld, Gloucestershire Constabulary

6.2.2

Prof. Sergei Kazarian, Imperial College London

3.3.12

Tom Patrick, College of Policing

6.2.4

Dr John Bond, Northamptonshire Police

6.2.6

Prof. Rob Hillman, University of Leicester Prof. Rob Hillman, University of Leicester

(left)

Chapter 4 4.29

(top)

Katrina Lever, NCA

6.2.7

4.43

(top and bottom)

Martin Cox, Thames Valley Police

6.2.10

Dr Simona Francese, Sheffield Hallam University

4.58

(all photos)

Dr M Barber, SLR Forensics Ltd

6.2.13

Dr Melanie Bailey, University of Surrey

Chapter 5

(all photos)

(both photos)

6.2.15

Dr Paul Kelly, Loughborough University

John Smith, University of Westminster

6.2.16

Prof. David Russell, University of East Anglia

5.NS.1

Kenny Laing, SPSA

6.2.18

BVDA

5.NS.5

Kenny Laing, SPSA

6.2.19

Horiba Jobin Yvon

5.CF.7

(top left and right)

(all photos)

5.PS.17 (right, top and bottom) Dr Ben Jones, Brunel University and

5.VE.14 (right, bottom left

and right)

John Wiley & Sons, Inc

(both photos)

Fingermark Visualisation Manual

Photo Credits

Chapter 7 7.4

Mayor’s Office for Policing and Crime

John Smith, University of Westminster

5.VE.15 (right, top and bottom) John Smith, University of Westminster 5.VE.16 (right, upper right,

upper left and bottom) John Smith, University of Westminster

5.VE.17 (right, top and bottom) John Smith, University of Westminster Home Office January 2014

iv

v

CO

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Acknowledgements................................................................................iii Photo Credits..........................................................................................iv Foreword.................................................................................................vi Preface...................................................................................................vii Chapter 1: About this Manual ............................................................ 1.1 Overview of the Manual and intended readership............................................... 1.2 User Guide........................................................................................................... 1.6

Chapter 2: Forensic Evidence Recovery........................................ 2.0.1

Section 2.1: An Introduction to Forensic Evidence Recovery........................... 2.1.1 Section 2.2: Understanding Fingermarks......................................................... 2.2.1 Section 2.3: Fingermark Visualisation Processes............................................. 2.3.1 Section 2.4: Fingermark Evidence Recovery Planning..................................... 2.4.1 Section 2.5: Using and Understanding Fingermark Evidence.......................... 2.5.1

Chapter 6: Category B-F Processes............................................... 6.0.1 Category B Processes...................................................................................... 6.1.1 Category C Processes...................................................................................... 6.2.1 Category D Processes...................................................................................... 6.3.1 Category E Processes....................................................................................... 6.4.1 Category F Processes....................................................................................... 6.5.1

Chapter 7: Integrating Forensic Processes...................................... 7.1 Appendices....................................................................................... A.0.1

Appendix 1: Case Studies................................................................................A.1.1 Appendix 2: Fingermark Research....................................................................A.2.1

Glossary..........................................................................................GLO.1 Index................................................................................................. IND.1

Chapter 3: Safe and Effective Implementation of the Processes.3.0.1

Section 3.1: Requirements for Implementation................................................ 3.1.1 Section 3.2: Working Safely.............................................................................. 3.2.1 Section 3.3: Working Effectively....................................................................... 3.3.1

Chapter 4: Process Selection............................................................. 4.1

Important General Notes...................................................................................... 4.2 Primary Chart Definitions..................................................................................... 4.4 Chart 1 Non-Porous............................................................................................. 4.5 Chart 2 Porous................................................................................................... 4.24 Chart 3 Semi-Porous......................................................................................... 4.35 Treating Items of Varying Complexity ............................................................... 4.49 Preparation Processes Overview ...................................................................... 4.55 Contaminants Overview .................................................................................... 4.56 Optical Processes Selection Guide .................................................................. 4.60 Category B-C Process Options......................................................................... 4.61

Chapter 5: Category A Processes...................................................... 5.1

Preparation Processes.................................................................................... 5.PP.1 Optical Processes...........................................................................................5.OP.1 Chemical and Physical Processes................................................................5.CPP.1

Home Office January 2014

v

Fingermark Visualisation Manual

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Following publication of the earlier editions of the Manual

Identification of individuals through the use of fingermarks

This Manual represents a significant contribution to UK

available, publication of this radically new edition of the

though other forensic disciplines, such as DNA have

standards for fingermark recovery that have been mandated

and various updates as new information has become Fingermark Visualisation Manual is now called for. It

includes more comprehensive background information

and brings practitioners up to date with current knowledge.

remains a vital tool for the investigation of crime, even

developed significantly since the first Manual of Fingerprint

Development Techniques was published by the Home Office in 1986.

The recovery of fingermark evidence remains at the core

Since 1986, police forces and other law enforcement

placing fingermark evidence recovery in the broader

Manual for their laboratory and crime scene activities. The

of the Manual but a less exclusive approach is taken by

context of integrated forensic recovery. It reflects the

changing role of practitioners, who may no longer be solely working in fingermark recovery.

The opportunity has been taken to make the Manual electronic and interactive and gives further options for

agencies in the UK and overseas have adopted the

policing, reinforcing and supporting the revised quality throughout the EU. It provides a level of information which

will not only assist UK law enforcements agencies to work

to a more consistent standard, it also enables practitioners to develop their competence in fingermark recovery,

mindful of their responsibility to preserve other forensic evidence.

intervening years have seen many changes to operational

I am confident that this latest Manual will continue to

provides a significant update to the information available

detection.

policing. I am pleased to support this new Manual, which to practitioners as they continue to provide their valuable

make a valuable contribution to best practice in fingermark

service to the Criminal Justice System.

updating the information in a more streamlined manner. I trust that this Manual will make as significant a contribution

to criminal identification as its predecessors have done before.

Rob Coleman OBE BEng Director

Home Office Centre for Applied Science and Technology Home Office January 2014

CC Chris Sims OBE QPM

Chair of the Forensic Science Portfolio Board

Andrew Rennison M.Sc

Forensic Science Regulator Home Office

vi

Fingermark Visualisation Manual

Foreword

vii

Contents

viii

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

This Manual is being published at a time

continues at a number of institutions

of a criminal investigation. Practitioners

guide and advise practitioners to enable

for fingermark evidence is under great

be able to include some answers that

duties as a more integrated approach to

fingermark recovery in the situations

when the integrity of and scientific basis scrutiny. It is also being produced at a

time when many new developments are on the horizon, which may change the way fingermarks are recovered in the

future. The Manual captures a snapshot of the Home Office Centre for Applied

Science and Technology’s (CAST) current knowledge and is written with the aim of promoting good practice by those involved in the use of fingermarks. It

focuses on raising fingermark recovery to a high minimum standard by those

responsible for their visualisation on items associated with criminal activity.

Even though research and development

into fingermark recovery has been active for many years, including numerous

studies at the Home Office, there are still many unanswered questions, such as:

●● Did a man or woman leave the mark? ●● Was the donor a smoker or drug-

taker?

●● When was the fingermark left on the

item?

●● Was the fingermark generated before

or after the page was printed?

The answers to many of these questions may not be far away as research Home Office January 2014

and future editions of the Manual should currently elude us. There is one more

question, to which the answer may always be in the negative:

‘If no fingermarks have been visualised, even after comprehensive processing, does it mean that there were no fingermarks there?’

For now, we must be satisfied with the

answer that ‘absence of evidence is not evidence of absence’ of fingermarks.

Home Office expertise has largely rested on the development of fingermark

visualisation processes and these remain at the heart of the Manual. It includes a wide range of recovery processes that can be used to visualise fingermarks

generated on a variety of materials and aims to provide a means of achieving good practice in fingermark evidence recovery. While the main purpose of

the Manual is to provide information

for maximising fingermark evidence, it

recognises more explicitly than previous Home Office Manuals of Fingerprint Development Techniques (MoFDT) that this cannot be done without

acknowledging that additional pressures

will manifest themselves during the course

may now be required to incorporate other forensic recovery is emerging and police

budgets are placed under greater pressure to offer value for money. The Manual aims to reflect this in the content by placing more emphasis on the integration of

fingermark evidence recovery with other forensic disciplines.

Another significant driver for making the changes to the Manual has been the

introduction of mandatory ISO 17025

accreditation for EU laboratories providing

fingermark recovery services. The Manual is not an ‘ISO 17025 Manual’. However, it has been compiled with those seeking accreditation to the ISO 17025 standard

in mind by including information that will

help to raise practitioners’ understanding of fingermarks and of the processes

them to make confident decisions about with which they are faced. To this end, extensive details of the routinely used

processes, as well as some information about those not routinely used by UK

law enforcement laboratories, have been included, with sufficient information for

practitioners to make informed choices

about the suitability of their use. Many of

the non-routine processes have not been subject to CAST’s rigorous evaluation, so would require critical appraisal

before they could be used on evidential

material. Much more information on many

processes for fingermark visualisation can be found in the Home Office Fingerprint Source Book (Home Office, 6 June

2012). [https://www.gov.uk/government/ publications/fingerprint-source-book]

routinely used to visualise them. The

The result of needing to include significant

for presenting the process instructions

the decision to provide the Manual in an

standard format used in the Manual

should also assist in writing procedures to

demonstrate their effective implementation in local operational situations.

ISO 17025 accreditation includes

assessment of the competence of

practitioners to undertake the tasks given to them. The emphasis of the Manual is

not to offer ‘prescriptive’ solutions but to

amounts of additional material has driven electronic format. This has also enabled a degree of interactivity to create links

between parts of the Manual, to provide the user with easy access to supporting information, or reference material. With such significant departures from the

previous MoFDT it has been decided

to name this Manual the Fingermark

vii

Fingermark Visualisation Manual

Preface

ix

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Preface Visualisation Manual. The Home Office has not been able to produce this Manual without the help of a large number of individuals and

organisations, acknowledged on pages

ii and iii, who have provided information and challenges to aid its production.

It is impossible to achieve unanimous agreement on something as complex as the visualisation of fingermarks.

However, every attempt has been made to take into account as many views as

possible, especially from the perspective of police operational use of processes, before incorporating the information in

the Manual. Indications are given of the confidence that CAST places on the

information included in the Manual but we continue to welcome comments from all

those involved in the recovery and use of fingermark evidence so that knowledge can continue to grow. The Editor

Home Office January 2014

viii

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

1 About this Manual

Fingermark Visualisation Manual

Chapter 1: About this Manual

1.1

CH1

Contents Overview of the Manual and intended readership 1.2 User Guide.................................................................. 1.6 How to navigate around the Manual....................... 1.6 How to use the Manual for Fingermark Visualisation............................................................ 1.7

Introduction

This chapter has been included in the Manual to explain what it contains and to identify its intended readership.

Also, since this Manual represents a departure from the previous content and style of presentation, it includes

a User Guide to help practitioners become familiar with using it. Many readers will have been familiar with the

previous Home Office Manual of Fingerprint Development Techniques (MoFDT) and how the information was

presented in it: it is important for readers to understand how they may use the information in this Manual most effectively.

Home Office January 2014

1.1

1.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

This Manual has been produced to provide

comprehensive information for practitioners involved in the recovery of evidential fingermarks in the UK*. Its primary focus is to present information that can be accessed easily by those who want to recover

fingermarks in a laboratory environment. Additional

considerations for the use of fingermark visualisation processes at scenes can also be found in the

fingermarks visualised can be maximised. These four aspects are considered in detail throughout the Manual. As much relevant information as possible

has been included, to support practitioners deciding on

the best plan of action for fingermark recovery within the constraints imposed upon them and to offer guidance and advice in executing the plan most effectively.

Manual. Although the Manual touches on the use of

The Manual has been created for use by many

consideration.

responsibility for recovering fingermark evidence and

fingermarks for making identifications, this is not a prime Fingermarks are complex and the places where they may be found are diverse. The Manual cannot be prescriptive in its advice but does indicate where confidence can

be placed upon the information included in it to assist

practitioners in the difficult task of deciding on how to go about recovering them.

This Manual aims to provide the most appropriate and comprehensive information for current UK policing applications and recognises that the: ●● context;

●● knowledge;

●● planning; and ●● execution

of fingermark recovery all require careful consideration

practitioners with either practical or managerial

gives an indication of how their efforts will be used

ultimately to seek identification of those connected

with criminal activity. For some, such as Laboratory Practitioners, the information in the Manual will be

used on a ‘daily’ basis for the practical visualisation

of fingermarks, while others will find it more useful for

reference when evaluating situations, e.g. when deciding whether scene use of a process is likely to be beneficial or practical.

Although the Manual is intended to be of most value if

used electronically and interactively, it has been compiled

so that it can be read from ‘cover to cover’ if necessary. It has also been produced in a way that enables those who wish to work from hard copies to print individual pages if this is preferred.

by practitioners to ensure the evidential value of any

The Manual has been designed to be easy to use but later

*N.B. The Manual has been written for UK police

to navigate around and use it for planning and executing

operational reference and throughout reflects common UK policing practices and the need for compliance with UK or EU legislation only.

Home Office January 2014

in this chapter there is a User Guide which describes how fingermark visualisation.

The four main themes, context, knowledge, planning

and execution run through seven chapters, which have been further subdivided to provide information in as

concise a way as possible. Two appendices, a glossary of terms and an index have also been included. The principal chapters are:

Chapter 2: Forensic evidence recovery Chapter 3: Safe and effective implementation of the processes

Chapter 4: Process selection Chapter 5: Category A processes Chapter 6: Category B–F processes Chapter 7: Integrating forensic processes Throughout, the Manual strives to place aspects of fingermark recovery in context. Examples include:

●● discussing the planning of fingermark recovery in the

context of an investigation (Chapter 2, Section 2.1);

●● a reminder that fingermark recovery may need to be

considered in the context of other forensic evidence (Chapters 2 and 7);

●● ensuring practitioners working in laboratories or at

scenes consider how they can work safely in the

context of the risks to themselves and others (Chapter 3);

●● reflection of the end-to-end requirements to ensure

recovery is optimised with consideration in the context of providing the best information to aid identification

(Chapter 2, Section 2.5 and Chapter 3, Section 3.3). With the advent of mandatory ISO 17025 accreditation

1.2

Fingermark Visualisation Manual

Overview of the Manual and intended readership

1.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

for fingermark laboratories, the Manual has focused on

How to plan the most appropriate fingermark recovery

done to visualise them in a given a set of circumstances

is covered in two sections:

passing on knowledge about fingermarks, what may be and why a certain approach may be most beneficial. For example, the Manual includes:

●● detailed information about fingermarks: how they are

generated and how they behave when exposed to

various environmental conditions (Chapter 2, Section 2.2);

●● detail of fingermark visualisation processes: which

constituents are present in fingermarks, how they

may be targeted and how their effectiveness changes if the item submitted has been exposed to various external conditions (Chapter 2, Section 2.3); how

they are evaluated and considered suitable for use on evidential material (Appendix 2).

Home Office January 2014

Fingermark Visualisation Manual

Overview of the Manual and intended readership processes to use is a major component of the Manual. It ●● the general principles of planning (Chapter 2, Section

2.4);

●● in greater detail in Chapter 4 but with reference to

Chapters 5, 6 and 7, which include information on individual processes or other forensic disciplines which will assist in the fine-tuning of the plans.

Information on the execution of the processes can be

found in Chapters 5 and 6 but with strong reference to

Chapter 3 to ensure that they can be carried out safely

and effectively in order to provide the best information to

those practitioners responsible for making identifications. A more detailed breakdown of the various chapter contents follows.

1.3

1.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Guide to the chapters

Who should find this chapter useful?

Chapter 4: Process selection

be found in each chapter and who might find it useful. It

of fingermark evidence should find this chapter of value

individual process or processes in sequence through the

An indication has been given below of the material to

is acknowledged that police forces’ structures vary and

practitioners carrying out similar duties will have different titles within their organisations. The responsibilities

assigned to various practitioners will also vary from force to force and may change with time, so it is difficult to be precise about who should find parts of each chapter of most value.

Chapter 1: About this Manual

This chapter gives an overview of the Manual and its content, including who should find it useful, how it is

structured and includes a User Guide to indicate how it can be used for fingermark visualisation planning and execution.

Who should find this chapter useful?

All practitioners involved in recovering and making use

both for gaining knowledge about fingermarks and their recovery and as an introduction to later chapters of the Manual.

approving plans for fingermark evidence recovery

and using fingermark visualisation processes safely and effectively, principally in a laboratory environment, but

with reference to the additional considerations that may

be needed when using them at scenes. This information is not prescriptive since the location in which the processes are carried out and any risks to safety must be assessed locally for the most appropriate arrangements to enable people to work safely, efficiently and effectively.

processes should use this chapter in conjunction with

or managers deciding the most appropriate plans for

visualisation of fingermarks in the laboratory or at scenes. Chapter 2: Forensic Evidence Recovery

This chapter contains general background information

about fingermark evidence and its recovery in the wider context of the investigative process and the recovery of other forensic evidence. It provides background

evidence recovery.

This chapter provides general information for setting up

find this chapter useful, both to find out more about its will be most valuable to those technical practitioners

assist in refining the plan in order to maximise fingermark Who should find this chapter useful?

processes

Who should find this chapter useful?

content and how to access information. The User Guide

use of charts and additional supporting information to

Chapter 3: Safe and effective implementation of the

Anyone involved in fingermark evidence recovery,

especially those using the Manual for the first time should

This chapter guides the planning of the most appropriate

Practitioners carrying out fingermark evidence recovery local health and safety requirements, to understand the health and safety implications of their work.

Those in managerial positions and those responsible for the health, safety and welfare of staff and others

should find the information a useful contribution when

establishing safe and effective working practices both in a laboratory and at scenes.

Anyone responsible for proposing, generating or

(including at scenes). Practitioners who will be carrying

out the processes who may be consulted in the decisionmaking process.

Chapter 5: Category A Processes

This chapter contains full instructions for executing

individual Category A processes, i.e. those fingermark

visualisation processes which are routinely used. Health

and safety and troubleshooting information is included as well as additional considerations for scene applications. Who should find this chapter useful?

Practitioners carrying out the Category A processes

should make themselves familiar with the entire section relating to individual processes.

Others, such as managers, may find the information

they need on specific pages: key pages are the process instruction front page and the ‘Laboratory or scene?’

page for those who need to decide whether scene use of the process is advisable from a practical, safety or effectiveness perspective.

information required for an understanding of the remainder of the Manual.

Home Office January 2014

1.4

Fingermark Visualisation Manual

Overview of the Manual and intended readership

1.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Guide to the chapters continued Chapter 6: Category B–F processes

This chapter includes limited information on a number

of processes which have been proposed at some time

for fingermark visualisation: some may offer potential for

fingermark visualisation, some may be used with caution and others are included for reference as they are not recommended for use.

Who should find this chapter useful?

Experienced and competent practitioners involved in

planning and executing fingermark recovery processes

should take responsibility for reviewing the information for individual processes in this chapter before deciding if any of these processes should be used.

Chapter 7: Integrating forensic processes

This chapter provides information, where it is available, to highlight the possible interferences between fingermark and other forensic evidence recovery to assist when

planning the optimal sequencing of forensic evidence recovery to avoid loss of valuable information. Who should find this chapter useful?

Fingermark Visualisation Manual

Overview of the Manual and intended readership Appendices, Glossary and Index

Appendix 1 contains case studies. Appendix 2 is concerned with fingermark research and includes CAST’s development methodology and how

processes are assessed for their suitability for use on operational material.

A Glossary has been added to clarify how certain terms have been used in the Manual to avoid confusion. Finally, an index is included for quick reference. Who should find these sections useful?

The case studies in Appendix 1 are intended to assist

practitioners responsible for planning fingermark recovery, including those in a managerial position.

Those requiring a deeper knowledge of the development of the fingermark visualisation processes and how

they have been assessed and classified will find this information in Appendix 2.

Anyone using the Manual should find the information in the glossary and index of value.

Practitioners involved in planning fingermark evidence recovery where the recovery of other forensic material may be needed; this could include technical and managerial personnel.

Home Office January 2014

1.5

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

start of each chapter and each section.

v

Contents

About this Safe and Effective Process Category A Integrating 1 Manual 2 Forensic 6 Category Evidence 3 Implementation of 4 Selection 5 Process B-F Process 7 Forensic Recovery Processes Instructions Instructions Processes

Appendices

User Guide

Glossary

The banner at the top of each page gives

Contents Acknowledgements...............................................................................iii

Photo Credits .........................................................................................iv

Foreword ...............................................................................................vii Preface .................................................................................................viii Chapter 1: About this Manual ........................................................... 1.1 Overview of the Manual and intended readership .............................................. 1.2 How to navigate around the Manual ................................................................... 1.6 How to use the Manual for Fingermark Visualisation.......................................... 1.7

Chapter 2: Forensic Evidence Recovery ....................................... 2.0.1

Forensic Evidence Recovery ............................................................................ 2.0.1 Section 2.1: An Introduction to Forensic Evidence Recovery.......................... 2.1.1 Section 2.2: Understanding Fingermarks ........................................................ 2.2.1 Section 2.3: Fingermark Visualisation Processes ............................................ 2.3.1 Section 2.4: Fingermark Evidence Recovery Planning .................................... 2.4.1 Section 2.5: Factors Influencing Identification ................................................. 2.5.1

Chapter 3: Safe and Effective Implementation of the Processes 3.0.1

Chapter 4: Process Selection ............................................................ 4.1

Process Selection ............................................................................................... 4.1 Important General Notes..................................................................................... 4.2 Primary Chart Definitions .................................................................................... 4.4 Chart 1 Non-Porous ............................................................................................ 4.5 Chart 2 Porous .................................................................................................. 4.24 Chart 3 Semi-Porous ........................................................................................ 4.35 Chart 3.1 Paper (White, Glossy) ........................................................................ 4.36 Chart 3.2 Printed Paper and Card .................................................................... 4.37 Chart 3.3 Silk/Satin-Painted Walls and Wood................................................... 4.38 Chart 3.4 Adhesives with Semi-Porous Backings ............................................ 4.39

Contents

this Safe and Effective Process Category A Integrating 1 About 2 Forensic 6 Category Manual Evidence 3 Implementation of 4 Selection 5 Process B-F Process 7 Forensic Recovery Processes Instructions Instructions Processes

Appendices

Glossary

Index

Chapter 5: Category A Processes......................................... 5.INTRO.1

Preparation Processes ...................................................................................... 5.PP.1 Adhesive Tape Removal ...............................................................................5.ATR.1 Numberplate Splitting ................................................................................... 5.NS.1 Soot Removal................................................................................................ 5.SR.1 Thermal Coating Removal........................................................................... 5.TCR.1 Optical Processes ..............................................................................................5.OP.1 Colour Filtration.............................................................................................. 5.CF.1 Fluorescence Examination .............................................................................5.FE.1 Infrared Reflection ........................................................................................ 5.IRR.1 Monochromatic Illumination........................................................................... 5.MI.1 Multi-Spectral Imaging .................................................................................5.MSI.1 Ultraviolet (UVC) Reflection ...................................................................... 5.UVCR.1 Visual Examination .........................................................................................5.VE.1 Chemical and Physical Processes ................................................................ 5.CPP.1 Acid Dyes ...................................................................................................... 5.AD.1 Basic Violet 3 .............................................................................................. 5.BV3.1 DFO .............................................................................................................5.DFO.1 ESDA .........................................................................................................5.ESDA.1 Lifting ............................................................................................................. 5.Lif.1

Section 2.1: An Introduction to Forensic Evidence Recovery The investigative process

THE INVESTIGATIVE PROCESS

A useful way of viewing the contribution of forensic

Guidance from force policy.

evidence recovery to an investigation is to consider

the passage of time from the moment the crime was

committed and the various sequences of activities that follow with respect to:

Home Office January 2014

Police intervention.

v

●● the investigation itself;

From the start of each

●● the fate and recovery of forensic (including fingermark)

Police decide whether to proceed or not.

Strategy developed for the investigation and for Forensic Evidence Recovery.

Information used for identification purposes.

The activities undertaken will ideally be subject to a

dynamic interaction, ensuring a good flow of information

more detailed chapter

between all the practitioners involved in the investigation.

The crime is committed.

The crime is identified.

The particulars of the case are identified.

The diagram on the right aims to illustrate this.

contents can be accessed.

An index

provides an

indication of

where specific

information can

evidence left at the crime scene.

Chapter the sections and

Fingermark Visualisation Manual

Safe and Effective Implementation of the Processes ...................................... 3.0.1 Section 3.1: Requirements for Implementation ............................................... 3.1.1 Section 3.2: Working Safely ............................................................................. 3.2.1 Section 3.3: Working Effectively....................................................................... 3.3.1

access to the start of each chapter.

Chart 3.5 Adhesives with Cellulose Backings................................................... 4.40 Chart 3.6 Fabric ................................................................................................ 4.41 Chart 3.7 Non Paper-Based Wallpaper ............................................................. 4.42 Chart 3.8 Cellophane Packaging ...................................................................... 4.43 Chart 3.9 Leather (and Leatherette) .................................................................. 4.44 Chart 3.10 Brick and Concrete ......................................................................... 4.45 Chart 3.11 Skin ................................................................................................. 4.46 Chart 3A Blood Contamination ......................................................................... 4.47 Chart 3B Grease Contamination ....................................................................... 4.48 Treating Items of Varying Complexity ............................................................... 4.49 Preparation Processes Overview ..................................................................... 4.55 Contaminants Overview ................................................................................... 4.56 Optical Processes Selection Guide .................................................................. 4.60 Category B-C Process Options ........................................................................ 4.61

2.1.2

Page gives access to the

CO

Index

Fingermark Visualisation Manual

The Manual Contents

Glossary

Scene examined for items with potential evidence.

be found.

Items submitted for forensic examination.

Time FORENSIC EVIDENCE RECOVERY

Contents

About this Safe and Effective Process Category A Category B-F Evidence 3 Implementation of 4 Selection 5 Processes Forensic 1 Manual 2 Forensic 6 Processes 7 Integrating Recovery Processes Processes

Contents

to other information.

Laboratory or Scene? .................5.Nin.2 Laboratory Use ............................5.Nin.3 Health and Safety .................... 5.Nin.3 Equipment ............................... 5.Nin.5 Chemicals ................................ 5.Nin.7 Solutions .................................. 5.Nin.8 Processing ............................... 5.Nin.9 Post-Processing .................... 5.Nin.11 Scene Use ..................................5.Nin.12 Additional Considerations...... 5.Nin.12 Troubleshooting .........................5.Nin.13 Supplementary Information ......5.Nin.19

Safety and Effectiveness Summary ✘ Non-Porous ✔ Semi-Porous ✔ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

Ninhydrin reacts with amino acids and possibly other

in blood.

It is a chemical process that involves the application of a

solution to the item or surface followed by use of a specialist

oven (if possible) to increase the speed and effectiveness of the reaction.

More Details

as they can be easily

The Process

●● Ninhydrin can be used safely and effectively in a laboratory. ●● The process can be used at scenes but precautions are

required to mitigate the asphyxiate nature of the solvent and the effectiveness is significantly reduced with processing times being considerably increased.

●● The effectiveness may be influenced by the method of

applying the solution.

●● The effectiveness linked torelationship the ability to control thebetween stages of an Diagram A:isThe

temperature and relative humidity of the item or surface post-

investigation and forensic evidence recovery.

application. This requires the use of specialist equipment to

Initial assessment of items for forensic evidence potential.

Decide on and carry out Forensic Evidence Recovery Plan (including a Fingermark Recovery Plan if needed).

Provide information to support the investigation and identification.

carry out successfully.

●● The process is most effective at developing both latent and

2.1.2

●● Ninhydrin is not effective on items or surfaces that have been

wetted, even if they have been subsequently dried.

●● It is effective on items or surfaces that have been soaked

with petrol or paraffin.

Integrated Use

Ninhydrin may be detrimental to subsequent fingermark or forensic processing.

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

and other forensic processes.

Home Office January 2014

Forensic evidence may or may not offer potential in the case.

The Item or Surface

●● See Chapter 4 for information on its sequential use with other

assessed via the banner at

Forensic evidence may be affected as time passes due to environmental conditions but must be preserved as far as possible once the case is opened.

bloody fingermarks on porous surfaces although it can also Home Office January 2014 be used on semi-porous surfaces.

also reacts with amine-containing compounds (mainly proteins)

chapters are not linked

Home Office January 2014

✔ Latent ✔ Blood ✘ Grease

components in latent fingermarks to give a purple product. It

References to particular

the top of the page.

Main Uses

Forensic evidence generated.

Index

Fingermark Visualisation Manual

Nin

links provide easy access

Glossary

A Ninhydrin Alternative Names

On individual pages,

Appendices

Arrows can be used to

navigate page by page, or 5.Nin.1

through history.

1.6

Fingermark Visualisation Manual

How to navigate around the Manual

5.Nin.1

1.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Overview

User Guide

The main aim of this Manual is to

Providing information

Providing guidance

practitioners involved in the recovery

Manual.

carrying out fingermark recovery.

The aim of this guide is to ensure that

anyone using the information within it for best advantage.

Chapter 7 gives an indication of the impact of different forensic processes on one another.

CH4

The appendices contain supporting information to both the Manual and the guidance for fingermark recovery.

Important General Notes .......................................... 4.2 Chart 1 Non-Porous .................................................. 4.4 Chart 2 Porous ......................................................... 4.23 Chart 3 Semi-Porous ............................................... 4.34 Supplementary information .................................... 4.48 Treating Items of Varying Complexity ................. 4.48 Preparation Processes Overview ........................ 4.54 Contaminants Overview ...................................... 4.55 Optical Processes Selection Guide .................... 4.59 Category B-C Process Options ........................... 4.60

sequence to target constituents of the fingermark or

This chapter provides detailed background information substrate materials. However, their effectiveness can be Section 2.1: Its part in an investigation ................ 2.1.1 about fingermarks and the processes employed to significantly altered if the fingermark has been exposed to Section 2.2: Understanding fingermarks.............. 2.2.1 Section 2.3: Fingermark visualisation maximise the evidence from them in both the context of different conditions. processes ................................................................ 2.3.1 an investigation and the recovery of evidence from other Contents About this Forensic Safe and Effective Process Category Using A Integrating Appendices Glossary all Category the information available to practitioners will Section 2.4: Fingermark evidence recovery forensic disciplines. It aimsof to provide appropriate detail Manual Evidence Implementation Selection Process not only help B-F Process Forensic CH3 to define the best approach to evidence planning ................................................................... 2.4.1 Recovery Processes Instructions Instructions Processes to create a foundation for using other parts of the Manual recovery planning but will also make the information in Section 2.5: Factors influencing identification .... 2.5.1 and to support those operating to an ISO standard. the Manual of greatest value in deciding how to produce

1

2

3

4

5

6

7

Many practitioners are involved from the time of a crime and refine plans for fingermark recovery. Effective 3 Safe and Effective Implementation the Processes is committed until fingermarks are used for comparison with reference fingerprints. A coordinated approach Introduction

Contents

CH5

5.INTRO.1

Introduction

Index

1st proof

communication of many of the factors associated

with the item and the way that havehas been Section 3.2:fingermarks Working safely much more information

is needed in order to create and the carry out Forensic visualised will assiston those going on to make comparisons Establishing capability to carry out fingermark the general health, safety and welfare issues that Section 3.1: Requirements for Implementation ... 3.1.1 Evidence3.2.1 Recovery visualisation Plans most effectively. recovery with reference fingerprints the aim of making processes The safely and effectively requires need towith be considered when establishing and operating Section 3.2: Working safely ................................... of fingermark may be embedded within the Section 3.3: Working effectively ............................ 3.3.1evidence many factors to be taken into account. Theidentifications. competence a fingermark development laboratory. It stresses in end-to-end processofand it must be to recognised thatprocesses, there practitioners carry out the the efficiency will be various constraints and limitations imposed along of the operational facility and effectiveness of local

Advisory Note

the way.

●● a laboratory (or a scene) is a place of work and

procedures all contribute to optimising the information

2 Recovery 3 Processes

4

employers must therefore meet the requirements of the Health and Safety at Work Act 1974;

associated with them and the items on which they

may be used. These must be assessed locally and

7.1

committed. Forensic affected by theProcesses work of the organisation. 7 Intergrating

Glossary

Index

areas where good practices are required to maximise

hse.gov.uk/toolbox/index.htm.

fingermark recovery. These are concerned with effective:

chapter adds contains advice andofguidance to support Thestandards visualisation of This fingermarks another layer All references to legislation, regulations and

●● working in a laboratory environment; Introduction important, e.g. swabbing first for DNA where an item is and their complement local or is procedures concerned in this manual applyContents just to the UK and only at the time complexity to ensuring contribution topolicies the case ●● handling of items;likely and to have been handled. This chapter provides overviews of a number of evidence Ballistics ..................................................................... 7.2 withchemical health, safety and welfare. It also considers aspects of writing. Users must only work from current versions optimised. The optical, and physical processes ●● imaging of fingermarks. types to generalresults. information Body and Fluids ................................................................ 7.4used of working effectively toprovide obtain optimal It is on the potential of legislation, regulations standards, including developedany for the purpose canmost be singly or in Similarly, employment of fingermark visualisation CCTV ........................................................................... synergies between examination Chapter 5 specifies any dedicated thattoisbe detrimental to other presented in7.6 three sections, theand firstincompatibilities of which (3.1) gives amendments or whatever has superseded them. processes thatequipment are believed Digital Forensics ........................................................ 7.8 and recovery processes for different types of forensic needed and providesevidence detailed instructions out with caution, an overview of what might be needed when establishing types shouldfor becarrying considered Home Office January 2014 DNA ........................................................................... 7.10 evidence. is included in the Manual it is processes safely and effectively. It also includes specific the laboratory operation of the It processes. The need for since 2.0.1 especially if a number of processes are used in sequence Documents ............................................................... 7.12 that additionfacility, to fingermarks, there mayon the specific hazards associated with information competent staff and recognised the provision of ainsuitable where the effects may be magnified. Optical fingermark Drugs ........................................................................ 7.14 be with otherequipment, types of forensic evidence (including someprocesses not individual and possible means of mitigating the but care needs appropriately furnished are emphasised. processes are usually non-destructive, Fibres ........................................................................ 7.16 included that need to be consideredrisks. as part of an section must not be read here) in isolation, since three Contents About this ForensicMarks....................................................... Safe and Effective ThisProcess Category A Category Integrating Appendices to be Glossary taken not to Index contaminate or damage other forensic Footwear 7.18 overall Forensic Evidence Recovery Manual Evidence Implementation of other Selection Process B-F Process ForensicCareful parts 7.20 of the Manual contain more information that Strategy. AP Glovemarks .............................................................. evidence, e.g. molecular damage caused by highRecovery Processes Instructions Instructions planning may be needed maximiseProcesses evidence recovery, should also7.22 be consulted by those planning toto implement Hairs.......................................................................... intensity light sources. Physical fingermark processes ideally in consultation with appropriate practitioners in the processes: Toolmarks ................................................................. 7.24 are generally non-destructive but deposits of trace their field. Consideration must be given to prioritising Trace Evidence ........................................................ 7.26 material such as powder and the physical nature of their evidence recovery as part of the Forensic Evidence application may cause disruption to other evidence types. Recovery Plan, as recovery processes for fingermarks or Contents Introduction Chemical processes are generally more destructive and other forensic evidence types are potentially disruptive to Home Office January 2014 In Chapter 2 the planning of fingermark recovery was introduced.may It was discussed remove or disrupt other evidence types and as such Appendix 1: Case Studies .....................................A.1.1 3.0.1 each other. in terms of the various considerations that need to be taken into they account, from the will usually be used after all other evidence has been Appendix 2: Fingermark Research .......................A.2.1

1

2

3

4

5

6

7

the processing of items or surfaces with the potential to yield fingermarks. It is important to read the User Guide

since there is much supporting information in the Manual and knowing how to access this is vital to using it most effectively.

At the core of the decision-making process are three

primary charts that provide a processing sequence which

the most comprehensive approach for recovery of fingermarks in the most serious cases.

The most effective processes within the sequences are indicated since single processes may be adequate in many cases.

The final choice of processes must be made locally as

there may be numerous constraints and limitations placed upon the organisation.

should be chosen on the basis of the porosity of the

perspective of the case, the policies and procedures as well as It is not possible to prescribe a definitive approachof tothe organisation recovered.

knowledge offorensic the itemrecovery and howbecause its history cansituation be usedisto guide the development of integrated each

theunique. most suitable Appendix 1 has a number examples of operational situations As seenplan. in Chapter 2, strategic directionofwill be

which demonstrate how plansincluding have been afterand consideration of all the relevant governed by many factors thegenerated requirements facts, constraints limitations. priorities of the and case, the need for preservation of certain

forensic evidence types as well as local constraints. Fingermark research is discussed in Appendix 2. The number of variables associated However, practitioners should be aware that there may be with fingermarks and their visualisation makes the development of processes to visualise published guidelines for some forensic disciplines, e.g. them particularly challenging, especially if the process is to be used on operational digital forensics, which may give firm advice. material. The Home Office uses a methodology which has proven suitable for fingermark

this Safe and Effective Process Category A B-F 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Category Processes 7 Integrating Forensic Recovery Processes Processes 1.

Non-porous;

3.

Semi-porous.

2.

Porous; or

Glossary

Index

visualisation processes that have been demonstrated 5 Category A Processes

to be effective on these particular surface types. They also include greater detail on how the effectiveness Introduction

Contents

properties of the fingermark. They can be used to

of individual in the sequences may change process or Having decided on the most appropriate Preparation Processes......................................... 5.PP.1 processes when more is known aboutitthe nature or history of are thecarried out most processes, is important that they Adhesive Tape Removal .................................5.ATR.1 item or surface,effectively. e.g. if it has a rough surface or has Numberplate Splitting ...................................... 5.NS.1 This chapter contains full been instructions on the wetted. The primary also Aform a hub for optical, accessing Soot Removal .................................................. 5.SR.1 use ofcharts Category preparation, chemical and

visualise latent marks or further enhance previously treated items or surfaces.

Each process is presented in a consistent style making it easy for the reader to find information. (See User

important notes visualisation and supplementary information Thermal Coating Removal ............................. 5.TCR.1 general physical processes which have been fully Optical Processes ................................................5.OP.1 to guide the practitioner by indicating evaluatedtobymodify CAST the andplan in most cases are routinely used Colour Filtration ................................................ 5.CF.1 suitable adjustments based ondevelopment. detailed knowledge of the for fingermark Fluorescence Examination................................ 5.FE.1type, the item and its history. substrate Standard processes for routine operational Infrared Reflection .......................................... 5.IRR.1 The5.MI.1 secondary charts should used when more in preference to other use. be They must be used Monochromatic Illumination ............................. category processes where information is known about the substrate type, e.g. ifpossible. it is Multi-Spectral Imaging ...................................5.MSI.1

Guide – Chapter 5 Process Instruction Contents). Different levels of information are available for each

process to target the information for different readers.

A

1

2

3

4

5

The first page of each process instruction is intended

to be a useful starting point for all, directing access to

further information if necessary, e.g. if deciding whether scene application would be beneficial. Step-by-step

6

7

guides and safety considerations provided Category A with health Category Integrating are Appendices Process B-F Process Forensic for those carrying out the process, with supplementary Instructions Instructions Processes

Glossary

Index

6 Category B-F Processes

Powders ......................................................... 5.Pow.1 attached surfaces. Category E Processes............................................ 6.4.1 They may be needed before any other used routinely for operational work. Powder Suspension..........................................5.PS.1 Category F Processes ............................................ processes are6.5.1 applied or within a sequence. The level of information provided for the Category B–F processes is in line with the Small Particle Reagent .................................. 5.SPR.1 The optical visualisation processes exploit the optical possible usage of individual processes, as indicated below: Solvent Black 3 .............................................. 5.SB3.1 Superglue Fluorescent Dye Staining ........... 5.SFDS.1 Superglue Fuming............................................. 5.SF.1 Vacuum Metal Deposition ............................. 5.VMD.1

properties of the item or surface when illuminated or

irradiated. They can be used to visualise marks prior to any chemical or physical processes or further enhance

B

previously treated items or surfaces.

target chemicals present in fingermarks or the physical Home Office January 2014

Optional processes for occasional operational use. Possible reasons for use: no other options available; all Category A options have been exhausted; niche application; or lack of equipment for other processes. These have varying levels of detail, from single-page summaries to more comprehensive information, as appropriate. The information is presented in a template similar to that used for the Category A processes.

The chemical and physical visualisation processes

C

Optional processes for occasional operational use. Possible reasons for use: no other options available; all Category A options have been exhausted; 5.1 niche application. Only a summary page for each is provided to give an indication of where the process may be beneficial.

D

Corrective action processes. Not generally for routine use but may be used to recover marks in situations where initial selection of processes has resulted in undesirable consequences. The two Category D processes may be used for corrective action and have more detail to explain how they may be used most effectively.

Home Office January 2014

research for this purpose those conducting studies of this nature are encouraged to The approach required and for handling one type of evidence usemay its principles to ensure or robust canwith be given. The methodology is supported be to the detriment lead advice to conflict another

Appendices

The primary charts include sequences of fingermark

Fingermark Visualisation Manual

Appendices

Fingermark Visualisation Manual

Chapter 7: Intergrating Forensic Processes

practicable.

Section 3.3: Working effectively, covers three particular

they may have exposed since the crime was to been remain safe, whether they are directly or indirectly control risks at work see HSE’s website atwhich http://www.

This chapter includes information to assist those planning

information for those wishing to learn more about the how the processes will be carried out most effectively Basic Violet 3 ..................................................5.BV3.1 Home Office January 2014 process. It is important that the processes are carried out DFO................................................................5.DFO.1 within any limitations imposed on individual operational 4.1 by competent personnel, who are familiar with the entire ESDA ...........................................................5.ESDA.1 laboratories. content of the process instruction n Lifting ................................................................ 5.Lif.1 The preparation processes are used to prepare surfaces Contents Introduction Multi-Metal Deposition ................................ 5.MMD.1 for subsequent application of visualisation processes Category B–F processes have been proposed at some time for the visualisation of Ninhydrin..........................................................5.Nin.1 Category B Processes ........................................... 6.1.1 and may involve the removal of contaminants or fingermarks. They are not regarded by CAST as meeting the criteria for Category A Physical Developer .......................................... 5.PD.1 Category C Processes ........................................... 6.2.1 potentially interfering Physical Developer Enhancement ............................................................ 5.PDE.1 Category D Processes 6.3.1 substances, or separation of processes (see Chapter 2, Section 2.3 for full classification details) and are therefore not

possible hazards kept to a minimum, there are risks

5 Instructions 6 B-F Process 7 Forensic Instructions Processes

onon which and in the to a laboratory or atenvironment scenes. Everyone has a legal right and welfare. For information and guidance how they to wereinplaced

Introduction

Ultraviolet (UVC) Reflection ........................ a5.UVCR.1 particular type of plastic, orprocess has an adhesive backing Full instructions are given. Visual Examination............................................5.VE.1 whether contaminants are Safe present. Contents Aboutor this Forensic andSecondary Effective chartsProcess It is anticipated that these instructions will be used to Chemical and CH6 Physical Processes ................... Manual Evidence Implementation are5.CPP.1 used in conjunction with the primary chartsofto give Selection Processes guide the production of local procedures to describe Acid Dyes......................................................... 5.AD.1 Recovery

●● although the processes have been developed with

depend of how they were generated and to keep people safe as far as isAppendices reasonably At the sameSafe time, providing a safe working environment the practitioner. you are advised to seekon knowledge Contents About this Forensic and Effective Process Category A mitigated Category Integrating CH7 However,

Manual Evidence Implementation ofbesurface Selection Process of the likelihood ofconcern their survival on the is a prime and must achieved when working specialist advice in all matters relating to judgement health, safety

Index

Fingermark Visualisation Manual

that can be obtained from fingermarks. From preliminary A good This chapter looks at the general requirements forunderstanding of how fingermarks are generated handling of items submitted for processing through to and how they may be visualised is fundamental to the safe application of fingermark development imaging of any marks visualised, effective working will the results that can be obtained from processes. The advice is based on CASToptimising experiences, help to achieve robust evidence and make the process of its own work environment and use of the fingermarks. fingermark However, fingermarks are complex. identification most productive. Evaluating visualisation processes, and is designed to assist their contribution to an investigation will

1

particular that:

Contents

6.0.1

viewed as either:

2 Forensic Evidence Recovery Contents

Glossary

surface type:

Fingermark Visualisation Manual

The Manual contents that can be broadly

Index

Chapter 5: Category A Processes

regarded as a fully interactive whole.

Glossary

Appendices

Fingermark Visualisation Manual

gain most from the Manual it should be

Appendices

Fingermark Visualisation Manual

all the information contained within but to

CH2

3.0.1

can be read from cover to cover to access

About this Safe and Effective Process Category A Integrating 1 Manual 2 Forensic 6 Category Evidence 3 Implementation of 4 Selection 5 Process B-F Process 7 Forensic Recovery Processes Instructions Instructions Processes

About this Safe and Effective Process Category A Integrating 1 Manual 2 Forensic 6 Category Evidence 3 Implementation of 4 Selection 5 Process B-F Process 7 Forensic Recovery Processes Instructions Instructions Processes

Contents

The Manual has been compiled so that it

Contents

Contents

4 Process Selection

Fingermark Visualisation Manual

fingermark visualisation can use it to the

Chapters 4, 5 and 6 contain information for planning and

Chapter 6: Category B-F Processes

of evidential fingermarks in the UK.

Chapters 2 and 3 form a foundation for the remainder of the

4.1

provide comprehensive information for

Index

E

Processes with no known operational benefits.

F

Processes should not be used for health and safety reasons.

Listed with short explanations of why they are not considered suitable for use.

Listed with short explanations of why they are not considered suitable for use.

6.0.1

by but additional information to illustrate how the Home Office assesses the maturity and may also be beneficial. Employment of forensic

Technical Readiness of damage processes proposed should for fingermark visualisation for law recovery methods Levels that may fingermarks enforcement be avoidedapplications. if evidence from fingermarks is considered

Home Office January 2014

Home Office January 2014

Home Office January 2014

7.1

A.0.1

1.7

Fingermark Visualisation Manual

How to use the Manual for Fingermark Visualisation

2.0.1

1.7

Contents

1.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

5.ESDA.7

Symbols

this Safe and Effective Process Category A B-F Manual Evidence 3 Implementation of 4 Selection 5 Processes Processes Forensic 1 About 2 Forensic 6 Category 7 Integrating Recovery Processes Processes

Appendices

ESDA

Glossary

Index

Scene Use

Additional Considerations

highlight:

For health and safety:

If a decision has been made to use ESDA at a scene, a number of

additional considerations need to be taken into account over and

●● there are generally no additional considerations with regard to the use of the

process at scenes.

above those given for laboratory use. The recommendations cannot be

prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and

●● where there is important information to read

in compliance with the requirements of the Health and Safety at Work Act 1974;

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of the constraints posed by the scene.

●● different approaches may be needed to make the process as effective as possible

For practicality, consider:

●● present a range of practical issues that need to be overcome.

●● provision of a suitable power source, if needed.

within the constraints of the scene;

before proceeding;

For effectiveness, consider:

Fingermark Visualisation Manual

Within the Manual the following symbols are used to

Contents

User Guide

●● access to the areas to be treated;

This page must be read in conjunction with the laboratory process instruction.

●● where there are health and safety

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

3, Section 3.1 - Scene Use of the processes and treatment of large areas for other

considerations to take into account;

general information.

●● where there is information about CAST’s

level of confidence for the information being provided. This ‘Maturity Bar’ is provided

for each process (Chapters 5 and 6) and

sequences of processes (Chapter 4) where: Low maturity: limited scientific data to

Home Office January 2014

support the information and no operational data;

5.AD.1

Contents

Protein Stains; Blood Dyes

Contents

be unclear and operational data lacking;

Options ......................................... 5.AD.2 Laboratory or Scene? ................. 5.AD.3 Laboratory Use ............................ 5.AD.4 Health and Safety .....................5.AD.4 Equipment ................................5.AD.6 Chemicals .................................5.AD.6 Solutions ...................................5.AD.7 Processing ................................5.AD.8 Post-Processing .......................5.AD.9 Scene Use .................................. 5.AD.10 Additional Considerations.......5.AD.10 Troubleshooting ......................... 5.AD.11 Supplementary Information ...... 5.AD.14

High maturity: the information was

developed after years of scientific research with supportive operational data.

identifies whether a process should be

routinely used, considered for use in specific

circumstances or not used at all (see Chapter 2,

Main Uses ✘ Latent ✔ Blood ✘ Grease

Glossary

Index

Safety and Effectiveness Summary ✔ Non-Porous ✔ Semi-Porous ✔ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for three

Category A Acid Dye formulations: ■● ■● ■●

Acid Black 1;

Acid Violet 17; Acid Yellow 7.

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

A

Acid Dyes stain protein present in blood and other protein-rich

contaminants to give a coloured or fluorescent product. They will

not detect the constituents normally present in latent fingermarks and therefore must be used in sequence with other processes when blood-contaminated items or surfaces are examined.

It is a chemical process that involves exposing the item or surface to three solutions in sequence.

Section 2.3).

More Details

Home Office January 2014

Home Office January 2014

Appendices

A Acid Dyes Alternative Names

supports the information but elements may

The process category (A–F) which broadly

this Safe and Effective Process Category A B-F Manual Evidence 3 Implementation of 4 Selection 5 Processes Processes Forensic 1 About 2 Forensic 6 Category 7 Integrating Recovery Processes Processes

The Process

●● Acid Dyes can be used safely and effectively in a laboratory

and at scenes provided precautions are taken to mitigate the flammability of the Staining and Washing Solutions.

●● Blood that is not suitably fixed by the first solution will

dissolve when exposed to the second solution and process effectiveness will be reduced.

●● Acid Yellow 7 requires subsequent Fluorescence

Fingermark Visualisation Manual

Moderate maturity: some scientific data

5.ESDA.7

Examination to be effective.

The Item or Surface

●● Be aware of the possible hazards from body fluids.

●● Acid Dyes will develop fingermarks in blood on most

surfaces.

●● The three dye formulations will vary in effectiveness

depending upon the colour of the item or surface and the surface porosity.

●● Acid Dyes can adversely stain the background of some

porous items, obscuring the fingermark.

Integrated Use

Acid Dyes may be detrimental to subsequent fingermark or forensic processing.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

and other forensic processes.

5.AD.1

1.8

Fingermark Visualisation Manual

How to use the Manual for Fingermark Visualisation

Index

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

1.9

Contents

Appendices

Using Chapter 4 for planning There are four steps to using the information in

User Guide

To simplify the Manual, there are only three Primary Charts, which are at the core of

Chapter 4 effectively. It is assumed that other

fingermark recovery planning.

limitations will be borne in mind by the practitioner

Charts 1 and 2 offer high maturity information, whilst Chart 3 offers moderate maturity.

and plans will be adapted accordingly (see Chapter 2, Section 2.4).

They provide a ‘hub’ from which further information is provided, either on the chart itself or via links to other parts of the Manual.

Step 1 is to identify the nature of the

Assessment of the porosity of the substrate(s) at this stage can generally be based on the

present. This will give direction to which of

below:

substrate(s) on which fingermarks may be

item type as indicated by the definitions and examples found in Chapter 4 and explained

the three Primary Charts 1-3 should be used.

4.5

Contents



Chart 1 Non-Porous



Chart 2 Porous



Chart 3 Semi-Porous

About this Safe and Effective Process Category A Category B-F 1 Manual 2 Forensic 6 Processes 7 Integrating Evidence 3 Implementation of 4 Selection 5 Processes Forensic Recovery Processes Processes

Appendices

Chart Substrate 1.1

Glass and Ceramics

1.3

Plastic Packaging (hard)

Preparation processes overview

VACUUM METAL DEPOSITION

Process effectiveness: influencing factors

Contaminants overview OPTIONS

Optical processes selection guide Category B-C process options User Guide Primary chart definitions

1.2 1.4 1.5 1.6

OPTIONS

Chart Contaminant 1A

1B

Blood

Grease

Unplasticised PVC

Plastic Packaging (soft) Expanded Polystyrene Currency (polymeric)

1.9

Plastic Packaging (cling film)

1.8

1.11 1.12 1.13

Plasticised PVC (vinyl) Rubber

Wax and Waxed Surfaces Gloss Painted Surfaces Untreated Metals

1.14a Adhesives with non-porous backings: light

1.14b Adhesives with non-porous backings: dark

OPTIONS

SUPERGLUE FLUORESCENT DYE STAINING

OPTIONS

POWDER SUSPENSION

Non-Porous surfaces

These surfaces are not permeable to water, other liquids and air. Examples are glass, many hard and soft plastics, metals, ceramics and painted metals.

Porous surfaces

These surfaces are composed of materials that absorb water and other liquids. Examples are paper, card, cardboard, untreated wood and matt-painted surfaces.

Semi-Porous surfaces

This is a broad category of surfaces which includes both materials of truly semi-porous nature, such as leather, silk- and satinpainted surfaces, and those with regions of porous nature interspersed with non-porous regions, such as heavily printed paper or cardboard.

Index

Rigid Plastics

1.7

1.10

Generally most effective sequence

SUPERGLUE FUMING

1

1

Links to: Important general notes Treating items of varying complexity

FLUORESCENCE EXAMINATION

POWDERS

Glossary

Primary Chart

KEY

Fingermark Visualisation Manual

Chart 1 Non-Porous VISUAL EXAMINATION

Index

Most effective processes BASIC VIOLET 3 Phenol-based

1

Superglue Fuming is one of the most effective processes only when it is followed with Superglue Fluorescent Dye Staining General impact of water on process effectiveness. Read full details

General impact of age of mark on process effectiveness. Read full details

General impact of surface roughness on process effectiveness. Read full details

Home Office January 2014

Home Office January 2014

4.5

1.9

Fingermark Visualisation Manual

How to use the Manual for Fingermark Visualisation

Glossary

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

User Guide

Using Chapter 4 for planning continued Step 2 is to assess the surface or item and its history

to determine whether there is sufficient information to modify the chart with confidence.

No further information about

The primary chart should be adopted as the ‘default’ plan

the item can be identified

and the processes indicated used singly or in sequence

as indicated in the chart. It is important to remember that the sequence indicated will need to be supplemented in line with important general notes.

More information is available about the item or surface.

Contents

this Safe and Effective Process Category A B-F 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Category Processes 7 Integrating Forensic Recovery Processes Processes

Appendices

Go to Step 3.

Primary Chart

VISUAL EXAMINATION

1.1

Glass and Ceramics

1.3

Plastic Packaging (hard)

OPTIONS

Process effectiveness: influencing factors Category B-C process options User Guide Primary chart definitions

1.2 1.4 1.5 1.6 1.7 1.8 1.9

1.10 Chart Contaminant 1A

1B

Blood

Grease

1.11 1.12 1.13

Rigid Plastics

Unplasticised PVC

Plastic Packaging (soft) Expanded Polystyrene Currency (polymeric)

Plasticised PVC (vinyl)

Plastic Packaging (cling film) Rubber

Wax and Waxed Surfaces Gloss Painted Surfaces Untreated Metals

1.14a Adhesives with non-porous backings: light

1.14b Adhesives with non-porous

SUPERGLUE FLUORESCENT DYE STAINING

OPTIONS

POWDER SUSPENSION

backings: dark

OPTIONS

1

1

Important general notes Treating items of varying complexity

Optical processes selection guide

Generally most effective sequence

SUPERGLUE FUMING

Chart Substrate

Contaminants overview

OPTIONS

POWDERS

Links to:

Preparation processes overview

FLUORESCENCE EXAMINATION VACUUM METAL DEPOSITION

Index

Fingermark Visualisation Manual

Chart 1 Non-Porous

Glossary

KEY Most effective processes

BASIC VIOLET 3 Phenol-based

1

Superglue Fuming is one of the most effective processes only when it is followed with Superglue Fluorescent Dye Staining General impact of water on process effectiveness. Read full details

General impact of age of mark on process effectiveness. Read full details

General impact of surface roughness on process effectiveness. Read full details

Home Office January 2014

Home Office January 2014

4.5

1.10

Fingermark Visualisation Manual

How to use the Manual for Fingermark Visualisation

4.5

1.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

1.11

Contents

Appendices

Glossary

Using Chapter 4 for planning continued

Supporting information

Step 3a: Use links to access supporting information.

Step 3 is to use knowledge about the item or surface

Links to:

to access further Manual information by using links

Important general notes

in the Primary Charts to supporting information and

Treating items of varying complexity

secondary charts.

Preparation processes overview Contaminants overview

a) Links to Supporting Information

Optical processes selection guide

b) Links to Secondary Charts

4.5

Contents

1

About this Manual

2

Forensic Evidence Recovery

3

Safe and Effective Implementation of Processes

4

Process Selection

5

Category A Processes

6

Category B-F Processes

7

Appendices

Primary chart definitions

1.1

Glass and Ceramics

1.3

Plastic Packaging (hard)

Optical processes selection guide OPTIONS

Process effectiveness: influencing factors Category B-C process options User Guide Primary chart definitions

1.2 1.4 1.5 1.6 1.7 1.8 1.9

OPTIONS

1.10 Chart Contaminant 1A

1B

Blood

Grease

1.11 1.12 1.13

Rigid Plastics

Unplasticised PVC

Plastic Packaging (soft) Expanded Polystyrene Currency (polymeric)

Plasticised PVC (vinyl)

Plastic Packaging (cling film)

Gloss Painted Surfaces

●● The important general notes must be consulted

since the sequences shown must be supplemented

treated?

backings: light

●● How should contaminations be managed in the

backings: dark

plan?

●● Which optical process(es) might be the best ones to

KEY

1

include in the plan?

Superglue Fuming is one of the most effective processes only when it is followed with Superglue Fluorescent Dye Staining

●● How might the history of the item affect process

effectiveness?

effectiveness. Read full details

General impact of age of mark on process

●● Are there any additional processes (Category B and

effectiveness. Read full details

General impact of surface roughness on process

C) that could be used?

effectiveness. Read full details

Home Office January 2014

information gathered about the item or surface.

●● Does the item need to be prepared before it can be

Untreated Metals

General impact of water on process

Home Office January 2014

used to develop a plan basing any decision on the

●● Is the item simple to treat or more complex?

Wax and Waxed Surfaces

Most effective processes BASIC VIOLET 3 Phenol-based

The links all go to additional information that may be

with additional general advice.

Rubber

1.14a Adhesives with non-porous

OPTIONS

OPTIONS

POWDER SUSPENSION

Fingermark Visualisation Manual

Important general notes Treating items of varying complexity

User Guide

Index

1.14b Adhesives with non-porous

1

1

Chart Substrate

Contaminants overview

Generally most effective sequence

SUPERGLUE FUMING

Links to:

Preparation processes overview

FLUORESCENCE EXAMINATION

POWDERS

Glossary

Primary Chart

VISUAL EXAMINATION

VACUUM METAL DEPOSITION

Factors that modify process effectiveness Category B-C process options

Integrating Forensic Processes

Chart 1 Non-Porous

SUPERGLUE FLUORESCENT DYE STAINING

User Guide

4.5

●● Is an integrated forensic recovery plan required?

1.11

Fingermark Visualisation Manual

How to use the Manual for Fingermark Visualisation

Index

1.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

User Guide

Using Chapter 4 for planning continued Secondary charts

Chart Substrate

where the substrate or contaminant can be identified further.

1.1

Glass and Ceramics

1-3 and any additional considerations

1.3

Plastic Packaging (hard)

of the case, local force policy etc. (see

Plastic Packaging (soft)

2.4).

Step 3b: Use links to access secondary charts for treating items These charts must be used in conjunction with the Primary Chart to develop the optimal plan for treating items.

See Using the information in secondary charts.

1.2 1.4 1.5 1.6 1.7 1.8 1.9

Step 4 is to develop the plan, based

on the information obtained in Steps

Rigid Plastics

and constraints, such as the particulars

Unplasticised PVC

Chapter 2, Section 2.1 and Section

Expanded Polystyrene Currency (polymeric)

Plasticised PVC (vinyl)

Plastic Packaging (cling film)

1.10 Rubber

1.11 Wax and Waxed Surfaces 1.12 Gloss Painted Surfaces 1.13 Untreated Metals

1.14a Adhesives with non-porous backings: light

1.14b Adhesives with non-porous backings: dark

Chart Contaminant 1A Blood

1B Grease

Home Office January 2014

1.12

Fingermark Visualisation Manual

How to use the Manual for Fingermark Visualisation

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Using Chapter 4 for planning continued

A

A Be aware of the maturity level of the chart as it indicates the level of confidence

User Guide

this Safe and Effective Process Category A B-F 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Category Processes 7 Integrating Forensic Recovery Processes Processes

Chart 1.14a Adhesives with Non-Porous Backings Light-Coloured

B

D

Vacuum Metal Deposition is ineffective.

Additional considerations and processes:

1.14b 2.8 3.4 3.5

that can be placed on the process sequence.

Adhesives with non-porous backings: Dark Adhesives with porous backings Adhesives with semi-porous backings Adhesives with cellulose backings

C

B Be aware of the association between this chart and its Primary Chart with respect to the content and uses.

C Check that the item or surface has been correctly identified and learn more about it by reading General Information.

G

Powders are less effective than Powder Suspension and Superglue Fuming.

2

Unless it has been wetted, the Superglue Fuming sequence is the most effective for the non-adhesive side. Superglue vapours will interfere with the performance of carbon-based Powder Suspension on the adhesive side if the adhesive side is not adequately protected.

E

3

Superglue Fuming (when followed by Superglue Fluorescent Dye Staining) is the most effective process on the non-adhesive side, provided the item has not been wetted.

4

Carbon-based Powder Suspension is the most effective formulation and it does not cause heavy background staining on the adhesive side.

5

The DOSS-based formulation is less likely to cause background staining than the phenol-based formulation.

Removing adhesive tapes from some surfaces will be extremely difficult and care must be taken. In addition to the category A preparation process, there is a category B process (see Preparation processes overview).

D Read about the changes that have been identified to make the Primary Chart

UVC Reflection can be effective on the non-adhesive side of these items. It is only suitable for smooth, unwrinkled surfaces and should be carried out before chemical processing.

process sequence more effective for this substrate; these may be MAJOR, or

H

MINOR or NO changes.

Index

VISUAL EXAMINATION FLUORESCENCE EXAMINATION

N.B. The processing options for the adhesive and nonadhesive sides of these items are different. Priority should be given to the evidentially more important side. Unless indicated, processes can be used on both sides. 1

Glossary

Secondary Chart continued

Use Chart 1 with MAJOR modifications X

Related charts

Appendices

Fingermark Visualisation Manual

Using the information in Secondary Charts

Contents

Index

X

Non-adhesive side only:

VACUUM METAL DEPOSITION

2

Generally most effective sequence

3

SUPERGLUE FUMING

3

SUPERGLUE FLUORESCENT DYE STAINING

Adhesive

side only:

F

POWDERS

1

4

POWDER SUSPENSION Carbon

4

POWDER SUSPENSION Carbon

5

BASIC VIOLET 3 DOSS-based

E Check whether the additional considerations for this substrate need to be taken into account as the plans are developed.

F Evaluate the revised process sequence, making reference to the Primary Chart

for process effectiveness where the history of the item or surface is known. The primary chart process forms the basis of the secondary process sequence, but

Home Office January 2014

In addition to the key used for the Primary Charts, secondary charts also include the following for chart modifications to denote:

identifies those processes that are not considered effective on the particular substrate and includes additional processes if needed.

4.20

x

G Consider any additional processes that are indicated, including their effectiveness; H Consider any additional charts that are proposed. +

PROCESS V

a process that has been removed from the sequence

PROCESS X

a process has been moved from its original position in the primary chart sequence

PROCESS N

an additional process a process that can visualise fingermarks in blood a process that can visualise fingermarks in grease a process that can visualise latent fingermarks

Home Office January 2014

1.13

Fingermark Visualisation Manual

How to use the Manual for Fingermark Visualisation 4.20

1.13

Contents

1.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

User Guide

Using Chapter 4 for planning continued Using the process sequences Full process sequences are generally presented as linear

Alternative routes may be shown which need to be

If one alternative route is generally more effective than

identified by arrows.

and its history and the anticipated effectiveness of the

additional information if necessary.

flow charts where possible and processing routes are

evaluated, depending on local constraints, the item process(es).

another: this is indicated by the line weighting and

If additional explanations are needed notes are attached and clearly flagged by means of a number, e.g.

1

Home Office January 2014

1.14

Fingermark Visualisation Manual

How to use the Manual for Fingermark Visualisation

Glossary

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

User Guide

Using Chapter 4 for planning continued Process information

Associated with each process are additional features to aid planning: Category A process instructions can be accessed via links from Primary Charts to look up particular

aspects of the use of the process that might guide decision-making.

Click PROCESS X Instructions for Category A processes added in

Secondary Charts can also be accessed via a link.

If additional

explanations are

needed notes are

effective process and where there are alternatives, a

the particular process. The ‘Options’ page in the

coloured background. There may not be a single most number of processes may be identified with a yellow background.

further decisions to be made regarding the use of process instructions should be consulted for further information. Examples include Acid Dyes and Powders.

1

SUPERGLUE FUMING

These symbols are used in combination to indicate the effects of a) b) c)

d) e) f)

Home Office January 2014

For processes with an ‘OPTIONS’ tab, there are

added in the Secondary Charts are colour-coded symbols.

flagged by means of a

1

Most effective processes are identified with a yellow

Embedded within the processes in the Primary Charts and processes

attached and clearly number, e.g.

PROCESS W

PROCESS Z

a) water, b) age of mark and c) surface roughness on the anticipated effectiveness of the process, i.e. d) little or no effect, e) some effect and f) significant effect.

Example:

This represents the Superglue Fuming process. Used in the

sequence from which it was taken, it is the most (or one of the most) effective process. It has no options. Its effectiveness will be reduced

significantly if the item has been wetted, will have decreased with the age of the fingermark but is very effective on rough surfaces.

1.15

Fingermark Visualisation Manual

How to use the Manual for Fingermark Visualisation

Glossary

OPTIONS

1.15

Contents

1.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

It aims to provide a summary of the main aspects of the use of

the process for those assessing whether it may be of value for a

particular application. It also acts as a hub to access other parts

B

of the section or the Manual.

A Be aware of the maturity level

of the process instruction as it

indicates the level of confidence that can be placed on it.

B Indicates the process and its Category.

C Provides links to pages within the process instruction (see next page).

D These boxes outline the main uses for the process. The

right-hand-side box indicates the Primary Chart that it is

associated with, whilst the

left-hand-side box indicates the type of mark that it normally targets.

E Key information for the process instruction.

understand the process in more depth.

G A brief summary of the process safety and effectiveness. It is

split into two sections: the first

User Guide

this Safe and Effective Process Category A B-F Manual Evidence 3 Implementation of 4 Selection 5 Processes Processes Forensic 1 About 2 Forensic 6 Category 7 Integrating Recovery Processes Processes

Appendices

Glossary

Index

A Acid Dyes Alternative Names Protein Stains; Blood Dyes

Contents Options ......................................... 5.AD.2 Laboratory or Scene? ................. 5.AD.3 Laboratory Use ............................ 5.AD.4 Health and Safety .....................5.AD.4 Equipment ................................5.AD.6 Chemicals .................................5.AD.6 Solutions ...................................5.AD.7 Processing ................................5.AD.8 Post-Processing .......................5.AD.9 Scene Use .................................. 5.AD.10 Additional Considerations.......5.AD.10 Troubleshooting ......................... 5.AD.11 Supplementary Information ...... 5.AD.14

C

Main Uses ✘ Latent ✔ Blood ✘ Grease

D

Safety and Effectiveness Summary ✔ Non-Porous ✔ Semi-Porous ✔ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for three

Category A Acid Dye formulations: ■● ■● ■●

Acid Black 1;

Acid Violet 17; Acid Yellow 7.

E

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

looks at what parameters are

Acid Dyes stain protein present in blood and other protein-rich

likely to affect the process,

contaminants to give a coloured or fluorescent product. They will

not detect the constituents normally present in latent fingermarks

independent of the item or

and therefore must be used in sequence with other processes

F

when blood-contaminated items or surfaces are examined.

substrate that it is used on;

It is a chemical process that involves exposing the item or surface to three solutions in sequence.

the second looks at how the

More Details

process performs on item

The Process

●● Acid Dyes can be used safely and effectively in a laboratory

G

and at scenes provided precautions are taken to mitigate the flammability of the Staining and Washing Solutions.

●● Blood that is not suitably fixed by the first solution will

dissolve when exposed to the second solution and process effectiveness will be reduced.

●● Acid Yellow 7 requires subsequent Fluorescence

Fingermark Visualisation Manual

A

The front page of each of the processes has a standard format.

Contents 5.AD.1

Chapter 5 Process Instruction Content

Index

Examination to be effective.

The Item or Surface

●● Be aware of the possible hazards from body fluids.

●● Acid Dyes will develop fingermarks in blood on most

surfaces.

●● The three dye formulations will vary in effectiveness

depending upon the colour of the item or surface and the surface porosity.

●● Acid Dyes can adversely stain the background of some

porous items, obscuring the fingermark.

Integrated Use

Acid Dyes may be detrimental to subsequent fingermark or forensic processing.

H

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

and other forensic processes.

or surfaces with varying properties.

H If the process is to be used in

Home Office January 2014

5.AD.1

sequence with other processes (either fingermark or other

forensics) then this section provides details on where

further guidance can be sought.

F A brief process overview is given with a link to further

information for those wishing to

Home Office January 2014

1.16

Fingermark Visualisation Manual

How to Use the Manual for Fingermark Visualisation

Glossary

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

1.17

Contents

Appendices

Glossary

User Guide

Chapter 5 Process Instruction Content continued enhancing blood on all types of surface.

Sequential Use of Acid Dyes

●● Acid Violet 17 may be used after Acid Yellow 7 to

develop and increase contrast of visible fingermarks,

●● When Acid Black 1 and Acid Violet 17 are used

porous surfaces.

although coloration will not be as dark as achieved

on porous and semi-porous surfaces, there may

●● It is most effective on very light or visually

by use of Acid Violet 17 alone.

be some background staining which will reduce

responds differently and for porous surfaces one

may prove more suitable than the other. If possible

a small part of the surface, away from the area of

●● Acid Black 1 should not be used after Acid Yellow 7

as the density of the staining is significantly less than if Acid Violet 17 is used after Acid Yellow 7.

●● The use of Acid Yellow 7 after Acid Black 1 or Acid

Violet 17 is normally of little benefit. However, it may

interest, should be tested for dye retention.

be used as a counterstain on porous surfaces where

●● Both Acid Black 1 and Acid Violet 17 produce visible

fingermarks.

Acid Violet 17 enhanced blood on a baseball bat.

it will produce a fluorescent background that boosts contrast with the developed, absorbing fingermark.

●● There is no benefit to be gained by using Acid

Black 1 and Acid Violet 17 in sequence with one another.

●● See Chapter 4 for information on its sequential use

with other fingermark visualisation processes.

●● See Chapter 7 for information on integration of

Acid Yellow 7 enhanced blood on a knife handle.

fingermark and other forensic processes.

* The number of fingermarks detected with

Fluorescence Examination is dependent upon many factors e.g. suitability of light source and viewing

filters, level of dark adaptation and the surrounding

Acid Black 1 enhanced blood on a stamp book.

5.AD.4

Contents

1

About this Manual

2

5.AD.2

3

Forensic Evidence Recovery

Safe and Effective Implementation of Processes

4

Process Selection

5

Category A Processes

6

Category B-F Processes

7

Integrating Forensic Processes

Appendices

Acid Dyes Hazards associated with Acid Dyes ●● Acid Dyes are chemical processes.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions or

are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’).These are based on CAST’s local risk assessment

mixtures and be aware of the possible biological hazards when body fluids are present.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional Hazard

situations, but are given as guidance only.

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

Risk

Suggested control measures

Creation of a flammable atmosphere when preparing and using Staining and Washing Solutions.

Fire

●● Prepare and apply Staining and

Nuisance odour from processed items.

Some individuals may experience watery eyes and sneezing.

●● Examine treated items in

Exposure to quantities of dye solution.

Staining hands, clothes and body with dye.

●● Wear appropriate gloves when

Washing Solutions in a wellventilated area or in a fume cupboard if the temperature is above 28˚C. See working with flammable liquids for further information.

●● In providing the Category A process instructions it is assumed that:

the process will be carried out in a laboratory that can provide a safe working environment;

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍●

an assessment of the practitioner’s competence to carry out the process;

❍●

a review of all the hazards associated with the use of the process, consulting

❍●

a review of all the hazards associated with the working environment, the

relevant documents, such as Safety Data Sheets (SDSs), where necessary;

preparing or using solutions to protect the hands, especially if they are to be immersed in the solutions.

item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

●● Wear a disposable apron to

appropriate PPE, and reviewed for their effectiveness.

1

2 Recovery 3 Processes

Category A Category B-F Selection 5 Processes Forensic 4 Process 6 Processes 7 Integrating Processes

protect the clothes and body.

●● Where information is included forAbout scenethis use of the processes, are Contents Forensic the considerations Safe and Effective

5.FE.8

Manual over and above those for laboratory applications of Evidence the processes. Implementation of

Appendices

Guidance

5.AD.4 Initial guidance for selection of output wavelengths for light sources and appropriate

General principles

Wavelength selection for Fluorescence Examination should take into consideration three

viewing filters both for searching for latent marks and for examining marks visualised

main factors:

with processes giving known excitation and emission spectra, are given on the

●● the output characteristics of the light source;

following pages:

●● the transmission characteristics of the viewing filter;

Wavelength Selection for Initial Examination

●● the excitation and emission characteristics of the substrate and the mark being

Wavelength Selection for Examination of Processed Fingermarks

examined (if known).

With so many high-intensity light sources and viewing filters available to the

high-intensity light sources and viewing filters are outlined in Equipment.

practitioner, it is not possible to give specific guidance for the use of certain light sources. The guidance is therefore generic and relies on the competence of the

For maximum fluorescence, it is important that: 1.

the light source output spectra overlaps as much as possible with the excitation

2.

the power of the light source is such that the intensity of illumination at the surface is

practitioner to ensure that appropriate equipment is used. Also, experienced

practitioners, who fully understand the principles of Fluorescence Examination,

spectra of the fluorescent mark or surface;

may be able to maximise the detail in faint marks via adjustments to the illumination wavelengths and viewing filters based on observations during examination.

There is also limited guidance on some of the labelling systems adopted by

high enough to produce sufficient fluorescence to be effectively observed;

manufacturers for light sources and viewing filters enabling compatible combinations

the viewing filter transmission spectra overlaps as much as possible with the

for a given scenario to be rapidly identified.

emission spectra of the fluorescent mark or surface;

the eyes are protected against the output illumination as outlined in Equipment.

Failure to optimally match the light source and viewing filter to the item or surface being

5.AD.7

Contents

About this Safe and Effective Process Category A Integrating Evidence 3 Implementation of 4 Selection 5 Process B-F Process 7 Forensic 1 Manual 2 Forensic 6 Category Recovery Processes Instructions Instructions Processes examined will result in lower-contrast marks caused by either weaker fluorescence or less discrimination between mark and substrate fluorescence. Although this may be

Appendices

Glossary

Index

a) Staining and Washing Solutions must be prepared in a well-ventilated area. They must be prepared in a fume cupboard if the temperature is above 28°C. b) The Staining Solution should be stirred for at least 30 minutes. c) Fixing and Washing Solutions are colourless. Staining Solutions are dark blue (AB1), purple (AV17) and yellow (AY7).

Consult Chapter 3 for general information on solution

preparation, safe storage of chemicals, solutions and

(1) Prepare solutions

mixtures (which includes information on packaging

and labelling), management of waste for2014 disposal of Home Office January solutions and guideline expiry periods. This page gives additional information relevant to this process.

Solutions

Fingermark Visualisation Manual

Laboratory Use

Solutions

5.FE.8

a) The Fixing, Staining and Washing Solutions should be labelled in line with the guidance in Acid Dyes Health and Safety.

(3) Store appropriately

a) Fixing, Staining and Washing Solutions have guideline expiry dates of 12 months after preparation if stored at room temperature.

and (4) Dispose of appropriately

Staining Solution

1 g Dye 1 L Washing Solution Dye options: Acid Black 1 (AB1) or Acid Violet 17 (AV17) or Acid Yellow 7 (AY7)

5.AD.9

Contents

and

Ready Reckoner Quantity

About this Safe and Effective Process Category A Category B-F 1 Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Integrating Forensic Recovery Processes Processes Solution

Chemical

Fixing Solution

Washing Solution

Staining Solution

Post-Processing

Washing Solution For other quantities Consult Chapter 3 for general advice on packaging, storage, disposal see Ready or Reckoner. return of items, and management of waste for disposal of

Water

Dye Washing Solution

1L

2L

23 g

46 g

1L

2L

1g

2g

1L

5L Appendices

115 g

Index

5L 5g

2L

Glossary

5L

Acetic Acid

50 mL

100 mL

250 mL

Ethanol

250 mL

500 mL

1.25 L

Water

700 mL

1.40 L

3.50 L

Laboratory Use

equipment, chemicals, solutions and mixtures. This page gives additional

information relevant to this process. Home Office January 2014

5.AD.7

Processed item

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner provided anti-viral disinfectants have been used.

(3) Disposal or return of processed items

Equipment and Chemicals

Using the process at the Scene

a) Fixing, Staining and Washing Solutions should not be

(4) Re-use of solutions

re-used.

Home Office January 2014

5.AD.11

Contents

5.AD.9

About this Safe and Effective Process Category A Integrating 1 Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Process 6 Category B-F Process 7 Forensic Recovery Processes Instructions Instructions Processes

Appendices

Index

Troubleshooting

Diffusion and/or Loss of Fingermark Detail Recognition

the fixing stage has been omitted. The

fingermarks were generated in such a way

that they contain similar amounts of blood prior to processing.

Cause

Effect

Prevention

Correction

The blood is insufficiently fixed prior to staining. Fixing blood with 5-sulphosalicylic acid causes the basic proteins to precipitate and become less water soluble. Once blood is fixed it is much less likely to be washed away during the subsequent application of Acid Dyes.

Insufficiently fixed fingermarks may manifest themselves in several ways including: ●● diffusion and loss of ridge detail; ●● higher background staining due to leeching of blood resulting in loss of contrast; ●● flaking of heavy blood deposits resulting in loss of significant detail; ●● loosened flakes interferring with other areas of fingermark development.

Ensure that: ●● the process instruction for fixing has been followed; ●● the fixing time has been appropriately extended where heavier blood contamination is present.

There are no corrective measures.

Home Office January 2014

Reference pages Troubleshooting. This section allows the practitioner to recognise common problems that may occur during processing and goes on to describe cause, effect, prevention and corrective measures.

Fingermarks in blood on plasterboard

developed with Acid Black 1 where (left) is

fixed with 5-sulphosalicylic acid, and (right)

5.AD.11

Supplementary Information. This section is for those who want a deeper understanding of the process and includes process theory and explanations for why the process instruction says what it does.

generally considered more practical to remove items back to a

below:

●● the detailed process instructions;

and

of the possible biological hazards from blood and other body

Acid Dyes are messy processes if not contained and it is

laboratory for treatment. Processing large items may require

The Staining and Washing Solutions of Acid Dyes are flammable

additional considerations to avoid run-off of solutions into areas

and if the temperature exceeds 28°C, there is a risk of

not requiring treatment. Removal of residual dye from processed

developing a flammable atmosphere when using them.

●● other factors dictated by the

items may be difficult.

●● In a laboratory, the risks of creating a flammable

investigation.

●● In a laboratory it should be possible to contain the Fixing,

atmosphere will be minimal as long as processing is carried

See Chapter 2, Section 4, ‘Fingermark

Staining and Washing Solutions.

out in a well-ventilated area or, if the temperature is greater

Evidence Recovery Planning’.

●● At scenes, residual biological hazards may make clean-up

than 28°C, in a fume cupboard.

problematic and this must be considered before the process

●● At scenes, the risk of fire may increase significantly,

is used. Consideration must also be given to the need for

especially at temperatures greater than 28°C, if it is not

At scenes consider use of the

possible to provide sufficient ventilation or to remove heating

based) although these are less effective

monitors may be required.

Category B Process Acid Dyes (waterthan Acid Dyes.

suitable equipment for the containment of the Fixing, Staining and Washing Solutions.

and ignition sources. The use of personal gas flammability

Home Office January 2014

5.AD.3

this Safe and Effective Process Category A B-F 1 About 2 Forensic 6 Category 7 Integrating Manual Evidence 3 Implementation of 4 Selection 5 Processes Processes Forensic Recovery Processes Processes

Contents

Appendices

Acid Dyes

Glossary

Index

Laboratory Use

Equipment

Acid Dyes only require general laboratory equipment as described in Chapter 3 but using unbreakable equipment to minimise the risk from possible biohazards. Equipment Processing Dishes

Requirements Processing dishes must:

●● be unbreakable and easy to clean and sterilise due to the biohazard risk.

A suitable material would be stainless steel.

Chemicals

Common Name

This table lists chemicals that are required for Acid Dyes. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

Unless specified, water used for making solutions or for rinsing items is purified.

See Chapter 3 safe handling of chemicals for general

information or effective use of chemicals for details on

Alternative Name(s)

Contents

CAS Number

Grade

5-Sulphosalicylic acid, dihydrate

5-SSA dihydrate

5965-83-3

Laboratory

Acid Yellow 7 (AY7)

CI 56205; Brilliant Sulphoflavin

2391-30-2

≥50%

Acid Violet 17 (AV17)

CI 42650; Coomassie Brilliant Violet R150

4129-84-4

≥50%

Acid Black 1 (AB1)

CI 20470; Amido Black 10B; Naphthol Blue Black; Naphthalene Black 12B

1064-48-8

≥80%

Acetic acid

Ethanoic acid

64-19-7

Ethanol

Ethyl alcohol

64-17-5

dye purity.

About this Safe and Effective Process Category A Category B-F 1 Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Integrating Forensic Recovery Processes Processes

Laboratory ≥96%

Appendices

Acid Dyes

Glossary

Index

Laboratory Use

Home Office January 2014

Equipment

5.AD.6

Acid Dyes only require general laboratory equipment as described in Chapter 3 but using unbreakable equipment to minimise the risk from possible biohazards. Equipment

Requirements Processing dishes must:

Processing Dishes

●● be unbreakable and easy to clean and sterilise due to the biohazard risk.

A suitable material would be stainless steel.

Chemicals

This table lists chemicals that are required for Acid Dyes. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

Unless specified, water used for making solutions or for rinsing items is purified.

See Chapter 3 safe handling of chemicals for general

information or effective use of chemicals for details on

Common Name

Alternative Name(s)

Contents

CAS Number

Grade

5-Sulphosalicylic acid, dihydrate

5-SSA dihydrate

5965-83-3

Laboratory

Acid Yellow 7 (AY7)

CI 56205; Brilliant Sulphoflavin

2391-30-2

≥50%

Acid Violet 17 (AV17)

CI 42650; Coomassie Brilliant Violet R150

4129-84-4

≥50%

Acid Black 1 (AB1)

CI 20470; Amido Black 10B; Naphthol Blue Black; Naphthalene Black 12B

1064-48-8

≥80%

Acetic acid

Ethanoic acid

64-19-7

Laboratory

Ethanol

Ethyl alcohol

64-17-5

≥96%

dye purity.

About this Safe and Effective Process Category A Category B-F 1 Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Integrating Forensic Recovery Processes Processes

Appendices

Acid Dyes

Glossary

Index

Laboratory Use

Processing

Home Office January 2014

Preparation

(3) Equipment and Solutions

a) Pour sufficient amounts of Fixing, Staining and Washing Solutions into separate dishes or vessels to treat the item. At least two Washing Solution dishes should be considered.

About this 1 Manual 2 Forensic Evidence 3 Recovery

Acid Dyes

Continued on next column

a) If using Acid Black 1 or Acid Violet 17, apply the Staining Solution to the item, ensuring that the surface is kept wetted, for three to four minutes using suitable means, such as immersion or pouring. Do not spray. Weak staining of marks will indicate that longer exposure times are required or dye concentration is insufficient. b) If using Acid Yellow 7, apply the Staining Solution to the Effective item, ensuring thatProcess the surface is kept wetted, A Safe and Category for five to ten using suitable means, such as Implementation ofminutesSelection Processes immersion or pouring. Do not spray. Weak staining Processes of marks will indicate that longer exposure times are required or dye concentration is insufficient. c) If immersing the item, the Staining Solution should be changed or replenished as required.

4

5

a) See drying of items.

(7) Dry item

a) Apply the Fixing Solution to the item, ensuring that the surface is kept wetted, for five minutes using suitable means, such as immersion or pouring. Longer times may be needed to fix heavy deposits of blood. See troubleshooting. b) If immersing the item, the Fixing Solution should be changed if it becomes contaminated with debris or changes colour.

Processing (4) Expose item to Fixing Solution

Contents

a) Apply the Washing Solution to the item, ensuring that the surface is kept wetted, until excess dye has been removed from the background and greatest contrast is achieved between the enhanced fingermarks and the background. This should be done using suitable means, such as immersion with gentle agitation or pouring. Do not spray. b) If immersing the item, the Washing Solution should be changed when it becomes heavily contaminated with dye. The final Washing Solution should remove final traces of excess dye from the item.

(6) Expose item to Washing Solution

a) If necessary, prepare item so that processing is practical to carry out (e.g. some items may need to be cut), whilst considering effective handling of items.

(2) Item

(5) Expose item to Staining Solution

5.AD.6

a) Flammable solutions (Staining and Washing) must be used in a fume cupboard if the temperature is above 28°C, otherwise a well-ventilated area can be used.

(1) Work area

(8) Examination (Acid Yellow 7) Primary: Fluorescence Examination

(Acid Black 1/ Acid Violet 17) Primary: Visual Examination Secondary: Fluorescence Examination

Category B-F 6 Processes 7 Integrating Forensic Processes

a) Items treated with Acid Dyes should be examined in a well-ventilated area, preferably on a down-draught bench. b) Visible marks are coloured dark blue (AB1), purple (AV17) and yellow/brown (AY7). Fluorescent marks are coloured yellow (AY7). c) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination and Fluorescence Examination, particularly for low-contrast marks or marks on dark or patterned surfaces. d) Mark up viable fingermarks appropriately and capture image. e) After examination, items can be re-treated if necessary. Appendices Glossary Index In this case application of Fixing Solution is not required.

Scene Use

Additional Considerations Home Office January 2014 If a decision has been made to apply Acid Dyes at a scene, a number of additional considerations need to be taken into

account, over and above those given for laboratory use. The recommendations below cannot be prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and

will require different control measures to mitigate

any risks identified before work can be carried out

safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

For health and safety, consider:

●● the risk of contagion due to biohazard and,

depending on the quantity of potentially hazardous

material, whether additional safety measures or PPE are required;

●● minimising the risk of fire by reducing the flammability

hazard by: ■●

the process as effective as possible within the constraints of the scene;

●● present a range of practical issues that need to be

overcome.

This page must be read in conjunction with the laboratory process instruction.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter 3, Section 3.1 –

ensuring adequate ventilation of the processing area, e.g. by opening doors and windows;

■● ■●

removing all sources of ignition;

limiting the area treated and restricting the

●● whether the process instructions as given for carrying

out the process in the laboratory can be followed,

after consideration of the constraints posed by the scene.

For practicality, consider:

●● access to the areas to be treated;

●● the additional time and costs of applying the process

at the scene, including: ■● ■●

application and avoid run-off onto areas not requiring treatment; ■●

needed for transporting the solutions (made in the laboratory) to the scene;

●● providing additional PPE to protect practitioners, and

if required specialist equipment such as personal gas flammability monitors and thermometers.

transport costs;

or plasticine™ to contain the solutions during

keeping surfaces for treatment and processing area below 28°C;

●● what additional packaging and labelling will be

additional equipment to make the process safe and effective and to minimise mess, e.g. tissue

application of the processing solutions; ■●

5.AD.8

For effectiveness consider:

amount of flammable material used by targeted

●● different approaches may be needed to make

scene clean-up, which may involve dismantling surfaces contaminated with residual biological hazards or stained surfaces for disposal;

●● use of the Category B Process Acid Dyes (water-

based).

Scene Use of the processes and treatment of large areas for other general information.

Contents

About this Safe and Effective Process Category A Category Integrating 1 Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Process 6 Instructions B-F Process 7 Forensic Recovery Processes Instructions Processes

Acid Dyes Theory

Blood consists of red cells (erythrocytes), white cells Home Office January 2014 (leukocytes) and platelets (thrombocytes) in a proteinrich fluid called plasma which makes up roughly 55%

of whole blood volume. The red cells principally contain the haemoglobin protein but also have specific surface proteins (agglutinogens) which determine blood group.

The white cells, which form part of the immune system,

also play a part in the affinity of Acid Dyes to protein molecules.

Acid Dyes are applied via a three-stage process. 1.

protein content and is made of four protein subunits each flat porphyrin ring and a conjugated ferrous ion.

dye in an acidic solution that stains the precipitated a coloured (blue-black for Acid Black 1, violet for

Acid Violet 17, yellow/brown for Acid Yellow 7) and/or fluorescent (bright yellow for Acid Yellow 7) product. 3.

A washing stage is required post-staining. On nonporous substrates this just removes excess dye;

however, on porous substrates this also acts as a

performing the fixing stage.

the background substrate. The Washing Solution has

The Acid Dyes are characterised by the presence of one

or more sulphonate (-SO3) groups. These groups function in two ways: firstly to provide solubility in water and/or alcohol, the major solvents from which to apply these dyes, and secondly by virtue of their negative charge

(anionic). If acidic conditions are used the blood protein molecules acquire a positive charge (cationic) and this attracts the acid dye anions. Hydrogen bonding and

(preferably using an area that does not contain ridge

detail) before proceeding to visualise with Acid Dyes n

The fixed fingermarks are then treated with the acid

proteins, including haemoglobin, are water soluble and

may be diffused or lost if the dye is applied without first

determining whether a fingermark is in blood. Other 5.AD.10 tests should be used to confirm the presence of blood

basic proteins in the manner described above to give

Dyes and function by staining any proteins present, such

proteins to the substrate. This is important as most

Firstly the blood-contaminated fingermarks are fixed using a solution of 5-sulphosalicylic acid in water;

solutions. 2.

as egg white, milk and many other foodstuffs, and as

such are not at all specific for blood (human or animal).

Index

diffusion and any associated loss of detail in aqueous

Acid Black 1, Acid Violet 17 and Acid Yellow 7 are Acid

They incorporate a stage that either denatures or fixes

Glossary

The Acid Dyes cannot be used as the sole means of

this precipitates the basic proteins, preventing

have a nucleus which contains DNA.

containing a haem group. The haem group is made of a

Appendices

Supplementary Information

other physical forces such as Van der Waals bonds may

Haemoglobin makes up roughly 95% of red blood cells’

Home Office January 2014

Home Office January 2014

can be followed.

Practicality

fluids remaining on items or surfaces after processing.

Fingermark Visualisation Manual

After processing, some or all of the ridge detail is diffuse or missing.

Fingermark Visualisation Manual

Acid Dyes

Glossary

Additional Considerations for Scene Use. It is not possible to give process instructions for scenes as every scene presents its own difficulties. This page highlights some of the problems that must be considered.

Acid Dyes are equally effective if used in the laboratory or at the scene, provided the details as written in the process instruction

Health and Safety

Both in the laboratory and at scenes practitioners must be aware

Fingermark Visualisation Manual

a) It may not be possible to return items to their original state. If possible, items may be thoroughly wiped or washed with an anti-viral disinfectant (if body fluids are present), followed by soap and water. Some solvents may be effective at removing residual chemicals, although they may cause further damage to the item.

(2) Cleaning processed items

Effectiveness

flammability of the Staining and Washing Solutions.

consider in addition to the information

Processing. A flow diagram is used to guide the practitioner through the process and includes details for setting up, carrying out the process and, for chemical and physical processes, examining the item or surface post-treatment. Post-Processing. This page gives information (in addition to that identified in Chapter 3) on clearing up after the item or surface has been treated, rather than the examination and imaging of marks.

a) Items treated with Acid Dyes may emit a nuisance odour comprising of acetic acid vapour. Its concentration is likely to be below the WEL.

(1) Residual processing chemicals

Fingermark Visualisation Manual

Acid Dyes

50 mL Acetic acid 250 mL Ethanol 700 mL Water

5-SSA dehydrate

Acid Dyes can be used safely and effectively in a laboratory

and at scenes provided precautions are taken to mitigate the

the laboratory or at the scene, e.g. crime scene managers or investigators, must

Solutions. This provides formulation details for a range of solution volumes. A flow diagram explains (with links to other chapters or sections) how to prepare, label, store and dispose of solutions.

Fixing Solution

23 g 5-Sulphosalicylic acid dihydrate 1 L Water

Index

Fingermark Visualisation Manual

(2) Label appropriately

for deciding whether to process items in

Chemicals. This table details process-specific chemicals giving alternative names, CAS numbers and grades.

acceptable for brightly fluorescing marks, weakly fluorescing marks will almost certainly be missed.

Acid Dyes

practical issues associated with the

use of this process. Those responsible

Equipment. This table details process-specific equipment and their requirements, clearly identifying where requirements ‘must’ or ‘should’ be followed. Detailed Selection. This page only appears in some of the optical process instructions and includes useful information for processes requiring further guidance e.g. wavelength selection within Fluorescence Examination.

Glossary

Fingermark Visualisation Manual

These are explained further in Supplementary Information whilst the requirements for

4.

Index

Laboratory Use

Wavelength Selection

3.

Glossary

Fingermark Visualisation Manual

Fluorescence Examination

Home Office January 2014

This page only gives an overview of

Health and Safety. This provides a reminder of general health and safety warnings, specific hazards associated with the process and labelling guidelines for solutions (where applicable).

a well-ventilated area or preferably on a down-draught bench.

Appendices

Fingermark Visualisation Manual

(and Safety Data Sheets) and must not be assumed to be appropriate in all

General Health and Safety Information

■●

Fingermark Visualisation Manual

●● Consult Chapter 3 for general information on working safely with Category A

this Safe and Effective Process Category A Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Process 6 Category B-F Process 7 Forensic Recovery Processes Instructions Instructions Processes

health and safety, effectiveness and

Using the process in the laboratory The following sections have been written on the assumption that the process will be used in a laboratory environment where most factors can be controlled. Sections include:

Index

Laboratory Use

Health and Safety processes.

●● Acid Dyes may be carried out with no known hazards to health provided practitioners

■●

Glossary

Contents

Acid Dyes Laboratory or Scene?

Laboratory or Scene? This page gives a brief overview of the benefits and pitfalls of using the process in the laboratory or at the scene and will assist with deciding on processing location.

examination environment.

Home Office January 2014

Options. Some processes have several options associated with them e.g. Acid Yellow 7, Acid Black 1 and Acid Violet 17 are all options within the Acid Dyes process instruction. This page identifies the options and explains when they should be considered for use and how they are integrated into process sequences.

Fingermark Visualisation Manual

contrast with the stained blood. However, each dye

imperceptible deposits of blood (heavy deposits of blood fluoresce weakly due to quenching effects).

●● It produces fluorescent fingermarks*.

Behind the Front Page of each process instruction a set format is followed as far as possible. This may include:

5.AD.6

●● Acid Black 1 and Acid Violet 17 are both effective at

dye.

●● It is only effective at enhancing blood on non-

5.AD.8

Acid Black 1 and Acid Violet 17

●● Acid Yellow 7 is generally the most sensitive acid

Fingermark Visualisation Manual

Acid Yellow 7

5.AD.3

Index

5.AD.6

Glossary

5.AD.10

5.AD.2

Appendices

Options

5.AD.14

this Safe and Effective Process Category A Integrating 1 About 2 Forensic 6 Category Manual Evidence 3 Implementation of 4 Selection 5 Process B-F Process 7 Forensic Recovery Processes Instructions Instructions Processes

Contents

Acid Dyes

de-stainer, removing dye that has been absorbed by to be carefully constructed so that it: a) dissolves the dye; b) does not either diffuse or wash away the stained fingermark; c) retains the intensity of colour of the stain in the fingermark. For these reasons the same solvent mix as that used for the dyeing process is used for washing.

5.AD.14

1.17

Fingermark Visualisation Manual

How to Use the Manual for Fingermark Visualisation

Index

1.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

User Guide

Chapter 6 Processes from the charts in Chapter 4.

This section is ordered by category from ‘B’ to ‘F’.

Categories B–D may have some use on are not always given and the process

would have to be validated for its intended

the process could be

Brief explanation for why the

used

process in not Category A Contents

this Safe and Effective Process Category A B-F 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Category Processes 7 Integrating Forensic Recovery Processes Processes

Appendices

Glossary

Index

B Natural Yellow 3 Alternative Names NY3; Curcumin

use and its effect on other processes if not

Key Information Where this process could be used

Natural Yellow 3 may be of use on dark non-porous surfaces where marks developed with Basic Violet 3 or Solvent Black 3 may be difficult to see and optimal excitation is not available for effective Basic Violet 3 fluorescence. See Category B-C process options.

used at the end of a sequential processing route. The level of information presented,

Why the process is not in Category A

along with the maturity bar, is an indication

The Natural Yellow 3 formulation has not been optimised. This process has not been extensively compared to other lipidspecific processes.

of the amount of knowledge CAST have

●● Competent personnel specialising in fingermark

on the process. In many cases, only front

visualisation must be consulted if considering the use of this process.

pages are presented. In all cases the front

●● Ensure all Category A process options have been explored

before using this process.

page outlines where the process could

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to

be used and why it is not a Category A

considering the use of this process.

process and in Chapter 5.

Process Overview

Natural Yellow 3 is a dye which stains grease- and oil-

contaminated fingermarks, and the fatty constituents of

Categories E–F are listed only to highlight

sebaceous sweat in latent fingermarks. It is effective on nonporous substrates and gives a fluorescent product.

that they must not be used.

Safety and Effectiveness Summary

The Process

●● Natural Yellow 3 can be used safely and effectively in a

laboratory.

●● The process requires subsequent Fluorescence Examination

to be effective.

The Item or Surface

●● The process is most effective at developing sebaceous latent

Fingermark Visualisation Manual

operational work. Full process instructions

Summary of where

6.1.43

Practitioners are linked to this section

and grease-contaminated marks on non-porous surfaces, especially those that are dark in colour.

Integrated Use

Natural Yellow 3 may be detrimental to subsequent fingermark or forensic processing.

Further Reading

1. Gaskell, C., Bleay, S. M., Ramadani, J., ‘The enhancement of

fingermarks on grease contaminated non-porous surfaces: Parts 1 – natural yellow 3, a novel, fluorescent reagent for use on dark surfaces’, J Forens Ident, vol 63 (3), 2013 p274-285.

2. Gaskell, C., Bleay, S. M., Willson, H., Park, S., ‘The

enhancement of fingermarks on grease contaminated, nonporous surfaces: Part 2 – a comparative assessment of

processes for light and dark coloured surfaces’, J Forens Ident, vol 63 (3), 2013 p286-319 n

It is a chemical process that involves applying a dye solution to the item followed by washing with water.

Home Office January 2014

6.1.43

Useful references for those requiring

further information about the process

Home Office January 2014

1.18

Fingermark Visualisation Manual

How to Use the Manual for Fingermark Visualisation

Index

1.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

User Guide

Chapter 7 Integrating Forensic Processes This chapter is referred to from many sections within the Manual. In most cases, a general reference to Chapter 7 is given and this is accessed via the top bar n

Brief description of forensic

evidence type including, where appropriate, information on

how the evidence is generated, Type of

this Safe and Effective Process Category A Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Process 6 Category B-F Process 7 Forensic Recovery Processes Instructions Instructions Processes

Appendices

Glossary

Note: This page gives an awareness of glovemarks evidence to

practitioners specialising in fingermark recovery. If considering glovemarks evidence in addition to fingermarks, competent glovemark practitioners must be consulted.

Overview

Analysis

Gloves are often worn to prevent

intelligence. Features such as patterning

Transfer

deposition of fingermarks. Glovemarks are closely related to fingermarks in

that they are deposited by contact with surfaces or handling of items. These

may be encountered as: positive marks,

A cautionary

where material adhering to the glove

is deposited upon a surface; negative

note

marks, where material present upon

a surface is removed by the glove; or impressed marks, which result from

regarding

contact with soft, deformable surfaces.

Recovery

Many fingermark processes also have

competence

applications in the visualisation of

glovemarks. In practice glovemarks

tend to be found whilst searching for fingermarks rather than a targeted

glovemark search and so Powders is one of the most productive processes. There has been limited research in using other processes to visualise glovemarks.

Contents

Index

Glovemarks Glovemarks may provide valuable

may be used to identify basic types of

glove such as knitted, rubber or industrial, enabling links to be established between

scenes where similar patterns have been encountered.

As gloves are worn, the contact surfaces of the fingers and palms will wear and

of the forensic evidence

glovemarks. Moulding defects in rubber glove patterning and surface patterning in synthetic leather materials, though

providing useful points of comparison,

are not unique as they may occur on any number of similar gloves.

Glossary

Index

●● Glovemark patterning and any fine detail must be preserved.

●● Glovemarks can be fragile and easily damaged. Recovery processes must minimise

the risk of rubbing, abrasion, diffusion of transferred material or distortion of any

features present. Some chemical and physical fingermark processes may damage or remove glovemarks whilst other may enhance glovemarks.

Glovemarks and Fingermarks

Effect of fingermark processes on glovemarks

●● Fingermark visualisation processes (optical) are unlikely to have any adverse effect

on glovemarks.

●● As for fingermarks, the degree of damage will be dependent upon the properties of

and forms the basis for comparison with

Appendices

Important Notes on Glovemark Evidence

●● Some fingermark visualisation processes (chemical and physical) may damage or

has the potential to be characteristic

recovery and vice versa

Glovemarks

and location of any damage features

present and patterning on natural leather

type recovery on fingermark

this Safe and Effective Process Category A Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Process 6 Category B-F Process 7 Forensic Recovery Processes Instructions Instructions Processes

acquire random damage. The degree and

distribution of wear, creasing, the number

Impact of forensic evidence

Fingermark Visualisation Manual

evidence

Contents

Fingermark Visualisation Manual

forensic

7.17

recovered and analysed

Main points about preservation

remove glovemarks whilst others may enhance them.

the glovemark and the process mechanism and there are a lot of similarities with fingermarks as outlined in Chapter 2.

Effect of glovemark recovery on fingermarks

●● There are no processes that specifically target glovemarks and they are normally

found using fingermark visualisation processes.

Maximising fingermark and glovemark evidence

●● Glovemarks recovery is rarely targeted in preference to fingermark recovery. In any

case, fingermark processes would be used for both types of evidence.

The gloves themselves may be a useful

source of DNA evidence and fingermarks.

An example of a glove (top) and a glovemark enhanced with Powders (bottom). Home Office January 2014

7.20

Home Office January 2014

7.21

Summary of the integrated use of the fingermark visualisation processes with other forensic evidence recovery Home Office January 2014

1.19

Fingermark Visualisation Manual

How to Use the Manual for Fingermark Visualisation

Index

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

2 Forensic Evidence Recovery Contents Section 2.1: An Introduction to Forensic Evidence Recovery.................................................. 2.1.1 Section 2.2: Understanding Fingermarks.............. 2.2.1 Section 2.3: Fingermark Visualisation Processes.2.3.1 Section 2.4: Fingermark Evidence Recovery Planning.................................................. 2.4.1 Section 2.5: Using and Understanding Fingermark Evidence.............................................. 2.5.1

Introduction

sequence to target constituents of the fingermark or

about fingermarks and the processes employed to

significantly altered if the fingermark has been exposed to

This chapter provides detailed background information maximise the evidence from them in both the context of

an investigation and the recovery of evidence from other forensic disciplines. It aims to provide appropriate detail

to create a foundation for using other parts of the Manual and to support those operating to an ISO standard.

Many practitioners are involved from the time a crime

is committed until fingermarks are used for comparison with reference fingerprints. A coordinated approach is needed in order to create and carry out Forensic

Evidence Recovery Plans most effectively. The recovery of fingermark evidence may be embedded within the

end-to-end process and it must be recognised that there

substrate materials. However, their effectiveness can be different conditions.

Using all the information available to practitioners will

not only help to define the best approach to evidence

recovery planning but will also make the information in

the Manual of greatest value in deciding how to produce and refine plans for fingermark recovery. Effective

communication of many of the factors associated

with the item and the way that fingermarks have been

visualised will assist those going on to make comparisons with reference fingerprints with the aim of making identifications n

will be various constraints and limitations imposed along the way.

A good understanding of how fingermarks are generated and how they may be visualised is fundamental to optimising the results that can be obtained from

fingermarks. However, fingermarks are complex.

Evaluating their contribution to an investigation will

depend on knowledge of how they were generated and

judgement of the likelihood of their survival on the surface on which they were placed and in the environment to

which they may have been exposed since the crime was committed.

The visualisation of fingermarks adds another layer of

complexity to ensuring their contribution to the case is

optimised. The optical, chemical and physical processes developed for the purpose can be used singly or in Home Office January 2014

2.0.1

Fingermark Visualisation Manual

Chapter 2: Forensic Evidence Recovery

2.0.1

CH2

2.1.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents The investigative process.................................... 2.1.2 Preservation of forensic evidence....................... 2.1.4 Initial assessment ............................................... 2.1.6 Forensic Evidence Recovery Strategy and Plans............................................ 2.1.11 Constraints and limitations................................ 2.1.13

Introduction

Although this Manual is primarily concerned with

providing information on the recovery of fingermark

evidence, it is recognised that many factors other than

fingermark recovery need to be considered in the course of an investigation. This section places fingermark

evidence recovery in the context of both the investigation and other forensic disciplines that may also be important in the case and stresses the need for a cooperative approach between practitioners to achieve optimal results.

The investigative process

This examines, in a theoretical manner, the stages of an investigation, to illustrate the interaction between the

investigative process and the decision whether to recover forensic evidence or not. The need for coordination

of activities and regular review is stressed to ensure

progress is made in the investigation, with appropriate

focus on forensic evidence recovery if it is shown to offer potential in the case.

Preservation of forensic evidence

The need for preservation of all forensic evidence from

damage, degradation and contamination is summarised,

explaining the different approaches that might be needed for different forensic evidence types.

Initial assessment

This explains the importance of an initial assessment of

evidence may have been left at the scene, survived since the crime was committed or is recoverable at all.

Forensic Evidence Recovery Strategy and Plans The relationship between the strategic approach and

plans for the recovery of forensic evidence within the investigation is examined, again from a theoretical

perspective. The ongoing need for cooperation and review by practitioners is stressed, especially with respect to deciding on the most effective order of

forensic evidence recovery (refer to Chapter 7 for more

information about possible interferences) and the need to accommodate new information into revised plans as the results from analyses emerge.

Constraints and limitations

In any investigation there will be numerous factors,

outside those connected with the potential for forensic

evidence recovery that may need to be taken into account when deciding how to progress. The types of constraints and limitations placed upon the investigation are

considered; some of these may be negotiable, depending on the case in hand, whereas others may be dictated by

the force or the nature of the case. These constraints and limitations may change as more information comes to

light. As the plans for fingermark recovery are developed more considerations may need to be taken into account (shown in Section 2.4).

items or surfaces from the crime scene in informing the

investigation of the likely presence of forensic evidence. Different scenarios are presented to illustrate the

approaches that might be taken if forensic or fingermark Home Office January 2014

2.1.1

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery

2.1.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

The investigative process

THE INVESTIGATIVE PROCESS

A useful way of viewing the contribution of forensic

Guidance from force policy.

evidence recovery to an investigation is to consider

the passage of time from the moment the crime was

committed and the various sequences of activities that follow with respect to:

Police intervention.

●● the investigation itself;

●● the fate and recovery of forensic (including fingermark)

Police decide whether to proceed or not.

Strategy developed for the investigation and for Forensic Evidence Recovery.

Information used for identification purposes.

evidence left at the crime scene.

The activities undertaken will ideally be subject to a

dynamic interaction, ensuring a good flow of information

between all the practitioners involved in the investigation.

The crime is committed.

The crime is identified.

The diagram on the right aims to illustrate this.

The particulars of the case are identified.

Scene examined for items with potential evidence.

Items submitted for forensic examination.

Time FORENSIC EVIDENCE RECOVERY Forensic evidence generated.

Diagram A: The relationship between stages of an investigation and forensic evidence recovery.

Home Office January 2014

Forensic evidence may be affected as time passes due to environmental conditions but must be preserved as far as possible once the case is opened.

Forensic evidence may or may not offer potential in the case.

Initial assessment of items for forensic evidence potential.

Decide on and carry out Forensic Evidence Recovery Plan (including a Fingermark Recovery Plan if needed).

Provide information to support the investigation and identification.

2.1.2

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery

2.1.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

The investigative process continued Once potential criminal activity has been identified,

The potential for recovery of forensic evidence will

The investigative process is dynamic, with progress

particular field, will be involved in the investigative

scene and particular items associated with the crime,

the case and from the potential forensic evidence, as

a number of practitioners, each competent in their process. It is important to ensure that all relevant

information, including witness statements, has been

reviewed by them to address the strategic aims of the

investigation and maximise the potential of all forensic

generally be evaluated by an initial assessment of the often by crime scene officers and laboratory practitioners.

depending on regular review of information from

indicated against the relevant portion of Diagram B:

Guidance from force policy.

evidence types.

The initial police involvement will result in their deciding

whether a crime has actually been committed or not. They will also consider potential lines of inquiry and take into

Police decide whether to proceed or not.

account any force policies or other possible constraints

to guide their decision whether or not to proceed with the investigation. Having established that a crime has been

committed and that it will be investigated, the strategy or

The particulars of the case are identified.

Scene examined for items with potential evidence.

Forensic evidence may or may not offer potential in the case.

Initial assessment of items for forensic evidence potential.

approach to the investigation can be developed.

When the crime was committed, forensic evidence,

including fingermarks, may have been generated and

left at the scene. The police may wish to know if there is potential for recovery of that forensic evidence as part

of their approach to the investigation. With knowledge of this potential and increasing information about the

REVIEW of:

a clearer understanding of the possible value of forensic

●● additional information from forensic evidence

particulars of the case, the police will be able to develop evidence to the investigation and therefore the part

that forensic evidence recovery may play in developing

●● additional information from the case;

analysis.

Diagram B: Demonstrating the dynamic interaction between stages of the police investigation and forensic evidence assessment.

their strategy. It is important to ensure that forensic

evidence is preserved as far as possible, from the earliest intervention at the crime scene. More information on this can be found later in this section. Home Office January 2014

2.1.3

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Preservation of forensic evidence

Damage

Preservation is the process of keeping items from a

appropriate handling of items throughout their recovery,

Preservation

Preservation of all forensic evidence through careful and

crime scene, which have the potential to yield forensic

storage and forensic examination is vitally important to

evidence, in the best condition for maximising the

prevent actual damage. However, items may be handled

chances of any evidence being recovered from them. A number of practitioners will be involved during the

investigation: they must all ensure that potential evidence is preserved as far as possible by preventing any

unnecessary further damage, degradation, contamination or cross-contamination both at the scene and during laboratory activities.

numerous times if they are to be comprehensively

examined in the recovery of forensic evidence and this may provide many opportunities for damage to occur. Poor packaging of items may also cause damage to

forensic evidence: in the case of fingermarks, friction

created between the surface of the item on which the

fingermark has been deposited and its packaging can

Poor preservation may result in serious consequences

damage or may completely erase the mark.

for the investigation, not only because vital evidence

Further information can be found in Chapter 3.

may be lost but also because evidence may have been

compromised and therefore questioned later with regard to its reliability.

The effort needed to preserve different types of forensic evidence will vary. For example, methods used for

preservation of digital format CCTV evidence will be very different from that for physical evidence, such as fibres,

where inappropriate handling of items may dislodge vital

strands. Also, the likelihood of transferring DNA to or from items of interest will be very different from the possibility of transferring a fingermark. More information on a

number of forensic types can be found in Chapter 7. When items are recovered from the crime scene, the

forensic material present on them may not be in the same

state as it was when it was generated, due to subsequent time or environmental effects. Little, if anything can

be done to reverse this. Of course, items may need to Home Office January 2014

Examples of a bloody knife (top) and numberplates (bottom) packed appropriately.

be ‘pre-treated’ before the target examination can be

conducted (e.g. drying of items found wet) but the same principles of preservation should apply: to act in ways

that enable forensic examinations to be conducted with minimal loss of potential evidence. For example, more

fingermark evidence is likely to be preserved if an item is dried slowly at low temperature rather than speeding up the drying by applying higher temperatures.

2.1.4

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery

© See Photo Credits

2.1.4

Contents

2.1.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery Preservation of forensic evidence continued Degradation

Further degradation of forensic evidence, i.e. deterioration rather than actual damage, may occur through

inappropriate storage of items prior to or during evidence recovery (see Chapter 3). For instance, exposure to high humidity or temperature may damage the item or any

potential forensic evidence beyond any which occurred before the item was retrieved from the scene.

Contamination

Although items may be contaminated with forensic

material not relevant to the case at the time the crime was committed, it is vital to prevent any further contamination and conserve the condition of the items as far as

possible. When an item is taken from a crime scene,

further contamination from external or alien sources may occur if proper control measures are not put in place. These would normally include the use of appropriate

concerned will be needed to minimise the risk of cross-

contamination and maintain the integrity of the evidence. For example, if items from two different scenes in the

same case come into contact, there may be a mutual

exchange of evidential material. This could render the recovery of forensic evidence from these items of no value to the case as it will be unclear if the evidence recovered was deposited during the course of the

criminal activity or if it was associated with the item

after the event. To prevent cross-contamination between connected crime scenes, it is important to segregate items and to ensure that the same personnel do not

attend scenes relating to the same case unless there

has been an adequate time span between visits or the personnel involved have showered and changed their clothes and personal protective equipment (PPE).

and secure packaging. For example, after fingermark

visualisation, DNA recovery from any fingermark ridges visualised may be needed. If items are not handled or

stored appropriately and become contaminated with DNA from another source, any DNA profile generated will be of no value to the case.

Cross-contamination

Care must always be taken to ensure that there is no

possibility of forensic evidence from one case or one

scene being compromised by transfer to or from another. A disciplined approach to the management of scenes, items returned to the laboratory and all personnel

Home Office January 2014

2.1.5

2.1.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Initial assessment

The initial assessment of individual items and crime scene

Conducting the initial assessment

to yield much useful information both to guide the

An initial assessment of an item or surface is usually

Evidence Recovery Strategy and Plans.

white light source. Images may be taken at this stage to

surfaces of interest in an investigation has the potential investigation and initiate the production of the Forensic At this stage, it is important that all potential forensic

evidence is considered, so that an integrated approach to the recovery of all types of evidence can be taken

to support the investigation most effectively. The initial assessment should therefore be conducted by staff

who are competent in their particular fields and familiar

carried out in ambient conditions or with the use of a

give an entire view of an item or surface and its context or position within a scene in its original or ‘as found’

condition. These images could be used subsequently to

provide a record of the position of any forensic evidence recovered. The information gathered at this stage may increase knowledge of the:

understanding of the likelihood of recovering forensic

Possible presence of a number of forensic evidence types

effects of time and environment on the item or surface

(e.g. body fluids, fingermarks, fibres, drugs) that are

with a range of evidence types. They will also need an evidence through a knowledge of materials and the

and the evidential material. Crime Scene Investigators

(CSI), in consultation with relevant Forensic Experts or, in

the case of fingermark recovery, staff from the Fingermark Development Laboratory will be most suitable for the task.

During the initial assessment, the forensic evidence types considered to be most likely to be present on the item

or surface may be identified. This knowledge, combined with as much information derived from the investigation as possible, can help to guide the most effective

Type and condition of the items or surfaces The material from which the item or surface is made (e.g. plastic, fabric, metal, paper) and its condition

(e.g. weathered, corroded, dirty, clean) may indicate the presence of and the potential to exploit different

evidence types. For example, rough surfaces are more

likely to generate and retain particulate evidence, such as hairs, fibres or paint flakes, longer than smooth surfaces, whereas smooth surfaces are more likely to produce fingermarks of high value.

History of the items or surfaces

The history of the items or surfaces, between the crime occurring and the point of initial assessment, if known, can also provide valuable information. Environmental

exposure to factors such as water, heat or contaminants, for example, may have affected the persistence of

the evidence and indicate the likelihood of successful evidence recovery.

recovery of different evidence types in a Forensic Evidence Recovery Plan.

Chapter 7 describes possible interferences between

forensic recovery processes. This information may assist when developing an integrated plan for the recovery of a number of forensic evidence types.

Home Office January 2014

2.1.6

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery

2.1.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery Initial assessment continued Outcomes of the initial assessment

The initial assessment may conclude that the item or surface is:

●● unsuitable for any forensic evidence recovery;

●● suitable for recovery of some forensic evidence types

but unsuitable for fingermark recovery;

●● suitable for both fingermark recovery and other

forensic evidence types;

●● only suitable for fingermark recovery.

Examples of each of these possible outcomes are given below:

A corroded tin can. If contact was made with the surface when it was pristine, then any traces will have been removed by subsequent corrosion.

Outcome 1 The item or surface may be unsuitable for any forensic evidence recovery.

Action No further action.

An area of a fire scene. The original surface of a table has been

charred away and any forensic traces will have been consumed.

However, information about the temperatures experienced in this

region of the scene may still be gathered, if considered important. Home Office January 2014

2.1.7

2.1.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery Initial assessment continued Outcome 2 The item or surface may be suitable for recovery of some forensic evidence types but unsuitable for fingermark recovery.

A carpet with possible traces of glass and blood. The pile and texture of the carpet make

it unsuitable for fingermark recovery, but trace evidence recovery, blood enhancement and footwear recovery are all feasible.

Action If necessary, a person competent in the recovery of all types of forensic evidence should be consulted. In some of these cases it may still be beneficial to use fingermark examination and visualisation processes because these may reveal the location of other types of forensic evidence. They may also indicate where contact has been made, thus providing additional contextual information or enabling subsequent evidence recovery to be targeted (see Chapter 7).

A breeze block with a rough texture

making it extremely unlikely to retain

usable fingermarks. The rough texture

makes it more likely that other types of trace evidence such as fibres may be retained.

CCTV recording media may hold valuable information, but will not have been

handled during the crime, so will not yield fingermark evidence. Home Office January 2014

2.1.8

2.1.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery Initial assessment continued Outcome 3 The item or surface may be suitable for both fingermark recovery and other forensic evidence types.

A soft drinks can. The smooth surface and the fact that it has been held to drink the contents

Action An integrated Forensic Evidence Recovery Strategy should be developed with input from staff competent in recovery of all types of forensic evidence (see also Chapter 7).

Home Office January 2014

make fingermark recovery possible. The mouth of the can could also be swabbed for DNA and droplets of drink sent for toxicology tests if this was considered relevant.

A threatening letter, suitable for both document examination

and fingermark recovery. Document examination techniques may also identify contact areas for DNA swabbing.

2.1.9

2.1.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery Initial assessment continued Outcome 4 The item or surface may be suitable for fingermark recovery only.

Action A Fingermark Evidence Recovery Plan should be developed if needed to support the investigation.

A polytunnel, representing a large area that would be extremely time-consuming to speculatively swab for DNA. It would be

relatively easy to treat using fingermark recovery processes and this may therefore offer the best practical approach.

Home Office January 2014

2.1.10

2.1.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Forensic Evidence Recovery Strategy and Plans With the emerging information from the case and

the initial assessment, a strategy will develop for the

investigation as a whole. Depending on the relevance

attached to forensic evidence in the case, it should also

be possible to draw up a Forensic Evidence Recovery

Strategy. This, in turn, should enable Forensic Evidence Recovery Plans to be drawn up, using all relevant

information gathered from the early activities associated with the investigation.

The Forensic Evidence Recovery Strategy should give a clear indication of the relative importance of different

forensic disciplines, taking into account the details of the case but also recognising that there will be additional

constraints and limitations that must also be considered. The constraints may be those imposed by local force

or sequences of processes should be applied to visualise any fingermarks with the potential to identify perpetrators of the crime under investigation. This plan will ensure

Over and above the constraints and limitations posed

by the case, there will be additional considerations that the practitioner will need to evaluate in developing the

plan: these are covered in detail later in this chapter, in

Section 2.4: Fingermark Evidence Recovery Planning more information on other forensic types and possible interferences in their recovery.

Whatever is included in the plans, correct execution of processes is most important to gain optimum results.

to the case, or the results of forensic analysis, comes to

practitioners to follow. This may include, for instance, a delayed submission for DNA profiling to check if useful

Review

Forensic Evidence Recovery Plans

See Chapter 5: Category A Processes.

may derive from the particulars of the case.

of all the restrictions and present a clear action plan for

Forensic Evidence Recovery Strategy

and in Chapter 4: Process Selection. Chapter 7 has

As the investigation progresses and more information

The Forensic Evidence Recovery Plans will take account

Strategy for the Investigation

that fingermark evidence is maximised as far as possible.

restrictions, such as local policies, availability of suitable resources or equipment to proceed. Other constraints

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery

about the case and the items, for example their relevance

Fingermark Evidence Recovery Plan

light, the strategy and plans will need to be reviewed and revised accordingly, since the additional information may have a bearing on the progress of the investigation and the associated strategies

fingermark information is forthcoming more quickly to save on cost.

If there is a requirement to recover fingermark evidence,

a separate Fingermark Evidence Recovery Plan will be

developed. Its purpose will be to identify which processes

Home Office January 2014

2.1.11

2.1.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery Forensic Evidence Recovery Strategy and Plans continued A plan for fingermark evidence recovery will almost always need to be drawn up with reference to the recovery of other forensic evidence types.

Chapter 7 looks in more detail, where it is available, at the various interactions between fingermark recovery

processes and those for other forensic disciplines. Some of these interactions will be obvious and may need to be

avoided to prevent loss of forensic material; for example, if both DNA and fingermark evidence is required from an item, swabbing for DNA over the target areas for

Fingermark ridge detail removed by previous swabbing for DNA

ridge detail. Delaying the swabbing until the fingermark

Superglue Fuming/Basic Yellow 40 enhancement.

fingermarks may remove any opportunity of recovering

has been visualised may give the potential for both DNA

on items treated with (left) Vacuum Metal Deposition and (right)

and fingermark evidence. However, the impact of this on DNA must also be considered, hence the importance of an integrated Forensic Evidence Recovery Plan.

Other sequences for forensic evidence recovery may be less obvious and may be directed by the requirements of the investigation. For example, removing data from a mobile phone as a priority in a case will require

considerable handling of the item, which may disturb other forensic material and result in loss of DNA or

fingermark evidence. Also, inappropriate handling of

firearms, to conduct test firings or to recover firing pin marks, for example, may compromise fingermark or

DNA recovery. Conversely, the application of fingermark development processes first may affect the results obtained for test firings.

Home Office January 2014

2.1.12

2.1.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Constraints and limitations

Local police force policy

Such policies may be generated for reasons of cost,

will be a number of constraints and other considerations

may dictate how crime is investigated within their force

different evidence types or, in the case of fingermarks,

Throughout the dynamic review of the investigation, there that will need to be acknowledged as the investigation progresses.

Some constraints and limitations may be evident at the

start of the investigation and remain unchanged, unless

contrary information comes to light. Others may become evident as the investigation progresses and will need

to be evaluated, most particularly as part of the review process, and changes made to accommodate them where necessary.

Every police force will have its own local policies which area. In some circumstances these local policies will clearly define what evidence types can or cannot be

analysed and also, with respect to fingermarks, which

visualisation processes can or cannot be used. In most cases the policies will reflect the different approaches

needed for investigations associated with volume crime or serious or major crime.

Examples of possible constraints that may be placed on the Forensic Evidence Recovery Plan are:

●● volume crime items will have only a single fingermark

visualisation process applied;

●● cling film drugs wraps will be swabbed for DNA and

not subjected to fingermark visualisation;

●● volume crime scenes will only be examined for

forensic evidence at likely points of entry.

the item type. Where these policies exist there is an

additional requirement under the ISO 17025 standard

for them to be approved by the customers who will be

receiving the service under consideration. This approval usually takes the form of a service level agreement between the service provider or laboratory and the

customer, where the customer may be internal to the police force.

Adherence to a local policy may be a justifiable reason

to deviate from recommendations that could maximise evidential recovery but again, to conform to the ISO

17025 standard, the reasons for this deviation should be recorded. However, each case should be treated on its

individual merits and there may be equally good reasons to deviate from force policy if optimising evidential recovery becomes paramount.

Time

as possible or to generate results while a suspect is held

scene may be in a very public place, may risk damage by

cases a non-optimal recovery process may be preferable

Some investigations are bound by time constraints. The

impending weather conditions or may need to be handed back to the owner quickly. Similarly, there may be a need for ‘quick intelligence’ to apprehend a criminal as soon

Home Office January 2014

time efficiency or from analysis of past success rates on

in custody. In these cases, using a rapid, and in some

to waiting for the results from a more effective one that may take several days.

2.1.13

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery

2.1.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Constraints and limitations continued Multiple evidence types

Health and safety

be numerous types of forensic evidence, including

visualisation processes, carry an associated health and

For any given case, scene, item or surface there may

Some forensic analyses, including fingermark

fingermarks, that could be recovered. The Forensic

safety risk: their use needs to be carefully considered

Evidence Recovery Plan, already mentioned, will be

before they are included in any plans. The legal

dictated by the particulars of the case and prioritise the

requirement for those responsible for health and safety

recovery of the evidence types of interest in a particular order. Decisions may be made to discount a particular

in an organisation is to assess reasonably foreseeable

evidence type or the sequential recovery of different

As the plans are carried out, especially for complex

For example, certain fingermark visualisation processes

take place, to agree any further compromises or possibly

evidence types may restrict the use of some processes. may not be used if subsequent DNA extraction and analysis is to be attempted.

cases, it will be important to ensure progress reviews to stop those activities that are no longer relevant as knowledge of the case builds.

risks from the activities of the organisation and to put in place control measures that will reduce the risk ‘so

far as is reasonably practicable’ for all those who might be affected. If this requirement cannot be met for any particular activity in investigating the case, then the

strategic approach or plans will need to be amended.

It has already been discussed that early intervention

Further information regarding decisions about treating

Many of the processes included in this Manual have

thinking for a case should benefit the success of forensic

this chapter and in Chapter 4.

by competent staff in a suitably equipped laboratory

of all appropriate forensic practitioners in the strategic evidence recovery, agreeing compromises where

necessary and guiding the individuals establishing plans in their particular disciplines: further discussion may

promote the use of joint examinations where this might be most profitable.

multiple evidence types can be found in Section 2.4 of More information on the recovery of other forensic

evidence and possible interferences with fingermark recovery can be found in Chapter 7.

been developed by the Home Office to be safe to use (see Chapter 4). Application of the processes at scenes or in laboratories that do not have suitable facilities

may necessitate the use of additional control measures to reduce the risk to an acceptable level. If this is not possible, then the processes must not be used and

other safe alternatives sought. For example, if there is a possible risk to members of the public from the use of a process where there may be lasting health risks, because of residual harmful chemicals, the process must be replaced by safer alternatives. For further information see Chapter 3.

Home Office January 2014

2.1.14

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery

2.1.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Constraints and limitations continued Evidence recovery location: at the scene or in the laboratory Decisions may need to be made regarding processing items at the scene or recovering them and processing

them in a laboratory. In some cases, it may be necessary to carry out preliminary treatment at the scene and then

remove items for subsequent treatment in the laboratory. Recovery of forensic evidence from surfaces or items that form the structure of the scene may have to be examined and processed in situ and this may not present any issues for some evidence types. For

Resource constraints There may be a number of resource constraints which affect the progress of an investigation. Availability of

staff, especially those with the correct skills, availability of equipment or particular processes may all affect the ability to proceed with the investigation.

Forensic evidence recovery will also carry a financial

burden, which cannot be accurately predicted at the start of the investigation and will vary considerably from case to case.

others, including fingermark recovery, this may present

The costs associated with an investigation will arise from

be employed, which may present health and safety

number of these in the course of the investigation. They

problems, especially if a chemical process needs to concerns during and post-processing.

In the case of fingermark recovery, items within a

scene which are moveable or easily detached from the structure of the scene can be packaged to transport them for processing in a laboratory. The benefits of

various sources and consideration will be given to a may include:

●● whether it is more economical to use an external

●● the labour costs incurred by the force or specialist

advisers;

●● costs of the processes;

●● equipment loan or processing fees if a particular

process is unavailable in force;

●● incidental costs of using the processes e.g. disposal

and scene clean-up costs, transport of processes to scenes;

●● replacement costs for items destroyed during

processing.

It may be possible to anticipate some costs from

historical information with regard to the success or

otherwise of various individual forensic analyses. This

information may already have formed the basis of some force policies but can be used to influence the Forensic Evidence Recovery Plan n

forensic service provider or to use in-house personnel and facilities;

treating the items in a controlled environment then need to be off-set against the risks of damage or

compromising the integrity of the item and any potential forensic evidence, both during the dismantling of

the item from the scene and its transportation to the laboratory.

Further information on the preservation of forensic

evidence can be found in Section 2.4 of this chapter.

Home Office January 2014

2.1.15

Fingermark Visualisation Manual

Section 2.1: An Introduction to Forensic Evidence Recovery

2.2.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Generation of fingermarks................................... 2.2.2 Persistence of fingermarks................................ 2.2.17 Visualising fingermarks...................................... 2.2.26

Introduction

Fingermark evidence relies on the persistence of the

structure of an individual’s skin creating the opportunity

to compare reference prints with marks left at the scene for identification purposes. The controlled way in which

●● How the finger acts as a tool for generating

fingermarks, and how the properties of the skin

enable a fingermark to be generated and used for subsequent identification.

reference prints are achieved and stored, either digitally

●● How different properties of substrates contribute to

fingermarks. Whatever mark was created at the time of

●● How the different types of interaction between the

or by ink printing, is very different from the situation for

the crime will have been subject to many influences and

it is only through a comprehensive understanding of how fingermarks are created and are influenced by various

environmental factors after their creation that they can be visualised optimally.

Those responsible for formulating a detailed plan for

developing fingermarks (see Section 2.4 in this chapter) will need to be familiar with information included in

this section of the Manual, about the generation and behaviour of fingermarks and how they interact with

surfaces or are affected by their environment with the

passage of time. This section also explores how these

factors may be exploited in order to visualise fingermarks:

Home Office January 2014

Generation of fingermarks

the generation of fingermarks.

finger and the substrate can affect the generation of fingermarks.

Persistence of fingermarks

●● The many factors that contribute to the persistence

of fingermarks in the time between their generation

and their discovery at a crime scene. The fingermark found at the scene will almost certainly not have the same composition as that generated.

Visualisation of fingermarks

●● Various properties of the fingermark and substrate can

be exploited to visualise marks by the application of a range of optical, chemical or physical processes.

2.2.1

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Generation of fingermarks

Using the fingers for identification

A typical fingerprint form.

Marks left by the fingers have been used for identification purposes for many years. Once a fingermark has been created and then recovered

from a crime scene it can be a powerful means of identifying a potential offender or eliminating those who had legitimate access to the scene.

Particular physical and chemical properties of an individual’s fingers (as well as the palms of the hand and the soles of the feet) are important in the process of creating and subsequently visualising marks left by an individual in order to identify them.

When a suspect is arrested for an offence, a recording of his or her hand and fingerprints are taken either digitally (using Livescan or portable

devices) or using paper and ink, coated on the surface of the hands, to

create an image of the individual’s fingers, palms and possibly the whole hands. These images aim to create the best representation of the skin

features for later comparison with marks retrieved from the crime scene. The familiar images of patterns created in this way are just the start of

understanding how the potential of fingermarks in crime investigation is maximised.

Further information can be found in Section 2.5 of this chapter on the use of fingermarks in the identification process.

Home Office January 2014

2.2.2

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Generation of fingermarks continued Properties of the skin The anatomy of the skin

Friction ridge detail

Ability to deform

skin, due to the presence of characteristic ‘ridges’,

compared at the identification stage, knowledge by

external forces are applied. This property allows for a

Skin on the hands and feet is known as friction ridge separated by ‘furrows’. This structure increases the ability to grip things by increasing friction between the skin

and the surfaces with which it makes contact. This ridge detail forms patterns on the surface of the skin which

are unique to each individual and have been exploited extensively in human forensic identification.

Although the ridge patterns are of most use when being practitioners of the ability of friction ridge detail to be

transferred to and persist on a surface is important in developing a Forensic Evidence Recovery Strategy.

The pads of fingers have the ability to deform when

two-dimensional fingermark to be created from a threedimensional finger.

Distribution of certain features, such as ridge endings

and bifurcations, within the friction ridge detail present

spatially arranged reference points to aid the comparison process.

The distribution of the ridges may also present additional issues in developing a plan for recovery of fingermarks if

the surface on which they were found also has a pattern, either within the material or printed on it.

A hand and close-up

image of one

A typical fingerprint (from

clearly showing

the distribution of features

of the fingers friction ridge skin. Home Office January 2014

a fingerprint form) showing

A fingermark on a textured surface (left) and a patterned surface (right).

including ridge flow, ridge endings and bifurcations.

2.2.3

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Generation of fingermarks continued Fingermarks are created when a finger makes contact

with a substrate or surface. Even the lightest of touches

can create a mark that has the potential to be visualised and then used for the identification of the donor.

In order for the fingermarks to be of maximum value for identification purposes, it is necessary for as much as possible of the patterns on the skin to be transferred to the substrate when contact is made. This will give

Much less information might be available if the ridge

While partial or smudged marks may still provide

or if a ‘smudged’ mark is created through indistinct

ridge detail will give the greatest confidence when the

detail has been transferred from only a part of the finger placement of the finger on the surface. These marks

may still be of value, either for their intrinsic fingermark

enough information for identification, the largest area of mark is compared with reference marks.

evidence or the source of other forensic information, e.g. DNA swabbing.

those practitioners concerned with identification most

information about the fingers that created the marks. To illustrate this point:

Maximum information might be provided if the spatial

arrangement of a number of marks created at the same time in a single movement is available, giving a clear indication of the way the hands were applied to the

substrate, for instance in handling a weapon. This will also help to identify which finger created a particular

mark, i.e. forefinger or thumb from the left or right hand.

Home Office January 2014

2.2.4

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Generation of fingermarks continued The properties of the substrate or surface on which a

Rigidity

Condition

mark and influence the ability to recover useful evidence.

can depend upon many factors including, but not limited

window frames or gloss-painted garage doors

fingermark may be left will also affect the quality of the

Texture

The ‘roughness’ of the substrate provides its texture. This can be directional (e.g. wood grain) or non-

The ability of the substrate to resist deformation. This to: the thickness of the item or substrate (e.g. a thin

sheet of plastic is very flexible, but a thick sheet less so); the material of which it is made (e.g. putty or metal); the temperature of the surface (e.g. wax candles).

Substrates may be new or weathered, e.g. u-PVC become ‘powdery’ over time. They may be clean or

contaminated with many materials (e.g. dust, grease, blood) prior to the fingermark being generated.

directional (e.g. computer casings). The depth,

width and uniformity of the surface features will vary considerably. In deciding whether or not a textured

substrate is capable of holding ridge detail, the size and distribution of the texture feature versus ridge spacing should be considered.

Size and shape

The size and shape of a surface can affect the ability to recover a usable mark.

Elasticity

This determines if any deformation of the substrate that may occur is recoverable or permanent.

Home Office January 2014

2.2.5

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Generation of fingermarks continued Different types of fingermarks may be generated which

Impressions

are:

The generation of impressions depends on the ability

depend on properties of the finger and the surface. These ●● Impressions ●● Negative marks ●● Positive marks

The quality of all these types of mark will be affected in some way by the properties of the substrate, either in general, or specifically for that type of mark.

of the ridge pattern of the finger to permanently deform soft substrates, such as putty or wet paint, leaving an

impression of the finger. Details of the ridge structure will

Finger

be impressed in the surface, leaving high points on the deformed substrate which represent the furrows.

Soft substrate

Impressions are found less frequently than positive marks in operational scenarios.

Finger Impressions left in soft substrate Soft substrate

Image of an impression on a wax candle.

Home Office January 2014

Generation of an impression on a soft substrate.

2.2.6

2.2.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Generation of fingermarks continued Negative mark

Positive mark

If the substrate condition is poor and covered in

During contact between the finger

loose particulate material (e.g. dust) or a continuous

and the substrate, material is

layer of contaminant, the ridges of the finger

transferred from the ridges of the

may pick up some of this material, thus leaving a

finger to the substrate, thus leaving

negative (or reverse) mark on the substrate.

a positive mark.

Negative marks are not found frequently on

operational material and may be extremely fragile.

Image of negative mark in dust.

Generation of a negative mark.

Image of positive mark on the rim of a plate (right).

Generation of a positive mark.

Loose particulates

Substances present on finger

Finger

Substrate

Negative impression left in loose particulates

Home Office January 2014

Substrate

Finger Particulates transferred to finger Substrate

Finger

Substances transferred to substrate

Finger Substances remaining on finger Substrate

2.2.7

2.2.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Generation of fingermarks continued There are a number of additional factors that need to be

taken into account when considering positive marks: they relate to the additional properties of the finger and its ability to transfer material to a substrate.

The transfer of material from the finger to the substrate may be:

Hair EPIDERMIS

●● natural sweat secretions from the skin of the finger

to create latent marks;

●● other substances or contaminants present on the

Sebaceous sweat gland

surface of the finger.

Latent marks

DERMIS

When a finger covered in sweat touches a surface a mark

in sweat may be deposited, reproducing the pattern of the

Arrector pili muscle

ridges of the finger. These marks are not usually visible and are therefore known as latent marks.

The generation of sweat

Apocrine sweat gland

The skin consists of an outer epidermis and an inner

dermis. The dermis contains millions of glands which

secrete sweat. There are three main types of secretory

gland: eccrine, apocrine and sebaceous. Apocrine glands are found associated with hair follicles in regions such as the groin and armpit and sebaceous glands occur

Schematic of skin cross section around a hair follicle,

skin of the forehead, face and neck.

sweat glands.

everywhere hair follicles are present but are largest on the

Home Office January 2014

showing relative positions of apocrine and sebaceous

2.2.8

2.2.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Generation of fingermarks continued Eccrine glands are found all over the body but are the

Ridge

only type of gland present on the palms, fingers and soles

Pore

Furrow

of the feet.

Eccrine glands cannot be controlled consciously. This is

an advantage in criminal investigation where thermal and

EPIDERMIS

emotional stimuli, experienced during the committing of

a crime, trigger the automatic response of sweating. The secretion of sweat is through pores located along the

DERMIS Papillae

ridges of the finger. As sweat is secreted from the pores it begins to cover the ridges and, assisted by natural movements of the hands and fingers, can cover the surface of the finger.

Eccrine sweat gland

Eccrine sweat glands and their location in relation to ridges on the skin of a finger (top) schematic of skin cross section

on a fingertip, (left) optical coherence tomography image of a fingerprint ridge showing sweat glands reaching the surface, (right) sweat forming around pores.

Home Office January 2014

2.2.9

2.2.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Generation of fingermarks continued The composition of sweat

The chemical composition of sweat is known to be widely

Source

Inorganic Constituents

Organic Constituents

Eccrine glands

Ammonia Bicarbonate Bromide Chloride Fluoride Iodide Metal ions - major e.g. calcium, iron, potassium, sodium Metal ions - trace e.g. cobalt, copper, lead, magnesium, zinc Phosphate Sulphate Sulphide Water

Amino acids e.g. serine, glycine, ornithine, alanine, aspartic acid* Creatine Creatinine Enzymes e.g. esterases, proteolytic enzymes Glucose and other reducing sugars Glycogen Lactic acid and lactate Peptides e.g. dermicidin, cathelicidin LL-37 Phenols Proteins e.g. albumin, cathepsin D, immunoglobulins (IgG, IgA, IgD, IgE), keratin 1, keratin 10 Pyruvic acid and pyruvate Urea Uric acid Vitamins e.g. ascorbic acid, choline, folic acid, niacin, riboflavin

different from one donor to another. Also, the same

donor can exhibit large variations from day to day and

even minute to minute due to factors such as exercise, fitness, food, drink intake, illness, medication, drugs,

distress or emotion. Knowledge of the constituents of sweat and the variance in composition under various

conditions, e.g. following exercise or consumption of food, is of importance in understanding its effects on mark development.

The main constituents of the secretions from the three

types of sweat gland found in the human body are listed on the right. It is important to note that the majority of

constituents of eccrine sweat are water-soluble, whereas many of those of sebaceous sweat are water-insoluble,

Sebaceous glands

Alcohols Fatty acids e.g. palmitic, palmitoleic, oleic, stearic, myristic acids* Fatty acid alkyl esters e.g. palmitic acid methyl ester, stearic acid methyl ester Glycerides e.g. mono-, di- and triglycerides Hydrocarbons (saturated and unsaturated) Squalene Squalene degradation products e.g. squalene epoxides, squalene hydroperoxides Sterols e.g. cholesterol Sterol esters e.g. cholesterol esters Wax esters e.g. myristyl myristate, palmityl palmitoleate, stearyl palmitate

since some mark visualisation processes target specific components known to be present in sweat.

*Examples which have been identified in latent

fingermarks and reported here in decreasing relative

abundance. Information obtained from Dr Ruth Croxton, University of Lincoln.

Home Office January 2014

Apocrine glands

Ammonia Iron Water

Androgenic steroids Carbohydrates e.g. glycogen Carboxylic acids Proteins Sterols e.g. cholesterol

2.2.10

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Generation of fingermarks continued It should be noted that the relative abundance of the

different constituents will vary depending on a variety of

circumstances as discussed above. Therefore no specific quantitative information has been given. It should also be noted that following deposition chemical changes take

place, the nature of which vary depending on conditions, and consequently further change the composition of the fingermark residue.

The water content of sweat

Source Epidermis

Inorganic Constituents

Organic Constituents Fatty acids Glycerides Proteins e.g. cathepsin D, keratin 1, keratin 10 Sterols e.g. cholesterol Sterol esters

Information obtain from Dr Ruth Croxton, University of Lincoln.

Water accounts for between 98% and 99.5% of eccrine sweat. Water content is so high to ensure that sweat is effective at maintaining an ideal body temperature by cooling the skin. Water may, however, depending on

the conditions, evaporate completely from deposited

fingermarks within a few hours leaving only the organic and inorganic constituents which can subsequently be targeted by appropriate visualisation processes.

Other sources of fingermark constituents The sweat glands are not the only source of material

that may be found in fingermarks. The hands are also in regular contact with other regions of the skin and the epidermis itself can act as a source of certain

constituents, as outlined in the table on the right. In some cases individual epithelial cells may be found within fingermark deposits.

Home Office January 2014

2.2.11

2.2.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Generation of fingermarks continued The distribution of sweat in latent marks

The chemical constituents within sweat are rarely homogeneously

distributed along the ridges of the fingers, as seen in the photographs on the right. Once latent marks have been processed to enable them to be visualised, these effects may become apparent and may influence the identification of the fingermark.

Transfer of other materials

Materials other than sweat, or in combination with sweat, may also be present on the ridges of the skin and may be deposited on surfaces

Above: Latent fingermarks showing

formation of a fingermark and may, unlike the latent marks created purely

constituents (left) a sebaceous mark

which are handled. These substances can play an important part of the from sweat, provide a visible mark, making their location on a surface

more easily identified. These marks are less common than latent marks at crime scenes but where other substances, or contaminants, are present

they may provide additional target material to aid recovery of fingermark evidence.

inhomogeneous distribution of

imaged using interference microscopy, (centre) an eccrine mark imaged

using interference microscopy, (right)

mark imaged using scanning electron microscopy.

Contaminants on the hands may be any combination of materials picked up on the hands during the course of the day: they coat the fingers and can then be transferred to items that are handled. These contaminants may include dirt, traces of foodstuffs, cleaning products or other

substances picked up from contact with surfaces or handled as part of a job, such as oil or chemicals. Others may include those deliberately applied to the hands, such as soap, cosmetics or lotions.

Contaminants in a crime scene environment may include body fluids such as blood. These may deposit visible marks on surfaces but even

when present in very small quantities provide additional material to aid recovery of forensic evidence.

A summary of the types of contaminant material that may be found in fingermarks follows.

Home Office January 2014

2.2.12

2.2.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Generation of fingermarks continued The presence of these contaminants may affect the

Exogenous Compounds Secreted In Sweat

External Skin Contaminants

Environmental Contaminants

as the oily compounds found in cosmetic creams and

Ethanol Illicit drugs or their metabolites Nicotine or its metabolite cotinine Pharmaceutical drugs or their metabolites

Biological fluids e.g. blood, saliva Cosmetics e.g. facial creams, hair gel Explosives Foodstuffs Illicit drugs and cutting agents Pharmaceutical drugs Tobacco products

Bacterial spores Cigarette smoke Dust Exhaust fumes Grease (food or mechanical) Trace material e.g. fibres, pollen, soil particles Water

properties of the fingermark. Some contaminants, such hair products, may affect how the fingermark ages.

Environmental contaminants, such as dust and bacterial spores, present either on the substrate prior to or

after fingermark generation may affect the deposited

fingermark. Further information is available later in this chapter.

Other contaminants may provide valuable intelligence information, especially if they can be detected and

their source identified. This could provide information of forensic value and demonstrate that an individual

has handled a particular substance e.g. explosives or

Examples of exogenous contaminants which can contribute to latent fingermark residue. Information obtained from Dr Ruth Croxton, University of Lincoln.

consumed a particular compound e.g. illicit drugs.

Home Office January 2014

2.2.13

2.2.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Generation of fingermarks continued The quality of fingermarks created and the ability to

Contact pressure

vary considerably, due to the vast number of variables

area by the finger on the surface. This can affect both the

find and use them subsequently for identification can

associated with the finger and substrate individually, but there are others which are associated with the way they

come together to generate the mark, i.e. their interaction. The first major interactions, concerned with compression of soft surfaces to form impressions and the transfer of

material between the finger and surface to form positive, negative, latent or visible marks, have already been

discussed in some detail. Other interactions to consider are:

Contact pressure is the amount of force applied per unit extent of the final contact area as well as the degree of

compression of the ridges and possibly of the substrate. The contact pressure and any movement encountered when the finger makes contact with the substrate can

also cause the ridges to distort i.e. move closer together or further apart. This can then affect the distribution of particular features in the resultant fingermark and may affect the ability to compare the mark to a reference print.

In reality, the effects of contact pressure on fingermarks generated on different substrates encountered at crime scenes may not warrant consideration, although it may be possible in a small number of cases to infer when

heavy pressure has been applied (i.e. when force would have been required).

Contact pressure is closely

finger deformation. The more pressure that is applied, assuming the substrate is rigid, the more the finger

deforms (within limits) and results in more substrate area contact.

Although more substrate area contact generally means

more ridge detail can be recovered, if the pressure is very high the ridge detail becomes harder to resolve as the

ridges tend to flatten and widen. In extreme situations, material on the fingers can be forced into the furrows

and it is this that generates a mark, rather than the ridge pattern.

linked to the amount of

Inked fingermarks on a

smooth substrate created

using decreasing pressure from left to right.

Home Office January 2014

2.2.14

2.2.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Generation of fingermarks continued Contact pressure in combination with a

Top: Where the substrate is smooth

maximising fingermark evidence recovery.

pressure, contact can occur over the

textured surface creates other issues for Firstly, the degree to which the mark is

affected by the substrate texture needs to be considered.

and the finger is applied with sufficient entire substrate area which comes into

contact with the finger and a full record of the ridge detail on the finger can be

Finger

Substances present on finger Finger Smooth, non-porous substrate

Substances present on finger

Substances transferred to substrate

Smooth, non-porous substrate

recreated on the substrate.

Centre: For ‘rough’ substrates with

larger surface features, the ridges on

the finger may only make contact with

Substances present on finger Finger

the uppermost regions of the surface

topography, even if the finger is applied

to the substrate with significant pressure.

Rough, non-porous substrate

Substances present on finger

Finger

Substances transferred to tips of substrate features

Rough, non-porous substrate

The result of such a contact is an

intermittent distribution of fingermark residue, which means that at best

only discontinuous ridge detail can be developed.

Bottom: The amount of ridge detail can

then change with pressure on a textured substrate where the amount and type

of texture is at the limit of being able to retain ridge detail. More ridge detail is

retained as the pressure increases, i.e.

there is more contact between the ridges and the substrate.

Inked fingermarks on a textured substrate showing (left) the surface topography, (centre) a ‘heavy’ mark, and (right) a ‘light’ mark. Home Office January 2014

2.2.15

2.2.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Generation of fingermarks continued Other interactions between the finger and substrate that may need to be taken into consideration are:

Contact angle

Contact time

item was handled. This will influence which parts of the finger are brought into contact

amount of sweat or contaminant deposited, the briefest of touches usually deposits

The contact angle between the finger and substrate can vary, depending how an

with the substrate and therefore the amount of ridge pattern that is deposited in the fingermark.

Since the way the item was handled will also affect the pressure applied, marks from the same finger may appear very different. This may give some insight into the way

items were handled, but also means that care in identification is needed as features used for comparison will be distorted.

Although the length of time the finger is in contact with the substrate may affect the sufficient material to evaluate the mark to be visualised for comparison purposes.

Contact environment

The temperature and humidity of the environment prior to and at the time the finger makes contact with the substrate can affect the composition and amount of sweat or contaminant deposited in the fingermark. More sweat is likely to be present on

the fingers on a hot day than at lower temperatures and consequently more material

may be transferred to the substrate. The environmental conditions, for example high humidity, may also affect the properties of the substrate, making it less receptive to material on the finger being deposited.

Home Office January 2014

2.2.16

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Persistence of fingermarks The age of the fingermark

All three elements will challenge singly or in combination the

A most important consideration for fingermark evidence recovery in the context of the investigation is whether there is any chance of recovering any fingermarks from the

ability of the fingermark to persist and therefore dictate its Environment

scene, as time will usually have elapsed since the crime was committed.

To provide this information, in addition to having an understanding of the likelihood

of any fingermark evidence being left initially, the practitioner also needs to consider

whether any evidence that may have been left at the scene remains a viable source of forensic evidence, i.e. have any fingermarks persisted?

●● The mark composition will almost certainly have changed since the marks were

generated.

●● The substrate may have changed from its state at the time fingermarks were

created.

●● The environment in which any fingermarks have survived will contribute to the

speed of change to both the mark composition and the substrate. The level of

exposure will affect fingermarks in different ways: exposure to high humidity will have different consequences from total immersion of an item. The order of changes in the

environment may also have significant effects. For example, if a fingermark fully dries out before it is immersed in water, it may be more resistant to the effects of water immersion than a freshly deposited fingermark exposed to similar conditions.

Fingermark Substrate

potential to provide a viable contribution to the investigation. It is important for the practitioner to develop an

understanding of how the fingermark may have been affected since its generation and, if possible, an

indication of the age of any fingermarks to guide the

choice of subsequent recovery processes and assist with interpretation of any results.

Estimating the age of a fingermark would be a useful tool in an investigation but, as with other forensic evidence,

this is not currently possible. The huge number of variables involved makes it impossible.

Generally little, if anything, will be known about the state

of the mark when it was generated and information about its subsequent history may be equally absent. Some

visualisation processes may respond better to fresh marks than aged ones and where the possible age of the marks can be roughly estimated, this knowledge can aid the

selection of the most appropriate process but this cannot be regarded as a reliable indicator of age.

In some cases, the location and environment in which a mark was found, coupled

with intelligence information, may assist in determining the approximate time of mark

deposition. For example, marks developed at a scene on an item which is known to have been washed or polished recently can give a time span of potential mark deposition.

Home Office January 2014

2.2.17

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Persistence of fingermarks continued It is self-evident that the substrate must survive the

conditions to which it is exposed for fingermark recovery to be possible. If the substrate does survive, knowledge of some of its properties are important in understanding

the behaviour of any fingermarks that were generated on it.

When a fingermark is deposited onto a porous substrate (e.g. paper) the fingermark materials wet the substrate and

are likely to be absorbed into it. A small proportion of the insoluble fingermark constituents may remain on the surface but the water in the residue carries the water-soluble constituents towards the interior of the material where they may continue to migrate at different rates. Immediately after deposition

Substances transferred to substrate

Porosity describes the ability of a substrate to absorb substances.

●● Porous substrates can absorb substances: examples

Porous substrate

are paper or card.

●● Non-porous substrates that do not absorb

substances include glass, metals, ceramics and plastics.

●● Semi-porous substrates exhibit neither truly porous

nor non-porous properties. Their material properties

Several hours after deposition Water insoluble constituents Water soluble constituents remaining on top of substrate migrating into porous substrate

may demonstrate semi-porous behaviour or the substrate’s surface may have regions of mixed

porosity in close proximity. Examples of semi-porous substrates are gift-wrapping paper and the glossy

Porous substrate

paper used in magazines. Fingermark material on ‘semi-porous’ substrates will behave in a manner

which is in between that of non-porous and porous

surfaces, or may be a combination of both in different proportions depending on the item being considered. Some items will have a combination of multiple types

of substrate i.e. one element of the substrate will have

Several weeks after deposition

Possible further Amino acid constituents Residual water migration of insoluble constituents remain close to original other constituents deposition point (e.g. salts, urea)

porous and another non-porous characteristics, such as a paper label on a glass bottle.

Home Office January 2014

Porous substrate

2.2.18

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Persistence of fingermarks continued When a fingermark is deposited onto an inert, non-

porous substrate, the fingermark residue spreads across the substrate in a manner determined by a number of

Immediately after deposition

Substances transferred to substrate

factors including the ‘wetability’ of the substrate (the

ability of a liquid to maintain contact with a solid surface) and the pressure of application. The residue remains on

the surface and does not penetrate into it. However, with time, the physical profile of the residue gradually shrinks

Smooth, non-porous substrate

as the fingermark dries out and the water content is lost.

Several hours after deposition Shrinkage due to evaporation of water and other volatile substances

Smooth, non-porous substrate

Several weeks after deposition Further shrinkage due to progressive evaporation of remaining volatile substances

Smooth, non-porous substrate

Home Office January 2014

2.2.19

2.2.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Persistence of fingermarks continued Substrate reactivity is the ability of the substrate to

interact chemically with its immediate surroundings and may play a significant part in both the persistence and

possible recovery of fingermarks. Serious deterioration of a substrate may have occurred since the crime was committed and remove any chance of recovering any fingermark evidence, e.g. rusting of metal surfaces.

However, the reactivity of the surface may assist the recovery of fingermark evidence when a chemical reaction

occurs between the fingermark and the substrate. Whilst most non-porous substrates may be considered chemically inert, with no reaction expected to occur between the substrate and the fingermark residue, others do create such chemical reactions. One example is metal substrates, where reactions are known to occur between some types of metal and the salts (and possibly other constituents) in the fingermark residue, resulting in corrosion products and possible etching of the surface.

Immediately after deposition Substances transferred to substrate

Substrate reactivity may be an important factor when

deciding which visualisation processes to use. Processes which react with the substrate as well as components of

the mark to produce the same or similar reaction products must be avoided as there will be no contrast between the

Metal substrate

mark and the substrate, making the visualisation of the mark difficult or impossible.

Several days after deposition

Residues remaining on surface

Reaction zone

Metal substrate Weeks after deposition Inorganic reaction product formed on substrate

AND/OR

Pit etched into substrate

Metal substrate

Home Office January 2014

2.2.20

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.21

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Persistence of fingermarks continued The nature of the environment to which both the mark and substrate are

Extreme environmental conditions

time of exposure. The environmental conditioning of the substrate before

In addition to the environmental conditions normally encountered, items may also be subjected to

‘accept’ fingermarks and possibly for them to persist.

that specific recovery processes are needed to give any chance

exposed is critical in determining the changes that may occur over the the crime will also have a bearing on both the ability of the surface to

It should be noted that some types of substrate (e.g. biodegradable bags or water-soluble polymers) are specifically designed to degrade during

extreme scenarios. In these situations, the intensity of the conditions is magnified to such a degree of recovering fingermarks that have survived. Examples of these extreme conditions are:

prolonged exposure to certain environments. Delays in examining them

Fire scenes

on a Forensic Evidence Recovery Strategy and Fingermark Recovery

deposition of atmospheric pollutants in the form of soot (and other

may result in loss of evidence and should be considered when deciding Plan.

Combinations of environmental factors Although the main environmental factors can be considered in isolation, the conditions encountered by the mark and substrate will almost

always be a combination of several different environmental factors. The combined effect on the exposed fingermarks will be more pronounced

These scenes produce a combination of very high temperatures,

burn products) and in some cases significant amounts of wetting.

Water immersion

Items recovered from water are subjected not only to the effects of the water but also any environmental pollutants contained within it and potentially light exposure.

than anticipated for any single environmental factor alone and this may need to be taken into account when assessing the possible impact of the environment on the possibility of fingermark recovery.

Also, the environmental conditions may not remain consistent during the period between the time of the crime and its discovery.

Home Office January 2014

2.2.21

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.22

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Persistence of fingermarks continued

Effects of temperature

The conditions to which crime scenes are most commonly exposed and an indication

In general, fingermarks will survive less well when exposed to higher temperatures than

of how those conditions might affect fingermarks and their substrates are shown in

the coloured panels on the next three pages. Further information on the effects these

conditions may have on the effectiveness of fingermark visualisation processes can be found in Section 2.3.

at ambient temperatures or below since their ‘ageing’ will be accelerated.

Items recovered from crime scenes may have been exposed to anything from below

freezing (e.g. outside during winter) to hundreds of degrees Celsius (e.g. fire scenes). Temperatures of indoor and protected locations are likely to be more consistent

and fluctuate over narrower ranges than those of outdoor locations but elevated temperatures may cause the following effects on the fingermark: ●● accelerated water loss;

●● accelerated evaporation of other volatile constituents; ●● melting and flow of low melting point constituents;

●● crystallisation of salts within deposits caused by water loss; ●● chemical degradation of constituents.

At lower temperatures, the constituents of fingermarks are more likely to be protected from degradation and water loss will be less. Low temperatures, however, may cause other problems such as the formation of condensation when the item containing the

mark is returned to room temperature. This will affect the water-soluble constituents of the mark so it is important to consider how recovered items are stored to minimise the occurrence of condensation (see Section 2.1 in this chapter and Chapter 3).

The condition of substrates may have been affected by temperature before the crime

was committed but since that time will have been exposed to the same environmental The effect of heat on marks

and substrates. (left) Plastic bottles in as received

condition and after exposure

to 120°C, (right) marks

developed on the melted

bottle which have shrunk to half original dimensions.

Home Office January 2014

conditions as the fingermarks on them. Temperature may influence the substrate in the following ways:

●● accelerated corrosion of the substrate; ●● oxidation of the substrate;

●● melting or distortion of the substrate.

Fingermarks from surfaces that have been exposed to extremely high temperatures may survive, depending on the nature of the mark and its substrate.

2.2.22

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.23

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Persistence of fingermarks continued

Effects of water immersion and exposure to high humidity

Water immersion can have an extreme effect on the persistence of fingermarks by

removing water-soluble constituents. Since these constituents are targeted by some visualisation processes, knowledge of whether a mark has been exposed to water

or high humidity is a prime concern when developing a plan for fingermark evidence recovery, since some processes will no longer be of value.

The direct application of water to a substrate which contains marks can also affect the distribution of the water-soluble constituents of the sweat in the mark, resulting in the indistinct visualisation of ridge detail.

Complete wetting of items can occur in both indoor (e.g. fire scenes) and outdoor (e.g. items exposed to the rain) environments.

Relative humidity in the UK is typically between 40 and 70% although it may reach

lower or higher values depending upon the weather and regional variations. Unless air conditioning systems are present to reduce room relative humidity, humidity is

equally likely to fluctuate in indoor and outdoor environments. It is therefore possible to

encounter environments where water is deposited on a substrate in both locations (e.g. rain and dew outdoors, high humidity and water deposition indoors in bathrooms).

Water exposure influences how rapidly the fingermark dries out as well as other factors, such as dissolution and migration of the water-soluble constituents. The potential effects of changes in the humidity on the fingermark are:

●● accelerated drying of the fingermark (low humidity conditions);

●● prolonged retention of water within the fingermark (high humidity conditions);

●● dissolution and/or diffusion of water-soluble constituents (high humidity conditions,

immersion).

Potential effects of changes in the humidity on the substrate include: ●● corrosion of the substrate, which may make the application of recovery processes

impossible.

Home Office January 2014

2.2.23

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.24

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks Persistence of fingermarks continued Effect of airflow As with elevated

temperatures, airflow

usually influences the drying of fingermarks and may result in

accelerated ‘ageing’ of

the marks as they lose water. Of course, airflow may also carry moisture which may have the opposite effect, as long as it is not excessive. Dust and pollutants from the atmosphere may also be carried onto the mark and could alter the effectiveness of visualisation processes.

Airflow is likely to be greatest in outdoor environments where the variable drying effects of winds may be encountered or in cases where vehicles are driven at high speed.

The effect of airflow will generally be limited for items recovered from typical indoor

environments where marks will not be exposed to significant airflow and generally not dry out so rapidly.

Substrates are generally less affected by airflow than other environmental conditions, although damage may be caused to both mark and surface when certain types of airborne particles (e.g. sand) are present.

Effects of optical radiation The effects that optical radiation or

light have on fingermarks will depend on the particular wavelengths of

the electromagnetic spectrum that are present in the incident light.

Visible radiation has little impact on the fingermark. However, sunlight

contains both ultraviolet wavelengths,

which can degrade mark constituents, and infrared wavelengths which, like visible light, have a heating effect.

Optical radiation may therefore cause: ●● accelerated degradation of some constituents.

Outdoor locations may be exposed to sunlight, while marks on substrates from indoor locations may be exposed to both artificial lighting and sunlight.

Substrates are most likely to be affected by the ultraviolet components of sunlight, with possible long-term effects including:

●● substrate degradation (e.g. rubber becomes brittle); ●● substrate bleaching or colour change.

In some cases other evidence present on the substrate will be damaged, e.g. removal of print from thermal receipts.

Home Office January 2014

2.2.24

2.2.25

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Persistence of fingermarks continued Effects of atmospheric pollutants or contaminants

The examples above give some indication of the possible effects of external conditions

a fingermark or its substrate, their continued presence may often be detrimental, or

been exposed to a number of different environmental effects, it will be impossible for the

Once atmospheric pollutants or contaminants have been adsorbed or deposited onto sometimes beneficial, to the subsequent use of fingermark recovery processes.

Atmospheric pollutants may be present in both indoor (e.g. cigarette smoke) and

on the persistence of fingermarks. Given that in the majority of cases items will have

practitioner to have a clear understanding of what may have survived in a fingermark. Neither will they have a clear understanding of what was there is in the first place.

outdoor (e.g. tree sap) environments and may be deposited on or otherwise interact

However, it is only through gathering as much information as possible about the item

droplets of cooking oil) or solid particulates (e.g. dust or soot).

others in their Fingermark Evidence Recovery Plans.

with the mark. These pollutants may be gaseous (e.g. exhaust fumes), liquid (e.g.

Various interactions between the fingermark and pollutants or contaminants may occur through adsorption, reaction or deposition.

In some cases, for instance where solid particulates have deposited on the mark, it may be possible to remove the contaminants with care. However, the effect on the

fingermark or the ability to visualise it by applying different processes will generally be very hard to predict.

and its history that the practitioner will be able to rule out certain processes and escalate It is vital that the evidence, once identified as important to the case, is not degraded

further. It should be removed from potentially damaging environments and protected

during processing from additional loss of evidential material. Correct storage of items is important to preserve them, but inappropriate use of processes can also damage

target materials or substrates. More information on this can be found in Section 2.1 and Section 2.4 in this chapter.

Some unexpected results may be explained by the presence of contaminants. Substrates may also be affected by pollutants or contaminants settling, being absorbed or reacting with them. Tarnishing or corrosion effects may be seen and affect the effectiveness of the visualisation processes considered.

Home Office January 2014

2.2.25

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.26

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Visualising fingermarks

Fingermark evidence recovery depends on the ability to

create contrast between a fingermark and the substrate

on which it was generated to enable the fingermark to be

visualised. Having created satisfactory contrast, it should then be possible to capture an image that can then be submitted for comparison with reference prints.

Earlier in this section, it has been demonstrated that the generation of a fingermark depends on the properties of the finger, the substrate and the interactions

between them and their environment. The properties of fingermarks can be exploited to provide forensic

evidence which may lead to the subsequent identification of the donor of the mark. These include its visibility and composition.

Visibility

●● Latent marks will not be immediately obvious to a

cursory visual examination and need to be visualised by some other means.

●● Visible marks are more or less obvious to the

unaided eye. Clearly visible marks may be imaged without further intervention, whereas less clear

marks may need additional processing. For example, marks in blood may be obvious on a light surface

but difficult to see on a substrate that is either of a similar colour or patterned.

Composition

●● Natural sweat secretions may be present. ●● A range of contaminants may be present.

There are other properties that fingermarks possess

which may also be exploited to visualise them. Some of these are physical and others are biological.

Physical attributes of fingermarks that have been

exploited to discriminate them from the substrate are: ●● adhesive properties; ●● electrical charge;

●● dielectric constant; ●● refractive index.

Biological properties may possibly aid in the visualisation of fingermarks, but currently no practical applications for use by the police are available.

Home Office January 2014

2.2.26

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.27

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Visualising fingermarks continued Understanding the properties of fingermarks enables practitioners to work most effectively using a range of processes to visualise the marks. Visible marks may offer the easiest route to image capture, although they may need some additional treatment to maximise the information available,

especially if the contrast between the mark and the substrate is initially insufficient, e.g. dried blood on a brown background.

Impressions and negative marks may also yield valuable information without the need for any

more significant intervention than suitable image capture conditions.

Increased contrast may be achieved by changing the mark or the substrate by the action of a process or range of processes to target the mark and substrate either individually or together. It is most important that during treatment potential evidence is not lost through damage to the mark or the substrate. A range of fingermark visualisation processes has

been developed following numerous studies over many years as a means of maximising fingermark evidence recovery across many different types of mark on an extremely diverse set of substrates.

In addition to knowledge of the fingermark and substrate and as much of their history as possible, the practitioner will need:

●● knowledge of the visualisation processes available to them;

●● knowledge of the effectiveness of those processes, given the particulars of the case

and the item.

The use of fingermark visualisation processes is introduced on the following pages

but more detail on the processes themselves and their effectiveness can be found in

Section 2.3 of this chapter, with further detail of how to plan the use of the processes in Section 2.4 and in Chapter 4: Process Selection.

Latent marks present the greatest need for a

range of treatment options before the information they hold can be maximised. The choice of

which of these options to use or, depending on the circumstances of the investigation, which sequence of options to use depends on a number of factors:

●● knowledge of the fingermark (by this stage

aged since the time of the crime) and its properties;

●● knowledge of the substrate (also aged with

time) on which the fingermark is present.

Home Office January 2014

2.2.27

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.28

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Visualising fingermarks: optical, chemical and physical processes Improving contrast to visualise fingermarks

The basis on which different processes are successful in aiding fingermark recovery

is to induce a change in the ‘appearance’ of either the fingermark or its substrate (or

possibly both) to enable distinct contrast to be created between them and provide the discrimination needed to capture an image.

Certain properties of the fingermark and substrate are exploited to facilitate an

Chemical processes target chemicals present in the mark, i.e. the constituents of sweat or contaminants, in order to form new products that aim to be more easily distinguished from the substrate following: ●● preferential staining of the mark;

●● reactions with the mark yielding coloured reaction products;

●● reactions with the mark yielding fluorescent reaction products; ●● polymerisation reactions initiated on the mark.

improvement in the contrast between them, through the application of optical, chemical or physical processes:

Processes that target the properties of the fingermark

Optical properties of the mark, e.g. its reflectivity, refractive index, emissivity,

colour or fluorescence, before or after initial treatment, may offer potential targets for

visualisation when illuminated or irradiated. Care needs to be taken as the fingermark and substrate are examined together and there may be optical properties of the

substrate that conflict with the aim of improving contrast in any of the examples given above.

Physical properties of the mark may be targeted, e.g. the adhesive nature of the mark

may allow materials to bind to it or electrical charge on the mark may be induced and offer a means of visualisation, resulting in:

●● preferential adhesion of material to the mark;

●● preferential deposition of material onto the mark.

Home Office January 2014

2.2.28

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.29

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Visualising fingermarks: optical processes

Maximising information from the fingermark

Optical processes are valuable tools for visualising latent fingermarks or marks that

most cases, the image capture of

Use of optical processes

have already been subjected to a chemical or physical treatment. In the latter case, the increased contrast aimed for by the application of a process may only be capable of being realised through subsequent illumination or irradiation.

The successful application of optical treatments for maximising fingermark recovery depends on three main factors:

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks It has already been stated that, in visible marks, impressions and

negative marks may be relatively

simple and require no more than a little manipulation of light sources to provide suitable illumination to capture a suitable image.

●● maximising information from the fingermark, pre- or post-chemical or physical

treatment;

●● minimising relative surface effects which may limit the development of contrast

between the substrate and the fingermark;

●● selection of the most effective illumination or irradiation process.

Latent marks may contain components, usually

contaminants, which can be visualised by the

direct application of illumination. Selection of a suitable light source will be needed to produce sufficient contrast between the mark and its substrate.

Latent marks, after treatment with a chemical

or physical process, may have been sufficiently modified to be regarded as visible marks,

impressions or negative marks with ridge detail easily recorded by relatively uncomplicated image capture.

Modifications of latent marks may have resulted in the need to apply more specific optical treatment in order to realise the contrast between them and their substrate. It

may also be necessary to use filtration to magnify the difference in response between the fingermark and surface so that it can be seen, for example the long-pass filters used in fluorescence examination.

Home Office January 2014

2.2.29

2.2.30

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Visualising fingermarks: optical processes continued Minimising surface effects

When applying optical processes there are a number of surface effects from both

Considering the combined fingermark and substrate surface effects that might be

positively to increase contrast or in conflict with one another as visualisation processes

the development of contrast:

fingermarks and the substrate that need to be considered. These effects may work

are applied. In order to examine this further it is useful to understand typical responses from a surface to incident light or irradiation.

Specular reflection

light or radiation may be reflection

absorption, transmission, or the excitation of an emission of radiation of another

Texture may cause incident radiation to be scattered and further hinder the opportunity to recover ridge detail, already poorly formed because of the surface topography. It is

The reaction of a surface to incident (specular, diffuse or highly scattered),

possible when using optical processes on recovery, the following may assist or hinder

Emission of radiation

wavelength (e.g. fluorescence, x-ray

Diffuse reflection

to view the fingermark and again, if the emissivity of the fingermark and substrate are

Transmitted radiation

Illustration of the potential response of a substrate surface to incident light or radiation.

the substrate surface is smooth.

Emissivity influences the response of the surface if infrared illumination is selected

Absorption

emission).

unlikely that any inherent topography of the fingermark will be a useful property unless

similar, little contrast will be observed.

Reflectivity of the surface influences the relative proportion of incident radiation that is

reflected and absorbed. If the reflectivity of the fingermark and the substrate are similar then optical processing may fail to give sufficient contrast for visualisation.

Refractive Index influences the extent to which incident illumination or radiation is

refracted at the surface. This may hinder development of contrast between the mark and the substrate if they have similar Refractive Indices.

Colour of the substrate influences which wavelengths of visible light are reflected and absorbed: this may help or hinder the visualisation of the mark.

Fluorescence influences the level of background fluorescence that will be emitted

from the surface at a given wavelength: this may also help or hinder mark visualisation, depending on the fluorescent properties of the fingermark or its reaction products.

Home Office January 2014

2.2.30

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.31

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Visualising fingermarks: optical processes continued Selection of the most effective illumination or irradiation process Using the most effective illumination or

irradiation treatment is vital to maximising fingermark evidence recovery when

applying optical processes targeting the

The power of the illumination or irradiation, which

The wavelength and bandwidth determines

be optimised to give maximum discrimination between

influences which constituents in the fingermark

influences the intensity of the incident light, will need to the fingermark and the substrate. For visual examination processes, too high an intensity can be detrimental

the colour of the incident radiation and also and substrate can be induced to fluoresce.

in visualising fingermarks, whereas high intensity of

incident light can increase fluorescence and improve discrimination.

fingermark or the substrate.

When a filter is used in combination with the illumination or irradiation source,

it effectively controls how much of the radiation reflected or emitted from the

substrate and mark reaches the viewer. Some important factors that need to be

considered for the selection of sources of illumination or irradiation are:

The diffusion of the

source influences how evenly the illumination or irradiation will be

distributed across the

substrate and fingermark.

Beam size

determines how

much of the surface

can be illuminated or

irradiated at one time.

The angle of the incident illumination or irradiation influences what types

of reflection are likely to occur from the surface

of the substrate and the fingermark.

Home Office January 2014

2.2.31

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.32

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Visualising fingermarks: chemical and physical processes

Since the fingermark and its substrate can only normally be treated together, it is

important that any process selected to target the fingermark does not react unfavourably with the substrate and inhibit improving the contrast. With chemical or physical processes the surface, or some properties of the substrate, may react

with a treatment and give a positive outcome with increased contrast with the mark. Conversely,

Texture plays an important part in the success or failure of the application of a physical or chemical process.

Smooth substrates have very few surface features to inhibit interaction between the

development process and the mark. Therefore, the performance of most chemical or physical processes on these substrates is good.

many properties of the substrate will need to

Where the substrate is textured, the surface topography may inhibit the ability of a

conflict with the aim of improving contrast

the selection of the most appropriate process is very important to enable visualisation

be considered prior to treatments as they may and potentially mask or obliterate the mark. In extreme conditions, the process may damage the substrate so significantly that valuable potential evidence is lost.

treatment to create clear contrast between the mark and the surface. Consequently

of any ridge detail present. For example, fine solid materials may become trapped in

surface features whereas coarser materials may not be as readily retained by them and

hence provide better discrimination. Selective vapour phase deposition processes may provide even more discrimination between the mark and its background.

Fingermark development on a textured surface using (left) a flake powder, (centre) a granular powder and (right) a vapour phase deposition process.

Home Office January 2014

2.2.32

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.2.33

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Visualising fingermarks: chemical and physical processes continued Porosity needs to be considered in conjunction with other factors, such as ‘wetability’

The surface chemistry of the substrate may interfere with the application of chemical

for liquids and permeability for gases. The porosity of a substrate can influence whether

processes selected for visualisation of the mark. Some substrates may contain

deciding what process is most appropriate: if the constituents of the fingermark residue

process and mask the products of the desired reaction with the fingermark. Ideally,

the treatment can penetrate the substrate or not and is a primary consideration when

have migrated to the interior of the material, then only development processes that can penetrate the substrate to interact with the constituents will be effective. There may be significant variations in porosity between substrates and it may not always be possible

additives or filler materials that give unwanted reactions with the development

the possibility of such reactions occurring needs to be considered during process selection n

to gauge how porous a substrate may be.

The colour of the substrate will determine whether the mark or the known products of any reaction can be readily distinguished from the background and processes should generally be selected to give maximum contrast.

Home Office January 2014

2.2.33

Fingermark Visualisation Manual

Section 2.2: Understanding Fingermarks

2.3.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Classification of processes.................................. 2.3.2 Category A processes and their dates of introduction.......................................................... 2.3.3 Purposes of the Category A processes: target constituents and properties................................. 2.3.5 Sequential processing......................................... 2.3.7 Process effectiveness: influencing factors.......... 2.3.9 Process effectiveness: effect of heat................. 2.3.11 Process effectiveness: effect of water............... 2.3.12 Process effectiveness: effect of fingermark age.2.3.13 Process effectiveness: effect of surface roughness.......................................................... 2.3.14 Process effectiveness: examples...................... 2.3.15

Introduction

Purposes of the Category A processes

visualisation was introduced. This section goes on to

their target properties or constituents.

In Section 2.2 of this chapter the concept of fingermark explain the processes that have been developed for this

purpose and how the various properties of the fingermark

and its substrate can be exploited to create the necessary contrast to enable an image to be recorded. It then

The Category A processes are further defined in terms of

Sequential processing

The rules for sequential processing are explained and how the Category A processes comply.

describes how the processes should be used and any

Effectiveness

may be compromised by their inappropriate use in

variety of factors can affect both the generation and

allowances that should be made where their effectiveness sequence or by various factors relating to the history of the item or surface under examination.

While Section 2.2 of this chapter explained how a

persistence of fingermarks, this section examines how the effectiveness of the processes can change, depending

Classification

on the history of the fingermark or substrate, with some

have been classified for the purpose of this Manual

The detail of how to plan the use of the processes can be

published in the literature have been developed for

Chapter 4: Process Selection.

The way in which different visualisation processes

is explained. This is important as not all processes operational use.

examples included to illustrate the points made.

found in Section 2.4 of this chapter, with further detail in

Category A processes

A full list of the optical, chemical and physical Category A processes is given, with the dates of introduction

into operational use. The importance of this to cold case reviews, for example, is given.

Home Office January 2014

2.3.1

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes

2.3.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Classification of processes

Although there have been many optical, chemical and physical fingermark visualisation processes reported extensively in the literature, not all will have been

comprehensively developed for operational use by the police. Those that the Home Office considers to have been fully evaluated for current routine application by

Category

Description

A

Processes extensively evaluated by the Home Office and considered suitably effective to be incorporated into processing charts in Chapter 4.

Standard processes for routine operational use. They must be used in preference to other category processes where possible.

B

Established processes known to be generally less effective than alternative options or processes that are likely to offer benefit but have not been fully evaluated by the Home Office.

Optional processes for occasional operational use. Possible reasons for use: no other options available; all Category A options have been exhausted; niche application; or lack of equipment for other processes.

C

Processes at a developmental stage exhibiting potential as an effective fingermark recovery process.

Optional processes for occasional operational use. Possible reasons for use: no other options available; all Category A options have been exhausted; niche application.

D

Processes extensively evaluated by the Home Office and considered unsuitable for incorporating into processing charts in Chapter 4.

Corrective Action Processes. Not generally for routine use but may be used to recover marks in situations where initial selection of processes has resulted in undesirable consequences.

E

Processes that are known to be less effective Processes with no known operational benefits. than alternative processes with no obvious niche application, or those with no reliable data on the success rate and no reason to believe that they are as good as or significantly better than other processes.

F

Processes with known health and safety issues. Processes should not be used for health and The process uses chemicals and/or conditions safety reasons. that expose operators to unacceptable health hazards.

the police have been nominally classified as Category A processes for the purpose of this Manual, with full process instructions given in Chapter 5.

References are made to other processes in the Manual

but these have been placed in Categories B-F, according to the Home Office view of their state of maturity, relative effectiveness and associated health and safety issues.

More information, with appropriate levels of detail, can be found in Chapter 6.

A summary of the classifications and possible use of all categories of process are indicated in the table on the

right. While the remainder of this section primarily focuses on Category A processes, the principles discussed will apply for all processes.

Home Office January 2014

Use

2.3.2

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes

2.3.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Category A processes and their dates of introduction Category A processes include optical, chemical and physical visualisation processes.

They are identified in the following tables, along with their dates of introduction into

Optical Processes - Dates of Introduction Process

First reported First use in use* UK*

First inclusion in Home Office Manual***

Latest modification in Home Office Manual***

The Category A processes and any subsequent modifications of them have been

Colour Filtration

Pre 1900s

Early 1900s

1986

2013

fundamental interactions with fingermarks, identification of the range of substrates for

Fluorescence Examination**

1930s

1930s

1986

2013

IR Reflection

1940s

Mid 1980s

2013

2013

Monochromatic Illumination

1980s

1980s

2013

2013

Multi-Spectral Imaging

Early 2000s

2006

2013

2013

UVC Reflection

1970

Late 1980s

2013

2013

operational use.

Since their introduction the formulations, processing conditions and the equipment used may have changed significantly.

introduced after a systematic evaluation procedure that includes assessment of their which the process is suitable, comparison of process effectiveness with alternative processes and determination of where the process adds most value when used in

sequence with other processes. This methodology, used by the Home Office for these assessments is outlined in Appendix 2.

Importance to Cold Case Reviews

An understanding of the dates of introduction for each of the visualisation processes is particularly important for those conducting cold case reviews. Such an understanding enables the processes available at the time of the initial investigation to be confirmed and processes that have subsequently been introduced to be identified and possibly used to improve the visualisation of any marks present.

Home Office January 2014

Early 1900s 1986 2013 Visual Examination Late 1800s * First reported use and first use in the UK refer to fingermark visualisation rather than other uses. ** Note that rapid advances in high intensity light sources since 2005 mean that there may be merit in re-examining any articles previously treated with processes that have the potential to yield fluorescent marks. *** New processes or updates to existing processes may have been communicated to the police prior to inclusion in the Manual on these dates.

2.3.3

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes

2.3.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Category A processes and their dates of introduction continued

Chemical and Physical Processes - Dates of Introduction Process

First reported use

First use in UK

First inclusion in Home Office Manual ***

Latest modification in Home Office Manual ***

Acid Dyes*

1961

1961

1986

2005

Basic Violet 3*

Late 1960s

Early 1970s

1986

2005

DFO*

1990

1990

1992

2001

ESDA**

Mid 1970s

1979

1986

2013

Lifting

1913

Late 1960s

1986 (as part of Powders process)

2013

Multi-Metal Deposition

Early 1990s

Early 1990s

2013

2013

Ninhydrin

1954

Late 1950s

1986

2001

Physical Developer

Early 1970s

1976

1986

1998

Physical Developer Enhancement

1977

1977

1986

2013

Powders

Late 1800s

Early 1900s

1986

2013

Powder Suspensions

1989

Late 1990s

2009

2009

Small Particle Reagent

1976

1981

1986

1998

Solvent Black 3

1980

1982

1986

2013

Superglue Fluorescent Dye Staining*

1983

1985

1986

2013

Superglue Fuming

Late 1970s

1980

1986

1986

1968 Mid 1970s 1986 2013 Vacuum Metal Deposition * Note that rapid advances in high intensity light sources since 2005 mean that there may be merit in reexamining any articles previously treated with processes that potentially yield fluorescent marks. ** Included as an option for porous surfaces from1986 but full process details not given until 2013. *** New processes or updates to existing processes may have been communicated to the police prior to inclusion in the Manual on these dates. Home Office January 2014

2.3.4

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes

2.3.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Purposes of the Category A processes: target constituents and properties

It has already been indicated that the visualisation processes are

Process

Target species/ properties

Sweat Sebaceous

Contaminants Eccrine

Blood

Grease

✓✓

-

effective as a result of their interactions with different components (i.e.

Acid Dyes

Proteins

In assessing which process to select for any application, it is important

Basic Violet 3

Lipids, epithelial cells

DFO

Amino acids, amine containing compounds

ESDA

Electrical properties

Multi-Metal Deposition

Possibly eccrine constituents held within a water-insoluble matrix

Ninhydrin

Amino acids, amine containing compounds

Physical Developer

Possibly eccrine constituents held within a water-insoluble matrix

✓✓

✓✓

-

Powders

Adhesive properties

✓✓

✓✓

-

Powder Suspension

Possibly eccrine constituents held within a water-insoluble matrix

✓✓

✓✓

Small Particle Reagent

Lipids, oily contaminants

✓✓

-

-

✓✓

Solvent Black 3

Lipids, oily contaminants

✓✓

-

-

✓✓

Superglue Fuming

Salts, eccrine constituents in combination with water

Vacuum Metal Deposition

Differences in surface properties between fingermark and background

natural chemicals, contaminants) and other properties of fingermarks.

for practitioners to have a basic understanding of which characteristic of

fingermarks each of the processes is likely to target, particularly when the effects of environmental exposure on marks need to be considered.

The optical processes are capable of detecting all principal types of

mark (sebaceous and eccrine sweat, blood and grease contaminants) and exploit the optical properties of the mark.

The chemical and physical processes are generally more discriminating than optical processes, targeting some principal natural chemicals, contaminants and properties, as shown on the right.

N.B. Processes may visualise marks of different composition from

those indicated in the table, but may present other issues. For example, Superglue Fuming can occasionally visualise sebaceous marks but the polymer structure formed on the ridges is not optimum for subsequent enhancement with dye. Therefore, if sebaceous marks are suspected, another process should be used in preference to Superglue Fuming.

-

-

✓✓

-

✓✓

-

✓✓

✓✓

✓✓

✓✓

✓✓

✓✓

✓✓

✓✓

-

✓✓

✓✓

-

-

-

✓✓

-

✓✓

✓✓

-

✓✓

-

✓✓ ✓✓

-

✓✓

-

✓✓

✓✓

General overview of target materials and properties for chemical and physical visualisation processes.

Home Office January 2014

2.3.5

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

2.3.6

Contents

Appendices

Glossary

Index

Purposes of the Category A processes: target constituents and properties continued Targeted development of sweat from different sweat gland types The practical benefit of having processes that can interact with constituents from

Differences in development of sweat from the same sweat gland type

different sweat types is that regardless of whether a mark is predominantly eccrine or

sebaceous in nature, there is generally a process capable of visualising it. By selection

Although fingermarks may be

of an optimal processing sequence, most marks containing natural constituents

broadly classified as ‘eccrine’ and ‘sebaceous’ the range of

can be visualised. This is illustrated below. Process

Eccrine-loaded mark

Sebaceousloaded mark

Natural mark

Ninhydrin

chemicals that may be present

in fingermarks is known to vary considerably both between

individuals or by an individual at different times. This may

result in developed marks from any one visualisation process Powder Suspension

appearing very different if the process reacts differently to

certain chemical components. This is shown on the right for Ninhydrin. Solvent Black 3

Coloured reaction products have only been produced

on filter paper impregnated with amino acids. Not all Vacuum Metal Deposition

Filter paper impregnated with individual eccrine sweat constituents including a range of amino acids, urea

and sodium chloride and processed with Ninhydrin.

amino acids give similar purple reaction products, and in practice variation in colour of developed marks from deep red to deep violet is possible. The resultant colour

of a fingermark, although usually perceived as purple in colour, will be composed of whichever amino acid reaction products are present. Results from using four chemical/physical processes on fingermarks where ‘eccrine’ and ‘sebaceous’ marks have been deliberately loaded with typical sweat from these glands. The ‘normal’ mark has not been ‘groomed’ in any way and may consist of sweat from a range of glands and possibly contaminants.

Home Office January 2014

Urea and sodium chloride have not reacted to give coloured reaction products. Other

processes may be used to target these and would be more suitable for detecting marks rich in these constituents, again demonstrating the potential benefits of sequential

processing for fingermark recovery.

2.3.6

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes

2.3.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Sequential processing

Just as it is important to use different forensic recovery treatments in an order which

maximises forensic evidence recovery, the use of fingermark recovery treatments in an appropriate order must also be followed in order to maximise fingermark evidence.

The different optical, chemical and physical processes can be used on a wide variety of items and surfaces to visualise fingermarks. If they are used in the correct sequence,

different properties or constituents of the fingermarks can be targeted without destroying the opportunity to maximise evidence from the remaining components. It may be more appropriate to use a single process, but a short or longer sequence of processes may be needed to maximise the contrast between the fingermark and the surface. More

discussion on planning the most appropriate sequence can be found in Section 2.4. In any case, it is important to image at each stage of development for recording

purposes and to prevent possible loss of information if subsequent actions do not go according to plan and evidence is lost.

There is a basic rule that can be applied to sequential processing: Processes should be used in the order of least to most destructive in order to maximise the opportunities for fingermark recovery.

This can then be supplemented by further rules, which form the basis for establishing the Fingermark Evidence Recovery Plan. Rule 1 Optical processes should be used at the beginning of any processing sequence (and after each process as required).

Optical processes are generally non-destructive to the mark or substrate.

Rule 2 Liquid-free processes should be used before any liquid-containing processes.

Liquid-free processes will not remove mark components but may physically hinder further enhancement.

Rule 3 Organic solvent-based processes should be used before water-based processes.

Organic solvent-based processes may dissolve some components of the mark and/or affect the substrate but are generally less destructive than water-based processes.

Rule 4 Water-based processes may cause significant staining Water-based processes or damage to the substrate and may dissolve watershould be used at the end of soluble components of the mark. any processing sequence.

Home Office January 2014

2.3.7

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes

2.3.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes Sequential processing continued The diagram below indicates how the Category A processes can be used in an order

which complies with the rules outlined above. Further detail on how to plan the use of

the processes in the most effective order to maximise fingermark recovery can be found in Section 2.4 and in Chapter 4.

Rule 1 Optical processes should be used at the beginning of any processing sequence (and after each process as required). They are generally non-destructive to the fingermark or surface and can be used in any order.

Colour Filtration Fluorescence Examination IR Reflection Monochromatic Illumination Multi-Spectral Imaging UVC Reflection Visual Examination

Rule 2* Liquid-free processes should be used before any liquid-containing processes. They will not remove mark components but may physically hinder further enhancement. There are no clear rules about the order of these processes, but the charts in Chapter 4 show the order that is likely to be most effective for different surface types.

Rule 3 Organic solvent-based processes should be used before water-based processes. They may dissolve some components of the fingermark and/or affect the surface but are generally less destructive than water-based processes. DFO must be applied before Ninhydrin. Rule 4 Water-based processes should be used at the end of any processing sequence.

ESDA Powders Superglue Fuming Vacuum Metal Deposition

Special case: Superglue Fuming is known to reduce the effectiveness of Acid Dyes. * Although ‘lifting’ is a liquid-free process, it is not included here as it can remove

fingermark components from the surface. Like the optical processes, it can be used

after most processes as an enhancement tool although this may limit further sequential

They may cause significant staining or damage to the surface and may dissolve water-soluble components of the fingermark. There are no clear rules about the order of these processes, but the charts in Chapter 4 show the order that is likely to be most effective for different surface types. Special case: Acid Dyes must be applied before other water-based processes as blood or other protein-rich contaminants targeted by acid dyes are water soluble.

DFO

Ninhydrin

Acid Dyes

Basic Violet 3 Multi-Metal Deposition Physical Developer Physical Developer Enhancement Powder Suspensions Small Particle Reagent Solvent Black 3 Superglue Fluorescent Dye Staining

processing. See Chapter 4 for further details.

Home Office January 2014

2.3.8

2.3.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes Process effectiveness: influencing factors

As indicated in Section 2.2 of this chapter, exposure of items to water or elevated temperature, the age of the mark and the texture of the surface are the four main factors which could impact on the composition and properties of fingermarks. The resultant changes may alter the effectiveness of the visualisation processes used: therefore knowledge of both the history of the item and the likely impact on the

effectiveness of the process will be needed to guide the choice of which process(es) to use.

The summary below is followed by more detailed information on the impact of each

of these factors on the fingermark and the visualisation processes: this is important in applying the recommended sequences of processes, given in Chapter 4 (from which there is a link back to these reference pages).

Has the item or surface been exposed to water? If yes, this will have a significant impact on the

effectiveness of some visualisation processes. It may

remove some of the mark constituents (see ‘what happens to the fingemarks’). The degree of impact will depend upon the extent of wetting e.g. light shower for a short

period of time vs. immersion for weeks and the age of the fingermark prior to wetting. See ‘impact on processes’.

How rough or textured is the surface?

Has the item or surface been exposed to elevated temperatures?

If yes, this will have a significant impact on the effectiveness of some visualisation processes. It may move or destroy some of the mark constituents (see ‘what happens to the fingemarks’). The degree of impact will depend

upon the temperature and time of exposure. See ‘impact on processes’. There may be additional problems if contaminants such as soot are also present.

Note: Exposure of marks to sub-zero temperatures is not

thought to be detrimental to fingermarks and may slow decomposition of constituents, provided they can be kept frost and condensation free at all times. In practice this is difficult to achieve.

The surface roughness will have an impact on the

How old is the fingermark?

two reasons: firstly, the ridge detail may be discontinuous,

the effectiveness of some visualisation processes.

effectiveness of most visualisation processes for one of

with the quantity and quality of any detail decreasing as

the texture increases (the visualisation process can only develop what is there); secondly, the texture may inhibit

the application of some processes. See ‘what happens to the fingermarks’ and ‘impact on processes’.

Home Office January 2014

The age of the fingermark will have an impact on

The composition of fingermarks will change as time

passes. The extent of this change will depend upon the environmental conditions to which the mark has been

exposed and the time period itself. See ‘what happens to the fingemarks’ and ‘impact on processes’.

2.3.9

2.3.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Process effectiveness: influencing factors continued What happens to the fingermark? The general introduction

to fingermark persistence

Latent Fingermarks Eccrine

Sebaceous

Blood

Grease

Water

Principally composed of water-soluble constituents which readily migrate, dissolve or are washed away in the presence of water. The composition of fingermarks is complex and some water-soluble constituents may remain in the mark if they are protected by a water-insoluble matrix such as sebaceous sweat.

Principally composed of water-insoluble constituents which are more resistant to water but may undergo leaching or compositional changes with prolonged water exposure.

Principally composed of water-soluble constituents which are more resistant than those in eccrine marks but will be dissolved or washed away under prolonged exposure to water.

Principally composed of water-insoluble constituents which are generally resistant to water.

Heat

At lower temperatures water will be driven off and marks dry out leaving organic compounds such as amino acids and inorganic salts. At higher temperatures organic compounds break down and may evaporate leaving only inorganic salts.

At lower temperatures constituents including waxes and fatty acids may melt and flow. At higher temperatures these compounds break down and may evaporate.

At lower temperatures the action of heat drives water from the blood. At higher temperatures organic compounds in blood progressively break down and may evaporate leaving only inorganic residues.

At lower temperatures grease may melt and flow. At higher temperatures it may break down and evaporate.

Age

Over short periods of time (days) water will evaporate and marks dry out leaving organic compounds such as amino acids and inorganic salts. Over much longer periods of time (years) organic compounds may degrade, whereas inorganic salts will be more stable unless exposed to moisture.

Some constituents (e.g. squalene) are lost within short periods of time (days), whereas others may persist for many years. In general the organic compounds present will progressively degrade over time.

Over short periods of time (hours-days) water will evaporate and marks dry out leaving proteins and other blood constituents. Over much longer periods of time (years) these proteins may degrade.

This represents a range of different types of contaminant that generally dry out and progressively degrade over time.

Surface Roughness

n/a

n/a

n/a

n/a

described in Section 2.2 needs to be examined in more detail when

considering the impact that the four main

influencing factors have

on process effectiveness. Additional information

on the fate of latent and contaminated marks is

summarised in the table on the right, noting that:

●● older fingermarks

(i.e. those present on the surface for some

time prior to exposure to heat or water) are

generally more resistant to degradation;

●● the period of exposure

to either heat or

water is important in

determining whether a

Contaminated Fingermarks

mark is likely to survive.

Home Office January 2014

2.3.10

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes

2.3.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Process effectiveness: effect of heat Optical Processes

Chemical and Physical Processes

The following table summarises the effect of heat on process

optical processes is likely to be variable

processes is process specific and influenced by the robustness

and proposes guidance on upper use limit for each, where it is

The impact of heat on the effectiveness of and very much dictated by the effect heat has on the constituent(s) influencing the most important optical properties (e.g.

fluorescence, refractive index, scattering). In most cases, heat is likely to reduce

The impact of heat on the effectiveness of chemical and physical of the constituents with the mark (i.e. whether they break down

or flow). See Section 2.2: The composition of sweat and target

effectiveness for all chemical and physical visualisation processes known.

constituents and properties. In most cases, heat reduces the effectiveness of chemical and physical processes. Process

the effectiveness of optical processes.

Upper use limit

Impact of Heat on Process Effectiveness

ESDA

Not known

Electrical properties are likely to be disrupted as heat increases causing a reduction in process effectiveness. It is not known at what temperature ESDA becomes ineffective.

Powders

100°C

Powders, which adhere to the moisture content of marks, are detrimentally affected by heat as marks dry out. Powders may also exploit adhesion to oily deposits and thus will also be affected once these constituents melt and flow.

Basic Violet 3; Solvent Black 3; Small Particle Reagent

100°C

Processes targeting constituents of sebaceous marks and/or greasy contaminants will be detrimentally affected by temperatures that cause the constituents to melt and flow, and will cease to be effective once these constituents have evaporated.

occurs.

DFO; Ninhydrin

150°C

Amino acid constituents of eccrine marks degrade sufficiently on exposure to temperatures above 150°C to make DFO and Ninhydrin ineffective.

(2) Visual Examination: Some marks

Acid Dyes

200°C

Processes targeting constituents of blood are likely to be relatively unaffected by lower temperatures and the heat may assist in fixing the mark. Once degradation of haem molecules and proteins begins to occur, performance will be detrimentally affected.

Multi-Metal Deposition; Physical Developer; Powder Suspensions

200°C

The effectiveness is relatively unaffected by exposure to lower temperatures. If the process is able to interact with eccrine constituents held within an insoluble matrix, performance may improve slightly after exposure to temperatures 80% RH) kept dry after

mark deposition

wetted after

mark deposition

after mark deposition

Fingermark visualised on paper using

Ninhydrin. The paper was exposed to

high humidity after mark deposition but Split fingermark visualised on paper using

prior to treatment.

Ninhydrin. The right-hand side was wetted after mark deposition but prior to treatment, whilst the left-hand side was kept dry.

Home Office January 2014

2.3.15

2.3.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes Process effectiveness: examples Example 2: The impact of water on fingermarks developed with Superglue Fuming (and enhancement) and Powder Suspension Theory

1. Superglue Fuming is initiated by constituents in eccrine sweat, which will be dissolved and washed away on exposure to water.

2. It is believed that Powder Suspension preferentially deposits on constituents of

eccrine sweat and may therefore continue to interact with those that are retained

within a water-insoluble matrix. This may explain why the process effectiveness is less affected by water exposure than Superglue Fuming is.

Both Superglue Fuming (with enhancement) and Powder Suspension give good results when the surface was kept dry for the time period between fingermark deposition and

However, when exposed to water spray the constituents targeted by Superglue Fuming are dissolved by the water droplets and the process principally develops the patterns formed by the droplets on drying. Although some diffusion is observed, Powder Suspension continues to develop ridge detail. Blurred ridge detail

Clearer ridge detail

treatment with the visualisation processes.

Clear ridge detail

Both kept dry after mark

deposition Fingermarks visualised on a ceramic surface using Superglue Fuming and

enhancement (left-hand image) and Powder Suspension (right-hand image). The surface was not wetted prior to treatment. Home Office January 2014

Both sprayed with water after mark deposition Fingermarks visualised on a ceramic surface using Superglue Fuming followed by

enhancement with a Superglue Fluorescent Dye Stain (left-hand side) and Powder

Suspension (right-hand side). The surface was sprayed with water after mark deposition but prior to treatment.

2.3.16

2.3.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes Process effectiveness: examples Example 3: The impact of heat on fingermarks developed with DFO

Theory

DFO targets amino acids present in eccrine sweat and proteins present in blood, which begin to degrade at exposure to temperatures above 150°C.

On cardboard bearing marks in blood that is exposed to heat, the proteins in the blood

are relatively unaffected by exposure temperatures up to 150°C and fluorescent reaction products are formed with DFO. With exposure to higher temperatures, the proteins

degrade and the reaction with DFO to form fluorescent products no longer occurs. Also, degradation of the cardboard substrate has occurred and background fluorescence has increased at the higher temperature. Similar trends are observed for latent marks where amino acids degrade with increasing temperature.

Marks in blood visualised on cardboard using DFO, (left) control mark kept at ambient

temperature, (left centre) mark exposed to 100°C prior to processing, (right centre) mark

exposed to 150°C prior to processing, (right) mark exposed to 200°C prior to processing. Home Office January 2014

2.3.17

2.3.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes Process effectiveness: examples Example 4: The impact of heat on fingermarks developed with an acid dye (Acid Yellow 7)

Theory

Acid Dyes targets blood proteins, which begin to degrade at exposure to temperatures above 150°C.

For a ceramic tile bearing marks in blood that is exposed to heat, the proteins in the

blood are relatively unaffected by exposure to temperatures up to 150°C with fluorescent reaction products being formed with Acid Yellow 7. With prolonged exposure to higher temperatures, the proteins begin to degrade and the reaction to form fluorescent products no longer occurs to the same degree.

Marks in blood visualised on ceramic tile using Acid Yellow 7, (left) control mark kept at ambient temperature, (left centre) mark exposed to 100°C for eight hours prior to

processing, (right centre) mark exposed to 200°C for one hour prior to processing, (right) mark exposed to 200°C for eight hours prior to processing.

Home Office January 2014

2.3.18

2.3.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes Process effectiveness: examples Example 5: The impact of heat on fingermarks developed with Vacuum Metal Deposition

Theory

Vacuum Metal Deposition (VMD) utilises differences in surface properties between

mark and substrate to give differences in growth rates of metal films. It is capable of

detecting regions where marks have previously been present, even if temperature has been sufficiently high to volatilise mark constituents.

On a ceramic tile bearing latent marks and marks in blood, exposure to 900°C results in both types of mark being volatilised. However, the presence of the mark on the tile has provided protection to the surface for a period of time, resulting in surface properties

sufficiently different from those of adjacent regions for them to be distinguished by the VMD process.

Marks on a ceramic tile exposed to 900°C for five minutes, (left) mark in blood visualised using gold/zinc Vacuum Metal Deposition, (right) latent mark visualised using silver Vacuum Metal Deposition.

Home Office January 2014

2.3.19

2.3.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes Process effectiveness: examples Example 6: The impact of fingermark age on fingermarks developed with Physical Developer Theory

It is believed that Physical Developer may target eccrine constituents held within a

water-insoluble matrix. As the water-insoluble matrix dries out around the constituents it may provide a protective layer that enables these constituents to persist for long periods of time, even if wetted.

In this case it can be seen that on documents known to be over 55 years old when processed, several potentially identifiable marks were successfully visualised after subsequent application of Physical Developer.

Marks visualised on an electricity bill dating from 1948 after processing with Physical Developer in 2003.

Home Office January 2014

2.3.20

2.3.21

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.3: Fingermark Visualisation Processes Process effectiveness: examples Example 7: The impact of surface texture on fingermarks developed with Powders

Theory

Fine powders become physically trapped in the features on the surface as they

are brushed across the surface using the brush or applicator. Uniform background

development occurs and the visualisation process is no longer able to distinguish the ridge detail from the background in this region.

In this case it can be seen that on a plastic storage box, fingermarks crossing a

boundary between adjacent smooth and textured surface regions are not fully visualised when using Powders containing fine particulates. Although the mark is well developed on the smooth region, the textured region retains the powder and little or no ridge

definition is achieved. Alternative processes that are less affected by surface texture (e.g. Superglue Fuming) should be considered for this type of surface n

Marks visualised on the surface of a plastic box with smooth and textured surface

regions using (left) aluminium flake powder, and (right) black granular powder. In both cases the ridge detail in the mark is not visible in the textured region. Home Office January 2014

2.3.21

2.4.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Gathering information.......................................... 2.4.2 Initial planning and the Manual Charts................ 2.4.4 Complex scenarios.............................................. 2.4.9 Additional considerations.................................. 2.4.11 Developing the plan........................................... 2.4.14

Introduction

sequencing charts, which appear in Chapter 4 for

maximise fingermark evidence recovery from those

they can be used as an aid to planning, following the

This section deals with drawing together a plan to

items or surfaces that are considered to provide the

best potential for fingermark evidence in support of the investigation. Depending on the circumstances in the police force and the particulars of the case, the way

in which the plan is developed may vary considerably

from crime to crime and between forces, stressing the

importance of involving competent personnel through all stages of the investigation.

Further detail on effective planning can be found in

Chapter 4. Once the plan has been agreed, instructions for carrying out the visualisation processes most

effectively can be found in Chapter 5, for Category A processes. Chapters 6 and 7 may also need to

be consulted with regard to the use of processes in categories B-F and possible interference with other forensic recovery, respectively.

Gathering information

The importance of gathering comprehensive information about the items or surfaces to be treated before

Fingermark Evidence Recovery Plans are drawn up is stressed, as well as the importance of good recordkeeping throughout the investigative and forensic evidence recovery process.

Initial planning and the Manual charts

The primary purposes of the processes for Preparation or Visualisation of fingermarks are explained as well as the importance of image capture at stages throughout the visualisation process. The fingermark development Home Office January 2014

Category A processes are introduced and shown how rules introduced in Section 2.3 of this chapter.

Complex scenarios

Not all situations presented to the practitioner will be

straightforward. A number of possible complex scenarios are included to illustrate how plans may need to be amended to maximise fingermark evidence.

Additional considerations

Some of the constraints and limitations for forensic

evidence recovery with respect to progressing the case

were discussed in Section 2.1. There may be additional considerations that need to be taken into account as

preliminary plans for the visualisation of fingermarks are

developed and before the plans can be finalised: some of these considerations are included here.

Developing the plan

With the advent of compulsory ISO 17025 accreditation for all UK providers of forensic services, the decisions

needed to draw the Fingermark Recovery Plan together

will rest with practitioners who are deemed competent to make them. The decisions they make will be on broad

and dynamic reflection of the requirements, limitations and constraints posed by the case set against their

knowledge, skills and experience: this will be especially so for high profile cases. An indication is given of some

of the considerations in drawing a plan together and how the Manual aims to provide support to the practitioner in this process.

2.4.1

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Gathering information

With the additional information generated, the practitioner will be in a stronger position

information, including the particulars of the case, to assist

bottle at the time of the crime and whether any might have survived.

It is important for the practitioner to use all available

them in deciding on the plans for fingermark evidence recovery from item(s) recognised as important in the investigation.

There may be sufficient information in the case about an item, including its composition and history, to enable a

plan to be drawn up easily. For instance, if an interior, clean window has been forced to create an entry point to steal

a wallet, the glass or window frame may be treated on the spot using standard processing: the glass and frame are made of commonly encountered materials and have not

been exposed to an outdoor environment or extremes of temperature which might affect the choice of processes to include in the plan.

A more complex scenario will require a more considered plan. For instance, a bottle was broken and then used to fatally wound someone in the street on a wet night in July and only located two weeks after the event. This will raise a number of questions where the answers may guide the best approach to recovering fingermark evidence. These might

to establish what might have happened to the fingermark evidence that was on the

By combining all the information available to them, practitioners should be able to start to draw up a plan to recover fingermarks that may have survived.

In the latter case, every effort will be made to recover all potential evidence. The plan developed to recover that evidence will almost certainly be more complex than the

first case but will also be different from that applied to a similar bottle with a different

history. Given the number of variables, including the availability and quality of information about the item in question, as well as the particulars of the case, there is every chance that a similar item received by different forces will be processed very differently. Also, apparently similar items from different cases managed by the same force may be processed very differently depending on the salient information.

In other words, there is no ‘formula’ and no single ‘right answer’ when it comes to planning for optimal fingermark recovery.

Case studies can be found in Appendix 1 to demonstrate how information about some items has been used to develop Fingermark Recovery Plans.

include:

●● What was the condition of the bottle

before it was used as a weapon?

●● What was the condition of the bottle

when it was found?

●● Is there blood present?

●● When did it start raining? ●● When did it stop raining?

●● Has it been exposed to rain or high

temperature since the night the crime was committed?

●● Where was it found - are there contaminants present?

Home Office January 2014

2.4.2

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Gathering information continued Records need to be made throughout the recovery and use of fingermark evidence from items associated with the investigation. Keeping contemporaneous notes of all actions throughout the handling of items is vitally important to ensure an unbroken chain of

evidence and to provide a robust position regarding the use of the evidence in court. As stated earlier, the development of plans is wholly dependent on the circumstances

Keeping contemporaneous notes will not only ensure a robust investigation but also

provide a means of updating all the personnel involved in the end-to-end process. This is especially important for fingerprint examiners, since they need as much relevant

information relating to the item or the surface and the recovery of any fingermarks as

possible, in order to make reliable identifications and avoid errors. More detail on this topic can also be found in Section 2.5 of this chapter.

understood at the time. The justification for taking a certain course of action will always need to be documented but this is especially important if there is any deviation from a standard approach which might usually be adopted. It has already been seen that restrictions of time, cost and availability of staff or equipment may affect the course of the investigation and later in this section, additional considerations regarding the

application of processes to recover fingermarks will be discussed. Keeping good records of the decisions made and the reasons for them is important.

Details of the case, the item and the item’s history will all have been taken into

consideration when drawing up the original plans but as time goes on and new

information comes to light, the plans may need to be amended. An explanation of the reasons for those changes will also need to be recorded.

Comprehensive records will need to be kept of the methods and chemicals and

equipment used for processing any items. This is a requirement of the ISO 17025

standard, which has very exacting requirements for record-keeping. These records will

generally be kept on a laboratory results sheet or may be recorded on an exhibit-tracking system.

Any marks developed in the laboratory or at the scene will also need to be clearly

identified: both to indicate their position for later examination but also to record the

process that was used to visualise them. Marks recorded electronically will also need

to include an audit trail which records all details of the image capture and any changes

made to the original image. Further information on good imaging practice can be found

in Chapter 3: Working Effectively – Imaging and manual recording of marks developed (‘marking up’) and using the developed marks can be found in Section 2.5 of this chapter.

Home Office January 2014

2.4.3

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning Initial planning and the Manual Charts

The term ‘visualisation’ is used throughout the Manual as a general term to describe the revealing of a fingermark by whatever means.

The Category A processes have been further grouped in the Manual according to their intended function, as

Preparation or Visualisation Processes. As plans are

generated, both process types may need to be included in the plan but as a general rule it is very important

to remember to capture images of any fingermarks

Preparation Processes

Their function is to create a surface that improves the chances of success of any

subsequent visualisation process. This may involve the removal of contaminants or potentially interfering substances, or separation of attached surfaces. While they

are often carried out at the start of a processing sequence, they may be needed at a later stage to maximise recovery of obscured marks, e.g. processing of an item with tape attached may be treated before and/or after the tape is removed.

visualised at each stage, including entirety images if

Visualisation Processes

3: Working Effectively – Imaging.

the point where a mark becomes visible to the observer or detection system being

appropriate. Further information can be found in Chapter Further explanation of the functional classification can

Their function is to increase contrast between the mark and the background to employed. These processes may be optical, chemical or physical in nature.

be found on the right, with an indication of the usual processing cycle. Further information on their use in

sequence can be found in Chapter 4 and instructions for carrying out each of these processes, identified in this way, can be found in Chapter 5.

Getting the most out of Chemical and Physical Visualisation Processes It may be possible to further increase the contrast between the mark and the

Image capture Images should be

captured of any marks that are visible prior to proceeding with any further processing.

Subsequent processes may not reveal any

additional ridge detail

and may be detrimental

to that which has already been revealed.

background with the objective of maximising the amount of ridge detail visible. Optical processes can be effective at enhancing detail developed with most

chemical and physical processes. There are also a limited number of chemical processes that enhance specific chemical visualisation processes.

Home Office January 2014

2.4.4

2.4.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Initial planning and the Manual Charts continued The schematic below indicates how individual Category A processes are grouped

according to their principal purposes and how they will be identified in the Manual.

Preparation Processes

Visualisation Processes

be grouped accorded to their purpose:

them optical; 16 of them chemical and/or physical.

There are 4 Category A preparation processes in Chapter 5 of this Manual. They can

There are 23 Category A visualisation processes in Chapter 5 of this Manual: 7 of

For the removal of contaminants and/or interfering substances

For the separation of surfaces

Optical Processes ●● Colour Filtration*

Chemical and/or Physical Processes

●● Soot Removal

●● Numberplate Splitting

●● IR Reflection*

●● Basic Violet 3*

●● Thermal Coating Removal

●● Adhesive Tape Removal

●● Fluorescence Examination* ●● Monochromatic Illumination* ●● Multi-Spectral Imaging* ●● UVC Reflection*

●● Visual Examination*

●● Acid Dyes ●● DFO

●● ESDA

●● Lifting

●● Multi-Metal Deposition ●● Ninhydrin

●● Physical Developer ●● Physical Developer

Enhancement**

●● Powders*

●● Powder Suspension

* These visualisation processes may be used to further increase the contrast between

the mark (already enhanced with another visualisation process) and the background in addition to finding marks in their own right.

** These visualisation processes may be used to further increase the contrast between the mark (already enhanced with another visualisation process) and the background

●● Small Particle Reagent ●● Solvent Black 3

●● Superglue Fluorescent Dye

Staining**

●● Superglue Fuming

●● Vacuum Metal Deposition*

only. This only applies to Physical Developer Enhancement which can only be used after

Physical Developer and Superglue Fluorescent Dye Staining which can only be used after Superglue.

Home Office January 2014

2.4.5

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Initial planning and the Manual Charts continued Fingermark Evidence Recovery Plans are the responsibility of a competent practitioner, who will be able to develop them on the basis of their complete

knowledge of the requirements of the investigation, the item, the possible visualisation processes available to them and any local constraints and considerations that need to be taken into account.

If the practitioner is faced with a simple scenario, they may decide to use a single

process to provide the most efficient response to the investigation. For example, routine recovery of paper items, such as envelopes, or of plastic bags may result in their being treated with a single process that is considered most appropriate for volume crime

investigations. In different circumstances, these processes might not be considered the

The Manual Charts have been developed to give as much assistance as possible to the practitioner in deciding an optimum plan. They are based on knowledge of:

Substrate

most effective but in the operational scenario these simple plans may provide the most time- or cost-efficient solutions.

Where a more comprehensive approach to planning is required and sequential

processing is needed for optimum recovery of fingermark evidence, help is provided

Fingermark

Home Office over many years, are provided to give both a starting point for planning information is available about the item and its history.

ceramic, recycled plastic or leather, for example.

possible target materials in the fingermark, whether a constituent

later in this Manual (Chapter 4). A number of charts, which have been developed by the as well as giving further guidance on the modifications that may be needed if further

the substrate type: whether it is porous, non-porous, made of glass,

Environment

of sweat or source of contamination; amino acids, inorganic salts or blood, for example that can be exploited effectively.

modifications needed to a sequence to maintain its effectiveness

when there is additional information about the environmental exposure of the item. These include changes that may need to be made if the

item is known to have been wetted or exposed to extreme conditions, for example.

the effectiveness of individual processes or of processes used Process

Home Office January 2014

in sequence on the substrate and fingermark, given their known

properties and possible history.

2.4.6

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Initial planning and the Manual Charts continued Sequential processing Rules Another major consideration in the

construction of the Manual Charts

is in ensuring that the most effective

sequence of processes is developed, following the Rules introduced in Section 2.3 of this chapter.

Incorporation of individual optical,

chemical or physical processes into the

sequences also requires some additional control, to minimise any possible

interference that might occur between

processes. This was explained more fully in Section 2.3 of this chapter.

The overarching requirement of

Rule 1

Optical processes should be used at the beginning of any processing sequence (and after each process as required)

Rule 2

Liquid-free processes should be used

before any liquid-containing processes

Rule 3

Organic solvent-based processes

should be used before water-based processes

sequential processing, which applies to

Rule 4

( A-F) is that:

at the end of any processing sequence

all categories of visualisation processes

Water-based processes should be used

Processes should be used in the order of least to most destructive in order to maximise the opportunities for fingermark recovery.

Modifications to the Manual Charts will be needed depending on the individual

circumstances of the item to be treated. Given the number of variables that might

manifest themselves in any particular case, although the Manual Charts are a valuable starting point, judgement of what modifications may be needed rests with the

competence of the practitioner. The following example is included to illustrate a number of the points raised above.

1. A document has been identified

of value to the investigation. Initially

only latent marks are expected to be

present. This results in the selection of

Chart for Porous Surfaces Visual Examination

the Manual Chart for Porous Surfaces. The chart follows the rules in that optical

Fluorescence Examination

processes are used at the start of the processing sequence (although they

can also be used after each process as

required). The chart then indicates that the

DFO

chemical processes should be used in a specified order, namely DFO, Ninhydrin,

Physical Developer, to avoid interference

Ninhydrin

between them and to maximise fingermark evidence recovery.

Physical Developer

Home Office January 2014

2.4.7

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Initial planning and the Manual Charts continued 2. On closer examination of the document it can be seen that it is standard white

3. Subsequent information about the environmental history of the item confirms that it

process, ESDA, being incorporated into the sequence to investigate possible indented

that neither ESDA, nor DFO, nor Ninhydrin will be effective for this item.

printer paper. Additional information for this surface results in another (physical) writing.

has been wetted. Consulting the additional information for Wetted Surfaces indicates

Rule 2 and knowledge of ESDA and its impact on processes have been used. The new

Ineffective processes have been removed and the chart that is finally generated takes

other processes unchanged in the sequence.

scenario.

process, which is liquid-free, is inserted before the liquid chemical processes, leaving the

into account all of the information gathered and is therefore optimised for the particular

Chart for Porous Surfaces

First modification to Chart

Second modification to Chart

Final process sequence planned

Visual Examination

Visual Examination

Visual Examination

Visual Examination

Fluorescence Examination

Fluorescence Examination

Fluorescence Examination

Fluorescence Examination

DFO

ESDA

ESDA

Physical Developer

Ninhydrin

DFO

DFO

Physical Developer

Ninhydrin

Ninhydrin

Physical Developer

Physical Developer

Home Office January 2014

2.4.8

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Complex scenarios

Little is known about the item

where some valuable information was forthcoming about the item.

suggested by the most appropriate primary Manual Chart (e.g. porous, non-porous or

Of course, not all scenarios will be as simple or straightforward as the example above, It has already been seen that Preparation Processes identified earlier in this section

need to be included in the plan to reveal marks that might have been obscured when

Where little information is known about the item, following the sequence of processes

semi-porous) may be the best option, assuming the substrate can be identified to this degree.

the item was presented, e.g. tape removal before applying a visualisation process to the

However, further investigation of the item may be needed if it is critical to the case but

consideration before plans can be agreed. Some examples of these are considered

classifications. It may then be possible to experiment using planted test marks on a

adhesive side. In other situations, complex scenarios might arise, requiring additional below, where:

●● little may be known about the item;

●● multiple types of mark may be present;

●● multiple types of substrate may be present.

the substrate cannot be easily recognised or placed in one of the principal substrate

similar item or on a suitable portion of the item itself, away from possible contact areas. These may be used to evaluate the relative effectiveness or any adverse reactions from the candidate processes. If any adverse reaction does occur, another small section of

the article might be treated with the next candidate process until a suitable process can be identified.

Application of visualisation processes to planted test fingermarks on an unfamiliar

substrate: in this case the evaluation of candidate processes (left) Carbon Powder

Suspension, (centre) Black Magnetic Powder and (right) Superglue Fuming and Basic Yellow 40 for suitability of use on hens’ eggs.

Home Office January 2014

2.4.9

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Complex scenarios continued Multiple types of mark

Multiple types of substrate

marks are most important in the investigation: for example, it may be more important

generated for each of the substrate types present, taking into account the history of the

For substrates where multiple types of mark are present, it should be established which to detect marks in blood than latent fingermarks that may also be present. This will determine which processes are most appropriate.

Additional Manual Charts have been developed for surfaces where blood or grease contamination may be present (Chapter 4) and provide information relating to

whether enhancement processes are most suited to detecting latent marks, marks

in contaminant, or both. This information can then be used to develop a processing

sequence optimised to the particular combination of marks present and their relative evidential priorities.

Alternatively, targeted application of a process, masking of areas of the item or

segregation of the substrate can be employed to enable selective treatment of areas with processes most suited to the type of mark suspected to be present in that area.

When an item is composed of a number of different materials, plans will need to be

item as before. By comparing the charts and considering the compatibility of the specific

processes selected, their target materials and suitability for different types of substrate, it should be possible to generate a plan which is appropriate for the item as a whole. Four possible solutions are likely:

1. Separate component parts

of similar substrate type, so that the most appropriate

processes can be applied

to each group of substrates

e.g. knife handle and blade. 2. Mask parts of the item to

protect them from exposure to a treatment with which

they are incompatible, e.g.

masking the paper label on a bottle.

3. Selectively target parts of

the article with a particular process, e.g. painting

on reagents rather than submersing the item.

4. Treat the item in its entirety using a sequence of processes that are both effective

on the substrates present and minimise any detrimental impact on the subsequent application of later processes in the sequence.

Further information can be found in Chapter 4. Home Office January 2014

2.4.10

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Additional considerations

As well as the overarching constraints and limitations posed by force policies and

Health and safety

chapter, there may be additional considerations that need to be taken into account as

protect their staff, visitors and members of the public is discussed.

by the particulars of the investigation itself, already examined in Section 2.1 of this

the Fingermark Evidence Recovery Plan is developed. These need to be considered collectively and include:

●● reviewing plans as new information comes to light;

●● health and safety risks arising from the planned activities;

●● restrictions placed on the ability to treat items at the scene or in the laboratory; ●● the time available to complete the plan versus the effort needed to execute it; ●● availability of the processes or other resources.

In Chapter 3: Health, Safety and Welfare, the responsibility placed on employers to In some instances the Fingermark Evidence Recovery Plan may involve few health and safety concerns if a ‘routine’ approach is taken; for instance, for standard laboratory

processing of regularly received items. Conversely, a plan that involves unique, complex scenarios, possibly requiring the use of infrequently used processes will require more

careful consideration with regard to its safety and possible health effects, both in its use and the possible long-term effects for all concerned. In particular, this needs to be carefully considered before any plan is executed for scene use of some processes.

Multiple evidence types: reviewing plans

Further details on health and safety of visualisation processes can be found in Chapter

intervention of all appropriate forensic

chapters of the relative safety of the use of processes where:

It has already been discussed that practitioners in the early strategic

thinking should benefit the success of forensic evidence recovery, agreeing compromises where necessary and

guiding the individuals establishing plans

in their particular disciplines. As the plans

5. Particular attention has been given to health and safety considerations within these

●● conditions can be controlled, i.e. laboratory use of the process as described in this

Manual;

●● conditions may be difficult to control e.g. at scenes or in a laboratory where there

is a requirement to deviate from the prescribed process and additional or possibly unacceptable risks to health and safety are posed.

progress it may be necessary to discuss any new information as it comes to light, since it might impact on the plans for forensic evidence recovery by other practitioners or investigators.

More information on the recovery of other forensic materials and possible interferences with fingermark recovery can be found in Chapter 7.

Home Office January 2014

2.4.11

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Additional considerations continued Scene vs laboratory treatment of items Section 2.1 of this chapter introduced some of

Items taken to a laboratory may:

the issues associated with forensic evidence

Receive more effective evidence recovery because they can be treated

on the progress of the investigation. Other,

processes may also be available to be included in the evidence recovery

recovery at the scene which might impact

additional considerations regarding treatment of items in situ rather than removing them to the laboratory will need to be reviewed as

the Fingermark Evidence Recovery Plan is developed.

Even if an item is difficult to remove and transport, such as a door, the option to process the item in a controlled laboratory environment to improve the chances of fingermark recovery may be preferable to treating it at the scene. For example, a full sequential

treatment may be necessary, which can only be achieved in a laboratory environment. The plan should consider all the options in line with the previous constraints posed

by the investigation, e.g. with the time available for treatment and details of the scene location in mind.

Whether items are processed in a laboratory or at the scene, there will be some

common issues, such as the timely recovery of evidence and the ongoing preservation

of evidence through careful handling of the item throughout its processing, especially if the item needs to be cut into manageable sizes. Items may also need to be packaged for transport and storage. Poor packaging can cause unnecessary deterioration of evidence through unwanted frictional contact between the item and its container or

evidence may be spoiled if inappropriate packaging is used. For example, evidence

in a more appropriate and controlled environment and where additional plan.

Be damaged prior to processing during additional handling for

packaging at the scene and unpacking in the laboratory and possible detrimental effects from poor packaging.

Items treated at the scene may: Be too large to consider removing to a laboratory and need to be treated in situ for any evidence recovery to be possible.

Be treated soon after the crime was committed and suffer minimal deterioration as long as the scene was suitably protected.

Fail to be treated optimally because the most effective processes cannot be used.

Be damaged by the environment if the scene is outdoors or unprotected. The same issues of poor packaging, as above, may arise if items need to be sent to a laboratory for additional processing.

on wet or contaminated items packed in non-porous containers will almost certainly

deteriorate if left in this environment for any length of time. See Chapter 3: Working Effectively – Handling Items for more information on packaging.

Health and safety concerns have already been discussed and Chapter 3: Health, Safety and Welfare and Chapter 4 should be consulted as necessary for further information.

Home Office January 2014

2.4.12

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Additional considerations continued Time available vs effort

Section 2.3 in this chapter and Chapter 5 discuss the fingermark development

possible availability of a scene or item

altered by either the condition of the item, e.g. if it has been wetted or the mode of

Time factors impact not only on the

during which examination of items must

be completed but also on the urgency of the results to the investigation and the

availability of resources to obtain them. The scene may be a public place that

needs to be returned to normal use as

soon as possible or the evidence may be short-lived or at risk of damage if not treated

urgently. In these situations, lengthy processes to obtain results may not be possible and valuable forensic evidence may be lost if the response is delayed.

Urgent results may be needed to support particular aspects of the case, especially if a suspect is in custody: effort may need to be directed to getting ‘sufficient’ information

processes in detail and give an indication of their effectiveness and how this may be application, e.g. whether it is being used in ‘controlled’ or ‘uncontrolled’ situations.

However, it is impossible to quantify the absolute effectiveness of processes on real-life

items since a huge number of variables is presented by individual items. Practitioners will therefore need to assess and select processes based on their view of their effectiveness in the particular application facing them.

Complex items

Items composed of different materials or of a construction that makes examination

difficult will draw even more on the competence of the practitioner. Again, guidance is

given throughout this Manual where possible, but individual circumstances must dictate the actions taken.

back quickly to the investigation rather than cause a delay by seeking the ‘best’ information through the use of optimal processing.

Some of the timing issues may be alleviated if the police force has imposed policies

regarding the use, where possible, of a single process for treating ‘routine’ items to remove the need for individual review of some categories of evidence.

Availability of processes and their effectiveness

It may not be possible to employ all appropriate processes if the equipment or

competent staff needed are not available or if the likely costs of using certain processes are prohibitive. Short-term unavailability of competent staff or essential equipment,

during servicing for instance, to carry out otherwise routine processing may result in

acceptable delays. In other cases, the delays cannot be tolerated and using another facility may be possible, with appropriate checks and agreements. If necessary,

alternative processes might be considered, even though they may be less effective or

pose other issues (e.g. health and safety), in order to satisfy the demands of the case.

Home Office January 2014

2.4.13

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning

2.4.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.4: Fingermark Evidence Recovery Planning Developing the plan

This and the earlier sections of this chapter have been designed to explain the ‘route’ to the development of a plan for fingermark development. However, there is no clear path

to a plan since those responsible for drawing up the plan will often need to take a broad view of many diverse pieces of information. Some of these are identified in the diagram on the right, recognising that every case will be different.

?

reasoned approach. Deciding on a

?

?

plan may be straightforward if there

of the investigation need to be

?

item?

sources in order to arrive at a well-

that take precedence in the

constraints and limitations

be learned from the

is to combine information from a variety of

What local

What can

The skill of the practitioner in developing a plan

are clear policies or local constraints

?

regarded?

What is known

about the history of the item?

Which processes will still be

decision-making process; one

effective on the item?

?

decision may be not to treat the item at all. At the other extreme, the case

may be of such high profile that every

consideration will be given to recovering

as much information from fingermarks as

used?

How should the processing

?

sequence be modified?

possible and all factors will need to be considered.

?

forensic material?

?

?

Should the item be treated in

? Who and

which processes

Further information can be found in:

What effect will the plan

have on the recovery of other

Which Manual

Chart should be ?

?

the laboratory or at the scene? ? ?

can be used?

Chapter 2: Sections 2.1-2.4

Chapter 3: Safe and Effective Implementation of Processes

Chapter 4: Process Selection

Chapter 5: Category A Processes

Chapter 6: Category B-F Processes

Chapter 7: Integrating Forensic Processes Appendix 1: Case Studies

Home Office January 2014

As much firm information about fingermarks, substrates and use of the visualisation

THE PLAN

processes as the Home Office has available at the time of writing has been included in the Manual. Where firm indications are not possible, as much useful information and

guidance has been included as possible. As stated before, it rests with the competence of the practitioner to evaluate all information and all options, bearing in mind the numerous constraints that are likely to be placed on any decisions. Some examples have been included in Appendix 1 n

2.4.14

2.5.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Fingermark comparison....................................... 2.5.2 Communication................................................... 2.5.4 Communication: marking up............................... 2.5.5 Communication: using ‘lifts’................................ 2.5.6 Communication: using images............................ 2.5.7 Communication: image transfer.......................... 2.5.9 Interpretation: examination................................ 2.5.10 Interpretation: distribution of constituents......... 2.5.11 Interpretation: substrate effects......................... 2.5.13 Interpretation: reverse-coloured/developed marks................................................................. 2.5.15 Interpretation: reverse-direction (mirrored) marks................................................................. 2.5.17 Interpretation: distortion of marks..................... 2.5.19 Interpretation: enhancement of digitial images. 2.5.20

Introduction

Interpretation

fingermark evidence and looks at the coordination

discussed during the interpretation of fingermarks are

This section examines the use and understanding of of activities between the fingermark development practitioners and those involved in fingermark identification.

Although an understanding of some of the specific

processes that are used for fingermark visualisation

might be useful before reading this section, the examples used do not rely on any specialist knowledge of them. However, familiarity with the earlier sections of this

chapter will help to place the examples in context. Topics covered in this section are:

Fingerprint comparison

It is not the intention of this Manual to cover in detail the way in which fingermarks are compared with reference

Some of the particular issues that may need to be

included. These include presenting as much information about the marks and their visualisation to the examiner as possible, to some particular effects that may need

further interpretation before the identification process can be effective. These include effects from the distribution

of constituents in the mark, or substrate effects, such

as surface features, transparency, reversed-colour and reversed-direction marks and physical effects such as distortion of marks.

Correct interpretation of images is covered in some detail to ensure that a number of effects do not mask

the possibility of correct use of fingermarks and result in missed identifications.

fingerprints. However, some information is included

here to give a brief description of the types of features

occurring in friction ridge detail that an examiner will use in the identification process.

Communication

The vital importance of good communication between

development and examining practitioners in maximising information from fingermarks is explained.

The methods for coordinating information between

them effectively is discussed, including day-to-day

discussion, ‘marking up’ and using lifts and images

to transfer fingermark evidence for examination. Special

note is made for the need to avoid unnecessary copying of any images, since vital information may be lost.

Home Office January 2014

2.5.1

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence

2.5.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence Fingermark comparison

The aim of fingerprint comparison is to identify the source of fingermarks left at

crime scenes. In most cases the comparison is conducted between the image of a

fingermark from a crime scene after it has been visualised and a fingerprint taken from a known source under controlled conditions (e.g. a custody suite). In conducting such a comparison the examiner will take into consideration all information relating to the

features that are visible within the fingermark, which generally fall into three categories.

First level detail:

Second level detail:

can be described as either loops, whorls or arches (illustrated below) although other

ridges end (ridge endings) or fork into two separate ridges (bifurcations). This type

This includes the general patterns formed by the flow of the ridges. Most ridge patterns patterns may also occur.

This includes the events occurring within the flow of individual ridges, including where of detail is that most commonly used during comparison, and the position, direction

and spatial relationship of such features is also used during searching by automated fingerprint identification systems.

Loop

Whorl

Arch

Mark with the position of several second level detail features highlighted.

Home Office January 2014

2.5.2

2.5.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence Fingermark comparison continued Third level detail:

This includes finer features associated with the individual ridge, such as ridge width, shape of the edge of the ridge, and size, shape and distribution of any pores visible within it.

Mark with the position of several third level detail features highlighted.

Because all of this information is potentially useful to the examiners, the types of feature that are present need to be assessed and taken into consideration at the image capture

stage to ensure all useful information is recorded, see Chapter 3: Working Effectively Imaging.

Examiners may also be asked to draw inferences about how items have been

handled and which finger has deposited the mark. This may require them to take into consideration other features associated with marks, including slippage and adjacent

smudges that may be associated with the previous contact with the item. It will therefore be necessary to ensure that images presented to examiners capture all information that could assist them with these decisions. Home Office January 2014

2.5.3

2.5.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Communication

Communication between practitioners

Exactly how practitioners communicate with one another will vary considerably from one

The documentation may be collated and sent to the examiner in a standard way,

those using them for identification have a good understanding of each others’ needs

fingermark images are delivered to the examiner varies and is covered later in this

organisation to another. However, it is important that those recovering fingermarks and in order to use any information about potential evidence to its best advantage. The

recording process of ‘marking up’ (see below) and imaging is just as important to the

practitioner performing this as it is to the fingerprint examiner: these activities effectively create the contemporaneous notes which they may rely on later, to produce statements or to provide evidence in chief to a court of law.

Records made as the processing plans are drawn up, as items are processed and as the visualised marks are imaged, are all vitally important to fingermark examiners as they go on to compare the crime scene marks with reference sets. Although some information

associated with the case will not be relevant to the examiner, or might introduce the risk

of contextual bias, many features of the item and any fingermarks found will help them in their examination including:

with any fingermarks visualised ‘marked up’ for their attention. The route by which section.

Even with the most comprehensive information passing between the laboratory and

bureau operations, the use of fingermarks for identification often requires more careful and detailed explanation, since what might appear as a straightforward situation, on closer examination may present additional information that proves vital to the

identification. If an examiner can easily visit the laboratory to discuss the item and view

a fingermark in situ, it may assist them in making the most appropriate comparison with reference marks as they will have a greater understanding of how the item was handled or how the fingermark was deposited. In addition, early identification of any issues may guide decisions about whether additional processing may be needed, especially for other items in the investigation that are yet to be treated.

●● Where was the fingermark positioned?

It is under these circumstances that good communication between the two operations

●● Did the fingermark or substrate exhibit any unusual properties?

developing a greater mutual understanding of each others’ needs.

●● Were there indications of other marks in sequence?

●● What processes were used to visualise and record the fingermark?

becomes invaluable, both in dealing with the particulars of the case, but also in

Systems are likely to be in place to facilitate day-to-day communication. These might include:

●● training in various aspects of fingermark recovery;

●● generic documentation, such as Standard Operating Procedures and quality

documents;

●● specific documentation, including notes, diagrams or audit trail; and

●● documentary information in the form of records, which might include before-

and-after photographs, entirety photographs, photographs of various stages of processing the item, such as dismantling a firearm.

Home Office January 2014

2.5.4

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Communication: marking up

Preparing fingermarks for examination is usually achieved by some form of ‘marking

Marking up generally consists of a label being placed on the item or surface to indicate

prior to imaging and sending the image to the bureau. Marks thought to be generated

identify the case reference, a mark reference number and there may also be a brief

up’ of any fingermarks thought to be suitable for comparison with reference marks

simultaneously, i.e. placed at the same time in one movement, need to be identified as

such and may include palm marks placed at the same time as fingermarks, for instance.

Marking up

There are three basic approaches that are generally used for the marking-up process: ●● development practitioners mark up;

●● fingerprint examiners involved in the identification of fingermarks mark up;

●● development practitioners generally mark up but fingerprint examiners advise on

marking up in serious crime cases.

Whichever approach is used, it is important that the person carrying out marking up has reached a level of competence in understanding both fingerprint examination

where fingermarks have been developed and are to be imaged. This label will usually

description of the item containing the marks. It will also be necessary to identify which processes have been used to visualise individual marks, which is especially relevant where a sequence of processes has been used on an item.

It is essential for a scale to be included in the image due to the increasing move towards electronic transfer of fingermark images both within the UK and between the UK and

other countries. If a scale has been omitted for any reason the label may be used as a

reference to ensure that the image is a true one-to-one-sized representation. Being able to ensure the image is correctly scaled is crucial to the success of any search against

the UK national fingerprint search database and also for searching against the database of any other country to which the mark may be sent.

and fingermark visualisation. The development practitioner needs an understanding

of the needs of the fingermark examiners, i.e. which marks might prove sufficient for

identification, and the fingerprint examiner needs to have an appreciation of the methods used by development practitioners to visualise marks.

Home Office January 2014

2.5.5

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence

© See Photo Credits

2.5.5

Contents

2.5.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence Communication: using ‘lifts’

Using lifts to transfer fingermark information

It may be possible to send the examiner a ‘lift’ of a mark, i.e. if the processed mark has been lifted with adhesive tape and placed on a transparent film. Although the lift will need to be scanned to load it onto the search database, there is no additional need

for imaging (although imaging may still be required by local working practices). In this case, the marked-up lift will be included in the information pack (often referred to as

a ‘docket’). The lift may also contain useful contextual information about the location where the marks were recovered from, and their orientation.

Fingermark lift with contextual information recorded on it.

Home Office January 2014

2.5.6

2.5.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Communication: using images

Preparation of fingermarks for examination will also require some form of imaging of any fingermarks thought to be suitable for comparison with reference marks.

Images required by the fingermark examiner may include entirety images to clarify the

It is of the utmost importance that a system of communication is established to

adequately inform bureau staff of all relevant information to avoid any misunderstanding of the presentation of the marks. Examples are given below but are not exhaustive:

relative positions of individual marks or sequences of marks visualised on the item or

●● Are higher quality images available, or can they be produced if necessary?

of images may be needed to capture the context of the marks to one another and the

●● Has the image been compressed, by how much, and why?

surface. If visualised marks cannot all be captured in a single image, then a number

images will then need to be cross-referenced in some way. Images of individual marks may also be required.

●● Has any process (chemical, optical, digital) introduced any artefacts?

●● Has there been any loss of quality between the digital image and any printed image?

There is specific good practice guidance for imaging in Chapter 3: Working Effectively – Imaging.

Higher quality images might be needed, for instance, if the examiner wishes to look at

the third level details of the ridge characteristics, such as ridge shapes and pore detail. In this case, re-imaging at 1000 ppi (right image above) to supplement the 500 ppi (left As well as passing on clear images to illustrate the positioning of fingermarks on the

image above) image presented originally may give the necessary image quality.

item, it is very important to confirm to the fingerprint examiner the image capture process that was used. The image presented to the examiner may appear very

differently from the original mark if, for example, it is presented in greyscale rather than

colour, with inverted contrast for fluorescent marks or with the background suppressed by optical means.

Home Office January 2014

2.5.7

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence

2.5.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence Communication: using images continued Those responsible for generating the images may have available to them a range of enhancement tools accessible through their image capture devices. Information in

Chapter 3: Working Effectively – Imaging stresses the importance of keeping an

audit trail, recording any image enhancements carried out since the original image was captured.

It is important for the imaging practitioners to understand the needs of those going

on to use the images they provide. What may be classed to the imaging practitioner

as a ‘better’ image following enhancement might not necessarily be the case for the

fingerprint examiner. For example, the application of some tools may increase or reduce the sharpness of the ridges which may not be to the fingerprint examiner’s advantage. The pictures on the right indicate the appearance of a fingermark after a range of

enhancement tools have been applied to an image, not all of which improve the ability to visualise ridge detail.

After discussion of all relevant marks and images, it may still be necessary to perform

extra tasks to visualise the marks most effectively. This may include returning the item

for the application of additional or repeat visualisation processing to give better contrast and detail for identification purposes.

Greyscale images of a lifted mark

developed using aluminium powder, (top) as captured, (centre) after adjustments to

contrast and brightness, and (bottom) after application of a sharpening filter. Home Office January 2014

2.5.8

2.5.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Communication: image transfer

Images of fingermarks may be sent to the fingermark examiner in a variety of ways,

A lift can be considered as a first generation copy of the mark, only requiring scanning

●● electronic files;

Electronic images of lifts or of fingermarks visualised in the laboratory can be regarded

including the lifts mentioned before, but also as: ●● digital printouts.

Chapter 3: Working Effectively - Imaging has more detail on the types of electronic file formats that may be used and discusses the use of digital printouts for making

to load an image onto the database.

as second generation reproductions with minimal loss of information, depending on the method of capture.

Digital printouts take the image to a third generation reproduction, with potential for

comparisons with reference sets of fingerprints. Inclusion of a scale in the image is

further loss of information at the printing stage and also as they are scanned into the

Increasingly electronic file transfer is being used to transfer marks from the scene or

The examiner should work with as low a generation copy number as possible to ensure

internationally. This method offers rapid image import to the system and avoids possible

to return to the original image, item or mark to ensure they work with the optimum

essential for all forms of data.

laboratory to the national fingerprint search system and also between organisations

loss of data, which might occur if the images are printed out and re-scanned to load them onto the database.

Loss of image quality may occur at various stages as an image is imported into

the database of the search system. It is recommended that the image is transferred

directly to a fingerprint database in its electronic form wherever possible to avoid any degradation in image quality associated with printing and re-scanning the image. It is

also recommended that the digital image (as distinct from any printed image) is viewed on screen by identification bureau staff prior to any decision being made regarding sufficiency of the detail present.

search database.

they are working with the best information available, but this may still require them information.

Mark

First generation copy

Lif t

Second generation copy

Third generation copy

Fourth generation copy

Scanned lif t

National Fingerprint Search System

Electronic image Digital printout

Scanned digital printout

Increasing potential f or loss of image quality

Home Office January 2014

2.5.9

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence

2.5.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Interpretation: examination

It is not the purpose of this Manual to discuss in detail the way comparisons are made

comparison on the search database. They may have to work with small areas of ridge

on the national database. Throughout the Manual, a major consideration has been

to work with a broad range of fingermarks generated by numerous means: they may be

between fingermarks submitted from the crime scene and the reference sets stored

to include information that will help the practitioners in the laboratory or at the crime

scene to provide the best information possible to those conducting the interrogation of the national search database. The Manual has also highlighted the need for good

communication between all the practitioners concerned to ensure maximum benefit can be obtained from fingermark evidence.

The importance of fingerprint examiners having as full a picture as possible of all

the history of the case, the item, the processes used and imaging method, to assist them in their tasks has also been discussed. Their need to refer to the laboratory or

scene practitioners who developed the marks or examine the original items for more

information, or to request additional treatment of the items to enhance the marks has also been mentioned.

Depending on the information supplied, the examiner will need to decide whether there is sufficient information in a fingermark or series of fingermarks to submit them for

Home Office January 2014

detail and require additional images before they can make comparisons. They will have distorted or smudged, negative marks, impressions or images of marks that have been enhanced using digital processing tools.

Entirety images are especially important to the fingermark examiner. The spatial

arrangement of marks from the fingers or palms that are thought to have been generated simultaneously, i.e. marks placed on the item at the same time in one movement, will

assist them in deciding how the item was handled and possibly clarify the relationship of

the individual marks to particular fingers, i.e. thumb, index, middle, ring and little finger of the right or left hand. This information can then be used to refine the database search. It is the responsibility of all concerned to clarify any uncertainties that might manifest themselves during the end-to-end process. Examples are provided in the following

pages of the types of issues that might arise that will require detailed communication between practitioners.

2.5.10

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence

2.5.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence Interpretation: distribution of constituents

Earlier sections of this chapter identified the constituents that are commonly

encountered in sweat and that might be targeted by visualisation processes. The

appearance of the mark may therefore be influenced by both the types of constituent that are present and the visualisation process used.

Incomplete development of ridge detail may occur not only through low

concentrations of constituents but also through their inhomogeneous distribution across the ridges of the finger.

In Section 2.2 of this chapter, the structure of the skin and the distribution of the

sweat glands and pores was discussed. Illustrations showed how the sweat produced from them was inhomogeneous. Eccrine constituents have been shown to be most

concentrated around the openings of the pores of eccrine glands, as illustrated below. As a consequence, marks visualised using processes which target constituents of

eccrine sweat may occasionally produce marks that are ‘dotty’ and have discontinuous ridges, some examples being shown in the following images.

‘Dotty’ marks with incomplete development of ridge detail, visualised by (left) Superglue Fuming followed by enhancement with Basic Yellow 40 and (right) DFO.

High magnification images of ridges showing selective reaction

around pores. Marks visualised by (left) Superglue Fuming followed by enhancement with Basic Yellow 40 and (right) Ninhydrin.

Home Office January 2014

2.5.11

2.5.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence Interpretation: distribution of constituents continued

If presented with a developed fingermark that has ‘dotty’, discontinuous ridge detail, the practitioners may decide that there is sufficient detail to attempt an identification or they may decide to request treatment with additional processes to target other constituents which may be more uniformly distributed along the fingerprint ridges, as illustrated below.

This approach is an essential part of the sequential processing philosophy.

Example of a mark (left) partially visualised using Ninhydrin, showing incomplete,

dotty ridges and (right) subsequently processed with Physical Developer to target other constituents to produce continuous ridges.

Home Office January 2014

2.5.12

2.5.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence Interpretation: substrate effects

The knowledge of what type of substrate is involved may also be very important during the interpretation of marks.

As indicated in previous sections of this chapter (Section 2.2), the properties of the

substrates on which fingermarks are found, such as texture and chemical composition, can interact with the visualisation processes. In some cases this may result in the

appearance of features that may be misinterpreted as ridge detail unless the examiner is fully informed of the nature of substrate present and takes this into account when making their comparison.

An example is shown below. In this case the surface is on a gloss-painted wooden door that appears uniform and smooth under normal room lighting (right), below. However, under examination using oblique light it can be seen that the paint is not smooth and contains several discontinuities such as trapped dust and fibres.

When this surface is powdered (right, in this case using a black granular powder), the surface discontinuities are capable of retaining powder and develop as features in

the background. If a fingermark is also present in this area, there is the potential for

some of these features within the perimeter of the mark and around its periphery to

be misinterpreted as features associated with ridges, for example incipient ridges and continuations of ridges beyond the true boundaries of the mark. Home Office January 2014

2.5.13

2.5.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence Interpretation: substrate effects continued Marks visible on both sides of an article

There may be instances where fingermark constituents have penetrated through thin porous surfaces such as tissue wrapping paper and some thin plastic bags. Such

penetration may occur before or during treatment. In such cases it may be difficult to

decide on which side the mark was originally deposited unless both orientations of the

mark are considered during comparison. Any searches against records should consider finger choices with the ridge detail as originally presented and in the ‘flipped’ (reverse direction) orientation.

Similar ambiguity can arise in the case of marks developed on clear substrates such

as plastic packaging if both sides of the surfaces have been treated at the same time

(using processes such as Superglue Fuming followed by dye enhancement). It will be

possible to see developed marks from both sides and it may not be immediately obvious on which side of the material the mark was generated, although additional processes

such as oblique lighting or UVC Reflection may help reveal the correct orientation. If it is not immediately obvious on which side of the substrate the mark was generated, marks should again be submitted for search in both orientations.

Marks visualised using the Superglue Fuming/Basic Yellow 40 enhancement on a clear acetate sheet showing marks developed on both sides of the substrate and all marks visible during Fluorescence Examination (top), and each side of the sheet visualised separately using UVC Reflection (centre and bottom).

Home Office January 2014

2.5.14

2.5.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Interpretation: reverse-coloured/developed marks

In the majority of cases, the appearance of marks will be unambiguous in terms of how

Influence of mark and substrate composition on reverse-coloured marks

they should be orientated: ridges will be easily recognised as such, with furrows between them. However, there may be situations where it is possible to misinterpret marks if there

Some processes (in particular Vacuum Metal Deposition) may produce marks that

is any confusion about which way the mark has been presented after visualisation.

can vary in appearance due to the influence of the type of substrate and the age and

composition of the mark. For example, what is described as ‘normal’ development for

It is essential that the identification practitioner who will be comparing the image of a mark with other records has an understanding of: ●● the process used to visualise the mark;

●● the substrate on which the mark is present;

●● any changes that have been made to the image since it was taken.

Armed with this information, it should be possible to remove any ambiguity and give the best chance of a successful comparison.

Visualisation processes will routinely give marks where the contrast between the ridges and the furrows between them conforms to an expected result. For example, some

Vacuum Metal Deposition produces a mark with little or no deposition of zinc on the

ridges and high levels of zinc deposition on the background, seen as light ridges against a dark background in transmitted light. However, on certain types of plastic and/or for situations where the mark may have dried out or contains contaminants, preferential

zinc growth may occur on the ridges resulting in a ‘reverse-developed’ mark with dark

ridges against a light background. Both types of development may be observed on the

same substrate (and even within the same mark) on occasion. Both normal-coloured and reverse-coloured scenarios should be considered when making comparisons of marks developed using Vacuum Metal Deposition unless positions of features such as pores enable ridges to be clearly identified.

processes, such as Ninhydrin, will routinely produce coloured ridges which appear dark against a lighter background. Others, such as superglue enhanced with a fluorescent dye, will usually give ridges that appear lighter than the background.

Unexpected results may arise, in which the contrast between the marks is reversed from that which is normally seen. That is, if the ridges normally appear dark against

a light background, they will appear as light ridges against a dark background. In the

interpretation of marks it is important that practitioners are aware of the possibility that these reverse-coloured marks may occur. It is therefore essential that practitioners

possess as much information as possible about the mark, the substrate, the visualisation process used and any changes made to the original images.

There are a number of ways in which reverse-coloured marks can arise, through the: ●● influence of mark and substrate composition; ●● effect of surface contaminants; ●● effect of pressure.

Home Office January 2014

Marks visualised using gold/zinc VMD on (left) an HDPE bag with ridges lighter than

the background and (right) on an LDPE bag with ridges darker than the background.

2.5.15

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence

2.5.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Interpretation: reverse-coloured/developed marks continued

Influence of surface contamination on reverse-coloured marks For some processes, reverse-coloured marks may be generated when the finger removes or partially removes contamination present on the substrate. If the

contaminating substance also interacts with the visualisation process then the regions where the contamination has been removed will interact less strongly than the areas

where the contamination remains. For some processes, such as Superglue Fuming, this

Influence of deposition pressure

Reverse-coloured marks may also occur where the finger (or substrate) is covered with a relatively sticky substance such as blood and the finger is applied to the substrate

with sufficient pressure to drive the substance from the ridges into the furrows. When a

visualisation process is applied, the regions that interact most strongly are those where most material is present, namely the furrows.

will give the reverse situation from that which is normally expected (i.e. the ridges will appear darker than the background instead of more brightly fluorescent). Again, both types of development may occasionally be observed within a single mark which may make interpretation difficult.

Marks on an axe handle, visualised using Acid Violet 17, with blood pushed into

the furrows of the mark by the pressure Marks on a ceramic tile visualised using Superglue Fuming and enhanced using Basic

of contact.

Yellow 40: (left) ‘normally’ visualised mark with ridges brighter than the background,

(centre) reverse-developed mark with ridges darker than the background and (right) mark exhibiting regions of normal (bottom) and reversed (top) development.

Home Office January 2014

2.5.16

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence

2.5.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Interpretation: reverse-direction (mirrored) marks

There are situations where marks may be visualised as a mirror image of their correct

Transferred marks

identifications being missed if the potential for this effect is overlooked. The means by

This transfer may happen if:

orientation e.g. what appears as a left thumb is actually a right thumb. This can result in which marks may be ‘mirrored’ include:

●● transfer of fingermarks from one surface to another;

●● penetration of constituents of the fingermark through substrates so that they are

detected on the opposite surface from where they were deposited, e.g. fine tissue paper;

Fingermarks present on one surface can occasionally be transferred to another surface. ●● adhesive surfaces are in close contact with another surface (porous or non-porous); ●● surfaces are placed in close contact for a prolonged period, possibly at elevated

temperature or pressure;

●● two tacky surfaces come into contact with each other.

●● fingermarks being developed on both sides of a transparent substrate;

all of which may result in ambiguity regarding on which side of a surface marks are present.

Marks visualised using Multi-Metal Deposition on cling film used to form a simulated drugs wrap and then unwrapped

for subsequent processing. Tacky surfaces have come into

contact during the wrapping process resulting in numerous examples of marks that have been transferred to different

regions of the surface prior to development. All marks were

originally deposited within the boundaries of the grid drawn on the cling film. Home Office January 2014

2.5.17

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence

2.5.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence Interpretation: reverse-direction (mirrored) marks continued Transfer of marks has been observed both to and from the adhesive side of tape:

both orientations of any marks visualised on either the adhesive side of the tape or

the substrate itself after tape has been removed from a non-porous surface should be considered for identification purposes.

Mark transfer between (left) tape removed from acetate sheet showing a palm mark

originally deposited on the tape, visualised using Carbon Black Powder Suspension and

(right) the acetate sheet processed using Superglue Fuming and Basic Yellow 40 showing evidence of the palm mark in the reverse direction. Home Office January 2014

2.5.18

2.5.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence Interpretation: distortion of marks

It is important that the fingerprint examiner is made aware of any circumstances that could have resulted in undue distortion of a fingermark. Although automated search algorithms in fingerprint databases will take some distortion into account when

attempting matches between marks and prints, in circumstances where significant

stretching or shrinkage of a mark could have occurred this will be outside those limits and potential identifications could be missed.

Examples where such distortion may occur include where marks have been deposited

on an inflated item such as a balloon which has later deflated, or when marks have been deposited on an item which has softened and flowed or shrunk under the influence

of heat. In these circumstances the visualised mark may appear significantly larger or

smaller than the finger that has deposited it. Such distortion may occur uniformly across the mark or be confined to one dimension. The relative positions of the features within the fingermark will be unchanged, but their spatial relationships may have changed

significantly. An example where heat has caused an item and the fingermarks on it to shrink is illustrated on the right.

If the fingerprint examiner is made aware of the possibility that distortion may have

occurred, it may be possible to take this into account during subsequent comparisons.

A mark deposited on a PET water bottle and exposed to ~120°C for 15 minutes before being visualised using Superglue Fuming. Exposure to

heat has caused the item to shrink, with a corresponding reduction in the

dimensions of the mark. Some impression of the extent of shrinkage can be obtained by reference to the finger that deposited it.

Home Office January 2014

2.5.19

2.5.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Interpretation: enhancement of digitial images It is critical that the identification specialist should be made aware of any adjustments that have been made to the image prior to receipt.

The captured image of a fingermark may in some cases be modified before it is

transferred to an examiner. In most cases the image of the mark is captured in colour and converted to a greyscale image that can be compared to the black and white reference images of fingerprints taken in custody.

In some cases the practitioner may apply some additional enhancement processes to

with the arrangement on a fingerprint form. It may also include other functions such as

‘mirroring’ if the imaging practitioner believes that this is required to present the mark in the correct orientation.

Making the fingermark examiner aware of any adjustments made will enable them to understand what constitute ridges or furrows in the image and any changes to

orientation that may have been made. It may not always be possible to determine

which regions are ridges from a greyscale image and it may be necessary to refer back to a colour image to remove any ambiguity. Other visual clues to prior adjustments

such as the colour balance and orientation of text on scales and labels should also be considered n

the image, post-capture, to convert it to a form with which the identification specialist is more familiar. This may include greyscale inversion (i.e. creating a negative image)

of fluorescent marks to produce black ridges on a light background, to bring it in line

Mark visualised using Superglue Fuming followed by enhancement with Basic Red

14, giving ‘normal development’ with superglue on ridges - (left) colour image, (centre)

colour image converted to greyscale, and (right) negative of greyscale image. The ridges are orange in the colour image, light in the greyscale image, and dark in the inverted greyscale image. Although it is evident in image (left) which regions are the ridges, it

may not be immediately apparent in images (centre) and (right) unless the examiner is

informed how the mark has been visualised and what adjustments have been made to the image post-capture.

Marks visualised using Ninhydrin as (left) colour image and (right) converted to

greyscale for comparison. The ridges are purple in the colour image and dark in the

greyscale image and should be compared to the dark ridges on the fingerprint form.

Home Office January 2014

2.5.20

Fingermark Visualisation Manual

Section 2.5: Using and Understanding Fingermark Evidence

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Contents

Appendices

Glossary

Index

3 Safe and Effective Implementation of the Processes Contents Section 3.1: Requirements for Implementation.... 3.1.1 Section 3.2: Working Safely.................................... 3.2.1 Section 3.3: Working Effectively............................. 3.3.1

Introduction

Section 3.2: Working safely has much more information

visualisation processes safely and effectively requires

need to be considered when establishing and operating

Establishing the capability to carry out fingermark

many factors to be taken into account. The competence

of practitioners to carry out the processes, the efficiency

Advisory Note This chapter looks at the general requirements for the safe application of fingermark development

processes. The advice is based on CAST experiences, its own work environment and use of the fingermark visualisation processes, and is designed to assist

of the operational facility and effectiveness of local

procedures all contribute to optimising the information

that can be obtained from fingermarks. From preliminary handling of items submitted for processing through to

imaging of any marks visualised, effective working will

help to achieve robust evidence and make the process of identification most productive.

the practitioner. However, you are advised to seek

At the same time, providing a safe working environment

and welfare. For information and guidance on how to

in a laboratory or at scenes. Everyone has a legal right

specialist advice in all matters relating to health, safety control risks at work see HSE’s website at http://www. hse.gov.uk/toolbox/index.htm.

is a prime concern and must be achieved when working to remain safe, whether they are directly or indirectly affected by the work of the organisation.

All references to legislation, regulations and standards

This chapter contains advice and guidance to support

of writing. Users must only work from current versions

with health, safety and welfare. It also considers aspects

in this manual apply just to the UK and only at the time of legislation, regulations and standards, including any amendments or whatever has superseded them.

and complement local policies or procedures concerned of working most effectively to obtain optimal results. It is

on the general health, safety and welfare issues that a fingermark development laboratory. It stresses in particular that:

●● a laboratory (or a scene) is a place of work and

employers must therefore meet the requirements of the Health and Safety at Work Act 1974;

●● although the processes have been developed with

possible hazards kept to a minimum, there are risks associated with them and the items on which they

may be used. These must be assessed locally and

mitigated to keep people safe as far as is reasonably practicable.

Section 3.3: Working effectively, covers three particular areas where good practices are required to maximise

fingermark recovery. These are concerned with effective: ●● working in a laboratory environment; ●● handling of items; and

●● imaging of fingermarks.

presented in three sections, the first of which (3.1) gives

Chapter 5 specifies any dedicated equipment that is

the laboratory operation of the processes. The need for

specific processes safely and effectively. It also includes

an overview of what might be needed when establishing competent staff and the provision of a suitable facility,

appropriately furnished with equipment, are emphasised. This section must not be read in isolation, since three

other parts of the Manual contain more information that

needed and provides detailed instructions for carrying out information on the specific hazards associated with

individual processes and possible means of mitigating the risks n

should also be consulted by those planning to implement the processes:

Home Office January 2014

3.0.1

Fingermark Visualisation Manual

Chapter 3: Safe and Effective Implementation of the Processes

3.0.1

CH3

3.1.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents

Training and competence.................................... 3.1.2 Laboratory requirements ....................................... 3.1.3 Planning and organisation................................... 3.1.3 Managing items................................................... 3.1.3 Dedicated areas for optical processes................ 3.1.4 Dedicated areas for chemical, physical and preparation processes......................................... 3.1.6 Installation of ‘fixed’ equipment.......................... 3.1.9 General laboratory equipment........................... 3.1.13 Storage of equipment........................................ 3.1.14 Storage of chemicals, solutions and mixtures... 3.1.15 Scene Use ............................................................. 3.1.16 Scene Use of the processes and treatment of large items......................................................... 3.1.16 References ............................................................ 3.1.18 Chemicals inventory.......................................... 3.1.18

Introduction

This section provides preliminary information on the

requirements for a safe and effective working facility for carrying out the processes by discussing:

●● Training and competence of practitioners,

recognising that some activities will require specialist knowledge;

●● Laboratory requirements with respect to the

laboratory arrangements and equipment;

●● ‘Scene’ use of the processes and treatment

of large items includes the requirements for

situations where it may not be possible to apply the

processes in optimal conditions and where additional considerations need to be taken into account.

It also includes a comprehensive chemical inventory of all chemicals used in Chapter 5. This section should not

be read in isolation, since three other parts of the Manual contain more information that should also be consulted by those planning to implement the processes:

they may be used. There is a legal requirement to

assess all hazards locally and to keep people safe as far as is reasonably practicable.

Useful information can also be found on the HSE website (www.hse.gov.uk).

2. Chapter 5 gives detailed instructions for carrying

out specific processes safely and most effectively and includes information on the specific hazards

associated with individual processes and possible means of mitigating the risks.

3. Section 3.3: Working effectively covers three

particular areas where good practices are required to maximise fingermark recovery. These are:

●● Effective working in a laboratory environment,

including use of chemicals and solution preparation;

●● Effective handling of items for fingermark recovery;

and

●● Effective fingermark imaging.

1. Section 3.2: Working safely has much more

information on the general health, safety and welfare

issues that need to be considered when establishing and operating a fingermark development laboratory. In particular:

●● it must be remembered that the laboratory (or a

scene) is a place of work and therefore must meet the requirements of the Health and Safety at Work Act 1974;

●● although the processes have been developed with

possible hazards kept to a minimum, there are risks

associated with their use and from the items on which Home Office January 2014

3.1.1

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

3.1.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Training and competence

The Manual refers throughout to the competence of

practitioners. It is not within the remit of the Manual to

forensic recovery. For instance, good record keeping is

●● legislation, regulations and standards applicable to the

results is not included.

●● health and safety requirements to comply with current

encouraged, but the interpretation and presentation of

explain how that competence is achieved, since there

A fundamental requirement for all those working with the

working with fingermark evidence recovery will be judged.

safety and welfare issues that affect them and others

will be local and national standards by which individuals

The ISO 17025 standard is now applicable in the UK to all providers of fingermark recovery services (in addition to other forensic disciplines). Competence of practitioners is an important element of the requirements for

accreditation to the standard, as well as the competence

processes will be a thorough understanding of the health,

authorising certain activities. The Manual provides

guidance only and indicates where to find up-to-date information where appropriate.

which in the UK is the United Kingdom Accreditation

to managing waste. Local procedures must ensure that

Manual has been written with the ISO 17025 standard in

mind in certain areas, it is not an ‘ISO 17025 Manual’. For

instance, the process instructions in Chapter 5 have been written in such a way as to help create local procedures for carrying out the processes, but do not replace the

need for local procedures. Procedures for carrying out the processes will need to be written according to the

way they are used locally, after confirming that they are effective.

Nor is the interpretation of the ISO 17025 for forensic applications within the remit of this Manual. The

authors, although extensively supported by practitioners in creating the Manual, are not directly involved in

operational forensic recovery. It would be inappropriate

to include more than the current level of detail that relates to the recovery of fingermark evidence in the context of

Home Office January 2014

sources, e.g. a Laser Safety Officer.

needs to be taken locally for training, auditing and

There will be many laboratory activities which require a

Service (UKAS). It should be noted that although the

legislation;

●● safety requirements for the use of high-intensity light

when carrying out fingermark recovery. Responsibility

of the organisation and its technical capability. Each of

these will be assessed by the national accreditation body,

organisation;

level of competence, ranging from ordering chemicals

practitioners receive adequate training for the tasks they will undertake and that their training needs are reviewed periodically to confirm their ongoing competence and recognise any needs for further training.

The levels of training needed to carry out the processes will vary considerably. Many of the processes are

uncomplicated, while others require more experience before they can be fully effective. Those responsible

for training staff will need to account for the different

levels of training and experience needed to ensure the

competence of staff carrying them out. It is anticipated that familiarity with the information in the Manual will assist in the training of those involved in fingermark

recovery and will support local training programmes. Specialists will almost certainly be required for some key activities that relate to health, safety and welfare. These will include those with in-depth knowledge of:

3.1.2

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

3.1.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Planning and organisation

It is not possible to be prescriptive about the way the

laboratory is planned and organised, since the needs of each will be different. The facility will need to be based on the space available and the anticipated tasks of the laboratory.

Section 3.2 discusses in some detail both the need for legal compliance and the general requirements for

setting up and maintaining a safe laboratory facility, with respect to:

●● health, safety and welfare;

●● regulatory and practical requirements;

●● providing suitable services and utilities; ●● laboratory ventilation;

●● workflow and housekeeping.

This section is concerned with two main elements of planning and organising a fingermark development laboratory for:

1. managing items submitted for fingermark evidence recovery, including space for:

■■

storing and handling items;

2. carrying out the processes, in particular, ●● dividing the space to provide: ■■ ■■

dedicated areas for the optical processes;

‘wet’ and ‘dry’ areas for the chemical, physical and preparation processes;

●● installing fixed equipment to carry out the processes

safely and effectively;

●● making available appropriate general equipment,

including measuring equipment;

Home Office January 2014

●● providing suitable storage for equipment; and

●● providing suitable storage for chemicals, solutions and

mixtures.

Managing items

Glossary

Index

Laboratory requirements for unpacking items to avoid contamination and crosscontamination before processing.

Further information can be found in handling items.

Storage

Once booked in, items submitted to the laboratory will usually need to be stored at various stages: ●● before processing;

●● between processes, if submitted for sequential

Picture of an exhibit store - shot from main lab area.

processing; and

●● awaiting disposal, possibly requiring long-term

storage.

In order to preserve fingermark evidence on items

submitted, a general storage area conveniently close to

the laboratory and maintained at ambient temperature is

ideal. If the store is too cool, condensation may appear on some items and if too warm, fingermarks may deteriorate. Low-level extraction of the storage area is recommended. This will prevent the build-up of nuisance vapours from

items that are contaminated with organic solvents, such

Clear area for unpacking items.

as petrol or paraffin or those that have been treated with Ninhydrin or Superglue Fuming, for example.

Items known to be contaminated with biological hazards will also need to be stored appropriately: this may require specialist containment.

A lockable store may be needed for valuable items, e.g.

currency, or for potentially hazardous items, e.g. firearms.

Handling

A suitable dry area(s) of the laboratory should be assigned

3.1.3

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Dedicated areas for optical processes

Glossary

Laboratory requirements Optical process

General examination room or area

Fluorescence examination room

General examination area or room

Colour Filtration

✓✓

✓✓

examination area or room for examining, marking up or

Fluorescence Examination

x

✓✓

IR Reflection

✓✓

✓✓

Monochromatic Illumination

✓✓

✓✓

General examination area with a tilting bench.

Multi-Spectral Imaging

x*

✓✓

sources, a semi-enclosed viewing/imaging system

Fluorescence examination room

UVC Reflection

✓✓

✓✓

equipment;

to provide a fluorescence examination room so that

Visual Examination

✓✓

✓✓

Many optical processes can be used in a general

imaging visible fingermarks before processing or those

visualised after processing with Ninhydrin or Powders, for example.

The area must: ●● be sufficiently large to accommodate a range of light

(if used), an area for open-beam work and ancillary ●● have suitable imaging equipment to record visualised

fingermarks;

●● have a means of excluding direct sunlight, e.g. blinds

fitted at the windows.

The area should: ●● have sufficient electricity sockets.

Examination benching should: be ergonomically designed to facilitate the examination

If high-intensity light sources are to be used it is essential

Index

the process can be used safely and effectively. This

* Multi-Spectral Imaging can be used in the general

affected by stray light or any of the optical processes

mode, it must be used in the fluorescence examination

room can also be used for optical processes that are

(indicated by a red tick in the table on the right), even

though the specification of the facility may far exceed

their requirements. Strict safety measures are needed for

examination room. However, if it is used in fluorescence room and it may be more appropriate to install the equipment there.

using high-intensity light sources which would restrict the simultaneous use of the room for less hazardous processes.

and imaging processes, e.g. tilting benches may be useful.

Home Office January 2014

3.1.4

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

From a safety perspective:

The examination room should:

case of emergency.

●● have walls, fixtures and fittings that are dark and non-

Access to the examination room must:

that the risk of exposure to high-intensity light and

interruptions to the examiner are minimised. Suitable

reflecting;

An illuminated sign indicating when the light is in use. A clean and tidy laboratory.

the type of examination or item being examined;

during Fluorescence Examination); non-fluorescent

a suitable notice to prevent unnecessary

disposable bench covering may be used and replaced

interruptions;

when necessary to aid this.

a buzzer to alert the operator if anyone wishes to

Examination benching should:

enter.

●● be ergonomically designed to aid the user in carrying

The examination room must:

out examinations and imaging of items, e.g. tilting

●● have sufficient ventilation to cope with the heat

produced by some light sources and ozone produced by some ultraviolet radiation sources;

●● be kept clean and tidy - working in the dark poses

additional risk of tripping if unfamiliar obstacles are in the way.

The examination room should:

●● be separate from other areas;

●● have a remote control for room lighting;

●● if possible, have electrical interlocks between the light

source and all doors into the room for open beam

mode work; light emission must stop when any door is opened, and not automatically start on door closure. Home Office January 2014

maintained.

●● be kept clean (visually and under lighting used

in use;

■■

light is essential and dark adaptation needs to be

●● be as non-fluorescent as possible, depending upon

an illuminated sign, normally outside the room and

above the door to indicate when the light source is ■■

●● have dull red background lighting for use when some

Examination benching must:

controls may include one or more of the following: ■■

Laboratory requirements visualised fingermarks.

rapid evacuation is needed or if others need to enter in

●● be restricted during fluorescence examination so

Index

●● have suitable imaging equipment to record any

During an examination doors must not be locked in case

●● be limited to authorised personnel;

Glossary

benches may be useful. From an effectiveness perspective:

An example of an effective fluorescence examination room.

The examination room must:

●● be capable of being blacked out easily; if the room

has windows they must be blacked out using suitable means, such as black-out blinds; open beam mode

work should be carried out in near total darkness for maximum effectiveness;

●● be large enough to accommodate a range of light

sources, semi-enclosed viewing/imaging systems (if

used), an area for open beam mode work and ancillary equipment;

3.1.5

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory requirements

Dedicated areas for chemical, physical and preparation processes The Manual cannot be prescriptive about the way laboratory space is allocated for carrying out the

chemical, physical and preparation processes. Space

may be dedicated to housing equipment for particular

processes but for many of the processes general working areas are suitable, loosely designated as ‘wet’ and ‘dry’ areas. Many processes need a supply of water, others An example of an effective fluorescence examination

need to be kept dry, while some may be carried out where it is most appropriate, in either ‘wet’ or ‘dry’ areas of the

Treatment areas for larger items such as vehicles will

Both examination areas may require the installation of

‘Wet’ areas

effective application of processes.

hazardous or are giving off nuisance dust or fumes.

of processes, either for the operation of equipment,

Some processes, such as ESDA, Powders or Lifting

room.

a down-draught bench for examining items which are

‘Wet’ area used for drying items after treatment with Superglue Fluorescent Dye Staining.

laboratory.

need to be appropriately specified to permit the safe and

Water and suitable drainage is needed by a number

‘Dry’ areas

e.g. Ninhydrin and VMD, or for rinsing of items after

will need to protected from getting wet and should be

processing, e.g. Powder Suspensions or Acid Dyes.

Some will also require the use of fume cupboards, which

conducted in ‘dry’ areas of the laboratory.

must also be provided with suitable water supply and drainage.

If space is available, separate ‘wet’ areas may be

provided, within or outside the general laboratory area. Laboratory wet areas may be fitted with a wet bench

for processing items. They may also be used for drying items, in which case they should have: ●● hanging rails to suspend items;

●● drip trays to collect residual water or solutions; ●● good ventilation;

●● sufficient capacity to manage throughput demand.

Home Office January 2014

3.1.6

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Process

The table gives an overview of the requirements for

these processes. More information follows, but Chapter

Index

Laboratory requirements

Use in wet area

Use in dry area

5 process instructions should be consulted for full information.

Glossary

Use of ‘fixed’ equipment

Use of fume cupboard

Prep

App

Acid Dyes

✓✓

✓✓

✓✓

Basic Violet 3

✓✓

✓✓

✓✓

most require only general laboratory equipment, those

DFO

✓✓

✓✓

✓✓

✓✓

ESDA

✓✓

processes need access to a fume cupboard either for

Lifting

✓✓ ✓✓

✓✓

✓✓

✓✓

✓✓

✓✓

✓✓

The table identifies whether the processes need to be

carried out in ‘wet’ or ‘dry’ areas of the laboratory. While requiring special fixed equipment are identified. Many

solution preparation (Prep) or application (App). Those

indicated with a ‘red-tick’ are normally used in ‘wet’ areas although this is not essential but normally more practical.

Multi-Metal Deposition

✓✓

Ninhydrin

✓✓

Physical Developer

✓✓

Physical Developer Enhancement

✓✓ ✓✓

Powders

✓✓

Powder Suspensions

✓✓

Small Particle Reagent

✓✓

Solvent Black 3

✓✓

Superglue Fuming

✓✓

✓✓

Superglue Fluorescent Dye Staining

✓✓

✓✓ ✓✓

Vacuum Metal Deposition PREPARATION PROCESSES Thermal Coating Removal

✓✓

Adhesive Tape Removal

✓✓

Numberplate Splitting

✓✓

Soot Removal

✓✓

✓✓

Note: This table gives an indication only. Read the appropriate process instruction in Chapter 5 for full guidance.

Home Office January 2014

3.1.7

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Equipment for ‘wet’ areas

The ‘wet’ areas of the laboratory will generally contain the following ‘fixed’ equipment. Equipment

Additional requirement LEV*

DFO oven

LEV* External extraction hood

DFO

Ninhydrin oven

LEV* External extraction hood

Ninhydrin

Various

Superglue fuming cabinet LEV*

Superglue Fuming

Wet bench (with integral dyeing facility)

LEV*

Superglue Fluorescent Dye Staining

Vacuum metal deposition chamber**

Ancillary equipment

VMD

Water purification system Laboratory glassware washer

Index

Laboratory requirements

Equipment for ‘dry’ areas

The ‘dry’ areas of the laboratory will generally contain the following ‘fixed’ equipment.

For processes

Fume cupboards, plus possible walk-in fume cupboard

Glossary

Equipment ESDA

Additional requirement LEV*

Imaging systems, e.g. gel lift scanner, VSC

For processes ESDA Various, including Lifting

Powdering cabinet

LEV*

Powders

Down-draught bench

LEV*

Various

Equipment storage

General laboratory equipment

N/A

Chemicals storage

External storage area

N/A

* LEV: Local exhaust ventilation is needed for some equipment to remove the hazardous or nuisance fumes or dust. Since a number of pieces of equipment need LEV, careful balancing of air make-up will be needed to provide suitable laboratory ventilation.

Various Supply of purified water

N/A

Sinks with suitable water supply

Various

Hand wash basin

N/A

Eye wash stations

Suitable water supply

N/A

Drench shower

Suitable drainage

N/A

* LEV: Local exhaust ventilation is needed for some equipment to remove the

hazardous or nuisance fumes or dust. Since a number of pieces of equipment need LEV, careful balancing of air make-up will be needed to provide suitable laboratory ventilation.

** Vacuum metal deposition chambers are normally located dedicated areas, because of their particular installation requirements.

Home Office January 2014

3.1.8

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory requirements

Installation of ‘fixed’ equipment

on any exit route: materials handled within the confines

fixed equipment which may need to be installed in the

and any risk of accidental mishandling or spillage near an

The information below identifies various pieces of

of a fume cupboard are generally the most hazardous

laboratory. It is included here to highlight some of the

emergency exit route needs to be minimised.

issues relating to the appropriate siting of equipment in

Also, equipment needed for processing items that have

the laboratory to meet regulatory, safety and practical

had initial treatment in the fume cupboard should be

requirements. This information may need to be

sited nearby with any doors opening away from the fume

considered at the time the equipment is commissioned

cupboard to facilitate easy transfer of items from one to

or during its service and is provided to supplement

the other.

manufacturers’ information.

The specification for the equipment needed to

implement individual processes most effectively in

laboratory environments can be found in the Equipment

Correctly sited and installed ‘standard’ fume cupboard. Walk-in fume cupboard.

section of Chapter 5 (with the exception of fume

Another consideration will be the balancing of air flow

Fume cupboards provide a means of local exhaust

in the laboratory when all equipment ventilating to the

ventilation (LEV) which fully extracts hazardous materials

outside is working at capacity. Specialist assistance will

to the exterior of the laboratory. They are needed for the

almost certainly be required to ensure correct installation

safe laboratory handling of the chemicals, solutions and

and commissioning of this equipment and is essential for

mixtures for a number of the processes. Information on

ongoing routine servicing and maintenance.

their selection, installation and use follows.

Fume cupboards should be considered only as partial

The specification of fume cupboards selected for the

containment devices when carrying out risk assessments

laboratory must be suitable to manage the hazards

and additional control measures may be needed if there

associated with their intended use and may be chosen

is any possibility of leakage of hazardous material into the

health and safety regulations and British and European

As well as the legal requirements for the positioning of

installation, positioning and performance, intended

aspects that also need to be taken into account. For

Home Office January 2014

enclosure, bearing in mind that the positioning of air inlets

level drainage.

Fume cupboards

purpose and maintenance.

including ducting, fan-casing etc. and not just the

‘Walk-in’fume cupboards may require very low or floor-

needed for many of the processes and covered fully here).

standards, with respect to their design, manufacture,

encompass the physical integrity of the whole system,

and discharge outlets is also controlled by legislation.

cupboards, which are general pieces of equipment

from ‘standard’ or ‘walk-in’ types. They must comply with

Installation of the fume cupboard selected must

working environment.

fume cupboards, there are a number of practical safety

There are some general principles for the use of fume

example, fume cupboards should not be located near or

effective and provide the necessary protection.

cupboards that must be followed for them to be fully

3.1.9

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory requirements development oven to remove acidifed water vapour

expelled when the door is opened; the hood should be as wide as the oven and extend out further than the door in the open position, as shown, to be fully effective.

(left) Correct use and (centre and right) incorrect use of a fume cupboard. ●● No work should be carried out in a cupboard that is

DFO and Ninhydrin development ovens

●● Before the fume cupboard is used it should be tested

items during their treatment with DFO or Ninhydrin.

not approved for use.

to check that it is extracting and that the flow rate

indicator, low flow alarm and light are all functional.

●● Under no circumstances should a process require a

practitioner to position their head inside the cupboard enclosure at any time whilst hazardous substances are present.

●● Chemicals and equipment should not be stored

permanently within the fume cupboard.

●● Only items used for the current process should be

placed within the fume cupboard.

●● Avoid using large pieces of equipment inside the

fume cupboard. Most fume cupboard manufacturers suggest a 100-150 mm equipment-free zone behind the sash.

●● The sash should never be above the maximum

safe opening height when the fume cupboard is operational.

●● The sash should be at the lowest convenient level

when carrying out hazardous processes.

Home Office January 2014

These are used to provide heat or heat and humidity to Development ovens must be installed correctly including: ●● oven outlets coupled with a continuous upward

slope to a negative pressure, low-level, local

exhaust ventilation (LEV) system which provides

the extraction rate needed to meet the specification for the equipment - this extraction reduces the level

of fumes building up during the heating of items and

limits the exposure of practitioners to fumes when the door is opened;

●● an extraction pipe made of a material that is resistant

to the outlet acetic acid vapour at high temperature which may reach 80˚C for Ninhydrin;

●● a drainage pipe, also resistant to acetic acid, to

remove condensate, which must be connected with a continuous downward slope to a suitable outlet, such as an open drain.

In addition, there should be:

●● an extraction hood fitted above and in front of the

(top) Ninhydrin oven to show the air inlet (which has

adjustable vents to control the necessary air flow through the oven) and the upward sloping outlet to the LEV.

(bottom) Correct positioning of an extraction hood for DFO and Ninhydrin ovens.

3.1.10

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Superglue Fuming cabinet

Wet bench, with integral dyeing facility

first is to provide a safe means of using the process by

proving more versatile than smaller laboratory sinks for

The Superglue Fuming cabinet has two purposes. The

containing and then purging the fumes developed during

the heating of the superglue. The second is to develop an effective environment in which the superglue fumes can develop and visualise fingermarks.

The cabinet is often installed in the ‘wet’ area of the

laboratory but it is more important to ensure it can be

installed in a position where temperature variation across the cabinet can be minimised. The position relative to

windows or radiators must therefore be considered when selecting a suitable location.

Many cabinets have an internal filtration system for

purging the fumes when processing is complete but

others will require a local exhaust ventilation system

to extract the fumes to the exterior. In the latter case,

A wet bench may be useful for a number of processes, handling some items.

A wet bench with an integral dyeing facility may be used to carry out the Superglue Fluorescent Dye

Staining process. If an ethanol dye formulation is used a

flammability hazard will be introduced unless the vapour

Laboratory requirements An extraction hood must:

●● be installed if assessments of the LEL indicate that the

provision of local exhaust ventilation, located behind the tank to draw vapours away from the practitioner, is not sufficient to reduce the ethanol vapour to a concentration below the flammability limits;

●● be positioned at a height above the bench to allow

enough space to work.

The dye tank can be filled with a suitable dye solution

flammable liquids.

recommendation for repeat use of working solutions

the methods indicated below. Also see working with A wet bench with integral dyeing facility should:

●● be made from a chemical-resistant material of suitable

thickness and suitably sealed to prevent leaks;

●● contain a dye tank fitted with a drain to facilitate

and topped up when required. This opposes the general (using chemicals).

A typical wet-bench (top) and (bottom) an intergrated dye tank with floating spheres.

disposal of contaminated dye and for cleaning purposes;

●● have a catch tank large enough to collect all the dye

positions for the equipment.

●● contain a dye tank designed so that wide and tall

A correctly positioned Superglue Fuming cabinet.

Index

is kept below the lower explosive limit (LEL), using

appropriate ducting to meet appropriate legislation will be needed and may further compromise the possible

Glossary

from a ruptured dye tank;

items can be easily treated - an L-shaped dye tank

may be suitable as larger items can be treated (and minimising the quantity of stored ethanol, if used);

●● contain a dye tank covered by a lid when not in use to

reduce evaporation of ethanol and build-up of highly

flammable vapours in the laboratory; the evaporation

of ethanol can be further reduced by use of a floating bath lid or floating spheres;

●● incorporate a similar wash tank with water inlet and

outlet valves so that the flow of water is sufficient to remove excess dye; alternatively a hose or shower head can be used to rinse items.

Home Office January 2014

3.1.11

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory requirements

Vacuum Metal Deposition equipment

Laboratory glassware washer

vacuum chamber.

other equipment by hand is to use a glassware washer

Vacuum Metal Deposition (VMD) is carried out in a

The alternative to washing general glassware and

designed for laboratory use. This should be connected

The equipment for VMD is expensive and its installation

to a supply of purified water for the final rinse. For correct

requires a number of specific considerations. The system

installation it may need one phase of a three phase

will require:

electricity supply to supply the heater unit.

●● an access point large enough to take the vacuum

chamber into position in the laboratory;

These washers are specialist equipment: they should

●● a three-phase power supply;

●● a suitable water supply and drainage for the cooling

include features such as a number of different washing

system of the equipment;

A Vaccum Metal Deposition Chamber.

atmosphere;

It may be preferable to site the roughing pumps externally

damped to manage the considerable weight of the

building where the chamber is housed.

●● an exhaust system from the roughing pumps to the ●● a strengthened or reinforced floor, possibly vibration-

system and the noise created during its operation;

●● a good maintenance programme and regular servicing

to keep it in good running order.

Roughing pump located in a purpose built out-building.

to keep noise levels at an acceptable level inside the

regimes, chemical-resistant surfaces and spindle racks

and baskets for securing delicate items. They need to be well maintained to keep them in good working order and topped up regularly with consumables. A typical laboratory glassware washer.

Water purification system

In addition to tap water, the processes require a source of purified water: this may be provided by a number of methods, alone or in combination, such as distillation,

reverse osmosis or deionisation. In addition to needing purified water for making up solutions and mixtures,

laboratory glassware washers will normally need purified water for the final rinse.

If purified water is required at any stage of any of the processes, this is clearly stated within the process

instructions in Chapter 5. If tap water is adequate this is also made clear.

Home Office January 2014

3.1.12

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory requirements

Powdering cabinet

Down-draught benches

General laboratory equipment

and no suitably ventilated area is available, a filtered,

odours and fumes which are below the Workplace

stock a range of appropriately sized beakers, measuring

If there is a requirement to powder items in the laboratory reverse laminar flow cabinet should be used. The

resultant filtered air may be recirculated back into the

laboratory or extracted to the exterior of the laboratory.

An airflow monitor should be used to indicate when filters need to be replaced.

A typical laboratory powdering cabinet.

These are designed to protect users from nuisance Exposure Limits (see classification of chemical hazards).

Items received into the laboratory or after some

treatments, such as Acid Dyes, Basic Violet 3 or

Superglue Fuming, may emit fumes, dust or odours which

cylinders and bottles that are typically made from sodalime glass, borosilicate glass or one of many types of plastic. Other useful items include stirring rods and

plates, dishes and Petri dishes, plastic bottles, tissue and plasticineTM.

may be harmful or cause discomfort to those handling

Soda-lime glassware is generally suitable for transporting,

draught bench with a local exhaust ventilated system

crack when subjected to rapid temperature changes.

them. These items should be examined on a down-

which will draw air and the nuisance materials away from the practitioner. The contaminated air may be extracted or filtered appropriately.

A typical down-draught bench.

Home Office January 2014

A fingermark development laboratory will generally

mixing and storing chemicals but on heating it can Borosilicate glass, sometimes referred to by its

commercial names such as Duran® or Pyrex®, is more

resistant than soda-lime glassware to rapid temperature An assortment of general laboratory equipment.

3.1.13

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

changes and to chemical attack. Also, being harder it

Storage of equipment

solutions and mixtures, plastic-coated borosilicate glass

desirable but essential for fragile equipment that may be

is more scratch-resistant. For most prepared chemical bottles are ideal for storage.

Plastics vary in chemical and heat resilience depending

on the resin used to manufacture the item. It is important that the plastic selected is appropriate for its intended purpose.

Glossary

Index

Laboratory requirements

Having suitable storage space for all equipment is

damaged if not housed appropriately, e.g. if light guides are damaged their effectiveness can be significantly reduced.

If frequently used equipment has to be housed on a

bench, adequate space must be left around it for access.

When using general laboratory equipment it is important to select the correct size of container, especially when making up solutions to avoid spills.

Measuring equipment Measuring cylinders

Unless otherwise stated in the process instructions, measuring cylinders conforming to the standards

‘ISO 4788’ (for glass) and ‘ISO 6706’ (for plastic) are

Damage to light guides stored inappropriately may reduce

sufficiently accurate for measuring liquids required for the

the power output from light sources significantly.

processes.

Viscous solutions may be more accurately measured by weight than volume.

See measuring cylinders for more information.

An organised storage area for general laboratory equipment.

Mass balances

Where equipment

0.01 g (two decimal places) will generally be suitable for

situ, such as gel-

A balance with a capacity of 100 g and a resolution of preparing the Process solutions.

However, capacity and resolution requirements will depend on the mass of chemical chosen for the

preparation of specific quantities of solutions or mixtures. See mass balances for more information. Home Office January 2014

needs to be used in scanning equipment on a bench top, it is important to leave

workspace alongside if possible and not to store items on it.

3.1.14

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Storage of chemicals, solutions and mixtures The reference documents at the end of this section

contains an inventory of the chemicals required for the processes. It is important that the correct chemicals are

Flammable chemicals (liquids)

Oxidising chemicals (solids)

Toxic chemicals (solids)

Iron (III) nitrate nonahydrate

Basic Violet 3

Section 3.2 gives the general requirements for the safe

Acetone

Silver nitrate

Phenol

the rules that need to be applied for the segregation of

Ethanol

incompatible substances.

Butanone Ethyl acetate

Chemicals, solutions and mixtures for the processes will

Methanol

●● area(s) for the storage of compatible substances;

1-Methoxy-2propanol

require:

●● segregated storage area(s) for incompatible materials,

including: ■■

a fire-resistant cabinet for containers of flammable liquids which comply with the appropriate

■■

■■

solutions can be found in Chapter 5, which may be used to assist in deciding on suitable storage arrangements.

An external store may be needed for larger quantities of

which must be kept locked and with controlled

of quantities of ethanol if the permitted storage quantities

access to the key;

a separate store for acids.

A typical external store.

Guidance on the hazards associated with the process

regulations and standards;

a robust storage cabinet for toxic chemicals,

Laboratory requirements

chemicals need to be segregated.

Acetic acid

storage of chemicals, solutions and mixtures, including

Index

The table below indicates how some of the process

ordered and used: further information can be found in the Chapter 5 process instruction.

Glossary

chemicals. This may be especially relevant for the storage for the laboratory have been exceeded.

See safe quantities of stored chemical, solutions and mixtures for further information.

Home Office January 2014

3.1.15

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Scene use of the processes and treatment of large items

The processes have been developed so that they may

be carried out with no known hazards to health provided practitioners are trained and competent, if appropriate

control measures are in place and carried out in suitable laboratory facilities as described in this Manual.

In providing the processing instructions, it has been

assumed that the processes will be used in the majority

of situations in a laboratory environment, where the safety of practitioners and the conditions for processing can be

closely controlled. Transferring the processes to a scene poses a number of additional considerations which may give rise to concerns regarding the:

●● health and safety of all those involved, directly or

indirectly;

●● effectiveness of the process; and

●● practicalities of applying the process in the particular

environment.

bathroom.

the hazards identified must be subject to dynamic risk

of large items that cannot be handled according to

be considered include:

carried out ‘as described in this Manual’. The treatment the process instruction will also require additional considerations to be taken into account.

Chapter 5 includes some additional considerations for the scene use of all the processes, which will assist in

deciding whether scene use is possible or of value and

to highlight particular health and safety concerns. These should also be considered in any situation, such as the

treatment of large items in the laboratory, where optimal processing conditions cannot be provided. Chapter 2

contains useful information to aid planning scene versus laboratory treatment of items from the perspective of maximising fingermark evidence recovery.

In every situation where fingermark visualisation

processes are used, there is a requirement to provide a safe working environment. However, every situation will be different and someone with the necessary

the specific hazards associated with the local use of the process(es) and put measures in place to keep people safe as far as is ‘reasonably practicable’.

Section 3.2 contains general information about the

classification of the types of biological, physical and chemical hazards that are likely to be encountered

when recovering fingermark evidence and the need for comprehensive risk assessment. However, when the processes are used at scenes or outside the optimal

control offered by the laboratory there will be many more issues that need to be considered. In every case, all Home Office January 2014

Scene Use

Similar concerns will arise when a process cannot be

competence, responsibility and authority must assess A scene examiner working in the confined space of a

Index

assessments. Some of the additional points that need to ●● the environment, area or situation in which the work is

undertaken. For example, a scene may pose a variety of issues if practitioners have to work in potentially

dangerous situations, such as drugs manufacturing laboratories or arson scenes; practitioners may

need to work in confined spaces where handling of chemicals becomes more difficult and more

hazardous and where additional regulations apply;

●● the additional risks of manual handling of equipment

and materials to the scene;

●● the complex regulations that apply independently

to both the transport and labelling of hazardous

chemicals for carriage by road; taking chemicals to

scenes while complying with both sets of regulations may prove impractical;

●● the possible short- and long-term risks of using the

processes where the public may also be involved and scene clean-up may be incomplete - the risk

assessment must include aspects of the health, safety and welfare of all concerned, including members of the public.

There are a number of possible outcomes of the risk assessment.

●● The risks associated with working at a scene may be

controlled with no compromise to health or safety

and no loss of process effectiveness. Improved results may even be achieved in some cases if processes are applied at the scene rather than taking items

back to the laboratory. This is generally the case for

3.1.16

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Glossary

3.1.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Scene Use

Powdering, as fingermarks may be visualised more effectively with this process when they are fresh.

●● The risks cannot be controlled to a ‘reasonably

practicable’ level and the processes must not be

used. For instance, the use of Basic Violet 3 at scenes needs to be very carefully assessed for the possibility of leaving residual hazardous material. Safer alternatives may need to be found.

●● In other cases, the effectiveness of the process may

be so compromised for a number of reasons, such

as the need for particularly stringent safety measures, or factors associated with the case or the scene,

that using the process would offer no advantage and alternative approaches will need to be taken.

Home Office January 2014

3.1.17

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.1.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

References

Chemical inventory Common Name

Alternative Name(s)

CAS number

Grade required

Process

Common Name

Alternative Name(s)

CAS number

Grade required

Process

Acetic acid

Ethanoic acid

64-19-7

Analytical ≥ 99.7%

DFO, Ninhydrin

Citric acid anhydrous

77-92-9

Analytical

Acetic acid

Ethanoic acid

64-19-7

Laboratory

Acid Dyes

2-hydroxypropane-1,2,3 tricarboxylic acid

Acetone

Propanone

67-64-1

Analytical

Thermal Coating Removal

MMD, Physical Developer, Physical Developer Enhancement

DFO

1,8-Diazafluoren-9one

54078-29-4

Analytical

DFO

DOSS

Dioctyl sulfosuccinate, sodium salt; DSS; Aerosol OT™, AOT™

577-11-7

≥ 96% (or appropriate concentration solution)

BV3, SPR

Acid Black 1 (AB1)

CI 20470; Amido Black 10B; Naphthol Blue Black; Naphthalene Black 12B

1064-48-8

≥ 80 %

Acid Dyes

Acid Violet 17 (AV17)

CI 42650; Coomassie Brilliant Violet R150

4129-84-4

≥ 50 %

Acid Dyes

n-Dodecylamine acetate

Laurylamine acetate

2016-56-0

As supplied by CAST

Physical Developer

Acid Yellow 7 (AY7)

CI 56205; Brilliant Sulphoflavin

2391-30-2

≥ 50 %

Acid Dyes

Ethanol

Ethyl alcohol

64-17-5

≥ 96 %

Ammonium iron (II) sulphate hexahydrate

Ferrous ammonium sulphate, Ammonium iron sulphate

7783-85-9

Analytical

MMD, Physical Developer, Physical Developer Enhancement

Acid Dyes, Superglue Fluorescent Dye Staining

Ethanol

Ethyl alcohol

64-17-5

Analytical

BV3, Ninhydrin

Ethyl acetate

Ethyl ethanoate

141-78-6

Analytical

Ninhydrin

Ethylene glycol

Ethane-1,2-diol

107-21-1

> 99 %

Powder Suspension

Gold

Gold wire

7440-57-5

99.9 %

VMD

Gold (III) chloride hydrate

Tetrachloroauric acid

27988-77-8

Analytical

MMD

Basic Red 14 (BR14)

Yoracryl Red 4G

12217-48-0

> 50 %

Superglue Fluorescent Dye Staining

Basic Violet 3 (BV3)

CI 42555; Crystal Violet; Methyl Violet 10B

548-62-9

≥ 85 %

BV3

Basic Yellow 40 (BY40)

There are many alternative names

29556-33-0 Basic Yellow 40 refers to several dyes with different CAS numbers. Alternatives are structurally similar and may be indistinguishable, in terms of mark enhancement, from the one given.

> 80 %

Superglue Fluorescent Dye Staining

Home Office January 2014

≥ 99.7%

3.1.18

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Glossary

3.1.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

References

Chemical inventory continued Grade required

Process

Common Name

Altenative Name(s)

CAS number

Grade required

Process

Methyl nonafluorobutyl HFE7100 is ether, 1 Methoxy only available nonafluorobutane as a mixture of two isomers. The isomers are inseparable but have essentially identical properties. Each isomer has its own CAS number (163702-08-7 and 163702-07-6). The isomeric mixture within HFE7100 does not have its own unique CAS number.

As supplied

DFO, Ninhydrin

Molybdenum disulphide

MoS2

1317-33-5

Superfine powder, average particle size approx. 1.5µm

SPR

Ninhydrin

2,2-Dihydroxy-1,3indandione; 1,2,3-indantrione

485-47-2

Analytical

Ninhydrin

Nitrogen, liquid

-

7727-37-9

Standard

Numberplate Splitting

PGME

Propylene Glycol Monomethyl Ether; 1-Methoxy-2-propanol

107-98-2

≥ 99.5 %

SB3

Phenol

Carbolic acid

108-95-2

Laboratory

BV3

50% 1-Methoxynonafluorobutane 50% trans-1,2 Dichloroethylene (Azeotropic mixture)

163702-08-7, 163702-07-6 and 156-60-5 (DFO)

As supplied

Photo-Flo

-

Multiple

Made by Kodak. Use as supplied.

Superglue Fluorescent Dye Staining

KBr

7758-02-3

Laboratory

Iron (III) nitrate nonahydrate

Ferric nitrate nonahydrate; iron nitrate; ferric nitrate

7782-61-8

Potassium Bromide

Physical Developer Enhancement

Potassium Ferricyanide

Potassium hexacyanoferrate (III), Prussian Red

13746-66-2

Analytical

Physical Developer Enhancement

Iron (II/III) oxide

Iron Oxide (FeO. Fe2O3), Magnetite, Pigment black 11 (CI 77499)

1317-61-9

Potassium Iodide

KI

7681-11-0

Laboratory

Physical Developer Enhancement

Silver

Silver wire

7440-22-4

99.9 %

VMD

Silver nitrate

Silver (I) nitrate

7761-88-8

Laboratory

MMD, Physical Developer

Sodium citrate tribasic dihydrate

Sodium citrate

6132-04-3

Analytical

MMD

Common Name

Alternative Name(s)

HFE7100

HFE71DE

CAS number

Analytical

DFO

MMD, Physical Developer, Physical Developer Enhancement

Precipitated (synthetic), magnetic, particle size: 200nm 1μm.

Powder Suspension

Maleic acid

Cis-butenedioic acid; Malenic acid; Toxilic acid

110-16-7

Laboratory

Physical Developer

Methanol

Methyl alcohol

67-56-1

Analytical ≥ 99.7%

DFO

Home Office January 2014

3.1.19

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Glossary

3.1.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

References

Chemical inventory continued Common Name

Alternative Name(s)

CAS number

Grade required

Process

Sodium Hydroxide

Caustic soda

1310-73-2

Reagent grade

Physical Developer Enhancement, Soot Removal

Sodium Hypochlorite

Bleach

7681-52-9

10-15% Available chlorine

Physical Developer Enhancement

Solvent Black 3 (SB3)

CI26150; Sudan Black; Sudan Black B, Fat Black HB

4197-25-5

≥ 90 %

SB3

5-Sulphosalicylic acid, dihydrate

5-SSA dihydrate

5965-83-3

Laboratory

Acid Dyes, Soot Removal

Superglue

Ethyl cyanoacrylate , ECA, CNA

7085-85-0

Standard commercial superglue with no, or minimal, thickening additives

Superglue Fuming

Synperonic N

Isononylphenol ethoxylate

9016-45-9

As supplied by CAST

Physical Developer

Thiourea

Sulfourea, Thiocarbamide

62-56-6

Analytical

Physical Developer Enhancement

Tween® 20

Polysorbate 20

9005-64-5

Unspecified

MMD

Triton® X-100

There are many alternative names

9002-93-1

Laboratory

Powder Suspension

Zinc

Zinc foil; Zinc pellets

7440-66-6

≥ 99 %

VMD

Home Office January 2014

3.1.20

Fingermark Visualisation Manual

Section 3.1: Requirements for Implementation

Appendices

3.2.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Safe working environment...................................... 3.2.2 Setting up and maintaining a safe laboratory facility................................................................... 3.2.2 Recovering fingermark evidence safely................ 3.2.6 Hazards and risk.................................................. 3.2.6 Personal Protective Equipment (PPE)................. 3.2.7 Hazards associated with items.......................... 3.2.12 Physical hazards associated with the processes.......................................................... 3.2.14 Chemical hazards associated with the processes.......................................................... 3.2.20 Controlling risks from chemical hazards............ 3.2.23 Post-processing ................................................... 3.2.28 Management of waste....................................... 3.2.28 Disposal or return of items................................ 3.2.29 References............................................................. 3.2.30 Hazard symbols................................................. 3.2.30 Artificial Optical Radiation classifications.......... 3.2.34

Introduction

(This section does not include the requirements for

laboratory situation, there are some basic requirements

3.1 and Chapter 5 highlights specific considerations to

In providing safe and suitable working facilities for any

for the health, safety and welfare of personnel. Additional

issues are introduced when the activities of the laboratory are concerned with forensic evidence recovery and some specific hazards when recovering fingermark evidence using the processes in this Manual.

This section looks at the general requirements for the safe application of fingermark development processes. Having sought guidance from the Health and Safety Executive

(HSE), CAST was advised to present the information in this section to provide assistance to practitioners but

to do this as non-experts, basing the content on CAST experiences, its own work environment and use of the fingermark visualisation processes. References are

made throughout the Manual regarding the need to seek specialist advice in all matters relating to health, safety and welfare.

Safe working environment

Whereas Section 3.1 looked at the requirements for

implementing the processes safely and effectively, this

section provides more general information on establishing and maintaining safe laboratory facilities in which to

carry them out. While the HSE website must be regarded

working safely at scenes, since this is covered in Section each of the processes.)

Recovering fingermark evidence safely This part of the chapter identifies how the hazards

to which those working with forensic items and the

processes may be mitigated through assessing and

controlling risk. The biological, physical and chemical hazards associated with fingermark evidence recovery are discussed, identifying the place of personal

protective equipment (PPE) and other measures to

keep practitioners safe. Particular emphasis is placed on the control measures needed when working with

high-intensity light sources, flammable liquids, and chemicals, solutions and mixtures.

Post-processing

After the processes have been used, there will be

materials that need to be disposed of. Some may be

reusable but waste will be created in a number of ways: spillage, exhaustion of working solutions, obsolete

chemicals and treated items no longer required. This

part of the chapter discusses how each of these can be managed.

as the definitive source of information on health, safety and welfare matters, a number of examples have been included to illustrate the difficulties encountered when

providing a practical workspace, which at the same time meets all the regulatory requirements.

Home Office January 2014

3.2.1

Fingermark Visualisation Manual

Section 3.2: Working Safely

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Section 3.2: Working Safely Provision of facilities that are safe, legal, efficient and effective may be most readily achieved during new

building or refurbishment of laboratories. In addition to

any legal or regulatory controls or standards that may be required, successful planning and installation of suitable facilities will need to take account of:

●● the operational requirements of the laboratory with

regard to the tasks that will be carried out;

●● a suitable workflow arrangement for current tasks and,

if feasible, potential future needs;

●● the employment of specialist planning staff who are

familiar with all the requirements;

●● the employment of specialist contractors to complete

the work to be undertaken and others to approve or commission it, if necessary.

Providing value for money will be a major consideration. If the laboratory is to remain in good order through its

anticipated lifetime, changes to specifications for shortterm financial gain may seem attractive. However, they

may result in additional costs later and value for money

not achieved in the longer term. Examples of this might be the installation of fixed benches with specifications

budget for the best possible outcomes. The legal requirements, regulations, guidance and

standards that are applicable to the laboratory will need to be adhered to throughout the lifetime of the facility. It

may be necessary to update it to remain compliant with all the requirements; for instance, as new equipment is added or as legal requirements change.

Although regular checks of health and safety matters

by suitably qualified personnel should identify areas for improvement, all those working in the laboratory have a responsibility to ensure that any issues are raised

appropriately and passed to a responsible person to be dealt with.

Health, safety and welfare requirements All employers must comply with current legislation

to protect the health, safety and welfare of both their employees and those who may be impacted by their work. The most recent details of this, the Health and

Safety at Work etc. Act (1974), should be obtained from the Health and Safety Executive (HSE) (www.hse.gov.

●● toilets and hand basins, with soap and towels or a

of the laboratory must be included in the important communications with those responsible for the

installation of the laboratory and those managing the Home Office January 2014

Health issues

To have a healthy working environment, make sure there is:

●● good ventilation — a supply of fresh, clean air drawn

from outside or a ventilation system;

●● a reasonable working temperature (usually at least

16°C, or 13°C for strenuous work, unless other laws require lower temperatures);

●● lighting suitable for the work being carried out;

●● enough room space and suitable workstations and

seating;

●● a clean workplace with appropriate waste containers.

Safety issues

To keep your workplace safe you must:

●● properly maintain your premises and work equipment; ●● keep floors and traffic routes free from obstruction;

●● have windows that can be opened and also cleaned

safely;

Working within a suitable office environment.

requirements of the Act.

costs may result in compromised health, safety and

Those fully knowledgeable about all the requirements

Safe working environment

used. The HSE has provided the following list of basic

Welfare facilities

welfare of staff, or breaches of legislative requirements.

Index

uk) to ensure that the most up-to-date information is

more suited to kitchen use, than those with adequate chemical resistance. More significant attempts to cut

Glossary

Fingermark Visualisation Manual

Setting up and maintaining a safe laboratory facility

Appendices

For your employees’ well-being you need to provide:

© See Photo Credits

3.2.2

Contents

hand-dryer;

●● drinking water;

●● a place to store clothing (and somewhere to change if

special clothing is worn for work);

●● somewhere to rest and eat meals.

3.2.2

3.2.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Setting up and maintaining a safe laboratory facility continued

and adequate storage for all general and specific

facilities but may present numerous difficulties not only

environment and to enable good work flow and good

requirements pose additional restrictions.

storage, e.g. for chemicals, to provide a suitable work housekeeping; ■■ ■■ ■■

eye wash stations and drench showers; fume cupboards;

chemical spills ‘kit’.

Providing suitable services and utilities This is a fundamental consideration in all laboratory

●● make sure that any transparent (e.g. glass) doors or

walls are protected or made of safety material.

There is additional guidance on the HSE’s website to help in implementing these requirements.

Regulatory and practical requirements

Some of the specific requirements to consider when

setting up a general laboratory facility that meets both the regulatory and practical requirements are listed below.

The list is not exhaustive and all elements for providing a safe and efficient laboratory environment must be

considered by a practitioner with the appropriate skills and authority.

●● Services and utilities, including providing suitable: ■■ ■■ ■■

air quality, temperature and humidity; electricity supply;

water supply, suitable drainage and waste disposal;

●● fixed laboratory equipment, fixtures and fittings

Home Office January 2014

Index

Safe working environment

●● safety ‘equipment’ and first aid measures, including:

A clean and tidy laboratory environment.

Glossary

Example: Laboratory ventilation

There is a current legal requirement that ‘Effective and suitable provision shall be made to ensure that every

enclosed workplace is ventilated by a sufficient quantity

of fresh purified air’, and with minimum standards set for the number of changes of air per hour.

In order to provide draught-free air at constant pressure in a workspace that also has to maintain effective

containment within laboratory equipment, such as fume cupboards, careful balancing of the air make-up and

extraction systems is needed. This may prove difficult to achieve, especially when all the equipment contributing to the air burden is in use.

The installation and positioning of fume cupboards are two of the controls included in British and European

standards and health and safety regulations for their

use. (Further details can be found on the HSE website or in fume cupboards.) It is essential that compliance with the regulations and standards is achieved even if

local constraints, including those relating to positioning

from a practical perspective but also where regulatory The example below illustrates the complex situations

that may arise when trying to establish good laboratory ventilation when a number of different practical and

regulatory requirements all need to be satisfied. Balancing air make-up to provide a suitable environment is a

common problem when venting from a number of pieces of laboratory equipment is needed.

in relation to walls, workbenches, doors and supporting columns, etc., make this appear impossible to achieve. While large ‘walk-in’ fume cupboards may be useful

facilities in a laboratory dealing with large items, they

exhaust large volumes of air, which must be replaced,

placing additional complications on the balancing of air make-up.

The legislative requirements for positioning of air

inlets and discharge outlets from the local exhaust

ventilation system into the environment are clear and

must be adhered to. These requirements may then pose further complications as routing of ducts, both inside and outside the

building becomes constrained.

A walk-in fume cupboard

showing the

ventilation duct at the top.

3.2.3

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Setting up and maintaining a safe laboratory facility continued

Water supply, drainage and waste disposal also require the same degree of careful planning and flexibly as other services. Specialist knowledge will also be required

Glossary

Index

Safe working environment to manage the practical considerations and specific regulatory requirements. For example:

Current first aid regulations state that water used to

supply laboratory eye irrigation measures and drench

showers must comply with specific recommendations

and any mains water supply to them must provide tepid water fit for the purpose.

Material discharged into the mains drainage system must only be with the correct approvals (see management Fume discharge stacks above a chemistry laboratory. Providing electricity is not generally a problem as the UK

supply is suitable for most general laboratory equipment*. However, there may be practical considerations that

need to be taken into account. These include providing

enough power points in suitable positions to avoid trailing leads or the possibility of exposure to liquid spills as

well as providing the flexibility to cope with changing

operational needs. The use of retractable leads positioned in the ceiling may provide a safe method of powering some equipment.

*VMD equipment and laboratory glassware washers may require a different electricity supply.

A retractable

lead positioned in the ceiling.

Home Office January 2014

of waste) and the appropriate approval authority will

advise on what may be discharged and how this may be achieved.

A typical eyewash station. Powder suspension being disposed of in a sink. There will be other practical issues to consider, such as: ●● the need for all pipes and conduits to be made from

materials appropriate for their function, e.g. purified water delivery systems require pipes and fittings made from inert material;

●● drench showers and ‘walk-in’ fume cupboards may

require very low or floor-level drainage.

Example: Acetic acid contaminated water from a

Ninhydrin oven will be discharged at 80˚C and requires

pipes made of suitable material. See DFO and Ninhydrin ovens and Chapter 5 for further information on the requirements for Ninhydrin.

3.2.4

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Setting up and maintaining a safe laboratory facility continued Workflow and housekeeping

Good workflow and housekeeping will help to make the laboratory more efficient, but will also create an environment where people can work safely.

Suitable positioning of sufficient workbenches which are

hard-wearing and resistant to any chemicals used will be

needed and ideally kept as versatile as possible in case of change of use. Specialist benching might be considered in some areas to provide, for example:

●● support for heavy equipment, such as ovens in the

most appropriate position;

●● suitable benching for siting balances, where vibration

can be minimised;

●● tilting benching in examination areas, especially where

Glossary

Index

Safe working environment ●● having sufficient suitable space to store all equipment

and materials when not in use, so that as much as

possible can be kept away from work areas (see Safe handling of chemicals for specific requirements for storage of chemicals, solutions and mixtures and managing items: storage requirements);

●● keeping work areas clean and tidy;

●● good management of waste to avoid the build-up of

unwanted materials.

people are working seated.

Good housekeeping will not only keep people safe but

will also make the running of the laboratory more efficient. Laboratories with ISO 17025 accreditation may have

procedures for laboratory practitioners to follow, but the aims of good housekeeping should include:

Image of a well-organised, clean and tidy laboratory. Workflow may be dictated in some cases by legal or

A practitioner working at a tilting bench.

regulatory requirements and in many others by more

practical issues. Good workflow is a requirement of the ISO 17025 standard.

Ideally, the flow of work around the laboratory will need to take account of the tasks to be undertaken and

the practitioners carrying out the tasks as well as the regulatory issues that apply. The positioning of fixed

equipment, such as fume cupboards and other fixtures and fittings, needs to be considered both for current

needs and ideally anticipate possible future demands on the facility.

Home Office January 2014

3.2.5

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Recovering fingermark evidence safely

Hazards and risk

Identification and classification of hazards

for the classification and labelling of lasers, LEDs, and

defines a hazard as:

responsible for assessing the risks they may pose should

if powered by electricity, further understanding of the

The current entry on the HSE website (www.hse.gov.uk) ●● something, e.g. an object, a property of a substance,

a phenomenon or an activity, that can cause adverse effects;

and a risk as:

●● the likelihood that a hazard will actually cause its

adverse effects, together with a measure of the effect.

It goes on to explain that effects can be expressed

in different ways, e.g. numbers of accidents, injuries or illnesses, while likelihoods can be expressed as probabilities, frequencies or in a qualitative way. One example given is: The lifetime risk of an employee developing asthma [effect] from exposure to substance X [hazard] is significant [likelihood expressed qualitatively].

It is a clear requirement of the Health and Safety at

Work etc. Act 1974 that people must be protected from harm as far as is ‘reasonably practicable’. The law

recognises that it may not be possible to eliminate all

risks associated with potentially hazardous procedures

but that work can be carried out if sufficient, ‘reasonable’ measures are put in place to control exposure of personnel to any perceived hazards.

Identifying and classifying hazards is complex and those consult recognised sources of up-to-date information, such as the HSE (www.hse.gov.uk) and BSI (www.

bsigroup.co.uk) websites. Specialist knowledge will be needed in many cases and suitable training given.

A number of regulations apply to managing hazards identified in the workplace, including lifting of heavy

equipment, electrical and fire safety and noise. Again, the HSE website should be consulted for current information, as these fall outside the remit of this Manual.

Hazards which arise through the activities of fingermark

development laboratories fall into three main categories. ●● Biological:

Biological hazards are classified in four groups of

increasing severity based on the ability of the agents to infect humans. ●● Physical:

The regulations and standards for classifying some physical hazards can be highly complex and will

require someone suitably trained and authorised to

other sources such as arc and discharge lamps. Also,

regulations on their use would be needed to establish a safe way of working with them. ●● Chemical:

Classification of chemical hazards is also

complex, but a systematic scheme for classifying

and identifying chemical hazards is in place and is described in full later.

Scene

Additional biological, physical and chemical hazards will almost certainly be introduced if scenes are attended or if items need to be treated outside the control that

laboratory conditions can normally provide. However,

the same rules for risk assessment apply and all hazards must be identified if practitioners are to work there. This will include the hazards associated with transferring the use of the processes to the scene, as well as possible risks to members of the public or long-term effects of

using the processes. See scene use of the processes and treatment of large items.

interpret them.

For example, to identify the hazards associated with specific high-intensity light sources, the responsible

person, possibly a Laser Safety Officer, would need to identify and mitigate the hazards presented from

exposure to the ‘light’ emitted from all artificial sources

(visible, ultraviolet, infrared, lamps, LEDs and lasers) from an understanding of the latest regulations and standards Home Office January 2014

3.2.6

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Hazards and risk continued

that they are the only risk assessment required when

activity must be carried out. Anyone carrying out risk

Controlling risk

or knowledge of the relevant statutory requirements

and Safety at Work Regulations,1999 and Control of

An assessment of the risks associated with an

assessments must have sufficient training and experience and an appreciation of the hazards involved to be fully effective. Details of how to carry out risk assessments

should be obtained from a qualified source, such as the

HSE, but the summary below covers some key elements. 1. Identify what could harm people in the workplace, i.e. the hazards.

2. Identify who might be harmed and how.

3. Evaluate the risks and decide on appropriate

controls, taking into account the controls already in place.

4. Record the risk assessment.

5. Review and update the risk assessment to include further controls if the risk is judged to be too high.

All potential hazards must be assessed, including, for

chemicals are used.

Some regulations, e.g. The Management of Health

any new information.

N.B. Control of Substances Hazardous to Health

(COSHH) regulations require risk assessments to be

carried out. These are only applicable to risks associated Home Office January 2014

put in place to control risks and ensure the safety of practitioners in the tasks they undertake.

‘Standard PPE’, when entering a laboratory environment

1. eliminate the risk if possible;

2. control the risk at source or by using a safer design; 3. use physical engineering controls and safeguards.

Control measures that may be taken to eliminate risks

or minimise them to an acceptable level may be included in developing a safe way of working. Examples might include selection of the most appropriate:

●● equipment, including fume cupboards;

level of PPE, referred to throughout this Manual as

to protect the body, hands, eyes and feet from various

hazards. It may be considered appropriate for visitors to the laboratory to be given Standard PPE, in which case

disposable body and foot protection may prove suitable. Most PPE has BS EN Standards ratings, identifying the

level of protection it provides against particular hazards. Standard PPE.

●● practitioner to carry out the process;

Laboratory

●● chemical to use, e.g. a safer non-flammable

alternative;

●● personal protective equipment (PPE).

changes, then the risk assessment must be repeated with

only be considered after other measures have been

any risks identified, i.e.

must be shown to be sufficient to reduce risks to an

If the activity or the environment in which it is carried out

Personal Protective Equipment (PPE) must normally

However, it is usual practice to maintain a minimum

recommend the approach that should be taken to control

●● viewing distance for observers, e.g. If high-intensity

acceptable level and sufficiently robust to avoid failure.

Personal Protective Equipment (PPE)

Substances Hazardous to Health Regulations (COSHH))

example, the lack of experience of the staff wishing to

carry out the task. The control measures recommended

Index

Recovering fingermark evidence safely

with the use of chemicals: it must not be assumed

Risk assessment

Glossary

light sources are being used;

coat or Eye

protection

alternative body

protection

Once all the risks have been assessed and mitigated, as far as possible, a written record must be produced that records in detail what has been done to control the risks so that the process can be used safely. (If necessary, a permit to work may be needed if any task needs to be restricted to individual personnel.)

Hand

protection Foot

protection

3.2.7

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Personal Protective Equipment continued

Regulations cover the use of PPE to ensure that it is: ●● properly identified and evaluated in the risk

assessment to ensure it is suitable and offers an

The eyes must be protected at all times when in a

the process instructions in Chapter 5. When carrying out

where hazards have been identified. As with all other PPE,

filtered eye protection is not only essential for protecting

laboratory environment or when carrying out activities

the level of eye protection provided will depend on the outcome of the risk assessment.

The eye protection provided should meet the required

equipment which may no longer offer the expected

fit the practitioner properly, be disposed of if it becomes

level of protection;

●● provided with instructions on how to use it safely; and ●● used correctly by employees when fitting and

removing to ensure their protection from any

contamination accumulated during the execution of tasks.

Failure of PPE

The PPE selected should protect the practitioner from

anticipated risks, including small spills and splashes. If

PPE has become damaged or degraded, or a more major

spillage has occurred, action must be taken to protect the wearer from exposure to the hazard. The course of action

Index

Recovering fingermark evidence safely

appropriate level of protection;

●● maintained and stored properly, discarding damaged

Glossary

specifications and any applicable BS EN Standards, must

Fluorescence Examination, selection of the correctly the eyes but also for effectively applying the process.

A selection of different

types of eye protection.

damaged and not be handled whilst wearing potentially contaminated gloves.

Different types of eye protection are available including

some which can be fitted with prescription lenses. These include:

●● safety glasses (with and without side protection); ●● safety goggles;

●● face shield or visor.

Selecting the correct eye protection is especially

important when using high-intensity light sources: this

is covered in full later in this section and reinforced within

may simply include the replacement of damaged PPE but more serious incidents may require first aid measures, decontamination or seeking medical attention.

For emergency decontamination, practitioners must know how to operate the emergency drench shower and eye wash station.

Eye protection

Unprotected, the eyes will be vulnerable to a number of hazards posed by chemical splashes, dust, projectiles, gas and vapour or radiation when carrying out the fingermark visualisation processes. Home Office January 2014

3.2.8

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Personal Protective Equipment continued

Body protection

‘Standard’ body protection would normally include a suitable laboratory coat to:

which can be autoclaved, if necessary. Polycotton is

being carried out and the correct specification of gloves

Cotton is heavier and less easy to launder than polyester, commonly used and is a good compromise between the two.

●● protect the integrity of items or surfaces being

coat with a suitable alternative. For example, a full

V-neck and Howie styles of laboratory coat are available, usually with popper fasteners to facilitate fast removal

in an emergency. Howie style lab coats provide greater

protection for the chest and neck area and often feature knitted cuffs.

Howie laboratory coat

(below), disposable coverall (right).

Recovering fingermark evidence safely The appropriate level of hand protection must be

Depending on the task being carried out and the risk

handled.

Index

Cotton, polyester or polycotton coats offer further choice.

●● protect the clothes and body from accidental spills

and splashes;

Glossary

determined as part of the risk assessment for the task purchased to provide:

●● protection from any hazards identified;

●● protection for the length of time the task will take.

identified, it may be necessary to replace a protective

As with other PPE, gloves should be the right size for

coverall will provide greater protection for scene use, or

should be available to suit the needs of practitioners

wearing a plastic apron in addition to a laboratory coat

will protect the clothes when using Basic Violet 3 or other processes that require quantities of dye solution. Laboratory coats or suits should be removed

the individual and a number of different types of glove and the likely hazards to which they will be exposed.

Gloves containing latex and other allergenic substances, sometimes employed as part of the manufacturing process, should be avoided.

when leaving the hazardous environment to avoid

BS EN Standards apply to gloves: manufacturers

to be laundered regularly, using a suitably qualified

hazard ratings of gloves in line with these (see the HSE

contaminating other areas. Body protective wear needs company, being careful to ensure that appropriate

procedures are followed when dealing with contaminated items of PPE.

It may be useful to have disposable coats and suits

available for use in some situations, where the greater protection from more robust body protection is not needed, e.g. for visitors.

Hand protection

This is an important consideration to:

●● protect the hands from a range of biological, physical

and chemical hazards;

●● protect the integrity of items or surfaces being

handled.

should provide the chemical, biological and physical

website (www.hse.gov.uk) for more information). The

gloves selected must protect the hands from all the risks

identified. Double-gloving is a common recommendation, such as a cotton or nitrile inner glove and nitrile outer

glove depending on the hazard. When dealing with sharp items that are also suspected of associated biohazard,

appropriate double-gloving will be needed to protect the wearer from both types of hazard.

Knowing when to change gloves to maintain the level of

protection necessary is an important factor. Breakthrough times for chemicals may be as short as 20 minutes and less than this for some individuals, whose hands may

become excessively sweaty. Frequent changes of gloves will also be required to ensure that contaminants picked up on the gloves are not transferred to other surfaces.

Home Office January 2014

3.2.9

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Personal Protective Equipment continued

Biohazard protection

The gloves worn should provide protection from body-

fluid-borne pathogens for the duration of the task being

undertaken. The wearing of more than one pair of gloves in combination may need to be considered.

Physical hazard protection

Mechanical handling gloves offer various levels of

protection from abrasion, cuts, tears and punctures,

in line with the BS EN Standard. These gloves may be

needed to handle sharp items such as knives or broken glass or to handle broken laboratory ware.

Chemical hazard protection

Disposable gloves, suitable for handling solids, may only offer limited protection from liquid splashes. If the hands

are to be immersed in liquids or exposed to more severe hazards, such as Basic Violet 3 solutions, the greater protection offered by rubber or plastic laminate film

gloves, for example, will be needed, even though they

may limit dexterity. Wearing an inner glove is advisable as this will reduce the risk of self-contamination when removing the outer, contaminated gloves.

Specialist gloves

Some manufacturers also produce specialist gloves to

protect the hands from specific hazards, such as extreme

Glossary

Index

Recovering fingermark evidence safely

Using gloves

1. Inspect gloves for damage before use. For disposable

(a)

non-porous gloves such as nitrile gloves, it is

possible to do this by trapping air inside (a) to check the glove’s integrity. Never blow into a glove.

2. Change disposable gloves regularly as they will deteriorate with wear, are prone to mechanical

damage with time and eventually will not give the necessary protection.

(b)

3. Take care not to touch the skin with contaminated glove surfaces.

4. Never wear potentially contaminated gloves

outside the laboratory or touch surfaces whilst

wearing contaminated gloves to which others may be unknowingly exposed, such as door handles, telephones and computer equipment etc.

5. Remove general disposable gloves from the sleeve,

turning them inside out as they are withdrawn so that any contamination is kept on the inside (b and c).

Liquid and mechanical handling gloves may require a different removal approach.

(c)

6. Decontaminate or dispose of contaminated gloves appropriately.

7. Wash hands after removing gloves.

cold from liquid nitrogen.

Home Office January 2014

3.2.10

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Personal Protective Equipment continued

Foot protection

Sandals and open-toed shoes do not offer adequate

protection in the laboratory environment and must not be worn. Durable boots and shoes with non-slip soles

should be worn in the laboratory and at scenes to provide

protection from chemical splashes, slips or falling objects. Disposable boot and shoe covers may be useful in

some situations to protect normal footwear and limit the spread of contamination. Various boot and shoe cover

designs are available which have similar specifications to disposable coveralls.

Glossary

Index

Recovering fingermark evidence safely

Respirators vary from disposable face masks to

individual responsible for monitoring the practitioner

disposable filters. Respirators should be considered when

that they need to enter the risk area to help the other

power-assisted units that generate an air-flow through substances are present in the atmosphere which are

irritating or detrimental to health but where there could be

also needs to wear appropriate RPE in the event retreat to fresh air.

sufficient good quality air to breathe if these substances were to be filtered out. The equipment must fit well,

particularly when the user’s breathing is relied upon to draw air through the respirator. If a good fit cannot be

achieved, following face-fit testing, then other solutions need to be pursued.

Breathing apparatus must be used when there is

an inadequate supply of air, or if the air is extremely contaminated.

Example: Local depletion of breathable air is possible when using Ninhydrin to treat even small areas where conditions cannot be fully controlled, so the use of

breathing apparatus will be required (see Ninhydrin). The decision to use RPE must only be made after careful consideration of a number of factors, including: Examples of foot protection (safety boot) and footwear protection (shoe covers).

Respiratory protective equipment (RPE) RPE includes all types of respirator and breathing

apparatus. It is a sub-category of PPE and not part of

the standard PPE required in fingermark development

laboratories but may be required in some situations. The use of RPE requires specialist knowledge and training is

essential: the HSE website (www.hse.gov.uk) should be consulted for further information. Home Office January 2014

●● all other control measures that could mitigate the

hazard (see Risk assessment);

●● the availability of a source of fresh air;

●● identification and availability of suitable RPE;

●● medical approval for use of the equipment by

practitioners, especially if they suffer from a respiratory condition;

●● that two practitioners must be available when

breathing apparatus is needed, so that one person can remain away from the treatment area, in fresh

air, to monitor and ensure the safety of the other. The

3.2.11

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Hazards associated with items

There are many possible hazards associated with the

safe handling of items for fingermark recovery and they

may be biological, physical or chemical in nature. In many operational situations there will be local procedures to

manage the risks posed by them, e.g. handling of items

with suspected biohazard. Specific labelling or packaging for storage or transport of items need to be considered

when assessing risks to practitioners, who, if they are in any doubt, should treat items received as hazardous.

●● Biological hazards are most likely to be introduced

into the laboratory by contaminated items or surfaces.

Items may be contaminated with body fluids, including

blood, urine, faeces, sputum, pus etc., each of which may carry biological agents that cause infection in humans.

Information on the classification of biological hazards can be found on the HSE website (www.hse.gov.uk), which

Glossary

Index

Recovering fingermark evidence safely

includes the latest information on biological agents listed by the Health and Safety Commission.

●● Physical and chemical hazards may arise from the

handling of sharps, firearms, drugs wraps or items

saturated with petrol: these can be managed in the laboratory environment through good practices of

handling, packaging, storage and disposal to maintain safety in the laboratory.

After treatment, it must be remembered that the original

hazard may still be present, but additional hazards due to residual hazardous chemicals may also be present post-processing.

Examination of those items may need to be done on a

down-draught bench, to protect the practitioner from harm until they can be disposed of or returned to the owner.

A collection of drug wraps. A broken bottle with blood presents multiple hazards.

General handling of items, including packaging and

storage, is discussed in some detail in handling items

with further information on disposal in disposal or return of items.

Controlling risks from biological hazards Careful handling of items suspected of being

contaminated with biological hazardous material is essential to minimise the risk of infection.

The skin and mucous membranes are major routes of Poorly packaged item presenting a physical hazard from broken glass and potential biohazard from blood. Home Office January 2014

infection and appropriate personal protective equipment will be needed.

3.2.12

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Recovering fingermark evidence safely

Hazards associated with items continued Suitable protective gloves should be worn and care taken not to puncture them. If possible, unbreakable equipment should be used and re-use of equipment or solutions

restricted to prevent spread of any hazardous material. As the risks from biological agents are assessed, note of

any specific COSHH recommendations, such as working with specific containment requirements, e.g. within a

biological safety cabinet, need to be taken into account

(as well as assessing whether vaccination of employees is appropriate).

Work areas that have been exposed to biohazards should be disinfected using suitable cleaning regimes.

Biological safety cabinets are designed to contain

biohazard material, offering different specifications to

provide different levels of protection. If available, they may be suitable for drying items contaminated with

body fluids, but are not suitable for processing items,

especially if the chemical hazards require the use of a fume cupboard.

Home Office January 2014

3.2.13

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Physical hazards associated with the processes Physical hazards may arise from poor arrangement

and management of laboratory workspace in which the processes may be used. The risks can be minimised

through good laboratory design and management (see workflow and good housekeeping).

The majority of the processes generally present no

physical hazards more serious than those encountered

emit ultraviolet (UV), visible and infrared (IR) optical radiation will be needed and will vary depending on

individual process requirements. Arc-lamps, discharge

lamps, light emitting diodes (LEDs), UVA mercury vapour lamps, low pressure mercury lamps and lasers may

be required and detailed information can be found in

the appropriate Chapter 5 optical process instructions regarding advice on their selection and use.

HSE provides comprehensive guidance on the use

are four major areas associated with the use of individual

(www.hse.gov.uk) and should be consulted for further

instance caused by breakage of glass. However, there

processes where particular hazards need to be carefully

controlled, two of which should only manifest themselves when working in confined areas, e.g. at scenes.

●● Hazards associated with the use of light sources,

with the greatest risk from those needed for

Fluorescence Examination and UVC Reflection. ●● Hazards from working with flammable liquids,

e.g. Acid Dyes, Solvent Black 3.

●● Hazards associated with air depletion,

e.g. Ninhydrin.

●● Hazards from handling liquid nitrogen,

e.g. Numberplate Splitting.

Hazards and controlling risks from light sources

Artificial light sources, also known as Artificial Optical Radiation (AOR) sources, are needed for the optical

processes either for the initial examination of an item or to

Home Office January 2014

Index

Recovering fingermark evidence safely

visualise fingermarks prior to imaging. Light sources that

during the handling of general laboratory equipment, for

Glossary

of Artificial Optical Radiation sources on its website

information, especially that relating to particular legislation regulating the use of AOR.

This Manual indicates the hazards associated with the

optical radiation emitted from light sources suitable for the processes and proposes some control measures. Although some of light sources used in fingermark

visualisation are classified as hazardous, some are not.

However, the following points illustrate good practice and should be applied wherever possible:

●● no light source should be directed towards the

eyes at any time;

●● irradiation of the skin and eyes by emissions

from light sources must be reduced as far as is

●● additional control measures may be needed to

protect those with particular medical conditions

or circumstances that place them at greater risk. More information can be found on the Public Health England website (www.gov.uk/phe).

Hazard classifications of light sources

Artificial light sources are subject to risk group

classification, identified in the UK by various British

Standards (see www.bsigroup.com for more information and reference documents at the end of this section). The classifications take into account three main criteria:

●● the quantity of optical radiation (often referred to as

‘power’;

●● the wavelength distribution of the emitted radiation; ●● human access to optical radiation.

Exposure limit values (ELVs) for the exposure of people to artificial optical radiation are set by legislation and must not be exceeded.

Many Artificial Optical Radiation sources, including

photocopiers and photographic flash-lamps and some light sources used for fingermark visualisation, are not

classified as hazardous. However, if used inappropriately, such as placing them very close to the eyes or skin, they may cause harm and this must be avoided.

‘reasonably practicable’. If there is any doubt

Other light sources are classified as hazardous and

light source, the level of irradiation must be

using them or others in the vicinity. Those responsible

about the safety of the use of a hazardous

calculated by a competent person to ensure the

recommended exposure limit values (ELV) are not exceeded;

present a ‘reasonably foreseeable’ risk of injury to those for the use of hazardous sources of Artificial Optical Radiation must comply with legal requirements to safeguard people’s health, safety and welfare.

3.2.14

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Physical hazards associated with the processes continued The development and anticipated use of the light sources needed may not have been considered originally for

radiation to the eyes or skin and the divergence of the

suitably qualified and accountable person who is

of the emitted radiation, the proximity of the emitted beam.

responsibility, over and above the Health and Safety at

the optical processes and all have the ability to harm

Work Act etc. (HSWA), to ensure employees and others are kept safe when AOR sources that are classified as

hazardous are used. Suppliers of hazardous light sources also have a duty, under the HSWA, to provide equipment that is designed and manufactured to be safe in use as

far as is ‘reasonably practicable’. Manufacturers and the equipment suppliers should therefore be able to assist

with enquiries about the safe use of their equipment for a particular application.

‘Hazards’ associated with the quantity of optical radiation (power) from light sources The majority of the optical processes in the Manual

require only low-output power light sources and as long

as they are used appropriately should not pose any risk. High-output power sources will be required for

Fluorescence Examination and as they are classified as

hazardous will carry ‘reasonably foreseeable’ risk of injury. Ideally, the process will be carried out with adequate

controls to avoid the need for calculating the reasonably foreseeable maximum level of personal exposure. The calculations needed are complex and as well as the

measured power output (energy) of the equipment other

Recovering fingermark evidence safely Evaluation of hazards and assessment of risks

therefore to consider how their proposed use can be

managed safely. Employers have an additional legal

Index

taken into account, such as the wavelength distribution

‘Wavelength hazards’ associated with light sources

fingermark visualisation. It is particularly important

Glossary

UV, visible and IR radiation are needed to carry out if used inappropriately. Each radiation band has a

nominal wavelength range, with further subdivisions.

When assessing the risks from artificial optical radiation

These can be complex and must be carried out by a

trained appropriately and has the authority to ensure control measures are in place and checked for their

effectiveness. This is especially important for use of

certain classes of lasers (3B and 4) and risk group 3 of

non-coherent sources, where competent persons are a

legal requirement to assess the Artificial Optical Radiation sources safety programme for the practitioners expected to use the equipment.

sources, it is important to remember that these ranges

Assessment of the risks will depend on a number of

artificial boundaries and require risk assessments which

the use of hazardous Artificial Optical Radiation sources.

are nominal and actual emissions may fall across these take this into account.

The hazards associated with high-energy, shorter wavelength emissions, such as UV, pose risks of

photochemical damage, possibly causing serious harm

to the eyes and the skin, causing both acute and chronic effects.

factors that are clearly stated in the regulations governing These include:

●● the level, wavelengths and duration of exposure; ●● the exposure limit values;

●● the effects of exposure on people whose health is at

particular risk;

●● the possible effects from interactions between the

AOR and photosensitising substances;

Hazardous radiation emissions in the visible range can

●● the indirect effects of exposure, e.g. temporary

High-power visible radiation (light) can cause damage

●● information from manufacturers.

pose risks of both photochemical and thermal damage. to the eyes following very short exposure times and can

burn the skin if held close to the source. ‘Blue light’ from high-power sources cause retinal damage to the eyes resulting from a photochemical reaction.

Longer wavelengths, e.g. IR, generally carry risks of

blindness;

A record must be kept of the risk assessment and any actions to address highlighted issues to ensure that

the risks are suitably managed. These must be made available to practitioners.

thermal damage to tissues.

factors contributing to the exposure level will need to be Home Office January 2014

3.2.15

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Physical hazards associated with the processes continued

Hazards from light sources for fingermark visualisation

The table below indicates the types of radiation used in

the eyes and skin. These are discussed more fully in the associated notes.

Ultraviolet

Visible

Infrared

Range/nm 100-400

380-780

780-1400

Home Office January 2014

Range of interest/concern

Processes

Index

Recovering fingermark evidence safely

the optical processes and the severity of the hazards to

Radiation

Glossary

Hazardous to eyes

Hazardous to skin

UVC 100-280 nm

UVC Reflection

See note 1

UVA 315-400 nm

Fluorescence Examination

See note 2

High intensity visible

Fluorescence Examination Multi-Spectral Imaging (Fluorescence mode)

See note 3

High intensity Fluorescence ~400-500nm Blue Examination light Multi-Spectral Imaging (Fluorescence mode)

See note 4

Low intensity visible

Colour Filtration Monochromatic Illumination Multi-Spectral Imaging (Reflection mode) Visual Examination

See note 5

Low intensity IR

IR Reflection

See note 6

Note 1: UVC is not visible, so people may not be aware of its presence and the potential hazard. It has the most potential to cause acute and chronic adverse health effects, some of which may not be apparent for many years. It can burn and cause genetic changes to the skin and cause inflammation of the cornea and conjunctiva (arc-eye) and cataracts in the eye. Those with heightened photosensitivity are at greatest risk. The key is to avoid exposure as far as possible by employing engineering controls as far as is reasonably practicable. Note 2: UVA is not visible. It is less hazardous than UVC, but can still cause damage to the eyes and burn the skin, especially if people are unaware of the potential hazard. Although the lens of the eye can block UVA and prevent it damaging the retina, high-power sources may damage the retina and cause yellowing or cataract formation in the lens. Cumulative exposure may increase the risk of cancer of the skin and eyes. Note 3: High-intensity visible light from class 3B and 4 lasers and risk group 3 non-coherent sources can damage the retina with very short exposure times, even if viewed from a distance. Burning can be caused if the light source is held close to the skin. Note 4: Blue light causes retinal damage. The blue light is believed to act by prematurely re-exposing photoreceptors, previously ‘shut-down’ by incident light, before they have recovered. Note 5: Visible light used at low intensity will generally pose negligible risk if used appropriately. The intensity needed may require adjustment to ensure image capture can be achieved without long exposure times, but must remain at a level that is safe for unprotected eyes. Note 6: Infrared radiation, if used at low power should pose no significant risk. However, since it is not visible people may be unaware of the potential hazard. Used at higher power, IR can cause corneal, lens and retinal damage to the eye and burning of the skin.

3.2.16

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Physical hazards associated with the processes continued Control measures

Engineering controls

●● use a safer alternative: ■■

■■

■■

be done by the use of control measures that provide

■■

Administrative controls

■■

controls to ensure people are fully protected; protection should the first two fail.

■■

follow local procedures and agreed safe working methods;

be aware of the hazards and potential risks to themselves and others;

use the artificial optical radiation source appropriately, i.e. when using in open-beam mode to always direct the beam away from those present or in the vicinity;

●● personal protection, which provides a final level of ■■

Examples of how these can be used to control the risks

take responsibility for corrective action if people have accidentally been exposed to irradiation; calculate and establish a safe viewing distance (Nominal Ocular Hazard Distance) taking

into account the spectral emission of the light source, the amount of emitted light, the beam

associated with the use of artificial optical radiation

divergence of the light source, the output aperture dimension and the period of exposure;

sources to carry out the processes can be found in the

■■

Personal protection

use appropriate restrictions and signage.

●● provide appropriate protective eye and face equipment for practitioners and observers; ●● use appropriate filters in eye protection (and viewing housings): ■■

filters, including those used in viewing housings must be selected appropriately to reduce the intensity of the emitted artificial optical radiation to a safe level while permitting transmission

measures for individual optical processes: the control

of radiation of interest – Fluorescence Examination in Chapter 5 should be consulted for more

measures employed when the processes are carried out must be selected on the basis of the local risk

(see personal protection for use of appropriate viewing filters to block hazardous radiation).

should:

■■

guidance and advice is given on selecting control

work in a safe viewing housing, especially if using hazardous artificial optical radiation sources

●● only permit use of the process to those who have been assessed as competent. The practitioner ■■

●● administrative controls, which support engineering

Within the process instructions in Chapter 5 further

use dedicated work areas, e.g. fluorescence examination room.

for long periods;

significant safety margins through the use of:

table on the right.

find a less hazardous Artificial Optical Radiation source that could give the same result.

●● provide screens to shield people from hazardous radiation:

radiation to which people may be exposed. This can

rigorous procedures;

Recovering fingermark evidence safely

●● isolate the hazard as far as possible:

it is necessary to calculate the levels of artificial optical

to the work planned and remove the need to follow

Index

General control measures

It is preferable, where possible, to avoid situations where

●● engineering controls, which build in safety features

Glossary

information on selection of filters; ■■

assessment.

well-fitting, undamaged eye and face protection is needed to prevent stray light, so all equipment to protect the eyes (and face, if needed) should be cleaned between users and checked for

damage or missing elastic or ventilation as well as ill-fitting filters. Consideration should be given to making these personal issue. ■■

Where necessary, provide personal protective clothing to cover the skin of practitioners and

observers. The clothing provided should cover the skin adequately and preferably be of closeweave material preventing penetration of the wavelengths of light being used.

Home Office January 2014

3.2.17

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Physical hazards associated with the processes continued Working with flammable liquids

Comprehensive information on the storage and use of

flammable substances can

be found on the HSE website (www.hse.gov.uk), which should be consulted for definitive information.

There are instances where the processes require the

use of flammable liquids. If they are used in a laboratory environment where there is sufficient ventilation, such

as that provided by a fume cupboard or local exhaust

ventilation (LEV), the flammability of the liquids should pose no hazard.

Ventilation of a work area outside a fume cupboard or

without LEV may be achieved simply by opening doors

of flammable liquids.

If there is a risk of the working temperature exceeding a

critical temperature identified for the process being used, flammable gas monitors must be used. They will indicate whether the vapour levels are approaching the LEL and

alert practitioners of the increased risk to themselves and others in the area. This will allow them time to evacuate

the area until the vapour can be reduced to a safe level. Any flammable liquid has the potential to create a

flammable atmosphere, whatever the flash point of the solution, if it is sprayed. The spraying of any flammable solution must not be considered for the processes

Processes that pose particular hazards with regard to flammability are:

Superglue Fluorescent Dye Staining Further information on the specific hazards associated

temperatures or if an ignition source, such as a naked

Chapter 5.

thermometers and equipment suitably designed to offer

protection in flammable atmospheres should be included

Home Office January 2014

However, hydrofluoroether (HFE), the principal solvent in these processes, produces vapour that is much

heavier than air and can displace it. Where adequate ventilation cannot be provided, e.g. when working in

confined spaces at scenes, a risk of asphyxiation may be introduced.

Air depletion should not occur where there is adequate ventilation, but treating even small areas without

adequate ventilation may reduce oxygen availability to a level that requires the use of breathing apparatus.

atomisation of HFE can increase the possibility of air

of the vapour exceeds a lower explosive limit (LEL) a fire

discharge is present. The use of anti-static PPE, infrared

Ninhydrin without the use of development ovens.

process instructions.

application must be used, as indicated in the Chapter 5

Solvent Black 3

flame, a spark from electrical equipment or electrostatic

It is possible to develop fingermarks with DFO and

The application of the working solutions for both DFO

If flammable liquids are used without adequate

may start if the surfaces being treated reach very high

Hazards from air depletion

used for visualisation of fingermarks. A safer method of

Acid Dyes

vapour concentration will increase. If the concentration

Index

Recovering fingermark evidence safely

in the control measures for any process involving the use

and windows to disperse the fumes.

ventilation, such as in confined areas of a scene, the

Glossary

with their use can be found in the relevant section of

and Ninhydrin by spraying is not recommended as the depletion in areas with insufficient ventilation.

Hazards from handling liquid nitrogen

Liquid nitrogen is required for Numberplate Splitting and presents a number of hazards, which if not controlled

through careful handling can put practitioners at risk from: ●● pressure build-up and explosions if not stored in

pressure-relief vessels;

●● material brittleness causing many common materials

such as carbon steel, plastic and rubber to become brittle or possibly fracture under stress;

●● frostbite and tissue damage, which may be

permanent;

●● asphyxiation if not used in well-ventilated areas.

Metal jewellery and watches should be removed from

3.2.18

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Recovering fingermark evidence safely

Physical hazards associated with the processes continued the hands and wrists to ensure there is no risk of them

freezing to the skin before putting on suitably insulated gloves designed to provide suitable hand protection.

Chapter 5 process instructions for Numberplate Splitting should be consulted for further information and control measures for the handling of liquid nitrogen.

Home Office January 2014

3.2.19

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Chemical hazards associated with the processes The processes have been developed with the aim

of minimising chemical hazards associated with the materials used. Where possible, more hazardous

materials have been discounted or replaced with safer alternatives, unless they are needed to provide an effective process for a particular application.

It is important for practitioners to be competent in the

safe handling of the chemicals that are needed. Even with careful handling, accidental spills and splashes on the

skin or in the eyes or accidental swallowing may occur.

In these cases the relevant SDS should be consulted for information on the first aid measures to be taken.

It is also important for practitioners to be aware of the

hazards associated with the chemicals they use and to be familiar with the classification and labelling conventions for the chemicals and solutions they use, as explained below.

to personnel working with chemicals is essential but

of chemical substances and mixtures adds one extra

is constantly growing and changing. Updating advice

obtaining up-to-date information can present difficulties and there can be discrepancies in the information provided by different sources.

or short-term to the hazard. Where data are available

for chemicals, the limits can be found under HSE EH40

Workplace Exposure Limits on their website (www.hse. gov.uk) along with more comprehensive information on the subject.

Home Office January 2014

element of classification (Hazardous to the Ozone Layer) and many additional hazard statements, identified with the prefix EU, e.g. EUH0014.

The Chemicals (Hazard Information and Packaging

or in medical journals. Special consideration must be

the Dangerous Substances Directive and the Dangerous

supplied by the manufacturers or suppliers of chemicals given to chemicals falling into higher hazard categories,

such as ‘carcinogenicity’, ‘mutagenicity’ or ‘reproductive toxicity’.

Hazard labelling of chemicals

Hazard labelling systems are in place to assist in

identifying the hazards associated with chemicals. The

regulations associated with this are complex and currently subject to change. Until 1 June 2015, two systems

will operate simultaneously and both systems will be represented temporarily in this Manual.

substances and mixtures becomes fully operational on

present in workplace air when people are exposed long-

GHS, the CLP Chemicals Classification of the hazards

Other information about safety of chemicals may be

levels. This classification is through officially recognised limits for the amounts of certain substances which can be

Recovering fingermark evidence safely (CLP) Regulation. Over and above the requirements of

The Globally Harmonised System (GHS) of

Workplace Exposure Limits (WELs) that set the legal

Index

Information about the harmful effects of certain chemicals

Classification of chemical hazards

One way of classifying chemicals is by quoting ‘safe’

Glossary

classification, labelling and packaging of chemical 1 June 2015.

●● The GHS classification is based on data obtained from

tests, the literature and practical experience.

●● The GHS symbols, hazards and general descriptions

of the hazards are grouped under three categories: physical, health and environmental hazards.

The GHS is implemented in Europe by the Classification, Labelling and Packaging of Substances and Mixtures

for Supply) Regulations (CHIP), which have implemented Preparations Directive, will be fully replaced by the CLP Regulation when it comes into force.

●● CHIP regulations apply to chemical elements and

compounds, solutions and mixtures.

●● Suppliers of chemicals and preparations must decide

whether they are ‘dangerous’ and what hazard they present, and pack and label them appropriately.

●● Safety Data Sheets (SDSs) must comply with

REACH (Registration, Evaluation and Authorisation

of Chemicals) regulations until CLP regulations come into force.

●● The CHIP symbols, hazards and general descriptions

of the hazards are grouped under three categories:

health, physicochemical, and environmental hazards. A full explanation of the hazards symbols can be found

on the Reference Documents at the end of this chapter: Hazard symbols.

Suppliers have a responsibility to ensure that chemicals

or mixtures they supply can be clearly identified on their

labels, with standardised label elements. They must also

make available Safety Data Sheets (SDSs) which provide

3.2.20

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.21

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Chemical hazards associated with the processes continued

12. Ecological information

13. Disposal considerations

Glossary

Index

Recovering fingermark evidence safely CLP (GHS) Classification: Label elements Product Identifier (ingredient disclosure)

The GHS label for a substance should include the chemical identity of the substance. For mixtures, the label should include the chemical identities of all ingredients that contribute to any hazard. Their use as described above.

essential part of the standardised label elements. All of

Symbols (hazard pictograms)

indicated in the table on the right.

Signal Words

Only one signal word corresponding to the class of the most severe hazard should be used on a label, e.g. “Danger” or “Warning”.

Hazard Statements

Standard phrases assigned to a hazard class and category that describe the nature of the hazard. Often these will not be the actual phrase but the assigned code e.g. H201 or H303 etc., which can be looked up from a standard list.

Precautionary Statements

Measures to minimise or prevent adverse effects. Often these will not be the actual phrase but the assigned code e.g. P101 or P202 etc., which can be looked up from a standard list.

5. Fire-fighting measures

Supplier identification

The name, address and telephone number should be provided.

7. Handling and storage

Supplemental information

Supplemental information may be used to provide further detail that does not contradict or cast doubt on the validity of the standardised hazard information.

employers and workers with concise relevant information about the hazards, uses and risk management of the chemicals provided by them.

14. Transport information

15. Regulatory information 16. Other information

Standardised label elements

Identifying the hazards associated with chemicals is an the elements required under the GHS classification are

Safety Data Sheets (SDS)

These are specifically aimed at the use of the chemical in the workplace and should provide comprehensive

information about each chemical product supplied. This will allow employers and workers to obtain concise,

relevant and accurate information that can be put in

perspective with regard to the hazards, uses and risk

management of the chemical product as it is used in their workplace. The SDS should contain 16 sections in the order specified:

1. Identification

2. Hazard(s) identification

3. Composition/information on ingredients 4. First-aid measures

6. Accidental-release measures 8. Exposure control/personal protection 9. Physical and chemical properties 10. Stability and reactivity

11. Toxicological information Home Office January 2014

An example page from a Safety Data Sheet (SDS).

3.2.21

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.22

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Chemical hazards associated with the processes continued Hazards associated with prepared solutions* The solutions needed for the processes are generally prepared in the laboratory, following the process instructions in Chapter 5.

Although hazardous chemicals may have been used for making up the solutions, the hazards associated

with the final solutions will almost certainly be different, following dilution according the formulation. Once

made, the solutions need to be labelled appropriately (see packaging and labelling) which must include a statement of the associated hazards.

The following advice can be found in Chapter 5,

explaining CAST’s position with regard to calculating the

Glossary

Index

Recovering fingermark evidence safely

that information from suppliers on the SDSs can change

as new information becomes available and also that it can vary from supplier to supplier. It is important, therefore, that the information provided by CAST in Chapter 5 is

used to guide local review of solution hazards and should not be regarded as definitive.

The following particular hazards are associated with the processes.

●● Fumes and dust generated when carrying out

various processes and from processed items

may pose hazards or nuisance odours making

●● Superglue is generally sold as an adhesive and

Superglue Fuming uses it in a way that was not

intended by the manufacturers. If people are exposed to vapour above the Workplace Exposure Limit

(WEL), some evidence suggests that this may cause sensitisation. Appropriate respiratory protective

equipment (RPE) must be worn if personnel are likely to be exposed to superglue fumes above the WEL.

Further information can be found in the relevant section of Chapter 5 on specific hazards associated with the use of Basic Violet 3 and Superglue Fuming.

unpleasant working atmospheres, which may need to be alleviated through the use of local exhaust ventilation (LEV).

●● Basic Violet 3 is particularly hazardous and requires

suitable handling to minimise risks.

hazard associated with the process solutions.

While the hazards associated with the chemicals used can be found on the SDS, those associated with the

solutions need to be calculated from their percentages in the final solution. To assist in this, in 2011, CAST

commissioned work to calculate the risks associated

with the solutions it was using at the time. The results of those calculations are given here for guidance only

to those responsible for risk assessments of solutions used locally.

It has already been seen that responsibility for assessing

*A solution is prepared by dissolving one or more solutes (minor components) in one or more solvents (major

laboratory must be taken locally. It has also been stated

some for the processes, have solid material suspended or dispersed through a liquid and for convenience they are

the hazards associated with the activities of the

Home Office January 2014

components) to form a product which is homogeneous and not subject to separation. Some preparations, including referred to collectively as ‘mixtures’ in this Manual. See standard method for solution preparation.

3.2.22

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.23

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Controlling risks from chemical hazards

The use of fume cupboards and personal protective

equipment have already been demonstrated to provide universal measures for controlling risks from chemical

hazards. Other measures to control risks from chemical hazards include:

●● various examples of local exhaust ventilation (LEV);

and

●● various aspects of safe handling of chemicals,

solutions and mixtures.

Local exhaust ventilation (LEV)

LEV, also known as dust or fume extraction, is a form of engineering control to reduce the exposure of

practitioners to dust, mist, fume vapour or gas. It is

designed to move hazardous materials away from the

●● Opening doors and windows to create air movement

workspace that is free from clutter is also a prerequisite

may be unsuitable.

may be considered LEV and in some cases may provide adequate ventilation to work safely.

There is comprehensive information about LEV on the HSE website (www.hse.gov.uk).

Careful balancing of air make-up needs to be achieved to ensure multiple LEV systems continue to work effectively when they are all operational at the same time. See laboratory ventilation.

Some processing or examination equipment requires LEV, which ensures that nuisance fumes or dust associated

with certain tasks can be controlled adequately. Examples are:

hazardous materials or discharged to a safe place, in line

●● Superglue cabinet

must be selected to be effective in controlling the hazards present. The following may be used.

●● A system, fully extracted to the exterior, e.g. standard

or ‘walk-in’ fume cupboards which are suitable for

carrying out the processes, as indicated in Chapter 5.

●● Recirculatory systems, which filter the air and return

it into the laboratory. They are generally suitable for

the control of dust, e.g. for Powders. They must not be used where their filtration system is ineffective in controlling the hazard. This is especially important

when considering the effective removal of the solvent Home Office January 2014

Recovering fingermark evidence safely area are aware of the tasks taking place is important to

●● Fume cupboards

with legislative requirements. The correct type of LEV

Index

used for DFO and Ninhydrin where this type of LEV

worker to keep the air they breathe free from harmful substances. The air is either filtered to remove the

Glossary

●● Ninhydrin or DFO oven

minimise risks. Having a well-organised and efficient

for safe handling of chemicals, solutions and mixtures. Care will be needed when: ●● using chemicals, solutions and mixtures. Basic

requirements will include training in an understanding of chemical hazards, good handling techniques,

awareness of the COSHH (Control of Substances

Hazardous to Health) assessment and the information held on the Safety Data Sheet. Spillage of chemicals should be kept to a minimum by using appropriate equipment, as in the illustrated example below.

●● moving solutions and mixtures, to make sure they

are in suitable containers to minimise spills, e.g.

beakers should not be filled to the brim or secondary

containers should be used when carrying Winchester bottles;

●● Wet bench with integral dyeing facility ●● Powdering cabinets

●● Down-draught benches

Safe handling of chemicals, solutions and mixtures This section is concerned with laboratory practitioners’ general awareness of the hazards associated with the

chemicals they will be handling and how risks to their own or others’ safety may be minimised.

Restricting access to chemicals to those trained and

competent in their use and ensuring that people in the

Example: Avoid filling a beaker or similar vessel close to

capacity when making solutions or mixtures, as the risk of spillage during stirring and transfer is likely to increase.

3.2.23

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.24

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Controlling risks from chemical hazards continued ●● storing chemicals, solutions and mixtures safely to

ensure they are: ■■ ■■ ■■ ■■

packaged and labelled correctly;

stored under the correct conditions; segregated appropriately;

stored in appropriate quantities.

Specific hazards associated with the chemicals needed

for individual processes and an indication of the hazards associated with prepared solutions can be found in

the appropriate process instructions in Chapter 5. The

on their effectiveness when used. Chemicals, solutions and mixtures should be stored: ●● in suitable containers, correctly labelled; ●● under suitable conditions;

●● separate from incompatible materials; ●● in suitable quantities.

Packaging and labelling Chemicals

Chemicals bought for the laboratory need to be correctly packaged and labelled, with standard information provided on a Safety Data Sheet (SDS).

Solutions and mixtures

for example, if a fume cupboard is needed for the

correctly packaged using a container of suitable size and

preparation or use of working solutions.

N.B. Management of waste chemicals, solutions and mixtures is also important but is discussed later.

Scene

N.B. Safe handling of chemicals at scenes may pose

additional hazards, since the materials will need to be

transported to the scene and then used in an environment where it may be difficult to control processing conditions.

See scene use of the processes and treatment of large items.

Safe storage of chemicals, solutions and mixtures There are various aspects to the safe storage of

chemicals, solutions and mixtures. Some of these will

also have an effect on their quality and therefore a bearing Home Office January 2014

Once prepared, solutions and mixtures need to be

made of a material that does not react with the solution or mixture. Glass and plastic are generally suitable.

Volumes exceeding about 3 litres may be better stored in

aspirators that have handles or taps to make pouring from them easier. Caps should be leak-proof. Labels must be A plastic-coated glass bottle deliberately broken to

illustrate the containment of the glass fragments and chemical.

Index

Recovering fingermark evidence safely

measures needed to control many of the risks associated with them are also included in the process instructions;

Glossary

applied to identify the solution or mixture and any hazards associated with them.

For prepared chemical solutions and mixtures, plastic-

coated borosilicate glass bottles are ideal for storage in

most cases as they retain the contents and the shattered glass if dropped accidentally.

Some small-volume mixtures that are not volatile, such as working powder suspension, may be stored in beakers or

pots over shorter timescales (days) provided that they are labelled clearly and covered with a suitable film when not in use.

Clear labelling of prepared chemical solutions and

mixtures is essential for correct identification and safe

handling, so that anyone using them or those working in

the area know exactly what they are and how they should be handled. Deciding on the actual hazard labelling that should be applied may require specialist knowledge, since dilution of the original components and their

hazardous properties have to be taken into account. (N.B. Hazards of the processing solutions and mixtures were calculated for CAST’s chemical solutions in 2011.

More information can be found in Hazards associated with prepared solutions, with further guidance in Chapter 5).

Keeping separate records of who made the solutions, when they were made and records of the chemicals

used (including purities and batch codes) is important

for traceability (including the requirements of ISO 17025),

especially after the bottle and label are no longer required. Any written labels applied need to be resistant to

3.2.24

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.25

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Recovering fingermark evidence safely

Controlling risks from chemical hazards continued chemical spills and splashes by using appropriate,

solvent-resistant pens or by applying protective stickers placed over the label.

A solution or mixture label should display the information demonstrated below for Basic Violet 3 (phenol)

concentrated solution labelled with CLP(GHS) health and safety symbols.

An identifier that links the

The name of the

solution or mixture to the

solution or mixture

The constituent chemicals

ID Example: XX/YY

[

The chemical hazards

BV3 (Phenol) concentrated solution

relevant record where

details of the constituent chemicals are recorded

Basic Violet 3 (5g) Phenol (10g) Absolute alcohol (50ml) Made on 5.06.12 Expires on 4.06.13 Made by J. Bloggs DANGER

The date the solution or mixture was made

]

and/or risk phrases in

For good practice, the solution label should

CLP(GHS) or CHIP system

●● the expiry date, if known;

accordance with the

also display the following:

●● the name of the person who made the

solution or mixture.

Home Office January 2014

3.2.25

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.26

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Recovering fingermark evidence safely

Controlling risks from chemical hazards continued

Segregation of chemicals, solutions and mixtures

Storage conditions Chemicals

solutions and mixtures must be segregated to prevent

The SDS will confirm how the chemical supplied should be stored in order to preserve its quality.

The label and SDS will also indicate the hazards

associated with the chemical, which will guide the most appropriate storage conditions. Where there are no

Where there are compatibility issues, chemicals,

the risk of them reacting and introducing new hazards. See Section 3.1 for an indication of the storage of

chemicals, solutions and mixtures for the requirements for segregation of the process chemicals.

The following classes of chemicals must be segregated:

compatibility issues, chemicals can be stored together

●● flammables;

practical purposes in cool, dry storage areas out of direct

●● mineral acids;

safely, with solids and liquids being segregated for sunlight. However:

●● flammable liquids must be stored in containers

and fire-resistant cabinets which comply with the appropriate regulations and standards;

●● toxic chemicals must be kept in a robust storage

cabinet, which is kept locked and has controlled access to the key;

●● flammable store acids may need a separate store.

Irrespective of the type of storage provided for chemicals, placing them in a secondary containment is a useful

safety precaution. Bottles may be stored on a plastic tray, or on bunded shelves to collect any accidental spillage.

Solutions and mixtures

Prepared solutions and mixtures may be stored together,

●● oxidisers;

●● organic acids; ●● bases;

●● toxic substances and poisons.

Some chemicals may belong to more than one of these classifications, in which case storage should be in line with the hazard that takes precedence. HSE guidance

should be sought if there is any doubt about the correct approach.

Example: Methanol is an organic solvent, classified as both highly flammable and toxic. In this case the flammability of methanol will dictate the storage

conditions as flammability classification takes precedence over toxicity for methanol.

following the guidance above, as long as there are no compatibility issues.

A range of storage conditions for chemicals including a shelving (top), a flammables cabinet (centre) and secondary containment (bottom).

Home Office January 2014

3.2.26

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.27

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Recovering fingermark evidence safely

Safe quantities of stored chemicals, solutions and mixtures

In many laboratories, the quantities of chemicals,

solutions and mixtures stored are generally small and can be stored in the laboratory safely, as long as the segregation rules are followed.

However, the volume of flammable chemicals that can be stored within a laboratory is controlled under legislation (www.hse.gov.uk) which requires that the quantity of

highly flammable substances stored within the laboratory is kept to a minimum and in any case must not exceed a maximum limit (50 litres at the time of writing). Bottles of

ethanol, dye tanks filled with ethanol- based dye solutions and flammable waste vessels all contribute towards this

An outside solvent store containing large quantities of solvents.

total permissible volume.

Chemicals that are required in larger quantities may

need to be stored outside the laboratory. This applies

particularly to solvents because of the volumes required,

e.g. HFE7100. The outside store may need to be sited at

a distance from other buildings if flammable substances’ storage is needed, e.g. ethanol in excess of the quantity that can be stored legally inside the laboratory.

Home Office January 2014

3.2.27

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.28

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Management of waste

After the fingermark visualisation processes have been used, the work area will need to be returned to a safe

working condition. This will include clearing the area of reusable equipment, cleaning it before returning it to store

and discarding disposable equipment appropriately. The disposal or return of items will need to be considered and for chemical and some physical processes, there will be other waste materials generated that must be disposed of appropriately. Chemical waste may be created through: ●● spillage; or

●● materials of no further use.

Spillage of chemicals, solutions and mixtures

Even with careful handling, it is inevitable that some spills

PPE, chemical-specific spillage kits and staff evacuation may be needed.

Disposal of the spillage, clean-up materials or damaged PPE must be managed in line with their hazard rating, which may or may not demand specialist removal

from the laboratory. The vessel used to contain waste

materials must be sufficiently robust and must be labelled appropriately while awaiting disposal.

The method of disposal of chemicals that are of no further use will depend on a number of factors:

●● whether it is classified as hazardous under current

regulations;

place. These might include:

in sufficiently robust packaging such as a zip-lock bag

solid.

non-halogenated waste, some laboratories may choose to isolate certain highly flammable waste solvents for

Chemical waste waiting for disposal must be collected material and construction. Plastic-coated borosilicate glass bottles with resistant caps are suitable for most

situations where non-volatile chemicals or solutions are

to be stored. Where volatile chemicals and solutions are involved, pressure releasing caps should be used but

require storage in specialist ventilated cabinets. Vessels

should not be overfilled: it is advisable to leave a gap of at least several centimetres above the liquid.

solutions. The contents should be logged and this

authority-approved waste contractor.

of non-hazardous waste should be collected by a local-

The level of response needed to make an area safe will

The Local Water Authority must approve any discharge of

spill. Small quantities of non-hazardous solids or liquids

usually require a list of what is intended for discharge in

Home Office January 2014

company. In addition to halogenated organic waste and

before disposal.

●● temporary barriers.

absorbent tissue. For more serious incidents, specialist

vessels for disposal by a local-authority-approved

Generally waste vessels are likely to contain a mixture of

All quantities of hazardous waste and larger quantities

may be safely cleaned up using a dustpan and brush, or

collected in separate halogenated and non-halogenated

be disposed of in general waste but should be contained

●● sand;

depend on the hazard(s) present and the size of the

laboratory drains into the public sewer and must be

in designated, clearly labelled containers of a suitable

Small quantities of non-hazardous solid chemicals can

●● sealing putties;

Liquid organic waste cannot be disposed of via

laboratory chemical waste.

Local restrictions will usually apply to the disposal of

In the event of a chemical spillage in the laboratory, it is

●● absorbent granules;

suspended solid.

collection and disposal.

●● whether it is an aqueous liquid, organic liquid or a

advisable to have easily accessible control measures in

Post-processing

Waste chemicals, solutions and mixtures

will occur that will need to be dealt with efficiently and effectively.

Index

waste to the public sewer. The appropriate authority will

this way before approval will be given. The list will include identification of the chemicals, the pH and quantities of

compatible used or expired working and concentrated information should be accessible to staff and the

approved company that will dispose of the waste. A container of combined chemical waste with an overall hazard classification must be segregated from other chemicals and chemical wastes with incompatible

hazard classifications. The segregation rules for chemical waste are the same as those applied for the storage of chemicals (see Segregation of chemicals, solutions

and mixtures). Similarly, storage cabinets for hazardous

3.2.28

Fingermark Visualisation Manual

Section 3.2: Working Safely

Glossary

3.2.29

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

waste must to be of a suitably robust design, conforming

Disposal or return of items

hazard(s).

many cases they will need to be disposed of.

to any legal requirements appropriate to the nature of the

Since some of the processes may cause lasting damage

independent evaluation and management and,

given to the fate of items before these processes are

specifically, consultation with the Environment Agency

will be required where there is the risk of waste chemicals entering a water courses, for example.

Index

Post-processing

There may be reasons to retain items in storage, but in

Scene

Disposal of chemicals at scenes will require

Glossary

to items or render them unsafe, consideration must be applied. Local policies may exist to confirm how these

decisions are made. Chemicals or biological agents may still be present on processed items and care must be

taken to protect practitioners from harm until they can be disposed of or returned to the owner.

Depending on the process(es) applied, even though the

treatment may have disfigured the item, it may be safe to: ●● return the item to the owner, even though it may not

be possible to return the item to its original condition after cleaning it with detergent and water or other

suitable cleaning regime as indicated in Chapter 5 for individual processes;

●● discard the item in the normal waste.

Some processes may leave residual harmful chemical, making it unsafe to return the item to the owner or dispose of it in the normal waste. In this case the

items will need to be regarded as hazardous waste and disposed of through a waste contractor. See management of waste n

Home Office January 2014

3.2.29

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.2.30

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

The Globally Harmonised System (GHS) of classification, labelling and packaging

chemical substances and mixtures becomes fully operational on 1 June 2015, replacing

CLP (GHS) classification: Physical hazards Symbol

Hazard

Description (see note )

Explosives, divisions 1.1, 1.2, 1.3 and 1.4 Unstable explosives

A solid or liquid substance or mixture which is capable by chemical reaction of producing gas at such a temperature and pressure and at such a speed as to cause damage to the surroundings. An unstable explosive is thermally unstable and/or too sensitive for normal handling, transport and use.

Compressed gases Liquefied gases Refrigerated liquefied gases Dissolved gases

Gases or gaseous mixtures contained in a receptacle at a pressure not less than 280 Pa at 20˚C or as a refrigerated liquid. This covers four types that address the effects of sudden release of pressure or freezing which may lead to serious damage to people, property, or the environment independent of other hazards the gases may pose.

Flammable gases, category 1

Substances and mixtures that have a flammable range in air at 20˚C and a standard pressure of 101.3 kPa.

Flammable aerosols, categories 1 and 2

Aerosols that contain any component, which is classified as flammable according to the GHS criteria (flammable gases, flammable liquids or flammable solids).

Flammable liquids, categories 1, 2 and 3

A liquid with a flash point ≤ 60°C.

Flammable solids, categories 1 and 2

A solid that is readily combustible or may cause or contribute to fire through friction or can be easily ignited by brief contact with an ignition source.

Chemicals (Hazard Information and Packaging for Supply) Regulations (CHIP).

Until that date, the two systems will operate simultaneously and both systems will be represented temporarily in this Manual.

The symbols, hazards and general description of the hazards used in the GHS

classification are categorised in three elements (physical, health and environmental) and are given in the tables that follow.

Self-reactive substances and mixtures, types A and B

Self-reactive substances and mixtures, types C, D, E and F

Substances or mixtures that are thermally unstable liquids or solids liable to undergo a strongly exothermic thermal decomposition even without participation of oxygen (air).

Note: Descriptions included here are CAST interpretations: for full information refer to CLP Regulation.

Home Office January 2014

3.2.30

Fingermark Visualisation Manual

Refer to Hazard labelling of chemicals.

Index

References

Section 3.2: Working Safely Hazard symbols

Glossary

3.2.31

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

References

CLP (GHS) Classification: Physical hazards (continued) Symbol

Hazard

Description (see note )

Pyrophoric liquids and solids category 1

Index

CLP (GHS) Classification: Health hazards Hazard

Description (see note)

A liquid or solid that is liable to ignite within five minutes after coming into contact with air.

Acute toxicity (oral, dermal, inhalation), categories 1, 2 and 3

Self-heating substances and mixtures, categories 1 and 2

A solid or liquid which, by reaction with air and without energy supply, is liable to selfheat.

Acute toxicity (oral, dermal, inhalation), category 4

Substances and mixtures that cause adverse effects occurring following oral or dermal administration of a single dose of a substance or a mixture, or multiple doses given within 24 hours, or an inhalation exposure of four hours.

Substances and mixtures, which in contact with water, emit flammable gases, categories 1, 2 and 3

Substances or mixtures that, in contact with water, emit flammable gases or by interaction with water, are liable to become spontaneously flammable.

Skin corrosion, categories 1A, 1B and 1C

Skin corrosion is the production of irreversible damage to the skin following the application of a test substance for up to four hours.

Oxidising gases, category 1

A gas that may, generally by providing oxygen, cause or contribute to the combustion of other material more than air does.

Skin irritation, categories 2 and 3

Skin Irritation is the production of reversible damage to the skin following the application of a test substance for up to four hours.

Oxidising liquids and categories 1, 2 and 3

A liquid or solid that, while not necessarily being combustible, may, generally by yielding oxygen, cause or contribute to the combustion of other material.

Serious eye damage, category 1

Serious eye damage is the production of tissue damage in the eye, or serious physical decay of vision, following application of a test substance to the anterior surface of the eye, which is not fully reversible within 21 days of application.

Eye irritation, category 2A

Eye irritation is the production of changes in the eye following the application of test substance to the anterior surface of the eye, which are fully reversible within 21 days of application.

Respiratory sensitisation, category 1

Substances and mixtures that induce hypersensitivity of the airways following inhalation of the substance.

Skin sensitisation, category 1

Substances and mixtures that induce an allergic response following skin contact.

Organic peroxides, types A and B

Organic peroxides, types C, D, E and F

Corrosive to metals, category 1

Symbol

Organic liquids or solids that contain the bivalent -0-0- structure.

Substances or mixtures that materially damage, or even destroy metals by chemical action.

Note: Descriptions included here are CAST interpretations: for full information refer to CLP Regulation. Note: Descriptions included here are CAST interpretations: for full information refer to CLP Regulation.

Home Office January 2014

3.2.31

Fingermark Visualisation Manual

Section 3.2: Working Safely

Glossary

3.2.32

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

References

CLP (GHS) classification: Health hazards (continued) Symbol

Hazard

Description (see note)

Germ cell mutagenicity, categories 1A, 1B and 2

Index

CLP (GHS) classification: Environmental hazards Symbol

Hazard

Description

Substance or mixtures which give rise to an increased occurrence of mutations in populations of cells and/or organisms.

Acute aquatic toxicity category 1

Substances or mixtures that are injurious to an organism in a short- term exposure to that substance or mixture.

Carcinogenicity, categories 1A, 1B and 2

Substance or mixtures which induce cancer or increase its incidence.

Chronic aquatic toxicity categories 1 and 2

Substances or mixtures which cause adverse effects to aquatic organisms during exposures which are determined in relation to the life-cycle of the organism.

Reproductive toxicity, categories 1A, 1B and 2

Substance or mixtures which cause adverse effects on sexual function and fertility in adult males and females, as well as developmental toxicity in the offspring.

Specific target organ toxicity following single exposure, categories 1 and 2

Specific non-lethal target organ toxicity arising from a single exposure to a substance or mixture.

Specific target organ toxicity following single exposure, category 3

All significant health effects, not otherwise specifically included in the GHS, that can impair function, such as narcotic, reversible and irreversible, immediate and/or delayed are included.

Specific target organ toxicity following repeated exposure, categories 1 and 2

Specific non-lethal target organ toxicity arising from repeated exposure to a substance or mixture.

Note: Descriptions included here are CAST interpretations: for full information refer to CLP Regulation.

All significant health effects, not otherwise specifically included in the GHS, that can impair function, such as narcotic, reversible and irreversible, immediate and/or delayed are included. Aspiration hazard, categories 1 and 2

Substances or mixtures that may pose an aspiration toxicity hazard to humans. ‘Aspiration’ means the entry of a liquid or solid substance or mixture directly through the oral or nasal cavity, or indirectly from vomiting, into the trachea and lower respiratory system.

Note: Descriptions included here are CAST interpretations: for full information refer to CLP Regulation.

Home Office January 2014

3.2.32

Fingermark Visualisation Manual

Section 3.2: Working Safely

Glossary

3.2.33

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

References CHIP classification: Health hazards

CHIP Chemicals Classification (Chemicals (Hazard Information and Packaging

for Supply) Regulations 2009) which deals with substances (chemical elements or

compounds) and preparations (mixtures or solutions of substances) will be replaced on

Index

Symbol T+

1 June 2015 by the CLP Regulations.

Refer to Hazard labelling of chemicals for more information.

Hazard

Description

Very toxic

Chemicals that at very low levels cause damage to health.

Toxic

Chemicals that at low levels cause damage to health.

The symbols, hazards and general description of the hazards used in the CHIP

classification are categorised into three elements (physicochemical, environmental and

Category 1 and 2 carcinogens

health) as given below.

Category 3 carcinogens

Chemicals that may cause cancer or increase its incidence.

CHIP classification: Physicochemical hazards Symbol

Hazard

Description

Explosive

Chemicals that explode.

Category 1 and 2 Mutagens

Category 3 Mutagens Oxidising

F+

Chemicals that react exothermically with other chemicals.

Extremely flammable

Highly flammable and flammable

Category 1 and 2 reproductive toxins

Chemicals that have an extremely low flash point and boiling point, and gases that catch fire in contact with air.

Category 3 reproductive toxins

Chemicals that may catch fire in contact with air, only need brief contact with an ignition source, have a low flash point (up to 55˚C) or evolve highly flammable gases in contact with water.

CHIP classification: Environmental hazards Symbol

Hazard

Description

Dangerous for the environment

Chemicals that may present an immediate or delayed danger to one or more components of the environment .

Home Office January 2014

Chemicals that induce heritable genetic defects or increase their incidence.

Chemicals that produce or increase the incidence of non-heritable effects in progeny and/or an impairment in reproductive functions or capacity.

Harmful

Chemicals that may cause damage to health.

Corrosive

Chemicals that may destroy living tissue on contact.

Irritant

Chemicals that may cause inflammation to the skin or other mucous membranes.

i

3.2.33

Fingermark Visualisation Manual

Section 3.2: Working Safely

Glossary

3.2.34

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Artificial Optical Radiation classifications

Index

References Non-Coherent (Broad-band) Sources (EN 62471)

Refer to Hazard classification of light sources

Group

Description (see note)

The Control of Artificial Optical Radiation at Work (AORW) Regulations came

Exempt

No direct optical radiation risks are reasonably foreseeable, even for continuous, unrestricted use. These sources do not pose any of following photo-biological hazards: ●● an actinic ultraviolet hazard within eight hours’ exposure; ●● a near-UV hazard within 1000 s; ●● a retinal blue-light hazard within 10000 s; ●● a retinal thermal hazard within 10 s; ●● an infrared radiation hazard for the eye within 1000 s; ●● an infrared radiation hazard without a strong visual stimulus within 1000 s.

1 – Low Risk

Products are safe for most applications, except for very prolonged exposures where direct ocular exposures may be expected. These sources do not pose any of following hazards due to normal behavioural limitations on exposure: ●● an actinic ultraviolet hazard within 10000 s; ●● a near-UV hazard within 300 s; ●● a retinal blue-light hazard within 100 s; ●● an infrared radiation hazard for the eye within 100 s; ●● an infrared radiation hazard without a strong visual stimulus within 100 s.

2 – Moderate Risk

Sources that do not pose any of following hazards due to aversion response to very bright light sources, due to thermal discomfort or where lengthy exposures are unrealistic: ●● an actinic ultraviolet hazard within 1000 s; ●● a near-UV hazard within 100 s; ●● a retinal blue-light hazard within 0.25 s (aversion response); ●● a retinal thermal hazard within 0.25 s (aversion response); ●● an infrared radiation hazard for the eye within 10 s; ●● an infrared radiation hazard without a strong visual stimulus within 10 s.

3 – High Risk

Sources that may pose a risk even for momentary or brief exposure within hazard distance. Safety control measures are essential.

into force on 27 April 2010 and aim to protect workers from the risks to health from hazardous sources of Artificial Optical Radiation (AOR).

AORW brings together in one document the classification of three types of light source (laser, non-coherent and machinery) which are each defined in a separate International Standard and are given below.

Laser Safety Classification (EN 60825) Class

Description (see note)

1

Products that are considered safe during use, including long-term direct intra-beam viewing, even when using optical viewing instruments (eye loupes or binoculars).

1M

Products that are safe for the naked eye under reasonably foreseeable conditions of operation, but may be hazardous if the user employs optics (e.g. loupes or telescopes) within the beam.

2

Products that emit visible radiation and are safe for momentary exposures, even when using optical viewing instruments, but can be hazardous for deliberate staring into the beam. They are not inherently safe for the eyes, but protection is assumed to be adequate by natural aversion responses, including head movement and the blink reflex.

2M

Products that emit visible laser beams and are safe for short time exposure only for the naked eye; possible eye injury for exposures when using loupes or telescopes. Eye protection is normally provided by aversion responses including the blink reflex.

3R

Products that where direct intra-beam viewing is potentially hazardous but practically the risk of injury in most cases is relatively low for short and unintentional exposure; however, may be dangerous for improper use by untrained persons. The risk is limited because of natural aversion behaviour for exposure to bright light for the case of visible radiation and by the response to heating of the cornea for far infrared radiation.

3B

Products that are hazardous for the eyes if exposed to the direct beam within the nominal ocular hazard distance (NOHD). Viewing diffuse reflections is normally safe, provided the eye is no closer than 13 cm from the diffusing surface and the exposure duration is less than 10 s. Those lasers which approach the upper limit for the class may produce minor skin injuries or even pose a risk of igniting flammable materials.

4

Products for which direct viewing and skin exposure is hazardous within the hazard distance and for which the viewing of diffuse reflections may be hazardous. These lasers also often represent a fire hazard.

Note: Descriptions included here are CAST interpretations: for full information refer to AORW Regulation.

Note: Descriptions included here are CAST interpretations: for full information refer to AORW Regulation.

Home Office January 2014

3.2.34

Fingermark Visualisation Manual

Section 3.2: Working Safely

Glossary

3.2.35

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

References

Machinery (EN 12198) Category

Restrictions and protective measures.

Information and training.

0

No restriction.

No information needed.

1

Restrictions: limitation of access, protective measures may be needed.

Information about hazards, risks and secondary effects to be provided by manufacturer.

2

Special restrictions and protective measures essential.

Information about hazards, risks and secondary effects to be provided by manufacturer. Training may be necessary n

Home Office January 2014

3.2.35

Fingermark Visualisation Manual

Section 3.2: Working Safely

Appendices

3.3.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Laboratory environment ........................................ 3.3.2 Equipment and maintenance............................... 3.3.2 Using chemicals.................................................. 3.3.3 Measuring equipment.......................................... 3.3.5 Solutions preparation, storage and use............... 3.3.7 Standard method for solution preparation ......... 3.3.8 Effective application of solutions......................... 3.3.9 Handling items ...................................................... 3.3.10 Fingermark evidence integrity........................... 3.3.10 Imaging................................................................... 3.3.16 Image management........................................... 3.3.16 Image capture.................................................... 3.3.16 Image capture resolution................................... 3.3.19 File format.......................................................... 3.3.20 Post-capture...................................................... 3.3.22 Audit trail............................................................ 3.3.24 Image storage.................................................... 3.3.25 Communication................................................. 3.3.25 References............................................................. 3.3.26 Measuring cylinder classification....................... 3.3.26

Introduction

Effective fingermark imaging

working most effectively to achieve the best results

fingermarks visualised throughout the processing of

In this section, three specific areas associated with

from the use of the processes are discussed. It is not concerned with the effectiveness of the processes

themselves in developing marks either in the laboratory or at scenes since this is covered comprehensively in Chapter 5.

Effective working in a laboratory environment This introduces the principles of ISO 17025 and Good

This reinforces the need for good image capture of

items. It gives details on the end-to-end process from

image capture through to submission of the images to

identification experts, creating a strong link to Chapter 2, Section 2.5. It goes into some detail on the systems that might be used, the image capture resolution that will be

needed and file formats that will be suitable before going on to present some of the difficulties presented by postcapture processing and printing of images.

Laboratory Practice (GLP) and identifies the need

for discipline to maintain an effective laboratory. The

importance of equipment maintenance and the need for

assuring the quality of chemicals, solutions and mixtures to ensure effective use of the processes is stressed. The use of measuring equipment for the standard method

of solution preparation and the effective application of

process solutions, especially for treating large items is also included.

Effective handling of items for fingermark recovery The importance of the competence of the organisation, its practitioners and the procedures they use to demonstrate evidence integrity is stressed. Elements of the effective management of items for optimal fingermark evidence recovery are included here, such as general handling

and storage of items before, during and after treatment, packaging and preparation of complex items. It is

acknowledged that there are many other aspects that

operational staff will need to address, which fall outside the remit of this Manual. Home Office January 2014

3.3.1

Fingermark Visualisation Manual

Section 3.3: Working Effectively

3.3.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

A well-managed laboratory, kept clean and tidy within a well-maintained building is central to all aspects of

effective fingermark processing, but particularly staff safety and working efficiency. Keeping equipment

well-maintained and materials returned to storage after use are basic requirements. In addition, especially for

laboratories accredited to ISO 17025, there is a need for

maintain continued integrity across the whole of scientific practice.

GLP, unlike the ISO 17025 standard, includes heath and safety issues concerned with laboratory working: these are implemented by the Health and Safety at Work etc. Act 1974.

continual improvement. All staff should be encouraged to

As stated at the start of this chapter, the purpose of this

improvement in the operation of the laboratory.

of the requirements for ISO 17025 accreditation nor for

report issues which, if addressed, could lead to general The ISO 17025 standard is concerned with working

effectively and many of the requirements of the standard will have a direct bearing on the quality of the work of a laboratory accredited in this way.

Manual is neither to provide a detailed understanding

GLP, but it does reinforce the need for many of the good practices that they promote.

Further information can be obtained from the UKAS

(www.UKAS.com) and OECD (www.oecd.org) websites.

A high-level document was produced by the Organisation

Training of those involved in fingermark evidence

called ‘OECD Principles on Good Laboratory Practice’

competence to work with the visualisation processes

for Economic Co-operation and Development (OECD)

(GLP ). Revised in 1997, it establishes the principles for ‘harmonisation of test methods and good laboratory practice’ by which good quality test data should be

obtained so that international comparisons can be made

and duplication of effort avoided. Although only aimed at non-clinical health and environmental safety studies, all scientific laboratories are encouraged to work to these principles as they are considered best practice.

GLP principles refer to good managerial organisation and scientific practices, including the conditions under which laboratory studies are planned, performed, monitored, recorded, reported and archived. They recommend

providing appropriate facilities, designed not only to ensure high quality and standardisation but also to Home Office January 2014

recovery has already been discussed with regard to their (training and competence). Staff working to clear

laboratory procedures, aware of their responsibilities with respect to general behaviour and to their tasks, will also lead to effective laboratory working.

Equipment and maintenance

It is important to ensure that appropriate equipment is

available to carry out the tasks assigned to the laboratory. Purchasing equipment to the correct specification initially is important but after that it is essential to keep it in good order and working effectively: this applies equally to

general laboratory glassware and balances and to more expensive or specialist equipment. If the equipment

ceases to perform as intended it should normally be

removed from service until it is repaired or disposed of.

Glossary

Index

Laboratory environment Training in the use of equipment will be needed to

ensure it is used effectively, moved safely (if permitted or possible), cleaned after use, stored appropriately,

serviced and maintained as stipulated to keep it in good working condition.

It may be necessary for some equipment to have routine maintenance, such as cleaning or routine change of

disposable parts. Other items may require calibration

to keep them working effectively and possibly to satisfy the requirements of ISO 17025 accreditation. Keeping good records for equipment calibration, maintenance

and servicing is also an essential requirement of the ISO 17025 standard.

Cleaning equipment

All equipment needs to be kept clean: manufacturers’ information should be consulted for suitable cleaning

regimes for specific equipment used in the laboratory. General equipment should be cleaned, dried and stored appropriately after use to avoid contamination and

damage. Specialist cleaning may be required if laboratory equipment is used for items to be submitted for DNA analysis.

Local procedures for cleaning glassware will vary but

effective washing by hand will often include a tap water

rinse, followed by a detergent wash and a thorough final rinse in purified water. Equipment should be left to dry in a drainage area, drying rack or cabinet to avoid the

use of paper towels or blown air, which might introduce

unwanted contamination. Quick drying of washed glass

items may be achieved by rinsing with ethanol or acetone, taking any necessary precautions.

3.3.2

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

For grease-contaminated glassware, its cleanliness can

be checked by spraying it with purified water: if the water forms droplets rather than sheeting over the surface,

then the glassware may be contaminated and should be returned for further washing.

The addition of a laboratory glassware washer may

needed to satisfy the requirements of ISO 17025. The key factors are to:

●● make sure the correct chemical is available when it is

needed;

●● keep the chemical, solution or mixture free from

contamination;

be beneficial but, like all equipment, must be properly

●● check that the chemical, solution or mixture is still

Using chemicals

Make sure the correct chemical is available when it is needed:

specified, installed and maintained.

While it is important that practitioners handle chemicals safely, as shown in Section 3.2, there are a number of

other considerations for the effective use of chemicals, prepared solutions or mixtures.

Assuring the quality at key stages of their use in the

visualisation processes and identifying any defects that might affect the quality of the results before use are

suitable for use.

When ordering chemicals:

●● the full identification, purity and grade needed must

all be specified (see examples below). The chemicals

printing industries). Commercially available solutions or

mixtures may not be supplied to published specifications or to sufficiently tight tolerances. Practitioners should be

aware of this when ordering and using these preparations, seeking further information from the supplier or manufacturer as necessary.

When receiving chemicals, check that:

●● the correct chemical has been delivered – this may

only require the label to be checked but other tests may be required if there is any doubt;

●● a current copy of the Safety Data Sheet (SDS) is

available so that the chemical or reagent may be put into use.

including their grade, purity and CAS (Chemical

identified in full, i.e Iron (II/III) oxide, precipitated

Abstract Numbers) numbers, which uniquely identify N.B. When ordering dyes, it should be noted that

1. Iron oxide for Powder Suspension must be

(synthetic), magnetic, particle size 200nm - 1µm, CAS

number 1317-61-9. Omitting information from an order will result in an incorrect form being provided.

allocation of CAS numbers can be confused. The

2. Both 96% ethanol and absolute ‘100%’ ethanol

Number or Name should be used.

difference between these purities can be crucial in some

information supplied in Chapter 5 for the Colour Index (CI) N.B. Commercially available dyes, although sold as biological stains, are rarely of high purity and often

have the common CAS number ‘64-17-5’. The

fingermark development solutions so the order must clearly identify which is required.

contain variable amounts of unconsumed reagents,

3. 5-Sulphosalicylic acid has the CAS number

their manufacture. Cost and consistency of colour

Sulphosalicylic acid dihydrate. The correct chemical

intermediate products or inorganic salts used in

specifications, achieved through post-manufacture

addition of diluents, dispersing agents and possibly other

Home Office January 2014

the demands of primary customers (textile dyeing and

Examples:

the reference documents at the end of section 3.1,

Index

Laboratory environment

specified for the processes can be found listed in

the chemical.

Beading on grease-contaminated glassware.

Glossary

dyes are generally the most important criteria to satisfy

‘5965-83-3’ which is also the same number as 5-

must be identified since the presence associated water molecules will result in less of the active chemical by weight.

3.3.3

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Keep the chemical, solution or mixture free from contamination:* ●● if larger quantities of chemicals are decanted into

smaller containers, these must be clean and correctly identified to prevent the use of incorrect chemicals later;

●● replace the cap or stopper of the container

immediately after use;

●● never return any excess chemical, solution or mixture

to its original container (unused working solutions

may be recombined, if appropriate (as indicated in the process instructions));

●● ensure spatulas, magnetic stirrer-bars etc. are clean

before use and not transferred between different chemicals, solutions or mixtures.

* The exception to this is the possible re-use of dye

solutions. Chapter 5 includes clear information about

whether a dye solution can or cannot be re-used. For

If in doubt, additional information should be obtained from the supplier because the material may be still

be suitable for use. Local verification procedures may be advisable to assign a suitable date beyond which chemicals, solutions and mixtures must not be used or which indicates the need for them to be checked for quality.

(Where possible, processing solutions have been

allocated guideline expiry periods in the Chapter 5 process instructions.)

Over time and with experience, practitioners should

Ninhydrin crystals. The sample on the right-hand side has anomalous yellow crystals.

become familiar with the chemicals they use regularly. If

any abnormalities are seen, then those chemicals should

not be used. Apart from the physical presence of external contaminants, these changes may include:

maintain the level.

●● unexpected odours;

●● if possible, stock suitably small quantities and re-order

Laboratory environment

information or one may have been assigned arbitrarily.

●● state changes;

Check that the chemical, solution or mixture is still suitable for use:

Index

a chemical may be difficult to determine from supplier

example, an ethanol dye tank may be used repeatedly for treating items, topping up with new dye solution to

Glossary

●● colour changes; ●● gas evolution;

●● liquid separation;

●● precipitation of solids from liquids.

fresh supplies as required;

●● ensure that the chemical, solution or mixture has

been stored correctly, e.g. in the dark or in a fridge,

and remains free from contamination and appears ‘as expected’ before use;

●● a chemical, solution or mixture may not be suitable for

use after the recommended expiry date. Shelf-life for

Home Office January 2014

3.3.4

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory environment

Measuring equipment

The eye line must be level

Mass balances

mixtures required for the processes in this Manual is

meniscus, which indicates

chemicals or viscous liquids for making up the solutions

The accuracy required for making the solutions and

with the bottom of the

generally low and this is reflected by the round-number

the volume of liquid being

quantities given in the formulations. The human,

measured.

environmental and other errors inherent in the processing

in the preparation of these solutions and mixtures.

However, for consistency the quantities specified in

Using the meniscus to accurately measure the volume of a liquid.

Chapter 5 for the processes should be used as far as is

Alternatively, liquids can be weighed to obtain the

Measuring cylinders

is known (NB: density is temperature dependent so

needed for the processes, volumetric flasks, burettes and

Mass (g) = Density (g/cm3) x Volume (cm3)

practical.

When measuring liquids to make up the solutions

pipettes offer an unnecessary level of precision while

beakers cannot provide sufficient precision. Measuring

cylinders of suitable size and volume are suitable for the

purpose. Alternatively, liquids may be weighed, as shown below.

More detail on the specification of measuring cylinders can be found at the end of the chapter in References - Measuring cylinders: classification but for the

needed for the processes. The balances will need to be: ●● suitable for the task; ●● kept in good order;

steps, in addition to the unknown properties of the item or surface being treated, negate the need for high precision

Mass balances will be required to weigh the solid

correct quantity, assuming the density of the liquid corrections may be needed).

Viscous materials should generally be weighed. Examples of different types of measuring cylinder.

●● checked that they are working correctly.

Suitability

To be suitable for the task, a mass balance must be of an appropriate capacity and resolution. The capacity is the maximum mass that the balance can measure. The resolution of the balance is the smallest interval

of mass that can be measured: this is often expressed on a balance as ‘d’, or the number of decimal places displayed.

Example: To weigh 1.1 g of a solid chemical, a balance

must be able to resolve 0.1 g reliably. 1.1 g displayed on a one-decimal-place balance could be any weight between 1.05 g and 1.14 g. This may be sufficient, but if greater

accuracy is needed to maintain the quality of the results,

a two-decimal-place balance may be selected to give the appropriate higher resolution.

processes, unless otherwise stated, those conforming to

Each balance will carry errors and uncertainty of

plastic) are sufficiently accurate.

and during servicing. These factors may be important in

the standards ‘ISO 4788’ (for glass) and ‘ISO 6706’ (for When using measuring cylinders, in order to achieve

the required volume, the meniscus of the liquid should be used as shown below.

measurement, which will be assigned at manufacture

defining the suitability of a balance, especially where the resolution is greater than two decimal places.

A balance with a capacity of 100 g and a resolution of

0.01 g (two decimal places) will generally be suitable for

preparing the process solutions in this Manual. However, Home Office January 2014

3.3.5

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

different capacity and resolution requirements may be needed, depending on the actual mass of chemical

required, for instance if making up large quantities of solutions.

Keeping in good order

Ideally, balances should not be moved but kept in a

position where environmental factors can remain as

constant as possible. In deciding on a position, the nature of the support surface and the likelihood of the balance being exposed to vibrations, draughts and temperature fluctuation all need to be taken into account. Electrical and magnetic interferences to the balance are also

possible, perhaps causing fluctuations in measurements or a gradual drift over time and should also be avoided.

Calibrations are always conducted with balances in their use positions and depend on the balances remaining in the same location (this is most important for balances with fine resolutions).

Excessive or inappropriate use of the equipment must be avoided. Regular cleaning and clearing of spilt materials is essential.

Checks that the balance is working correctly

It is not easy to gauge when balances provide erroneous readings and in order to confirm that balances are

working correctly, there are different checks that can be carried out.

Calibration

If the laboratory is working to the ISO 17025 standard, equipment critical to the quality of its work must be

calibrated. Mass balances are considered to be critical

Home Office January 2014

to the quality of fingermark development solutions and therefore it is essential that they are calibrated.

The supplier of the calibration service must be accredited

Glossary

Index

Laboratory environment error range must be defined and equipment taken out of service if the measurements fall outside this range until suitable corrective measures have been taken.

to ISO 17025 and their calibration work fully recorded

It is essential that records are kept of interim checks and

technician that has performed the calibration must issue

falling outside the agreed tolerance.

and traceable to national standards. The laboratory or

a certificate in a prescribed format that will include the

results (range and resolution), a statement of uncertainty and error and/or a statement of compliance with an

identified metrological specification. The equipment must also be labelled in the prescribed format.

Calibration will need to carried out on a regular basis.

The frequency will depend on a number of local factors

including the level of use of the equipment. Guidance may

any corrective actions taken after identifying balances Reference weights must be appropriate to the system

being evaluated. For example, weights of approximately 5 g and 50 g would be suitable for checking a balance

being used for weighing in that range. The nominal weight of each might be determined immediately after calibration of each balance used for the purpose and a tolerance agreed locally.

be provided by the manufacturer but a commonly used calibration interval is between 6 and 12 months.

In some cases, it may not be possible to have a piece of equipment calibrated to the standard required by

ISO 17025. In these cases extra effort is required by the

laboratory commissioning the work to ensure the chosen calibration organisation is working to an acceptable standard.

Interim checks

Equipment may become unreliable between calibrations

and additional checks may be a useful way of confirming correct working of equipment, either on a periodic basis or immediately before it is used. Although calibrated

weights might be used for interim checking, reference

weights should be sufficient and provide a solution that is ‘fit for purpose’. Whichever is chosen, a pre-determined

3.3.6

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Solutions preparation, storage and use

Simple, complex, saturated solutions and ‘mixtures’ are required for carrying out the processes.

●● The simplest solution is comprised of a single solute

(a solid or liquid minor component) completely

dissolved in a single solvent (major component).

Complex solutions may contain numerous solutes and solvents but in all cases the solutions are

homogeneous liquids which are not subject to separation.

●● A saturated solution is formed when the limit of

the solute’s solubility in the solvent being used has

The general requirements for the equipment needed

are given below, although process instructions should be consulted for their individual requirements. For measuring liquids and solids: ●● measuring cylinders; ●● mass balance.

For preparing solutions or mixtures:

●● suitably sized beakers and bottles made from soda-

lime or borosilicate glass or plastic alternatives will be needed;

undissolved and in the case of saturated solutions of

●● follow the method in standard method for solution

into layers. The solubility of a substance is generally temperature dependent.

●● The term mixture has been applied, for convenience,

to some of the preparations needed for the processes. They contain material suspended or dispersed

Laboratory environment

sections of Chapter 5.

●● stirring equipment, such as a magnetic stirrer plate

liquids, addition of more liquid will result in separation

Index

information can also be found in the ‘Troubleshooting’

been reached. For saturated solutions of solids, the

addition of more solid will result in the solid remaining

Glossary

and stir bars; preparation.

For storing solutions:

●● clean bottles of suitable material and labels (see safe

handling of chemicals, solutions and mixtures and packaging and labelling).

through a liquid, rather than dissolved, and include Small Particle Reagent and Powder Suspension.

For the guideline expiry periods and instructions for

the preparation of the processing solutions and mixtures the relevant information is in Chapter 5. This gives the quantities needed and any specific requirements for

making up and storing the solutions and mixtures. In each

case the expected appearance of the solutions is given so that any errors can be rectified before use. Some useful

Home Office January 2014

3.3.7

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory environment

Standard method for solution preparation

Select a clean beaker of suitable volume

Weigh out the appropriate amount of any solid or viscous liquid solute(s) required and transfer to the beaker*

Measure out the appropriate amount of any liquid solute(s) required and transfer to the beaker* Measure out the volume of solvent required and transfer to the beaker*

a) Select a beaker large enough to prevent spillage during handling and mixing, and place a clean stir bar in it. a) Mass balance preparation. Check the mass balance is clean and: ●● of the appropriate capacity and resolution; ●● is within calibration; ●● verified for accuracy (if required) by reference weight(s) being within tolerance; ●● used according to specific instructions given by the manufacturer. b) Place an appropriately sized weighing boat onto the centre of the pan ensuring the boat is supported entirely by the balance. Then set the balance to zero (tare). c) Using a suitable clean tool, transfer material from the container to the weighing boat, being careful not to drop any on the pan, until the desired weight is reached. d) If too much material is transferred, the excess should be considered waste and disposed of appropriately (not transferred back into the original container). a) Liquids should be carefully poured into a clean graduated measuring cylinder, that is sized appropriately for the volume being measured, until the bottom of the meniscus reaches the desired level (see measuring equipment). b) If too much liquid is transferred, the excess should be considered waste and disposed of appropriately (not transferred back into the original container).

Stir until completely dissolved

a) Place the beaker on the magnetic stirrer plate and stir gently until all solids have dissolved or liquids have thoroughly mixed. Ensure that mixing is conducted in a controlled way, using the magnetic stirrer on a slow speed. If the solution needs to be left mixing over an extended period of time, or unattended for any other reason, the beaker should be covered using a suitable film. This will prevent contaminants entering the solution, or volatile solvents evaporating. b) Some detergent solutions may become aerated during mixing and produce foam. If left to stand, the solution should settle within minutes.

Transfer solution to a suitable container for storage

a) Remove the stir bar from the beaker with a ‘stir bar retriever’ (a separate magnet on the end of a long stick, usually Teflon-coated). b) See safe storage of chemicals, solutions and mixtures for more details.

Consult Chapter 5 for additional requirements for individual processes.

*It may be necessary to use some of the pre-measured solvent to rinse all the solute(s) from the weighing boats to ensure all the chemical is transferred to the beaker. This is good practice, particularly if the solute is a viscous liquid.

Home Office January 2014

3.3.8

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Effective application of solutions

Once prepared and labelled, the solutions will be ready for use. Chapter 5 contains detailed information on

the appropriate methods of application of the process

solutions to items and any safety precautions that must be adhered to. For example, if flammable or hazardous

Glossary

Index

Laboratory environment

Example: treating a large, vertical surface Solvent Black 3 (SB3) is easy to use on small areas, no larger them 30 cm x 30 cm, but areas larger than this should be treated section by section. When applying

Solvent Black 3 in this way the aim, whether applying to

vertical or horizontal surfaces, is to prevent SB3 Working Solution and rinse water from running or splashing

onto adjacent sections which are yet to be treated. Any

visualised fingermarks should be imaged before the next section is treated.

solutions are being used there are clear warnings that they must not be sprayed.

C

Processing small items may not present any particular issues when applying process solutions to them, but

treating large items may present a number of issues. Dismantling surfaces from a scene or cutting items to make them more manageable is discussed later (see

B

B

preparation of items for processing).

There may be no alternative but to treat large items intact. This presents particular problems when applying dye

solutions, where the solution needs to be restricted to the area being treated and run-off onto areas still requiring

treatment prevented. The example below shows how this can be achieved when using Solvent Black 3 to treat a

door, but the strategy could apply equally to applications

A

A

SB3 Working Solution is applied in sections from the

After application of SB3 Working Solution, the area

over areas already treated (A). Any fingermarks found on

section A (treated previously). Any marks developed in

bottom up. In this way, excess dye solution runs down those areas will have already been imaged.

is rinsed with water. The rinse water flows down over section B will be imaged before section C is treated.

of other dye solution or mixtures, such as Powder

Suspensions or Small Particle Reagent to large areas.

Home Office January 2014

3.3.9

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

In Chapter 2 the importance of good handling of items was stressed in order to:

●● preserve any potential evidence that may be present; ●● prevent any further damage or deterioration to the

evidence.

Some other issues are covered here to illustrate how to handle the items or surfaces to maximise fingermark recovery while maintaining fingermark evidence

integrity. At all times, the practitioner needs to ensure

that recovery of evidence from other forensic disciplines

is not compromised unnecessarily. Chapter 7 has further information on possible interferences between different types of forensic evidence.

It is recognised that there are many more operational issues, requiring strict procedures to manage items

effectively, which fall outside the remit of the Manual, such as:

●● evidence continuity; ●● evidence security;

●● interpretation of evidence; ●● proficiency testing;

●● use of computerised results recording; ●● court statements and peer review.

Fingermark evidence integrity

During the handling of items for fingermark evidence recovery, there will be many opportunities, through

multiple handling, packaging, transport, storage and examination for evidence to be compromised. If the integrity of fingermark evidence is demonstrated to

be flawed, a strong case cannot be developed during Home Office January 2014

Glossary

Index

Handling items

the investigation and the opportunity for a satisfactory

carried and the validity of the procedures that have been

that the chain of evidence remains intact and every effort

carrying out the visualisation processes. Accreditation of

conclusion will be missed. It is therefore very important

made to maintain the integrity of any forensic evidence. Although many of the integrity issues relate directly

to the handling of the item and the evidence upon it,

followed as well as the competence of the practitioner(s)

forensic service providers to ISO 17025 addresses many

of these issues and it is not appropriate for the Manual to consider them in more detail here.

there are broader issues that may influence a decision

It is essential, however, to stress the importance of sound

the integrity of the organisation in which the analysis was

selecting the most appropriate approach to recovering

regarding the robustness of any findings. These concern

Imaging in the laboratory (top) and at scenes (bottom).

decision-making and record-keeping by practitioner(s) in

fingermark evidence, in line with the recommendations in Chapters 2 and 4.

Imaging

It is vitally important to record information from all

fingermarks visualised by imaging at key stages during

the recovery of evidence. Even with the most considered plan for fingermark recovery, evidence may be lost at any stage, so it is important after every process that any marks visualised are identified (see labelling of

visualised fingermarks) and imaged. Also, the location and orientation of any visualised marks on the item or surface must be imaged to aid later interpretation.

Images also need to be taken at scenes, possibly of

the item or surface in situ, as well as any fingermarks

visualised there. This will be most common for marks in contaminants or for powdered fingermarks.

Contamination and cross-contamination

This was first discussed in Chapter 2 with regard to the

care needed in the recovery of all forensic evidence from scenes and items. During the handling of items, the

risk of contamination or cross-contamination must be

considered, especially if items are being processed for

3.3.10

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Fingermark evidence integrity

Index

Handling items Changing gloves on a regular basis will also prevent

continued

the possible transfer of contamination picked up on the gloves to surfaces submitted for examination, which

fingermark recovery first, before later submission for DNA

in turn could interfere with the fingermark visualisation

analysis, for example.

processing.

Personal Protective Equipment (PPE) appropriate to

Preventing damage

the situation will be needed throughout the fingermark

Preservation of evidence by preventing damage to items

evidence recovery process whether at scenes or in the

or surfaces suitable for fingermark evidence recovery

laboratory. ‘Standard’ PPE will usually be needed as a

should start when the scene is first investigated, as seen

minimum, both to protect the practitioner from hazards

in Chapter 2. It is important that both the physical and

but also to help maintain the evidential integrity of the

chemical integrity of fingermarks is maintained as far as is

item.

practical.

In the case of fingermarks, the wearing of suitable hand

To minimise damage to fingermarks arising from frictional

protection is essential. As long as they are changed

contact, items should ideally be handled as little as

possible. They should also be handled as carefully as

The torch grip in this example would be a good place

possible wearing gloves and touching only the edges of

to handle the exhibit as the chances of recovering large

the item or in areas where fingermarks are least likely to

areas of friction ridge detail from the textured handle

be found.

would be low.

Effective packaging

There are various types of packaging, which commonly

include paper or plastic bags, rigid cardboard boxes, and

hard plastic tubes (sometimes reinforced with metal ends) Examples of good handling ensuring minimal damage to items.

frequently, gloves should prevent the examiner from contaminating surfaces with materials inadvertently

picked up on the gloves or avoid their own fingermarks being generated on the surfaces being handled. If this were to occur, original fingermarks could be obscured and the integrity of the evidence called into question. Home Office January 2014

for securing sharp objects. Used correctly, they should protect items from damage in transit or storage.

The benefits and disadvantages of using visualisation processes for fingermark recovery at the scene in preference to taking items back to the laboratory

environment were discussed in Chapter 2. A major

consideration was whether the removal and transport

of the items was likely to cause any deterioration of the evidential material and the need for suitable packaging

3.3.11

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Glossary

3.3.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Fingermark evidence integrity continued

to prevent this was emphasised. Although laboratory practitioners may not be responsible for the original

packaging, they have to manage the effects of poor

packaging, which may not only affect the potential to

recover fingermarks but may also compromise their ability

✘

When trying to protect fingermarks it is important to remember that:

●● latent fingermarks can be destroyed or their

✔

laboratory but may also require suitable storage after

processing for fingermark visualisation, perhaps waiting to be imaged or the next process to be applied.

Depending on the way items or surfaces are found, they

may have been in a suitable condition for immediate and

perhaps because it is too large, it will require careful An incorrectly packaged drinks bottle. composition compromised through inappropriate or careless packaging;

●● tight packaging is damaging to latent fingermarks,

especially on non-porous surfaces where they may be particularly fragile;

●● rigid packaging that allows movement of the item in

transit may cause damage to fingermarks through

frictional abrasion, so careful immobilisation of the

item using pins or ties is needed to minimise damage;

●● if an item has been packaged wet or was

contaminated when it was packaged, then drying it or removing the contamination may help to

minimise latent fingermark degradation or surface

contamination, particularly if the item will need to be stored for some time before it is processed.

© See Photo Credits

Items will generally need to be stored on arrival at the

laboratory. If the item or surface cannot be packaged,

reasons; from time issues, availability of suitable types of

damage.

preserve any fingermark evidence as far as possible.

appropriate packaging before transferring them to the

Poor packaging of items may occur for a number of

might be important or how it needs to be protected from

Index

Handling items

to store the items effectively.

bags or boxes, or lack of knowledge about what evidence

Glossary

Effective storage of items

Items must not only be stored securely, to enable the

handling and storage to prevent damage to any potential fingermarks.

However, items may have been found wet or damp

through exposure to water or body fluids or contaminated with organic materials, such as petrol or paraffin. In

these cases they need to be dried and imaged before

placing into storage. If containers have been packaged inappropriately with liquid still inside they should be

emptied fully, dried and repackaged before placing safely into storage.

Items that have been submitted for sequential treatment may need to be dried before interim storage or applying

the next process. Drying of items must be done in a way that prevents damage to any fingermarks that may be present.

Items that are no longer required may be removed from

the store and disposed of appropriately. See disposal or return of items.

chain of evidence to be sustained, but also stored A correctly packaged knife. Home Office January 2014

appropriately, to maintain the integrity of the item and

3.3.12

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Handling items

Fingermark evidence integrity

damage to fingermarks and does not compromise the

Drying of items

Items may need to be prepared for practical reasons.

continued

continuity of evidence. For example:

Items should normally be dried at temperatures below

●● some items may require separation of component

30˚C. The use of excessive heat, such as using hairdryers,

parts, e.g. a letter inside an envelope;

for instance, may speed up the process but may damage

●● significant lengths of adhesive tape may need to be

fingermarks and may destroy the integrity of the evidence.

cut into smaller, manageable sizes;

Fume cupboards are suitable for drying items

●● Numberplate Splitting or Soot Removal can be used

contaminated with organic materials and many items

awaiting imaging and further processing. Biological safety cabinets, if available, may be suitable for containing

biologically hazardous items while they dry. Care must be taken to avoid physical damage to the items or

to expose fingermarks.

Cutting technique to facilitate easier handling of a piece of

In other situations, items may need to be prepared to

to allow for correct reconstruction.

effectively:

adhesive tape. The tape sections are cut in different ways

fingermarks by preventing movement of the items in the airflow.

Some items, for example those that have been dyed after

Superglue Fuming, may be dried by suspending them in a

wet area of the laboratory, preferably near to an extraction system to remove residual vapour.

Some fingermarks may have been made visible by the drying process, so items should be re-examined and

images taken of any additional fingermarks visualised.

Conversely, wet marks can sometimes show more detail than dry ones and a better image may be obtained prior to drying or by re-wetting the item.

Preparation of items for processing

Items may need to be prepared before the processes

can be applied but care must be taken to ensure that any

action taken is recorded and done in a way that minimises

Home Office January 2014

ensure that visualisation processes can be applied most ●● complex items may need certain areas to be masked

A carrier bag can be split along the seams to open it up.

This may be necessary to aid drying after applying a dye process or to treat the inside surface for fingermarks.

to target the application of visualisation processes;

●● part of a larger structure may need to be removed

from a scene to the laboratory to be able to use a process that might be hazardous at a scene e.g. dismantling part of a tiled area of wall to apply Superglue Fuming;

●● cutting and opening out plastic bags to provide flat

surfaces for processing and examination.

If a decision has been made to dismantle or cut an item, every effort should be made to handle the item with

care and to cut along areas, or separate at joins that are unlikely to bear latent fingermarks.

If cutting physically separates an exhibit into two or

more pieces, consideration should be given to cutting in distinct patterns to aid re-assembly. Images or

sketches may be used to demonstrate the context of any

3.3.13

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Glossary

3.3.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Fingermark evidence integrity continued

fingermarks visualised and maintain evidential integrity.

Labelling of visualised fingermarks

Visible fingermarks or those visualised after processing,

Index

Handling items

Post-processing

Care must be taken when handling items after processing as visualised fingermarks can be fragile. Valuable

evidence may be lost if damage occurs before images can be taken.

need to be identified or ‘marked up’. (See Chapter 2 Section 2.5 for more information.)

It is important not to damage fingermarks during handling for marking up or to use an inappropriate means of

marking up. A method for marking up must be found that is fit for the purpose of identifying visible fingermarks or

those visualised after processing. There are many factors to consider, including:

●● ensuring there is sufficient information to clearly

identify the marks and how they have been visualised;

●● a permanent method of identifying marks that will

not fade or detach during subsequent processing or storage, such as the use of: ■■

appropriate pencils or chinagraph pencils for porous and non-porous items;

■■

suitable labels: ❍❍

Latent fingermark on glass, deliberately touched with a gloved hand to illustrate the damage that

can be done, where (top) is before and (bottom) is after contact.

labels that match the fluorescence expected during Fluorescence Examination so that

correct exposure can be found for imaging; ❍❍

labels that are not too large;

●● the positioning of markers so that latent fingermarks

are not obscured, or made harder to visualise.

Care will be needed to avoid disturbing areas when

subsequent processing may reveal additional marks, in part or whole, as in the example below. Home Office January 2014

After the initial mark visualisation process was applied, fingermarks were labelled. The positioning of the labels proved to be detrimental, as a second process

improved upon the initial development.

3.3.14

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Glossary

3.3.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Handling items

Fingermark evidence integrity continued

Silver VMD-treated plastic. Handling post-treatment has caused areas of the surface coating to be removed (seen in the right-hand image).

Fingermark developed

with Powder Suspension

has been damaged due to careless post-treatment handling.

Home Office January 2014

Damage caused to a fingermark visualised using Superglue Fuming through poor postprocessing handling.

3.3.15

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Imaging

Image management

Image capture

is essential that any image taken provides examiners with

for making comparisons with other fingermarks or

Before an image of any fingermark is captured, the

on identification or exclusion. Any image submitted for

To obtain a fingermark image that is of optimum quality fingerprints, it is necessary to consider the stages that

occur from image capture to the point at which the image is received by an examiner. All of these stages have

factors associated with them that need to be managed

if an image of appropriate quality is to be obtained. The main stages are outlined below.

Use of fingermark images

purpose for which the image is being generated must be

considered. This may influence which imaging equipment and image capture processes are selected.

There are three main reasons for image capture:

1. to produce an image suitable for identification (and/or intelligence) purposes;

2. to produce a permanent record of the fingermarks that have been visualised;

3. to produce an entirety or overview image suitable for

Lighting conditions

Master Copy

Working Copy

Post capture processing

Printed image

Transmission /transfer

Received by bureau

Home Office January 2014

item or surface on which they were visualised. Maintain audit trail of enhancement and capture processes, and all adjustments Maintain audit trail of enhancement and capture processes, and all adjustments

Image capture

placing fingermarks in context with respect to the

The first two purposes are not mutually exclusive and in many cases a single image of a fingermark may satisfy both objectives. In other cases it may be necessary to capture multiple images to satisfy one, or the other, or

both purposes. ‘Complex’ marks* may require a selection of images of the mark to be captured and presented to

the examiner so that they can decide which is most fit for purpose. This selection may include colour images which are often most informative in confirming the means by which the fingermark has been visualised.

Images created to place the fingermarks in context are

all the information necessary for them to make decisions comparison must:

●● be captured in sharp focus with an adequate depth of

field;

●● contain a linear scale or reference features to enable

accurate dimensions to be recorded;

●● contain all features of significance captured at a

resolution appropriate to that feature type.

In addition, images submitted should also: ●● have clear distinction between what constitutes a

fingermark ridge and what constitutes ‘background’;

●● be captured in a plane parallel to the fingermark to

prevent geometrical distortion.

The means by which the above criteria can be satisfied are described in greater detail below.

* ‘Complex’ marks in this context are taken to include those where the flow of ridge detail is not easily

discriminated or is open to differences in interpretation; for example, because they are blurred, distorted,

faintly developed, obscured by background features or background development.

not generally suitable for identification. Separate images should be taken for either identification or for contextual

purposes rather than trying to provide a single image that is a compromise between the two.

To meet the requirements for fingerprint identification, it

3.3.16

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Index

3.3.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Imaging

Equipment

The use of stable tripods, poles or arms etc. and shutter

predecessor of this Manual, contained information on the

image capture is recommended. This is particularly

The Manual of Fingerprint Development Techniques, the

use of film photography. However, since digital imaging is

now used throughout the United Kingdom this section will

exclusively refer to image capture using digital equipment. There is a wide range of equipment that is available for

digital image capture, including highly portable equipment

release cables or mechanisms to provide stability during relevant when exposure times longer than 1/100 second are required. The imaging system should be kept level

and perpendicular to the mark during image capture. A

spirit level and an angle finder are useful accessories for this purpose.

such as camera phones. However, it is recommended that

In some instances, for example when using specular

capture at high resolutions and controllable depth of field

a perpendicular position. In such cases, the use of the

only dedicated imaging equipment with the capability for is used for fingermark imaging, suitable examples being:

●● Digital Single Lens Reflex (DSLR) cameras or modern

equivalents which can be used with interchangeable lenses;

●● linescan cameras; ●● flatbed scanners;

●● machine vision cameras.

Where DSLRs are being used, the same general rules as film photography apply and images should be captured with an adequate depth of field and sharp focus.

A fingermark developed using Superglue Fuming on a cup with curvature in one direction and reducing diameter in

the other, (top) imaged with an aperture of f32 (high depth of field) showing most areas of cup in focus, and (centre) imaged with an aperture of f2.8 (low depth of field) with only the top of the cup in focus and (bottom) imaged

using the camera in hand-held mode rather than using

a copystand, exhibiting blurring of the ridge detail in the image due to camera shake.

Home Office January 2014

lighting, it is not possible to view or capture a mark from shift movement on a tilt-shift lens can avoid geometric distortion. If such a lens is not available, geometric

distortion should be kept to a minimum and an angled scale such as the ABFO (American Board of Forensic Odontology) standard small scale should be used.

The use of a geometric transform process should be

considered to restore the resultant image, although this should only be used if the angle from perpendicular is less than approximately 25˚.

For equipment such as flatbed scanners with fixed image capture conditions, it may be necessary to carry out

calibration and resolution checks to ensure that they meet requirements.

Where image capture is being performed outside the

visible spectrum, the image capture system used must

be capable of recording the type of radiation being used to produce the image. Conventional camera systems

usually have ultraviolet/infrared (UV/IR) blocking filters

fitted to the sensor and will therefore not be suitable for recording UV or IR images.

3.3.17

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Glossary

3.3.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Imaging

IR radiation can be recorded using either scientific grade

or objectionable lens aberrations. A lens that cannot

fingerprints on the arrest form or those stored on the

filter has been removed. UV radiation can be recorded

is unsuitable.

magnification, i.e. 1:1, for a valid comparison to be made.

or specially adapted cameras where the UV/IR blocking

using capture systems with specially modified sensors, or by using sensors coated with phosphors that convert UV

radiation to visible light. Special lenses are also required if

short-wave UV radiation is to be captured as conventional glass and plastic lenses block this radiation. See further notes on UV and IR imaging under the relevant sections of Chapter 5.

The equipment needed for capturing images of

fluorescent marks is essentially the same as that used

for imaging marks using reflected white light but with the

addition of specialist filters fitted to the imaging system to enable the fluorescence to be viewed. Imaging systems that are sensitive to low levels of light will be most effective when capturing fluorescent marks.

Imaging fluorescent marks may in many cases be easier than imaging some visible marks because results are

significantly less dependent on optimising the angle of

illumination. However, since exposure times for imaging

fluorescent marks are generally greater than 1/10 second, the use of equipment such as tripods to stabilise the

imaging system during image capture is recommended.

Lenses

Macro lenses (fixed focal length rather than zoom), should be used for fingermark imaging wherever possible. Macro lenses are designed to perform well at close range and to give minimal distortion across the entire imaging

area, whereas other lenses may perform poorly, e.g.

producing distortion towards the periphery of the image Home Office January 2014

focus at the close range necessary for fingermark imaging Standard lenses are suitable for capturing images in the

near IR region of the spectrum although some adjustment

fingerprint database. Both images must be at the same

Where colour is important a suitable colour scale should be used.

of focus position will be required. Conventional glass

Examples of scales and labels that may be included in the

UV region of the spectrum and specialist lenses fitted with

or for balancing colour.

optics are not suitable for UV imaging in the short-wave UV transmitting optical elements (made from materials

image of a mark to provide a means of rescaling the image

such as quartz) must be used in these applications.

Optical filters

A range of camera filters will be required in order to image fingermarks visualised using the processes described in this Manual.

Filters that selectively transmit certain wavelengths

(colours) of light are essential when imaging fluorescent fingermarks or when imaging in the IR/UV regions of

the spectrum. These types of filters can also be used to reduce background interference or increase the

contrast of fingermarks imaged in the visible region of the spectrum. Polarising filters are commonly used to reduce the glare from reflecting surfaces thereby increasing the

contrast between fingermark and substrate. More detailed information on filter selection is given in Chapter 5 of this Manual.

Scales

The image that is captured of the fingermark must contain a linear scale, or known points of reference, such as the

marking-up label, that enable the scale to be determined. This is essential otherwise it will not be possible to make a valid comparison between the fingermark and the

3.3.18

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Imaging

Image capture resolution Definition

One consideration associated with digital imaging is

to ensure that the image of the mark is captured at an

●● greyscale images captured at 500 ppi are

appropriate resolution.

generally sufficient to allow all second-level

detail (ridge endings and bifurcations) to be

The concept of pixels per inch is used in describing

resolved;

capture resolution; how this value is derived is illustrated

●● a sampling frequency of at least 1000 ppi is

below.

required if the image is to be used for analysis

A camera sensor consists of an array of light-sensitive

of fine ‘third-level’ features such as pore size

elements called pixels. These become visible in an image

and shape;

when it is significantly magnified. In simple terms the

capture resolution (in pixels per inch) is the number of

●● capturing images at higher sampling frequencies

pixels on the sensor (and therefore in the resultant image)

An image (right) containing a scale and a magnified

placed next to the mark would fall. In the example on the

form the image to indicate how the image resolution of

across which the projected image of a one inch scale

right, it can be seen that a one millimetre section of the

scale equates to approximately 50 pixels, giving a capture resolution of 1270 ppi.

Requirements

The capture resolution selected should:

●● allow reproduction of the features of interest within the

mark;

●● be compatible with the resolution requirements of the

appropriate local, national or international fingerprint database.

The resolution requirements for input of images onto the

UK national fingerprint database are that an image needs to be at 500 pixels per inch (ppi) sampling frequency. It should be noted that ppi is too simple a figure to fully

specify image resolution because it does not take into account the effects of focus, sharpness, image noise, Home Office January 2014

portion of the scale (left) showing the individual pixels that 1270 ppi can be derived.

resampling, e.g. from 1200 ppi to 1000 ppi, and rotation, for example.

It is important to remember that a higher level of detail may be initially captured but later discarded from a

working copy, e.g. when resampling from 1200 ppi to

500 ppi, but if the higher level of detail is not captured it cannot be recovered, e.g. attempting to resample from

500ppi to 1200ppi. A more detailed descriptor than ppi is the modulation transfer function (MTF) of an imaging device (or chain of devices, such as lens, camera,

software, printer). MTF requirements are specified in

some instances but in general, there is currently no widely adopted fingermark image resolution standard, in which

case the following guidelines allow a pragmatic approach:

(1000 ppi and greater) and rescaling to 500 ppi

provides better reproduction of fine detail than if the image is captured at 500 ppi initially;

●● capturing images at sampling frequencies below

500 ppi produces poor quality images and may compromise identifications;

●● a sampling frequency of 1000 ppi is required

when using a colour camera in order to capture a similar level of detail that would be captured by a

monochrome camera capturing images at 500 ppi. Capture resolutions in excess of 500 ppi can readily be achieved using digital cameras with sensors of greater

than 4 megapixels and filling the frame with the image of the mark. For flatbed scanners, scanning resolution can

be set to an appropriate value (either 600 ppi or 1200 ppi). Resolution scales consisting of sets of lines of decreasing separations may be imaged and used as a means of

checking that the required resolution is being achieved. The effect of different capture resolutions on the detail

within the resultant image of the mark is illustrated left.

3.3.19

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Index

3.3.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Imaging

File format

The file format for image capture must be selected to

take into account both the requirement to keep a master

copy of the image and to produce a working copy that is capable of being transferred onto the national fingerprint database.

DSLR cameras and image capture systems allow the

image files to be saved in various file formats, including JPEG (.JPG) (Joint Photographic Experts Group),

JPEG2000 (.JP2), RAW (the general term for proprietary

raw formats although each manufacturer has its own, e.g. Nikon’s .NEF and Canon’s .CR2) and TIFF (.TIF) (Tagged Image File Format).

Common terms

Bit depth refers to the number of discrete levels of grey that can be represented in an image, where the number of possible levels equals the number two raised to the

power of the quoted number, hence an 8-bit image can represent 28 or 256 levels of grey and a 16-bit image

can represent 216 or 65,536 levels. Colour images are,

in effect, combinations of three greyscale images – one for each of the primary colour channels: red, green and blue (RGB). The resulting numbers of possible colours

are then 256 x 256 x 256 and 65,536 x 65,536 x 65,536

respectively. Confusingly, an 8-bit colour image may also be referred to as a 24-bit image because 3 x 8 = 24. Bit depth is related to, but is distinct from, dynamic range.

Dynamic range relates to the overall range of exposure

Images of a fingermark visualised using Ninhydrin captured at 250 ppi (left) and 2000 ppi (right), showing the original

number of separate levels that may be coded within that

clarity in second-level detail, whereas the enlarged 2000 ppi image shows clear second-level features and defined pore

that may be recorded whereas bit depth relates to the range.

Home Office January 2014

image (top) and the image converted to greyscale and enlarged (below). The enlarged 250 ppi image shows lack of structure in the ridges.

3.3.20

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.21

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Imaging

Image compression refers to the process of reducing

file, i.e. image data remains unchanged. Raw files tend

capture of fingermark images. However, the selection

is achievable only at small compression ratios: data

than other file formats. Raw files are essentially ‘digital

should take into consideration a range of factors including

file size by discarding data. Lossless compression are discarded with no loss of information. ‘Lossy’

compression allows higher compression ratios; the

higher the ratio, the more data that are discarded, with a subsequent loss of information.

Imaging chain refers to the string of devices through which an image may pass from capture to output. A common example is: image captured with camera,

enhanced and resized with computer software, viewed on screen, saved to a database, output via a printer.

to have greater bit depth and greater dynamic range

negatives’: various subsequent images may be derived but the original is unaltered.

TIFF: files are generally uncompressed; however, the

standard does allow for certain types of compression

imaging chain. In other cases there may be many steps in the chain. The effect of every individual step in the chain

as well as the total effect of the entire imaging chain must be considered.

are changed.

change the actual raw file but apply the manufacturer’s decoding when opening these files and similarly no changes are made to the file when editing: editing

information is stored in an associated but separate Home Office January 2014

certain file formats.

and JPEG2000 will produce images that are perceptibly

already be compressed by a reduction in dynamic range and bit depth. JPEG images may display characteristic ‘blocking’ artefacts as a result of the compression algorithm. There are 12-bit and ‘lossless’ options

defined in the JPEG standard; however, these not widely supported in products.

that of the Wavelet Scalar Quantisation (WSQ) file format,

editing, printing ,etc. Raw converters (software) do not

the chain, are aware of, in particular, the weaknesses of

JPEG originating from a device with a higher bit depth will

data from the image sensor. A raw file is proprietary to

to be converted to a non-proprietary format for viewing,

relying on images, particularly the examiners at the end of

Generally the prime concern is in relation to lossy image

JPEG2000: is fundamentally different from JPEG. A

the manufacturer and the imaging system and may need

of the formats outlined previously needs necessarily be

which may result in the loss of relevant information.

Properties of common file formats

RAW: A ‘raw’ file is unprocessed or minimally processed

given below.

avoided but it is imperative that operators and those

changes are embedded into the file, i.e. the image data

Generally, JPEG files are 8-bit colour images so any

the image will undergo minimal change throughout the

subsequently transmitted and stored. Further guidance is

be either 8-bit or 16-bit. When a TIFF file is edited any

some cases an image may be captured at the required

a fully digital workflow, i.e. with no printing, in which case

processing software available and how the image will be

Each file format has its strengths and weaknesses. None

be discarded but no information is lost. TIFF files may

JPEG: files are compressed using lossy compression,

output resolution and at the required quality, possibly in

the clarity of the mark, the capture equipment and

although these are considered lossless, i.e. data may

Workflow refers to the ‘direction of travel’ of an image through the imaging chain from capture to output. In

of the most appropriate file format for image capture

different compression algorithm is employed, similar to which was specifically designed for fingerprint images. JPEG2000 is considered suitable for some fingermark

applications because it allows higher compression ratios with less perceptible artefacts. JPEG2000 compression does not result in blocking artefacts.

All the file formats outlined above can be used for the

compression. At relatively low compression ratios JPEG

identical to uncompressed images. In some cases, even high compression ratios can be achieved before any

visible difference is perceptible. This may be extremely useful at the end of an imaging chain, for example to

save transmission time over a wireless network. In other instances this apparent strength is a weakness of major concern. Consider a faintly fluorescent fingermark on a

disruptive background. The resulting image may have low contrast, poor colour definition and high noise content. In such a case it is precisely the initially imperceptible

differences that, for example, a 12-bit raw file will record and that may later be relied upon. The raw file can be enhanced to a far greater extent to reveal far more

information than if the image had been saved initially

as a JPEG. Once again it is a case of not being able to

recover data once they are discarded. Where and why,

3.3.21

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.22

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

data are discarded; where and why, in the imaging chain any particular file format is chosen are issues that must be considered.

For the purposes of producing a master copy of the

image, it is recommended that files are initially saved in RAW format. If RAW is not an option, TIFF is the next

preference. RAW files contain all of the original capture

information associated with the image. TIFF files do not suffer from compression artefacts.

File format compatibility with the national fingerprint database

The requirements of the UK national fingerprint database are that the file is at 500 ppi, 1:1 scale, 8-bit greyscale

and in TIFF, JPEG, JPEG2000, WSQ or BMP (Bitmap) file format.

TIFF files can be loaded directly onto the UK national

fingerprint database whereas RAW files cannot. However, RAW files can be readily converted to other file formats

that are compatible with the database requirements using most standard image processing software.

Post-capture Copying Master copy

Digital imaging procedures developed by the Home Office require the creation of a master copy of each

fingermark image that is captured. The master copy

represents the image in its original, unmodified state and,

as stated above, either TIFF or RAW file formats are most appropriate for this application.

The master copy must be stored on either a ‘write once,

read many’ (WORM) medium such as a CD-R or DVD-R, or saved on a secure database. The master copy must not be capable of being modified or overwritten and is kept to act as a reference image if digital evidence is

ultimately presented in court. A means of demonstrating the integrity of the master copy, e.g. sealing CDs in a

signed tamperproof bag, may be required by the court.

Working copy

In many cases, the original image as captured does not

represent the most useful image for comparison purposes and some processing of the image will be required prior to comparison. Processing tools must not be applied to the master copy so a separate working copy is created

from the master copy and any image processing required is applied to the working copy only.

TIFF files can be used as working copies but if continued use of RAW files is required the same software package must be used during subsequent viewing as that used for initial editing. This is because the associated file of processing modifications needs to be applied to the

image in the same way, e.g. proprietary RAW conversion Home Office January 2014

Index

Imaging software may not translate the processing file in the same

way as a commercial package. RAW files can be modified and then converted to another format (TIFF or JPEG) on saving as the working copy. The processing steps are

embedded in the image and they can be read by almost any image reader. Any processing that is applied to the

working copy must be recorded and this is described in

the audit trail section. An advantage of using RAW files is that this information is produced automatically during processing and kept in a separate associated file.

Processing It is generally far preferable to optimise the image

prior to capture by using appropriate lighting, camera settings and optics than by post-capture image

processing because in the latter case some of the original fingermark detail may be lost.

A wide range of digital enhancement tools and software applications exists, allowing myriad enhancements to be made to digital images. Post-capture processing

options range from simple enhancements, e.g. contrast and brightness or resizing/rescaling, through to the

application of advanced processing algorithms such as the Fast Fourier Transform. While it may be appropriate

for basic enhancement functions to be applied by those with a basic knowledge of image processing, advanced processing functions should only be carried out by

practitioners who are trained and competent in image capture and the use of such tools. The use of post-

capture processing must be accurately documented, which should be in the form of an audit trail. Useful

guidelines include the Home Office’s Digital Imaging

3.3.22

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Glossary

3.3.23

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Procedure and those published by The Scientific Working Group on Imaging Technologies (SWGIT).

If image processing has been applied it should

be communicated to bureau staff (see Chapter 2 Section 2.5).

Provision of detailed guidance on the use of the wide

range of post-capture digital processing techniques to

enhance images is considered to be beyond the scope of this Manual and other appropriate texts should be consulted for this information.

Printing images

Consideration needs to be given to the way in which

digital images are outputted for identification once they have been captured. It should be noted that very few

Glossary

Index

Imaging

digital printers are able to reproduce fingerprint images of

is another example, like ppi, where the simple figure is

is the requirement for input to the UK national database.

be conducted using a selection of representative images

500 pixels per inch (ppi) resolution at a 1:1 scale, which

Where possible, images should be kept and transferred in their digital form between the laboratory, the bureau and

the database to maintain image quality. If images must be

insufficient to define the exact requirements. Tests should to determine what detail is being lost with any printer and, therefore, its suitability for fingermark imaging.

printed, bureau staff must be made aware of the following issues.

The print resolution of most printers is in the range 300400 dots per inch (dpi) and therefore deterioration in

image quality will occur if the image is transferred to print at a 1:1 scale. Much higher dpi figures may be quoted,

particularly by inkjet printer manufacturers, partly because different printing technologies require different numbers of dots to reproduce similar detail. Dots per inch (dpi)

Original digital image (top right) and high magnification images of prints from different digital printers illustrating a range of abilities to reproduce fine detail.

Home Office January 2014

3.3.23

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.24

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Audit trail

Maintaining an audit trail from the time that the image is

or otherwise compromised. For example, non-image data

essential for evidential purposes. The audit trail should

image is printed.

captured to the time it is transferred to an examiner is include the following information:

Glossary

Index

Imaging

are not generally transferred to the hard copy when an

●● the method(s) used to enhance the mark and by

whom;

●● the conditions and equipment used to capture the

mark (camera, lens, lighting, aperture, exposure time);

●● the time and date of capture and by whom;

●● the nature and order of any post-capture processing

functions, including any change in file format, that have been applied to the image and by whom.

Digital images of marks that are presented in court are

usually modified working copies. If the provenance of any digital image comes under question, it may be necessary to demonstrate how the working copy has been derived from the original master copy. It should be possible to demonstrate that the working copy can be repeatedly

Master copy

obtained from the master copy by following the audit trail and therefore accurate recording of all relevant information is essential.

The audit trail may include both automatically generated and manually input data. Automatically generated

+

data may include the various camera settings, stored

as non-image data embedded in the image file. Some commercially produced laboratory imaging systems

automatically record audit trails. For portable equipment, camera settings, e.g. date and time, should be checked

regularly to ensure they are accurate. Image management must include assurance that the relevant data are not lost Home Office January 2014

Working copy

3.3.24

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.25

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Imaging

Image storage

Communication

colour balancing is carried out so that the representation

of developed fingermarks, other considerations become

good communication between those responsible for

reproduced accurately at a later step in the imaging chain,

For capturing images for storage as permanent records

important such as the longevity of the file format in which

the image is stored, the longevity of the medium on which it is stored, and the means of archiving the image.

These considerations are more fully covered in Home

Office publications. It is also proposed that stored images

Chapter 2, Section 2.5 highlights the importance of

image capture and those responsible for examination and comparison of fingermarks and gives examples of how

this might be achieved. It also presents some examples of specific situations where careful interpretation will be needed to avoid missing identifications.

should be reviewed after the periods of time dictated by

It is important to inform bureau staff of all relevant

retention or disposal of the image.

provided. The image of a mark may have a very different

the nature of the crime and decisions made regarding

of colours or grey levels seen in the digital image is

for example by a printer. Colour casts or poor colour

reproduction may make images less easy to interpret. Including a standard colour scale can greatly assist in answering questions of colour interpretation. A fully

colour managed digital image workflow using standard colour scales is ideal.

information about the generation of the images

To avoid any degradation of image quality associated

appearance from that of the original fingermark, e.g.

identification practitioners view a digital image on screen

greyscale rather than colour, inverted contrast for

fluorescent marks, background suppression by optical filtering or even Fast Fourier Transform.

If documentary photography is used for recording and

with printing and re-scanning, it is recommended that when deciding whether there is sufficient detail to

proceed. Ideally, the image should then be transferred

directly to a fingerprint database in its electronic form, if required.

communication it may be necessary to ensure that

Home Office January 2014

3.3.25

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Appendices

3.3.26

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

References

Measuring cylinder classification

The table below shows the maximum permissible error (applicable at any increment on

(A and B) as well as design types (Types 1a, 1b, 2). The standard ‘ISO 6706’, for plastic

with increasing measuring cylinder size, so it is important to choose an appropriate size

The standard ‘ISO 4788’ for glass measuring cylinders defines two accuracy classes measuring cylinders defines only one accuracy class.

Measuring cylinders conforming to the above standards express units in millilitres

or cubic centimetres (1mL = 1cm3), and unless stated by the manufacturer, they are designed to be used around 20˚C. Material

Standard

Type

Grade

Appearance

Use

Glass

ISO 4788

1a

A (higher) B (lower)

Tall with a spouted neck

General.

1b

A (higher) B (lower)

Tall with a stoppered neck

General (but not specifically required for the Category A processes in this Manual).

2

B (lower)

Squat with a spouted neck

In fume hoods or where there is restricted height.

N/A

N/A

As per manufacturer

General.

Plastic

ISO 6706

Measuring cylinders of suitable accuracy for using Category A processes.

the scale) for different measuring cylinders under the two standards. The error increases for the task. For example, a 10 mL cylinder and not a 100 mL cylinder should be used to measure 10 mL of liquid n

N.B. The accuracy between Type 1, Class B and Type 2, Class B glass cylinders for 5 mL and 10 mL also differs. See table below. Nominal capacity (mL)

Conforms to ISO 4788 Max. permissible error +/- (mL) Type 1a and 1b cylinders

Conforms to ISO 6706

Max. permissible error +/- (mL) Type 2 cylinders (Class B)

Max. permissible error +/- (mL) Plastic cylinders

Class A

Class B

5

0.05

0.1

0.2

-

10

0.1

0.2

0.3

0.1 or 0.2

25

0.25

0.5

0.5

0.5

50

0.5

1

1

1

100

0.5

1

1

1

250

1

2

2

2

500

2.5

5

5

5

1000

5

10

10

10

2000

10

20

20

20

The errors associated with the use of different types of measuring cylinders (adapted from ISO 4788 and ISO 6706).

Home Office January 2014

3.3.26

Fingermark Visualisation Manual

Section 3.3: Working Effectively

Glossary

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

4 Process Selection Contents Important General Notes........................................... 4.2 Primary Chart Definitions.......................................... 4.4 Chart 1 Non-Porous................................................... 4.5 Chart 2 Porous.......................................................... 4.24 Chart 3 Semi-Porous................................................ 4.35 Treating Items of Varying Complexity .................... 4.49 Preparation Processes Overview ........................... 4.55 Contaminants Overview .......................................... 4.56 Optical Processes Selection Guide ....................... 4.60 Category B-C Process Options............................... 4.61

Introduction

This chapter includes information to assist those planning the processing of items or surfaces with the potential to

yield fingermarks. It is important to read the User Guide

since there is much supporting information in the Manual and knowing how to access this is vital to using it most effectively.

At the core of the decision-making process are three

primary charts that provide a processing sequence which

the most comprehensive approach for recovery of fingermarks in the most serious cases.

The most effective processes within the sequences are indicated since single processes may be adequate in many cases.

The final choice of processes must be made locally as

there may be numerous constraints and limitations placed upon the organisation.

should be chosen on the basis of the porosity of the surface type:

1. Non-porous; 2. Porous; or

3. Semi-porous. The primary charts include sequences of fingermark

visualisation processes that have been demonstrated

to be effective on these particular surface types. They also include greater detail on how the effectiveness

of individual processes in the sequences may change

when more is known about the nature or history of the

item or surface, e.g. if it has a rough surface or has been

wetted. The primary charts also form a hub for accessing important general notes and supplementary information

to guide the practitioner to modify the plan by indicating

suitable adjustments based on detailed knowledge of the substrate type, the item and its history.

The secondary charts should be used when more

information is known about the substrate type, e.g. if it is a particular type of plastic, or has an adhesive backing

or whether contaminants are present. Secondary charts are used in conjunction with the primary charts to give Home Office January 2014

4.1

Fingermark Visualisation Manual

Chapter 4: Process Selection

4.1

CH4

4.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

These notes contain information that is common to

additional processes that could be used after Basic

produce Fingermark Recovery Plans.

in the sequence.

all charts and must be read before using the charts to

The Charts and Process Selection ●● It will not be possible to process every item and

surface by referring to a single processing chart.

Some items may necessitate combining information

from more than one chart or incorporating additional processes into the sequence. See treating items of varying complexity.

●● When processing items of high value (either financial

or personal), there may be limitations on which

processes can be used. Many of the physical and

chemical processes are capable of causing irreparable damage to items, and/or leave them contaminated with chemicals. Optical processes and other lowimpact processes (e.g. ESDA, Lifting) may offer

alternative means of recovering fingermarks from such items.

●● The processing charts consider fingermark recovery

only and do not include information on recovery of other forensic evidence types. Information

on integration of fingermarks and other forensic processes is given in Chapter 7.

●● On completion of the processing sequences given

in the charts, additional Category A processes can be tried if, in the opinion of the practitioner, they

have potential to visualise additional marks. Powder Suspension and Solvent Black 3 are examples of

Home Office January 2014

those in grease). A wide range of different lighting

Violet 3 on non-porous surfaces if not previously used ●● It is not possible to provide full processing charts

to cover every type of substrate that may be

encountered. For some types of substrate (e.g. skin, fabrics, brick), knowledge surrounding fingermark

visualisation is very limited. In these cases guidance has been provided on which processes may be

considered, but a full processing chart has been omitted.

●● The processing charts contain Category A processes

only. Situations may be encountered where it is not

possible to use Category A processes, or they have been exhausted, or the particular set of constraints

means that use of Category B or C processes is likely to be more productive.

Optical Processes

Optical processes are generally non-destructive towards fingermarks and substrates and can be

used at any stage of a sequential processing route to

improve the contrast of existing fingermarks and/or to facilitate the visualisation of additional marks.

techniques can be utilised to obtain the optimum contrast. ■■

Fluorescence Examination can be highly effective for visualising marks in contaminants, many

of which may not be detected by subsequent physical/chemical processes. Marks in

contaminant may be detected because the

contaminant is fluorescent, or the substrate is

fluorescent and the contaminant is absorbing.

●● Items or surfaces subsequently treated with

physical/chemical processes typically require Visual Examination or Fluorescence Examination to locate and image any marks. In this case the optical

processes are not explicitly included in the charts as it is expected that the most appropriate optical process will be selected.

●● There are additional optical processes that may

improve the contrast of marks. They are Ultraviolet (UVC) Reflection, Colour Filtration, Infrared

Reflection, Monochromatic Illumination and Multi-

Spectral Imaging. See Optical Processes Selection Guide.

●● Commonly used optical processes (Visual

Examination and Fluorescence Examination) appear at the top of the charts when used as a

visualisation process in their own right, i.e. during an initial examination of an item or surface. ■■

Visual Examination can be highly effective for

visualising impressions and ‘heavy’ marks (such as

4.2

Fingermark Visualisation Manual

Important General Notes

4.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Lifting

Imaging

Preparation Processes

advantages in removing the mark from the substrate

sequential processing route should be imaged before

stage of a processing sequence where it becomes

The Lifting process can be used where there may be rather than imaging it in situ.

●● Lifting may make imaging of the mark easier by

placing it in isolation from a potentially distracting background.

●● It can be applied to untreated latent fingermarks and

also to fingermarks that have been visualised using certain chemical and physical processes.

●● The Lifting process physically removes some

fingermark residue or any other material from the surface and transfers it to the lift. It cannot be

guaranteed that all of the ridge detail is transferred

to the lift. The lifting media may occasionally cause damage to the surface or leave a residue on the

surface. It may therefore reduce the effectiveness of subsequent processes.

●● Best practice would always be to image in situ before

considering Lifting. The decision not to image first

must be taken locally and will depend upon the type of crime, available resources, the type of mark and surface etc.

Home Office January 2014

Fingermarks that are visualised at any stage of a proceeding to the next process in the sequence.

●● Subsequent processes may be detrimental to any

developed marks.

●● Fingermarks developed using certain processes

require timely imaging as developed marks can fade

or change colour with time. Where this is the case it is

Fingermark Visualisation Manual

Important General Notes continued Preparation processes may be incorporated at any necessary to expose or clean a surface so that it is suitable for treatment.

●● See preparation processes overview.

Handling

Avoid over-handling items.

identified within the relevant process instruction.

●● Excessive handling can damage fingermarks or

can obscure developed ridge detail. The contrast

●● Although fingermarks on non-porous substrates and

●● Wet items or surfaces may reflect light in a way that

between the mark and background substrate may not be optimal. In most cases, items or surfaces should

be allowed to dry prior to fingermark imaging, taking

into consideration that drying at temperatures higher

than 30ºC may damage latent fingermarks and some

interfere with some visualisation processes.

fresh fingermarks are most easily damaged, all items

should be handled with care as damage is possible in most situations.

●● See handling items for further information.

substrates (see drying of items).

●● In rare cases, items or surfaces can be imaged

whilst wet. Imaging should therefore be considered if a fingermark is clearly visible before drying if it is

considered that the water layer improves contrast.

4.3

4.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

This page contains brief definitions for the

Non-Porous surfaces

Porous surfaces

Semi-Porous surfaces

the three primary charts:

water, other liquids and air. Examples are

that absorb water and other liquids.

includes both materials of truly semi-

level of porosity associated with each of

Chart 1: Non-Porous



Chart 2: Porous



Chart 3: Semi-Porous

These surfaces are not permeable to

glass, many hard and soft plastics, metals, ceramics and painted metals.

These surfaces are composed of materials Examples are paper, card, cardboard, untreated wood and matt-painted surfaces.

This is a broad category of surfaces which porous nature, such as leather, silk- and satin- painted surfaces, and those with regions of porous nature interspersed

with non-porous regions, such as heavily printed paper or cardboard.

For further detail on how this information should be used, see User Guide.

Home Office January 2014

4.4

Fingermark Visualisation Manual

Primary Chart Definitions

4.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Primary Chart

VISUAL EXAMINATION

1.1

Glass and Ceramics

1.3

Plastic Packaging (hard)

OPTIONS

Process effectiveness: influencing factors Category B-C process options User Guide Primary chart definitions Chart Contaminant 1A

1B

Blood

Grease

1.2 1.4 1.5 1.6 1.7 1.8 1.9

Rigid Plastics

Unplasticised PVC

Plastic Packaging (soft) Expanded Polystyrene Currency (polymeric)

Plasticised PVC (vinyl)

Plastic Packaging (cling film)

1.10 Rubber

1.11 Wax and Waxed Surfaces 1.12 Gloss Painted Surfaces 1.13 Untreated Metals

1.14a Adhesives with non-porous

backings: light



backings: dark

SUPERGLUE FLUORESCENT DYE STAINING

OPTIONS

POWDER SUSPENSION

OPTIONS

1.14b Adhesives with non-porous

1

1

Important general notes Treating items of varying complexity

Optical processes selection guide

Generally most effective sequence

SUPERGLUE FUMING

Chart Substrate

Contaminants overview

OPTIONS

POWDERS

Links to:

Preparation processes overview

FLUORESCENCE EXAMINATION VACUUM METAL DEPOSITION

Index

KEY Most effective processes

BASIC VIOLET 3 Phenol-based

1

Superglue Fuming is one of the most effective processes only when it is followed with Superglue Fluorescent Dye Staining General impact of water on process effectiveness. Read full details

General impact of age of mark on process effectiveness. Read full details

General impact of surface roughness on process effectiveness. Read full details

Home Office January 2014

4.5

Fingermark Visualisation Manual

Chart 1 Non-Porous

Glossary

4.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● Glass is primarily silica-based and may be

encountered in a number of forms, developed by

incorporating additives to provide specific properties: ■■

sodium in soda glass to reduce viscosity during

Index

Secondary Chart

Use Chart 1 with NO modifications Additional considerations:

1 Aluminium powder is the most effective powder for glass substrates.

VISUAL EXAMINATION

manufacture; ■■

boron in borosilicate glass to give kitchenware

FLUORESCENCE EXAMINATION

heat resistance.

●● Continued exposure to water may leach some alkali

species from the surface of some types of glass, and

VACUUM METAL DEPOSITION

certain salts in fingermarks may locally modify glass composition.

●● Ceramics may be found in the form of tiles or pottery

and are typically coated with silica-based glazes, but

these will also contain a variety of other metal ions for pigmentation and other purposes. Glazes may also

POWDERS

1

contain some degree of microscopic porosity and the surface may not be truly non-porous, or may not be evenly applied.

SUPERGLUE FUMING

Typical items:

●● Glass bottles, jars and drinking glasses, windows.

Crockery, drinking mugs and pottery.

SUPERGLUE FLUORESCENT DYE STAINING

Generally most effective sequence

POWDER SUSPENSION

BASIC VIOLET 3

Home Office January 2014

4.6

Fingermark Visualisation Manual

Chart 1.1 Glass and Ceramics

Glossary

4.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● Rigid polymers include a range of materials that

Index

Secondary Chart Use Chart 1 with NO modifications

are cast, moulded, or extruded into shapes and

either perform a structural role or act as a protective casing to interior components. Examples of these

VISUAL EXAMINATION

polymers include acrylonitrile butadiene styrene (ABS), polyamides (PA, nylons), polyacetals, polyesters,

high-density polyethylene (HDPE), polypropylene (PP), polymethylmethacrylate (PMMA), polycarbonate, and polystyrene (PS).

●● These items sometimes feature the following symbols

that may assist in identification:

FLUORESCENCE EXAMINATION

VACUUM METAL DEPOSITION

POWDERS

●● These non-porous materials may be smooth or

textured, the texture being easy to introduce when the polymer is cast or moulded into the desired shape.

SUPERGLUE FUMING

●● This category does not include unplasticised polyvinyl

chloride (uPVC) which is covered in Chart 1.4.

Typical items:

●● Cowlings, car dashboards, casings for electronic

SUPERGLUE FLUORESCENT DYE STAINING

Generally most effective sequence

POWDER SUSPENSION

goods, chairs, wheelie bins, melamine kitchen units

and worktops, drain pipes, the rigid melamine facings on laminated flooring.

Home Office January 2014

BASIC VIOLET 3

4.7

Fingermark Visualisation Manual

Chart 1.2 Rigid Plastics

Glossary

4.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● This type of material includes the more rigid, clear

types of polymer that are used for packaging

Additional considerations:

purposes. These films are either moulded or blown structural rigidity combined with transparency to

2 Provided that the item has not been wetted, the Superglue Fuming followed by Superglue Fluorescent Dye Staining route may be more effective than the Powder Suspension route.

enable the product inside to be both protected and seen. Polymers of this type include poly(ethylene

Secondary Chart

Use Chart 1 with NO modifications

1 A zinc coating may form very quickly when using Vacuum Metal Deposition.

into shape, and are required to provide some

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION

terephthalate) (PET) and polystyrene (PS).

●● These items sometimes feature the following symbols

that may assist in identification:

Index

1

VACUUM METAL DEPOSITION

POWDERS

2

Typical items:

Generally most effective sequence

●● Blister packs, plastic bottles, clear food containers.

SUPERGLUE FUMING

POWDER SUSPENSION

SUPERGLUE FLUORESCENT DYE STAINING

BASIC VIOLET 3

Home Office January 2014

4.8

Fingermark Visualisation Manual

Chart 1.3 Plastics Packaging (Hard)

Glossary

4.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● Unplasticised polyvinyl chloride (uPVC) is essentially

a subset of the group of rigid plastics outlined in

Chart 1.2. It is separated from them partly because of the high occurrence of this type of material at

crime scenes (it is the principal constituent of frames for double-glazed doors and windows) and partly because it has been observed to behave slightly

differently to other rigid polymers when treated using visualisation processes.

Index

Secondary Chart

Use Chart 1 with NO modifications Additional considerations:

1 Black magnetic powder is generally the most effective powder.

VISUAL EXAMINATION

2 It is unknown which sequential route is the most effective. 3 Higher degrees of background staining can occur with dyes. Test a small area before treating the whole item. Black magnetic powder, or VMD (gold/zinc) represent alternative superglue enhancement processes where dye staining is not viable.

FLUORESCENCE EXAMINATION

VACUUM METAL DEPOSITION

●● The material is prone to ageing effects and surfaces

exposed to outdoor environments may become

increasingly weathered, becoming matt in appearance and having powdery surface layers.

●● These items sometimes feature the following symbol

POWDERS

1 Black magnetic

that may assist in identification:

2

SUPERGLUE FUMING

Typical items:

POWDER SUSPENSION

SUPERGLUE FLUORESCENT 3 DYE STAINING

●● Door and window frames, fascia boards, trunking,

guttering and drain pipes.

3

Home Office January 2014

BASIC VIOLET 3

4.9

Fingermark Visualisation Manual

Chart 1.4 Unplasticised PVC (uPVC)

Glossary

4.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

Move Vacuum Metal Deposition to follow Superglue Fuming and Superglue Fluorescent Dye Staining for bags suspected of manufacture post-2005, due to changes in the substrate. Vacuum Metal Deposition is used here primarily to further enhance superglue deposits, but additional fingermarks may be developed. For plastics suspected of manufacture pre-2005, Vacuum Metal Deposition should be used in the sequence as per Chart 1.

and polypropylene (PP) films (excluding cling films).

Different types of the same basic polymer can have very different properties. Polyethylene is a good

example of this, with high density polyethylene (HDPE) being found in thin, ‘crinkly’ plastic bags, and low

density polyethylene (LDPE) used for thicker, ‘waxy’ ●● These items sometimes feature the following symbols

that may assist in identification:

X

can vary depending on the additives incorporated during manufacture. Different types of the same

basic polymer (e.g. LDPE, HDPE) may therefore give very different results with the same process. Some

additives are designed specifically to alter the nature of the surface which may hinder the recoverability of fingermarks with some processes.

●● Printing on the surface may result in different

performance of visualisation processes compared with unprinted areas.

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION

Powders are ineffective.

Additional considerations:

VACUUM METAL DEPOSITION

N.B. Superglue Fuming (followed by Superglue Fluorescent Dye Staining), and Powder Suspension are the most effective processes. 1 Both sequential routes are approximately equal in effectiveness.

●● The physical characteristics of these materials

Secondary Chart

Use Chart 1 with MINOR modifications

●● This material class covers the polyethylene (PE)

plastic bags.

Index

POWDERS

X

Typical items:

Plastic sheeting, carrier and rubbish bags, thin ‘crinkly’ plastic bags (HDPE) and thicker, ‘waxy’ plastic bags (LDPE) which are often printed.

1

SUPERGLUE FUMING

SUPERGLUE FLUORESCENT DYE STAINING

POWDER SUSPENSION

VACUUM METAL DEPOSITION Gold/Zinc

●● Some materials of this type are also modified to make

them biodegradable: any biodegradable bags should be processed and any developed marks imaged as

soon as possible because the surface may begin to

BASIC VIOLET 3

degrade over time.

Home Office January 2014

4.10

Fingermark Visualisation Manual

Chart 1.5 Plastic Packaging (Soft)

Glossary

4.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● This material is produced from small beads of

chemically treated polystyrene that have been

expanded by steam heating. Expanded polystyrene blocks are then produced by filling a mould with

Secondary Chart

Use Chart 1 with MAJOR modifications X

Vacuum Metal Deposition is impractical and may be destructive to the item. Powders are ineffective.

+

Small Particle Reagent can be used before Powder Suspension.

enlarged beads and applying heat which causes

VISUAL EXAMINATION

SMALL PARTICLE REAGENT

both further expansion and fuses the beads together. The resultant blocks are very light for the volume

FLUORESCENCE EXAMINATION

they occupy. Although the finished blocks are water

repellent, the individual expanded beads may absorb some solvents, and some liquids may also penetrate along the boundaries between expanded beads.

Some foams are also blown directly into moulds to

produce thinner articles such as takeaway cartons.

●● These items sometimes feature the following symbol

that may assist in identification:

Typical items:

●● Cups, takeaway cartons, packaging foam, and ceiling

tiles.

Additional considerations: N.B. Superglue Fuming (followed by Superglue Fluorescent Dye Staining), and Small Particle Reagent are likely to be the most effective processes. 1

It is unknown which sequential route is the most effective.

2

Higher degrees of background staining can occur with dyes. Test a small area before treating the whole item. Black magnetic powder, or VMD (gold/zinc), represent alternative superglue enhancement processes where dye staining is not viable.

X

VACUUM METAL DEPOSITION

POWDERS

X

1

SUPERGLUE FUMING

SUPERGLUE FLUORESCENT 2 DYE STAINING

2

Home Office January 2014

Index

+

SMALL PARTICLE REAGENT

POWDER SUSPENSION

BASIC VIOLET 3

4.11

Fingermark Visualisation Manual

Chart 1.6 Expanded Polystyrene

Glossary

4.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

Move Vacuum Metal Deposition to follow Superglue Fuming.

biaxially oriented polypropylene (BOPP). Potential life than paper equivalents.

●● In common with paper notes, polymeric bank notes

contain many security features, some of which

fluoresce under particular wavelengths of light.

Speciality inks are also used to print the notes, some

of which have particular features when viewed through

X

Additional considerations: N.B. No information is available on which processes are the most effective. 1

FLUORESCENCE EXAMINATION

The effectiveness of Powder Suspension and BV3 is unknown.

IR Reflection may be particularly beneficial after Vacuum

and Vietnam) have entirely converted to polymeric

Related charts

polymeric notes or are in the process of converting to

2.5

currency, others have either introduced some

VISUAL EXAMINATION

Powders are likely to be ineffective.

appropriate filters under infrared radiation.

●● Several countries (including Australia, New Zealand

Secondary Chart

Use Chart 1 with MINOR modifications

●● Most bank notes of this type are produced from

advantages of such notes include a longer circulation

Index

VACUUM METAL DEPOSITION

Metal Deposition to suppress background patterns.

Currency (paper-based)

POWDERS

X

them.

Typical items:

●● Australian dollars, New Zealand dollars, Mexican

pesos, Singapore dollars, Vietnamese dong, new

SUPERGLUE FUMING

issue Canadian dollars.

VACUUM METAL DEPOSITION

1

POWDER SUSPENSION

SUPERGLUE FLUORESCENT DYE STAINING

1

Home Office January 2014

BASIC VIOLET 3

4.12

Fingermark Visualisation Manual

Chart 1.7 Currency (Polymeric)

Glossary

4.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

General information:

●● Plasticised polyvinylchloride (PVC) is produced by the

addition of chemicals to the rigid polymer to give it a

high degree of flexibility. A range of additives are used

X

Powders are ineffective.

+

Multi-Metal Deposition can be an effective process for this surface type.

the material over time and result in a loss of flexibility.

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION

MULTI-METAL DEPOSITION

●● These items sometimes feature the following symbol

that may assist in identification:

1

Additional considerations: N.B. It is unknown which sequential route is the most effective.

PVC can be moulded with a surface texture to give a ‘fake

No information is available on which processes are the most effective.

Chart 3.9).

1

Only the silver Vacuum Metal Deposition process is likely to be effective.

●● PVC additives are usually fatty materials similar to

2

Powder Suspension (titanium dioxide-based) may be the most effective process for dark items.

3

Higher degrees of background staining can occur with dyes. Test a small area before treating the whole item. Black magnetic powder, or VMD (gold/zinc), represent alternative superglue enhancement processes where dye staining is not viable.

leather’ effect (referred to as leatherette, as per

some of the fatty components in latent fingerprints. This can make it difficult to visualise latent fingermarks.

Typical items:

Shower curtains, inflatable articles (e.g. rubber rings,

beach balls), insulation for electrical cables, aprons, fake leather clothing, sports bags, umbrellas, ring-binder

Index

Secondary Chart

Use Chart 1 with MAJOR modifications

including phthalates, some of which may leach from

Glossary

X

SUPERGLUE FUMING

VACUUM METAL DEPOSITION Silver

POWDERS

POWDER

2 SUSPENSION

MULTI-METAL

+DEPOSITION

SUPERGLUE FLUORESCENT 3 DYE STAINING

covers, table cloths.

3

Home Office January 2014

BASIC VIOLET 3

4.13

Fingermark Visualisation Manual

Chart 1.8 Plasticised PVC (Vinyl)

Appendices

4.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Plastic Packaging (Cling film) General information:

●● This class of material includes the cling film sold as

a food wrapping material and also the stretch wrap

material that is sold for the wrapping of large pallets

Powders are ineffective.

+

Multi-Metal Deposition is the most effective process, particularly for “screwed-up” items.

of goods. The fundamental properties required in both

VISUAL EXAMINATION

Move Vacuum Metal Deposition further down the sequence.

X

FLUORESCENCE EXAMINATION

MULTI-METAL DEPOSITION

applications are similar; a high degree of flexibility and transparency is required and the material needs to be

VACUUM METAL DEPOSITION

able to adhere both to itself and to other surfaces so that a seal can be formed.

●● Two types of polymer are used in the manufacture of

cling film, poly vinyl chloride (PVC) and low density polyethylene (LDPE). Both types of film are highly

plasticised to produce the high degree of flexibility and surface tack required. The additives used as

plasticisers progressively migrate to the surface of the film and interfere with many enhancement processes.

Typical items:

●● Cling film, wrapped food, drugs wraps, pallet wrap.

Additional considerations: N.B. Powder Suspension, VMD (silver), and Superglue Fuming are effective on rolls of cling film and large sheets, but are largely ineffective on “screwed-up” items. 1

Only the silver Vacuum Metal Deposition process is likely to be effective.

2

Higher degrees of background staining can occur with dyes. Test a small area before treating the whole item. Black magnetic powder, or VMD (gold/zinc), represent alternative superglue enhancement processes where dye staining is not viable.

POWDERS

X

Generally most effective sequence

SUPERGLUE FUMING SUPERGLUE FLUORESCENT 2 DYE STAINING

+

MULTI-METAL DEPOSITION

POWDER SUSPENSION

2

Home Office January 2014

Index

Secondary Chart

Use Chart 1 with MAJOR modifications

Glossary

VACUUM METAL DEPOSITION 1 Silver

BASIC VIOLET 3

4.14

Fingermark Visualisation Manual

Chart 1.9 Plastic Packaging (Cling Film)

Appendices

4.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● Rubber materials may be produced from natural

rubber (polyisoprene) or a synthetic alternative such

Secondary Chart Use Chart 1 with NO modifications Additional considerations:

as polybutadiene or styrene-butadiene. In most cases,

1 Vacuum Metal Deposition is likely to be effective only if the surface is in very good condition.

anti-oxidants that protect them from degradation by

2 High backgrounds can occur with Powders. Test a small area before treating the whole item.

contains sulphur which is used in the vulcanisation

3 Higher degrees of background staining can occur with dyes. Test a small area before treating the whole item.

the rubbers contain fillers such as carbon black and

ultraviolet radiation, ozone and oxidation. Rubber also process to give rubber additional strength.

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION

Typical items:

●● Car tyres, cable insulation, flexible hoses, rubber

mats, latex gloves, condoms, shoe soles, waterproof

Index

1

VACUUM METAL DEPOSITION

boots.

POWDERS

2

SUPERGLUE FUMING

SUPERGLUE FLUORESCENT 3 DYE STAINING

3

Home Office January 2014

Generally most effective sequence

POWDER SUSPENSION

BASIC VIOLET 3

4.15

Fingermark Visualisation Manual

Chart 1.10 Rubber

Glossary

4.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● Waxes are solid at room temperature and liquefy at

slightly elevated temperatures.

●● Waxes may be derived from a number of sources: ■■ ■■ ■■ ■■

insects and animals; vegetables; minerals;

Secondary Chart

Use Chart 1 with MAJOR modifications X

Vacuum Metal Deposition and Powders are ineffective.

+

Small Particle Reagent can be used before Powder Suspension. It is most effective on flat surfaces.

1

SMALL PARTICLE REAGENT

●● Waxed surfaces are no longer commonly encountered

since previously wax-coated drinks and food storage

Additional considerations:

packaging has been replaced by materials covered in

thin polymer layers. These modern forms of packaging

N.B. Drying at temperatures higher than 20°C may soften some types of wax.

should be treated as per Chart 1.

No information is available on which processes are the most effective.

Candles (often formed from petroleum wax or occasionally beeswax), crayons.

1 There is a higher chance of finding indented fingermarks on wax than other non-porous substrates; therefore Visual Examination (oblique lighting) may be of particular benefit. 2 It is unknown which sequential route is the most effective.

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION

synthesis.

Typical items:

Index

X

VACUUM METAL DEPOSITION

POWDERS

X

2

SUPERGLUE FUMING

SUPERGLUE FLUORESCENT DYE STAINING

+

SMALL PARTICLE REAGENT

POWDER SUSPENSION

BASIC VIOLET 3

Home Office January 2014

4.16

Fingermark Visualisation Manual

Chart 1.11 Wax and Waxed Surfaces

Glossary

4.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● Paints are composed of pigment and a water- or oil-

Index

Secondary Chart

Use Chart 1 with NO modifications

based binder system. The proportion of pigment to

binder in any paint dictates the amount of gloss the finished product will have.

VISUAL EXAMINATION

●● Paints with high gloss finishes are generally more

hardwearing and dirt resistant than matt finish paints and include resin to give them this hardwearing quality.

●● Most gloss paints have traditionally been oil-based,

although water-based gloss paints are becoming increasingly available.

FLUORESCENCE EXAMINATION

VACUUM METAL DEPOSITION

●● Vehicle gloss paint finishes may become increasingly

weathered and matt in nature if not maintained.

POWDERS

Typical items:

●● Painted doors, door frames, skirting boards, window

frames, car exteriors.

SUPERGLUE FUMING

SUPERGLUE FLUORESCENT DYE STAINING

Generally most effective sequence

POWDER SUSPENSION

BASIC VIOLET 3

Home Office January 2014

4.17

Fingermark Visualisation Manual

Chart 1.12 Gloss-Painted Surfaces

Glossary

4.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● This chart refers to metal items with exposed surfaces

as opposed to metals coated with non-metallic materials such as paints or lacquers.

●● Most metals pose additional problems over other non-

porous surfaces as they are generally more chemically active, although this can vary widely from metal to metal. This may result in fingermarks themselves

Additional considerations and processes: N.B. Chart 1 presents reasonable options for fingermark visualisation, but no information is available on which processes are the most effective. The surface reactivity of metals is not exploited by any of the processes featured. Some of the additional Category B-C processes may be more effective.

a rough grouping of metals and alloys although the

Visual Examination may be particularly effective on tarnished or corroded substrates.

2

that it is exposed to:

It is unknown which sequential route is the most effective.

3

The performance of Powder Suspension is likely to be dependent upon the type of metal; however there is limited knowledge available

reactivity will also be dependent upon the environment ■■

Some metals and alloys are resistant to oxidation and corrosion (such as gold, platinum and

Secondary Chart

Use Chart 1 with NO modifications

1

corroding the metal surface. The following provide

1

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION

VACUUM METAL DEPOSITION

POWDERS

stainless steel). ■■

Some metals and alloys have a thin protective

oxide layer on the surface (such as aluminium, chromium, tin and titanium) and so have a reasonable corrosion resistance. ■■

Some metals and alloys tarnish (such as copper, silver, lead, bronze and brass) when exposed to

moist air giving a change in the appearance of the surface over time. ■■

Index

Some metals and alloys corrode readily (such

2

SUPERGLUE FUMING 3

POWDER SUSPENSION

SUPERGLUE FLUORESCENT DYE STAINING

as iron, steel). These are often encountered in a galvanised form where a thin layer of zinc is applied to impart corrosion resistance.

BASIC VIOLET 3

Typical items:

Coins, jewellery, ammunition, ornaments, keys, knives,

pipes, tools, door fittings, fencing, security shutters, street furniture.

Home Office January 2014

4.18

Fingermark Visualisation Manual

Chart 1.13 Untreated Metals

Glossary

4.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Secondary Chart

Light Coloured General information:

●● This chart relates primarily to roll-delivered adhesive

tapes. Marks may be difficult to see and image

on very dark tapes and Chart 1.14b may be more appropriate.

●● These tapes generally consist of four different

layers. The two layers most relevant to fingermark visualisation are the adhesive and backing layers.

The backing layers are typically vinyl-based polymers for electrical tapes, and polypropylene or polyester polymers for packaging tapes, although some

clear tapes, such as Sellotape, have cellulose film

backings (see ‘related charts on the next page’). The backing and adhesive layers are bonded together

by a primer layer. A release layer is coated onto the

back of the backing layer and allows the adhesive to part from the remaining material on the roll when the tape is unrolled. The presence of this release layer

modifies the surface and means that the processes recommended differ slightly from a standard nonporous surface.

Typical items:

Brown packaging tape, clear adhesive tape, polymer-

backed adhesive labels and stickers, modern UK postage stamps, metal-backed stickers.

Home Office January 2014

4.19

Fingermark Visualisation Manual

Chart 1.14a Adhesives with Non-Porous Backings

Appendices

4.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Light-Coloured Related charts

VISUAL EXAMINATION

Vacuum Metal Deposition is ineffective.

Additional considerations and processes:

1.14b 2.8 3.4 3.5

Adhesives with non-porous backings: Dark Adhesives with porous backings Adhesives with semi-porous backings Adhesives with cellulose backings

FLUORESCENCE EXAMINATION

N.B. The processing options for the adhesive and nonadhesive sides of these items are different. Priority should be given to the evidentially more important side. Unless indicated, processes can be used on both sides. 1

Powders are less effective than Powder Suspension and Superglue Fuming.

2

Unless it has been wetted, the Superglue Fuming sequence is the most effective for the non-adhesive side. Superglue vapours will interfere with the performance of carbon-based Powder Suspension on the adhesive side if the adhesive side is not adequately protected.

3

Superglue Fuming (when followed by Superglue Fluorescent Dye Staining) is the most effective process on the non-adhesive side, provided the item has not been wetted.

4

Carbon-based Powder Suspension is the most effective formulation and it does not cause heavy background staining on the adhesive side.

5

Non-adhesive side only:

X

VACUUM METAL DEPOSITION

1

POWDERS 2

Generally most effective sequence

3

SUPERGLUE FUMING

The DOSS-based formulation is less likely to cause background staining than the phenol-based formulation.

Removing adhesive tapes from some surfaces will be extremely difficult and care must be taken. In addition to the category A preparation process, there is a category B process (see Preparation processes overview). UVC Reflection can be effective on the non-adhesive side of these items. It is only suitable for smooth, unwrinkled surfaces and should be carried out before chemical processing.

4

POWDER SUSPENSION Carbon

SUPERGLUE FLUORESCENT 3 DYE STAINING Adhesive

side only:

4

5

Home Office January 2014

Index

Secondary Chart continued

Use Chart 1 with MAJOR modifications X

Glossary

POWDER SUSPENSION Carbon BASIC VIOLET 3 DOSS-based

4.20

Fingermark Visualisation Manual

Chart 1.14a Adhesives with Non-Porous Backings

Appendices

4.21

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Dark-Coloured General information:

●● This chart relates primarily to roll-delivered adhesive

tapes that are dark in colour.

●● These tapes generally consist of four different

layers. The two layers most relevant to fingermark visualisation are the adhesive and backing layers.

The backing layers are typically vinyl-based polymers

N.B. Unless indicated, processes can be used on both sides. 1

Powders (for use on the non-adhesive side only) are less effective than Powder Suspension and Superglue Fuming.

2

Unless it has been wetted, the Superglue Fuming sequence is the most effective for the adhesive and nonadhesive sides.

3

adhesive layers are bonded together by a primer layer. A release layer is coated onto the back of

Superglue Fuming (when followed by Superglue Fluorescent Dye Staining) is the most effective process provided the item has not been wetted. This applies to both the adhesive and non-adhesive sides.

the backing layer and allows the adhesive to part

4

Titanium dioxide-based Powder Suspension is the most effective formulation.

tape is unrolled. The presence of this release layer

5

The DOSS-based formulation is less likely to cause background staining than the phenol-based formulation. Both sides of the item can be treated.

from the remaining material on the roll when the

modifies the surface and means that the processes recommended differ slightly from a standard nonporous surface.

Typical items:

●● Black electrical insulation tape.

VISUAL EXAMINATION

Vacuum Metal Deposition is ineffective.

Additional considerations and processes:

for electrical tapes, and polypropylene or polyester polymers for packaging tapes. The backing and

Secondary Chart

Use Chart 1 with MINOR modifications X

Index

Removing adhesive tapes from some surfaces will be extremely difficult and care must be taken. In addition to the category A preparation process, there is a category B process (see Preparation processes overview). UVC Reflection can be effective on the non-adhesive side of these items. It is only suitable for smooth, unwrinkled surfaces and should be carried out before chemical processing.

FLUORESCENCE EXAMINATION

X

VACUUM METAL DEPOSITION

1

POWDERS

Non-adhesive side only:

2

Generally most effective sequence

3

SUPERGLUE FUMING

POWDER SUSPENSION

4 Titanium-dioxide

SUPERGLUE FLUORESCENT DYE STAINING

Related charts 1.14a 2.8 3.4 3.5

Home Office January 2014

Adhesives with non-porous backings: light Adhesives with porous backings Adhesives with semi-porous backings Adhesives with cellulose backings

5

BASIC VIOLET 3 DOSS-based

4.21

Fingermark Visualisation Manual

Chart 1.14b Adhesives with Non-Porous Backings

Glossary

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Be aware of the possible hazards when handling

items contaminated with blood and other body fluids (see Chapter 3 - Hazards associated with items).

General information:

●● Blood-contaminated surfaces are generally

encountered as a result of violent crime. Although on

Use Chart 1 with MAJOR modifications

●● This chart will maximise the chances of recovering

both bloody and latent marks. If only marks in blood are required then processes that do not usually visualise blood can be omitted.

●● Although most latent fingermarks can be easily

damaged, fingermarks in blood are particularly fragile on this substrate. If items are to be transported,

great care must be taken in packaging and handling.

Although latent fingermarks can be easily damaged at elevated temperatures, fingermarks in blood can flake at temperatures greater than 30°C.

VISUAL EXAMINATION

X Superglue Fuming is not recommended. It adversely affects the performance of Acid Dyes. + Acid Dyes is the most effective process for the visualisation of blood-contaminated fingermarks.

ACID DYES

readily visible, the benefits of visualisation processes traces of blood are suspected to be present.

Index

Secondary Chart

many items the areas of blood contamination may be are most pronounced where faint and imperceptible

Glossary

FLUORESCENCE EXAMINATION

VACUUM METAL DEPOSITION

Additional considerations: 1 The careful application of powder is important, and areas with obvious blood contamination should be avoided. Do not lift fingermarks developed with powder, photograph in situ.

1

POWDERS

See Category B-C process options.

SUPERGLUE FUMING X SUPERGLUE FLUORESCENT X DYE STAINING

+

ACID DYES

POWDER SUSPENSION

●● Proof of blood cannot be established by any of the

processes on the chart.

BASIC VIOLET 3

Typical items:

●● Knives, broken bottles, miscellaneous handled items,

fixed surfaces that may be contaminated with blood.

Home Office January 2014

Key to additional chart symbols

Process can visualise fingermarks in blood



Process can visualise latent fingermarks

4.22

Fingermark Visualisation Manual

Chart 1A Blood Contamination

OPTIONS

4.22

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

This chart will maximise the chances of recovering both

Use Chart 1 with MAJOR modifications

greasy and latent marks. Process selections should be

Move Vacuum Metal Deposition to the middle of the chart.

X

Powders will likely cause detrimental effects.

are required then processes that do not usually visualise

+

Solvent Black 3 is effective for light-coloured surfaces.

grease can be omitted.

SOLVENT BLACK 3

●● Common grease contamination may arise from food

products or from engineering activities. Other possible contaminants include cosmetics.

●● Food fats and oils include animal fats, vegetable oil

and fish oil. They are commonly encountered in areas such as kitchens (e.g. where areas around cookers

may become coated in a thin surface layer of grease), or they may be transferred from these environments.

●● Natural and artificial oils that are used for engineering

purposes include lubricants, fuels, and greases.

Contaminants of this type may originate from garages or machine shops, or vehicles. Fuels such as petrol and diesel also fall into this category.

●● Cosmetics include soaps, moisturisers, lipsticks and

sun creams. Many of these are applied by hand and may be readily transferred to other surfaces.

Index

Secondary Chart



weighted where required, e.g. if only marks in grease

Glossary

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION

1

VACUUM METAL DEPOSITION Silver

Additional considerations and processes: N.B. Basic Violet 3 and Solvent Black 3 are the most effective processes for fingermarks in grease. They may target different contaminants. 1

Fluorescence Examination may be particularly effective with some grease contaminants.

2

The gold/zinc and silver Vacuum Metal Deposition processes are both effective, but silver is more sensitive for fingermarks in grease.

3

Superglue Fuming and Powder Suspension are not effective at enhancing grease. However, Powder Suspension can be used to find latent fingermarks underneath some contaminants such as WD40 or butter.

POWDERS

X

3

VACUUM METAL 2 DEPOSITION

SUPERGLUE FUMING

SUPERGLUE FLUORESCENT DYE STAINING

POWDER SUSPENSION

3

See Category B-C process options.

BASIC VIOLET 3

Typical items:

●● Miscellaneous handled items and fixed surfaces that

may be contaminated with grease.

+

SOLVENT BLACK 3

Key to additional chart symbols Process can visualise fingermarks in grease Process can visualise latent fingermarks

Home Office January 2014

4.23

Fingermark Visualisation Manual

Chart 1B Grease Contamination

OPTIONS

4.23

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Primary Chart Links to: Important general notes

VISUAL EXAMINATION

Treating items of varying complexity Preparation processes overview Contaminants overview

Optical processes selection guide

FLUORESCENCE EXAMINATION

Process effectiveness: influencing factors Category B-C process options User Guide

Primary chart definitions

DFO

Chart Substrate 2.1

Paper (light-coloured, matt)

2.3

Paper (brown), cardboard

2.2

NINHYDRIN

2.4 2.5 2.6 2.7 2.8

PHYSICAL DEVELOPER

KEY

Paper (dark-coloured, matt) Currency (paper-based) Untreated wood

Matt-painted surfaces

Adhesives with porous backings

Chart Contaminant Most effective process

PHYSICAL DEVELOPER ENHANCEMENT

Paper (thermal)

General impact of water on process effectiveness. Read full details

2A

2B

Blood

Grease

General impact of age of mark on process effectiveness. Read full details N.B. Items should not be subjected to unnecessary folding, creasing and abrasion, as this will cause excessive development during processing with Physical Developer.

Home Office January 2014

4.24

Fingermark Visualisation Manual

Chart 2 Porous

OPTIONS

4.24

Contents

4.25

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

General information:

●● The general term ‘paper’ describes a wide range

of materials including the high-grade, long-lived

material used for currency to low-grade recycled

newspaper and fine tissue paper. Most paper is based on cellulose fibres, although currency paper may

contain high contents of other fibres such as cotton.

Glossary

Index

Secondary Chart

Use Chart 2 with NO modifications Additional processes: ESDA can be used prior to DFO. It may be used to visualise fingermarks and indented writing (see Chapter 7: Other Forensics - Documents)

VISUAL EXAMINATION

Paper also contains additives, for example calcium

carbonate (chalk) which may be added as a bulking filler and also as a whitening agent. Other additives

such as colouring pigments and optical brighteners

FLUORESCENCE EXAMINATION

may also be present.

●● The fundamental paper composition and the additives

incorporated into it can vary significantly around the world, it being known that in some countries paper

DFO

can be acidic, and in other countries alkaline. This will affect the way in which visualisation processes work. There may also be other generic types of coating

applied to papers to seal them and reduce porosity,

NINHYDRIN

or printing may be applied which can again locally modify the properties.

●● There are also polymeric ‘papers’ produced from

polymer fibres, which may be encountered in the form

PHYSICAL DEVELOPER

of courier mail envelopes. Such materials should be treated as semi-porous surfaces.

Typical items:

Documents, newspaper, white envelopes, cheques,

PHYSICAL DEVELOPER ENHANCEMENT

paper-based wallpaper, lining paper.

Home Office January 2014

4.25

Fingermark Visualisation Manual

Chart 2.1 Paper (Light-Coloured, Matt)

Appendices

4.26

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● See ‘general information’ on Chart 2.1 for further

details about paper in general.

Secondary Chart Use Chart 2 with NO modifications

Additional considerations and processes:

layer. The substrate is often a standard type of paper,

1 DFO and Ninhydrin can react with thermal layers. Thermal layer removal may be performed before or after these processes, but better results may be achieved by using it prior to DFO in the sequence.

seals the substrate and provides a suitable surface for

It is likely that the thermal layers featured on these items will need to be removed. See Thermal Coating Removal.

●● Thermal paper has a multi-layer composition,

consisting of a substrate, a base coat and an active

and this is coated with the base coat layer which both the active layer to be deposited onto. Occasionally,

double-sided thermal papers are produced, with each side consisting of an active layer. The active layer is

most commonly a colourless leuco dye mixed with a range of additives including co-reactants, stabilisers and sensitisers. When this layer is exposed to heat, it darkens in the specific areas that heat has been

Index

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION 1

DFO

applied to, thus creating an image. This type of paper is most commonly encountered as point-of-sale

receipts and occasionally as facsimile paper from

older types of fax machine. Most of these papers are

NINHYDRIN

white, but some coloured variants are used by certain stores. Unless precautions are taken, the thermal layer will blacken during processing with some

chemical processes and developed fingermarks will

PHYSICAL DEVELOPER

be obscured.

●● Removal of the thermal layer will remove any printed

text on these items. If the text is evidentially important, it will need to be captured before treatment.

PHYSICAL DEVELOPER ENHANCEMENT

Typical items:

●● Fax documents, thermal receipts.

Home Office January 2014

4.26

Fingermark Visualisation Manual

Chart 2.2 Paper (Thermal)

Glossary

4.27

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

General information:

●● See ‘general information’ on Chart 2.1 for further

details about paper in general.

●● Brown paper and cardboard are closely related in that

both are typically produced from paper made using the ‘Kraft’ process. This pulping process removes most of the lignin from the wood pulp, enabling

Glossary

Index

Secondary Chart

Use Chart 2 with NO modifications Additional processes: ESDA can be used prior to DFO. It may be used to visualise fingermarks and indented writing (see Chapter 7 Other Forensics - Documents).

VISUAL EXAMINATION

stronger bonds to be formed between the cellulose

fibres. The resultant paper is strong, coarse in texture

and darker than papers produced by other processes, although it may be bleached if required. Grades

FLUORESCENCE EXAMINATION

of paper may also vary in the amount of recycled

material used in their production. Articles that may be produced from Kraft paper include brown envelopes,

DFO

wrapping paper and corrugated cardboard boxes.

White outer layers of paper may be used on boxes to create a more aesthetically pleasing product;

these are usually bleached Kraft paper and therefore

NINHYDRIN

chemically similar to the brown-coloured materials.

Typical items:

●● Brown envelopes, brown wrapping paper, cardboard

boxes.

PHYSICAL DEVELOPER

PHYSICAL DEVELOPER ENHANCEMENT

Home Office January 2014

4.27

Fingermark Visualisation Manual

Chart 2.3 Paper (Brown), Cardboard

Appendices

4.28

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

General information:

●● See ‘general information’ on Chart 2.1 for further

details about paper in general.

●● Dark-coloured (in particular black) paper is

manufactured in the same way as standard papers but pigments are added to the pulp to create a coloured end product. Such paper is rarely encountered in a

N.B. Physical Developer is the most effective process when used with Physical Developer Enhancement (Potassium Iodide). 1

Marks developed using DFO may be difficult to detect because the fluorescence can be re-absorbed by black paper.

2

Marks developed using Ninhydrin may be difficult to see because of the lack of contrast on black paper. However, some black papers may fluoresce and this may enable developed marks to be visualised.

3

Potassium iodide enhancement lightens fingermarks developed with Physical Developer, improving contrast against dark papers.

artwork or for blacking out windows. This surface should be regarded as truly porous.

although marks may be developed using conventional processes, for various reasons they may be difficult to see.

Typical items:

●● Art paper, black-out paper.

Secondary Chart

Additional considerations and processes:

it. Black paper is sold for various purposes including

●● Process selection is made more difficult in that,

Index

Use Chart 2 with NO modifications

laboratory, but it does present particular problems

for enhancement of any marks that are deposited on

Glossary

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION

1

DFO

2

NINHYDRIN

ESDA can be used prior to DFO. It may be used to visualise fingermarks and indented writing (see Chapter 7 Other Forensics – Documents). IR Reflection can be effective after Physical Developer (before Physical Developer Enhancement) for improving fingermark contrast.

PHYSICAL DEVELOPER

PHYSICAL DEVELOPER 3 ENHANCEMENT

Home Office January 2014

4.28

Fingermark Visualisation Manual

Chart 2.4 Paper (Dark-Coloured, Matt)

Appendices

4.29

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● See ‘general information’ on Chart 2.1 for further

details about paper in general.

Secondary Chart

Use Chart 2 with NO modifications Additional considerations and processes:

currently paper-based, as are almost all bank notes

1 Issues may be encountered with fluorescence from security features obscuring fluorescent marks. Alternative lighting and filtration may improve contrast.

notes such as the Euro and the US dollar are also

2 Printed backgrounds may make it difficult to visualise developed marks.

●● The currency used in England, Wales and Scotland is

issued in Northern Ireland. Other widely used currency paper-based. The paper used for currency, although

produced in a similar manner to conventional papers, differs in several important respects as the pulp may

contain materials such as cotton which gives greater

Index

The following optical processes may facilitate greater discrimination between developed fingermarks and complex backgrounds: Infrared Reflection; Monochromatic Illumination; Multi-Spectral Imaging.

strength and rigidity.

VISUAL EXAMINATION

1

FLUORESCENCE EXAMINATION

1, 2

●● Bank notes contain many security features, some of

DFO

which fluoresce under particular wavelengths of light,

© See Photo Credits

and as paper does not incorporate optical brighteners the main body of the note is non-fluorescent, making the security features stand out more. Speciality

inks are also used to print the notes, some of which

have particular features when viewed under infrared

radiation. Some bank notes (e.g. the Bank of England £5 note) may have a thin lacquer layer applied to

2

NINHYDRIN

2

PHYSICAL DEVELOPER

improve their life in circulation, and this serves to

make the surface less porous. Bank notes are also

more heavily handled than most other paper articles

PHYSICAL DEVELOPER ENHANCEMENT

and therefore may have heavy deposits of fingermark residues within them. Some countries use polymeric banknotes, which are described separately in Chart 1.7.

Typical items:

●● Bank of England pound notes, Euro, US dollar, South

African rand.

Home Office January 2014

Related charts 1.7

Currency (polymeric)

4.29

Fingermark Visualisation Manual

Chart 2.5 Currency (Paper-Based)

Glossary

4.30

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

General information:

wood. The category includes both wood and woodbased products such as chipboard and fibreboard

(MDF). The main materials present are the cellulose

and lignin forming the wood structure, and for natural wood there are variations in the level of porosity

Use Chart 2 with a MINOR modification: +

Powders may detect fresh or heavy fingermarks on smooth untreated wood or wood that has been treated with oil or preservative. Magnetic powders are likely to be more effective than other powder types.

POWDERS

according to the type of wood. Soft woods (e.g. pine) are highly porous, whereas harder woods

(e.g. mahogany) are significantly less so, and this

affects the way in which the fingermark residues are absorbed. Where other substances such as wood

preservatives and binders (for chipboard) are present, these may interact with fingermark development reagents.

●● It is unclear how effective the chart is for wood that

has been treated with oil or preservative.

Index

Secondary Chart

VISUAL EXAMINATION

OPTIONS

●● This surface type describes predominantly untreated

Glossary

FLUORESCENCE EXAMINATION

Additional considerations: N.B. Wood may fluoresce significantly during Fluorescence Examination, especially with shorter wavelengths. This may obscure marks developed using DFO, or may give benefits in visualising dark-coloured marks. No information is available on which processes are the most effective.

+

POWDERS

DFO

●● If wooden surfaces are varnished, polished, or coated

with wax they should be treated as non-porous (see Chart 1).

NINHYDRIN

Typical items:

●● Tool handles, wood carvings, baseball bats, tree

branches, planks, untreated interior doors, floor

boards, fencing, furniture, chipboard and fibreboard panels.

PHYSICAL DEVELOPER

PHYSICAL DEVELOPER ENHANCEMENT

Home Office January 2014

4.30

Fingermark Visualisation Manual

Chart 2.6 Untreated Wood

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● Paint consists of a blended mixture of pigments and

a binder. Traditionally, binders were oil-based but

+

binder systems that have less smell associated with their application. The binder makes up the majority

Secondary Chart

Powder Suspension (iron-oxide-based) may be effective on this type of surface. Consider the application and removal of Powder Suspensions to large areas such as walls as there are significant implications for scene cleanup.

POWDER SUSPENSION

of the paint composition, with the proportion of

pigment to binder determining the amount of gloss

the finished product will have. Paint with water-based

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION

binders dries purely by evaporation, whereas the

Additional considerations:

added. Vinyl or acrylic resins are added to modern

N.B. Fluorescence Examination may be extremely effective.

than traditional emulsions. Matt emulsion is the most

No information is available on which processes are the most effective.

water-based paints to make them more hard-wearing commonly used paint for walls and ceilings, giving a matt, non-shiny finish.

Typical items:

Index

Use Chart 2 with MINOR modification

there has been a progressive change to water-based

older, oil-based paints have chemical drying agents

Glossary

1

DFO and Physical Developer are normally considered impractical due to the size (typically walls) and location (fixed at the scene) of the substrate.

POWDER SUSPENSION Iron oxide +

DFO

1

NINHYDRIN

●● Painted interior walls.

1

PHYSICAL DEVELOPER

PHYSICAL DEVELOPER ENHANCEMENT

Home Office January 2014

4.31

Fingermark Visualisation Manual

Chart 2.7 Matt-Painted Surfaces

OPTIONS

4.31

Contents

4.32

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

General information:

●● These materials are mostly produced on release paper

from which they can be easily removed and stuck to

fingermark visualisation may be difficult. Consider the

The Adhesive Tape Removal process should be used to attempt to carefully separate the adhesive layer from the substrate. If this is unsuccessful, Chapter 6 should be consulted. See preparation processes overview.

3.6).

Typical items:

●● Paper-backed adhesive labels and stickers, surgical

tape

Secondary Chart

Additional considerations and processes: N.B. Processes should be applied to both the adhesive and non-adhesive sides.

information provided for general fabrics (see Chart

Index

Use Chart 2 with NO modifications

the surface where they are required.

●● For porous fabric-backed tapes and adhesives,

Glossary

Related charts 1.14a Adhesives with non-porous backings: light 1.14b Adhesives with non-porous backings: dark 3.4 Adhesives with semi-porous backings 3.5 Adhesives with cellulose backings

VISUAL EXAMINATION

FLUORESCENCE EXAMINATION

DFO

NINHYDRIN

PHYSICAL DEVELOPER

PHYSICAL DEVELOPER ENHANCEMENT

Home Office January 2014

4.32

Fingermark Visualisation Manual

Chart 2.8 Adhesives with Porous Backings

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

items contaminated with blood and other body fluids (see Chapter 3 - Hazards associated with items).

+

●● Blood-contaminated surfaces are generally

encountered as a result of violent crime. Although

on many articles the areas of blood contamination may be readily visible, the benefits of visualisation processes are most pronounced where faint and

imperceptible traces of blood are suspected to be present as these can be visualised.

●● This chart will maximise the chances of recovering

both bloody and latent marks. If only marks in blood are required then processes that do not usually visualise blood can be omitted.

Index

VISUAL EXAMINATION

Acid Dyes is one of the most effective processes for the visualisation of blood-contaminated fingermarks.

ACID DYES

General information:

Glossary

Secondary Chart

Use Chart 2 with MINOR modification

Be aware of the possible hazards when handling

Appendices

FLUORESCENCE EXAMINATION

Additional considerations: 1

DFO may be the most effective process for the visualisation of light, imperceptible blood-contaminated fingermarks.

1

N.B. Fluorescence Examination may be particularly effective after Ninhydrin and Acid Dyes, as background fluorescence may improve the contrast of developed fingermarks.

DFO

NINHYDRIN

See Category B-C process options

●● Fingermarks in blood can be easily damaged on

this substrate, the extent being dependent upon

+

how much blood is present. If articles are to be

ACID DYES

transported, great care must be taken in packaging and handling.

PHYSICAL DEVELOPER

●● Although latent fingermarks can be easily damaged at

elevated temperatures, fingermarks in blood can flake at temperatures greater than 30°C.

●● Proof of blood cannot be established by any of the

PHYSICAL DEVELOPER ENHANCEMENT

processes on the chart.

Typical items:

Wooden tool handles, miscellaneous handled items, and fixed surfaces that may be contaminated with blood.

Home Office January 2014

Key to additional chart symbols

Process can visualise fingermarks in blood



Process can visualise latent fingermarks

4.33

Fingermark Visualisation Manual

Chart 2A Blood Contamination

OPTIONS

4.33

Contents

4.34

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

General information:

●● This chart will maximise the chances of recovering

both greasy and latent marks. Process selections

should be weighted where required, e.g. if only marks in grease are required then processes that do not usually visualise grease can be omitted.

●● Common grease contamination may arise from food

products or from engineering activities. Other possible

1

Fluorescence Examination may be particularly effective with some grease contaminants.

and fish oil. They are commonly encountered in areas

3

Sebaceous residues play a role in the Physical Developer fingermark visualisation mechanism, but Physical Developer does not ‘target fats’ or grease contaminants.

or they may be transferred from these environments.

●● Natural and artificial oils that are used for engineering

VISUAL EXAMINATION

N.B. The Chemical and Physical processes on this chart are ineffective at targeting grease. Consider the additional category B-C processes for targeting greasecontaminated fingermarks.

Fats and oils generally do not interfere with the reaction between DFO or Ninhydrin and latent fingermarks.

may become coated in a thin surface layer of grease),

Secondary Chart

Additional considerations:

2

such as kitchens (e.g. where areas around cookers

Index

Use Chart 2 with NO modifications

contaminants include cosmetics.

●● Food fats and oils include animal fats, vegetable oil

Glossary

1

2

UVC Reflection may be of particular value on this substrate type when contaminated with grease.

purposes include lubricants, fuels and greases.

2

Contaminants of this type may originate from garages

FLUORESCENCE EXAMINATION

DFO

NINHYDRIN

or machine shops, or vehicles. Fuels such as petrol and diesel also fall into this category.

●● Cosmetics include soaps, moisturisers, lipsticks and

3

sun creams. Many of these are applied by hand and

PHYSICAL DEVELOPER

may be readily transferred to other surfaces.

Typical items:

PHYSICAL DEVELOPER ENHANCEMENT

●● Miscellaneous handled items and fixed surfaces that

may be contaminated with grease.

Key to additional chart symbols

Home Office January 2014



Process can visualise fingermarks in grease



Process can visualise latent fingermarks

4.34

Fingermark Visualisation Manual

Chart 2B Grease Contamination

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Links to: Important general notes Treating items of varying complexity Preparation processes overview Contaminants overview Optical processes selection guide Process effectiveness: influencing factors Category B-C process options User Guide Primary chart definitions

FLUORESCENCE EXAMINATION

SUPERGLUE FUMING

POWDERS Black magnetic

POWDER SUSPENSION

OPTIONS

POWDERS Black magnetic

1

Chart Substrate Paper (white, glossy)

3.3

Silk/satin-painted walls and wood

3.4 3.5

DFO

3.6 3.7

KEY Most effective processes

NINHYDRIN

1 Superglue Fuming is one of the most effective processes only when it is followed with VMD or Powders (as enhancement processes). VMD is likely to be more effective in this regard.

PHYSICAL DEVELOPER

Home Office January 2014

3.1 3.2

VACUUM METAL DEPOSITION Gold/zinc

PHYSICAL DEVELOPER ENHANCEMENT

Index

Primary Chart

VISUAL EXAMINATION

VACUUM METAL DEPOSITION Gold/zinc

Glossary

General impact of water on process effectiveness. Read full details

3.8 3.9

Printed paper and card

Adhesives with semi-porous backings Adhesives with cellulose backings Fabric

Non-paper-based wallpaper (notes only) Cellophane packaging (notes only)

Leather and leatherette (notes only)

3.10 Bricks and concrete (notes only) 3.11 Skin (notes only) Chart Contaminant 3A

3B

Blood

Grease

General impact of age of mark on process effectiveness. Read full details

4.35

Fingermark Visualisation Manual

Chart 3 Semi-Porous

OPTIONS

4.35

Contents

4.36

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● Glossy paper in this context refers to high density

(grams per square metre, gsm) white paper that is

calendered (passed between heated rollers) to seal the surface and produce a shiny, silk or satin finish. This

Index

Secondary Chart

Use Chart 3 with NO modifications VISUAL EXAMINATION

Additional processes:

UVC Reflection may be of particular value on this substrate.

type of paper is often used in newsletters, advertising

FLUORESCENCE EXAMINATION

fliers and some books where a smooth paper finish is required for reproduction of finely printed or

photographic detail. It also describes smooth, white-

POWDERS Black magnetic

card items with a shiny finish such as business cards.

●● This chart does not cover coated papers or papers

heavily overprinted with dense patterns of coloured

inks which are similar in nature but present additional issues of visualising developed marks against the coloured, patterned background (see Chart 3.2).

Typical items:

●● Newsletters, leaflets, posters, business cards, some

VACUUM METAL DEPOSITION Gold/zinc

SUPERGLUE FUMING

POWDERS Black magnetic

wallpapers.

POWDER SUSPENSION

VACUUM METAL DEPOSITION Gold/zinc

DFO

NINHYDRIN

PHYSICAL DEVELOPER PHYSICAL DEVELOPER ENHANCEMENT

Home Office January 2014

4.36

Fingermark Visualisation Manual

Chart 3.1 Paper (White, Glossy)

Glossary

4.37

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● This broad class of semi-porous material is distinct

from glossy white paper (Chart 3.1). The definition covers thin, shiny paper and card which is heavily overprinted with coloured inks (as found in cheap

magazines and cheap wrapping paper) through higher

Index

Secondary Chart

Use Chart 3 with NO modifications VISUAL EXAMINATION

Additional considerations: 1 Powder Suspension spot test: If a spot of powder suspension cannot be washed from the surface, it should not be used.

FLUORESCENCE EXAMINATION

quality wrapping papers overprinted with coloured, pearlescent and metallic inks, and finally high-end

POWDERS Black magnetic

magazines where the surface may be coated with a

thin polymer or lacquer layer. The chart also includes cardboard boxes with dense coloured printing on

the outer surface. These all vary significantly in the

way fingermarks are absorbed into the surface and

therefore which enhancement processes will be most

VACUUM METAL DEPOSITION Gold/zinc

SUPERGLUE FUMING

1

POWDER SUSPENSION

effective.

Typical items:

●● Glossy magazines, coloured wrapping paper, posters,

POWDERS Black magnetic

VACUUM METAL DEPOSITION Gold/zinc

highly printed cardboard packaging.

DFO

NINHYDRIN

PHYSICAL DEVELOPER PHYSICAL DEVELOPER ENHANCEMENT

Home Office January 2014

4.37

Fingermark Visualisation Manual

Chart 3.2 Printed Paper and Card

Glossary

4.38

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● Paints are composed of pigment and a water- or

oil-based binder system. The proportion of pigment to binder in any paint dictates the amount of gloss

the finished product will have. Silk, satin and eggshell finish paints are used to give a more subtle shiny

finish than traditional gloss and a greater resistance to liquids and dirt than matt paints. They are often used on walls in areas such as kitchens or bathrooms.

Typical examples: ●● Silk painted walls.

Index

Secondary Chart

Use Chart 3 with MINOR modifications

VISUAL EXAMINATION

X Vacuum Metal Deposition has been eliminated for practical reasons. Additional considerations:

FLUORESCENCE EXAMINATION

1 The Powder Suspension sequential route is likely to be most effective. However, consider the application and removal of Powder Suspensions to large areas such as walls as there are significant implications for scene clean-up.

POWDERS Black magnetic

2 DFO and Physical Developer are normally considered impractical due to the size (typically walls) and location (fixed at the scene) of the substrate.

1

VACUUM METAL DEPOSITION X Gold/zinc

SUPERGLUE FUMING

POWDERS Black magnetic

2

POWDER SUSPENSION

VACUUM METAL DEPOSITION X Gold/zinc

DFO

NINHYDRIN

2

PHYSICAL DEVELOPER PHYSICAL DEVELOPER ENHANCEMENT

Home Office January 2014

4.38

Fingermark Visualisation Manual

Chart 3.3 Silk/Satin-Painted Walls and Wood

Glossary

4.39

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

●● Masking tapes are the most common type of this

class of item. They consist of a paper, or paper-like semi-porous backing layer, coated with a primer,

Powders, DFO and Ninhydrin are ineffective.



Powder Suspension is an option for the adhesive side only. Iron-oxide Powder Suspension is the most effective process on this side (providing it does not stain the background - see note 2 below).

+

BV3 (DOSS-based) can detect additional fingermarks on the adhesive side.

to which the pressure-sensitive adhesive sticks

permanently. On the non-adhesive side of the backing layer is also a release layer, which allows the backing to part with the adhesive as the tape is unrolled.

Masking tape uses a low-tack adhesive, meaning it

BASIC VIOLET 3 DOSS-based

can be easily peeled off a surface without damaging it or leaving traces of adhesive. The main application of

masking tape is in decorating, for example to cover up areas of a surface that do not need to be painted.

Secondary Chart

Use Chart 3 with MAJOR modifications: X

VISUAL EXAMINATION FLUORESCENCE EXAMINATION Non-adhesive side only:

VACUUM METAL DEPOSITION X Gold/zinc

Vacuum Metal Deposition is the most effective process for the non-adhesive side.

Related charts 1.14a Adhesives with non-porous backings: light 1.14b Adhesives with non-porous backings: dark 2.8 Adhesives with porous backings 3.5 Adhesives with cellulose backings

Home Office January 2014

X

UVC Reflection can be used to visualise superglue fumed fingermarks (non-adhesive side).

VACUUM METAL DEPOSITION Gold/zinc

NINHYDRIN 2

PHYSICAL DEVELOPER

Spot test: If a spot of powder suspension cannot be washed from the adhesive surface, the Physical Developer sequential route should be used instead.

POWDER SUSPENSION

DFO

X

The Superglue Fuming sequential route should only be used if the item has not been wetted and the adhesive side can be protected from superglue vapours. Superglue vapours interfere with the most effective process on the adhesive side.

The Adhesive Tape Removal process should be used to attempt to carefully separate the adhesive layer from the substrate. If this is unsuccessful, Chapter 6 should be consulted. See preparation processes overview.

SUPERGLUE FUMING

POWDERS Black magnetic

N.B. The processing options for the adhesive and nonadhesive sides of these items are different. Priority should be given to the evidentially more important side. Unless indicated, processes can be used on both sides.

2

POWDERS

X Black magnetic

1

Additional considerations and processes:

1

Index

POWDER SUSPENSION Iron oxide

PHYSICAL DEVELOPER ENHANCEMENT Adhesive

side only:

+

BASIC VIOLET 3 DOSS-based

4.39

Fingermark Visualisation Manual

Chart 3.4 Adhesives with Semi-Porous Backings

Glossary

4.40

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

The most commonly encountered adhesive surfaces are adhesive tapes, which are delivered from a roll.

●● Adhesive tapes generally consist of four different

layers. The two fundamental constituents are the

adhesive layer and the backing layer. The backing

layers are sometimes clear (such as with Sellotape).

+

BV3 (DOSS-based) can detect additional fingermarks on the adhesive side. The non-adhesive side must not be wetted when carrying out this process.

BASIC VIOLET 3 DOSS-based

which are considered to be semi-porous.

part from the remaining material on the roll when the tape is unrolled.

Typical items:

●● Some clear adhesive tapes, such as Sellotape.

FLUORESCENCE EXAMINATION Non-adhesive

POWDERS Black magnetic

side only:

VACUUM METAL DEPOSITION

●● The backing and adhesive layers are bonded together

back of the backing layer and allows the adhesive to

VISUAL EXAMINATION

Vacuum Metal Deposition, Powder Suspension, DFO, Ninhydrin and Physical Developer are either ineffective or too destructive.

These clear tapes employ cellulose film backings

by a primer layer. A release layer is coated onto the

Secondary Chart

Use Chart 3 with MAJOR modifications: X

Additional considerations and processes:

X X

N.B. The processing options for the adhesive and nonadhesive sides of these items are different. Priority should be given to the evidentially more important side. Unless indicated, processes can be used on both sides.

SUPERGLUE FUMING

POWDERS Black magnetic

POWDER SUSPENSION

X

VACUUM METAL DEPOSITION Gold/zinc

The non-adhesive side of cellulose film-backed adhesives must not be wetted. Superglue Fuming (followed by enhancement with black magnetic powder or VMD) is the most effective process for the non-adhesive side.

X

The Adhesive Tape Removal process (pulling and prising only) should be used to attempt to carefully separate the adhesive layer. If this is unsuccessful, Chapter 6 should be consulted. See preparation processes overview.

X

X

Related charts 1.14a Adhesives with non-porous backings: light 1.14b Adhesives with non-porous backings: dark 2.8 Adhesives with porous backings 3.4 Adhesives with semi-porous backings Home Office January 2014

Index

DFO

NINHYDRIN

PHYSICAL DEVELOPER

PHYSICAL DEVELOPER X ENHANCEMENT Adhesive side only:

BASIC VIOLET 3 DOSS-based +

4.40

Fingermark Visualisation Manual

Chart 3.5 Adhesives with Cellulose Backings

Glossary

4.41

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Secondary Chart

General information:

●● Fabrics are a varied and complex surface and there

Use Chart 3 with MAJOR modifications:

are few fingermark visualisation processes that

X

macroscopic level most fabrics are porous, with the

Additional considerations and processes:

are capable of developing marks on them. On a

fibre diameter and weave style affecting the porosity level. The fibre type also influences the porosity

on a microscopic level, with natural fibres such as

cotton and wool being porous and rough in profile and synthetic fibres such as nylon and polyester

being non-porous and having more regular cross-

sections. Fibres also incorporate dyes and may be

Powders, Powder Suspension, DFO, Ninhydrin and Physical Developer (and Physical Developer Enhancement) are ineffective.

N.B. It is unlikely that fingermarks with ridge detail can be recovered if: - the fabric has a weave of less than three threads per mm; - the fabric surface has been worn against the skin in warm environments, during physical activity, and/or for prolonged periods of time. 1

treated with substances to make them waterproof

or stain resistant. There are many other factors that

If the fabric is made of natural fibre, only Vacuum Metal Deposition is suitable. If the fabric is comprised of synthetic fibres, both VMD and Superglue Fuming are viable options.

are detrimental to the chances of recovering marks

2

close contact with the skin and wearing the fabric for

IR Reflection can be effective after Vacuum Metal Deposition for improving fingermark contrast.

including exposure to moisture, wearing the fabric in prolonged periods of time, in hot environments, or

VISUAL EXAMINATION FLUORESCENCE EXAMINATION POWDERS

X Black magnetic

1

VACUUM METAL DEPOSITION

the substrate, and the factors mentioned above,

The gold/zinc VMD process is likely to be the most effective, but silver can also be used.

POWDERS Black magnetic

X

X

fingermark development is unlikely. However, it may still be beneficial to carry out a fingermark

development process, as contact areas may be

SUPERGLUE FUMING

X2

during periods of strenuous activity.

●● Given the limitations imposed by the structure of

Index

X

POWDER SUSPENSION

X

VACUUM METAL DEPOSITION Gold/zinc

DFO

NINHYDRIN

revealed. These results can provide contextual

evidence, such as confirming push/grab scenarios, and furthermore could assist in targeted DNA swabbing.

Typical items:

Clothing, bedclothes, curtains.

Home Office January 2014

X

PHYSICAL DEVELOPER

PHYSICAL DEVELOPER X ENHANCEMENT

4.41

Fingermark Visualisation Manual

Chart 3.6 Fabric

Glossary

4.42

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Chart 3.7 Non-Paper-Based Wallpaper Non-paper-based wall coverings include vinyl-coated wallpapers, lacquer-coated wallpapers and blown

polyethylene wallpapers. They are resistant to moisture

and liquids and can be wiped clean although they are not necessarily entirely ‘non-porous’.

Although little is known about the best way to recover

fingermarks from these substrates, Powders followed by Powder Suspension (after optical processes) is likely

to be the most effective sequence of chemical/physical

processes on this type of substrate, although application and removal of Powder Suspension to large areas such

as walls has significant implications for scene clean-up.

Home Office January 2014

4.42

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Chart 3.8 Cellophane Packaging Cellophane is a clear polymeric film that is produced from regenerated cellulose. The principal uses of

encountered as a wrapping for foodstuffs and for illicit drugs. Although superficially resembling many other

transparent, polymeric packaging films, cellophane differs from them in that it is biodegradable and may have some permeability to the solvents used in reagents such as

DFO and Ninhydrin. In this respect cellophane should be

© See Photo Credits

cellophane are as a packaging material, and it is often

regarded as a semi-porous material.

After optical processes, Superglue Fuming or Vacuum Metal Deposition (VMD) are likely to be the most

effective chemical/physical processes for this substrate. If using VMD the silver method should be more effective than gold/zinc; however, marks developed using silver

VMD fade rapidly on cellophane and so must be imaged as soon as possible after processing.

Superglue Fuming and VMD can be followed by

Ninhydrin and Physical Developer. DFO should not be

used as the temperatures required for development may begin to damage the substrate.

© See Photo Credits

4.43

Contents

Home Office January 2014

4.43

4.44

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Chart 3.9 Leather (and Leatherette) Real leather is produced from animal hides in several stages which include tanning, dyeing and surface

finishing. Leather products vary widely from hard, smooth, essentially non-porous materials (patent leather) to soft

porous materials (such as suede). Although the recovery

of fingermarks from leather is generally poor, the chances

of developing marks on hard, smooth leather surfaces are notably better than on soft, flexible leather items.

The variability of leather makes it difficult to provide

generic advice for fingermark recovery. Furthermore,

artificial vinyl-based leather (‘leatherette’) may be difficult to distinguish from the real product (and real leather

goods may also feature concealed leatherette surfaces). For some leather items such as purses, wallets, handbags and laptop bags, Superglue Fuming and Powder

Suspension (after optical processes) may be the most effective visualisation processes. These processes are also amongst the most effective for leatherette

equivalents. The success rates are very low for real leather, but notably better for leatherette.

DFO may locate contact marks on real leather items,

but the process has not been observed to develop ridge detail. Development of contact marks may be of use for other forensic applications (see Chapter 7 - DNA).

Home Office January 2014

4.44

4.45

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Chart 3.10 Brick and Concrete Brick and concrete are substrates that are widely

encountered, but rarely treated for fingermarks. This is

because the recovery rate of marks from such surfaces is very low. The surface texture of both brick and concrete can range from very coarse, from which fingermark

recovery is very unlikely, to smooth. Both surfaces can also vary in nature from nearly non-porous to rough,

porous types. Brick and concrete are most likely to be

encountered in outdoor environments, making processes for wetted surfaces most likely to give results.

There have been no focused studies in this area on which to base specific advice. Following optical processes,

Powders, Powder Suspension and Superglue Fuming are all capable of developing marks; however, success rates are believed to be very low.

The use of DFO, Ninhydrin and Physical Developer on

this type of surface has not been tested and no comment can be made regarding their comparative performance. However, the alkaline nature of these substrates

may adversely affect the performance of these three processes.

Home Office January 2014

4.45

4.46

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Chart 3.11 Skin Skin is a multi-layered organ of the body which has

several functions including preventing the body from

drying out, temperature regulation and protection from

the environment. The structure of skin varies across the

different parts of the body, some areas being smooth and hairless, some rougher, and others covered in hair.

The secretion of sweat on the surface of the skin is

a continuous process that persists for some minutes after death. It can therefore be difficult to distinguish between a deposited mark and the secretions of the person being touched, unless the contact is several

minutes post mortem. The presence of hair and the fact that skin deforms during contact makes the deposition of an identifiable mark less likely. Therefore chances

of recovery are best on smooth, hairless regions of the

body that have been touched after death. Even in these circumstances, the chances of fingermark recovery are considered extremely low.

Very occasionally, operational successes have been reported in developing marks on skin and some

supporting research has been conducted using cadavers. Several processes have been noted to develop marks on

skin including: Powders, Superglue Fuming and Lifting. It should be emphasised that success rates are extremely low. Chapter 6 should be consulted for other potentially effective processes for fingermark visualisation on skin.

Home Office January 2014

4.46

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Secondary Chart

Use Chart 3 with MAJOR modifications:

Be aware of the possible hazards when

handling items contaminated with blood and other

X

Superglue Fuming is not recommended. It adversely affects the performance of Acid Dyes.

with items).



The Powder Suspension process will cause the removal of blood from the surface and therefore is moved further down the process sequence.

+

Acid Dyes is the most effective process for the visualisation of blood-contaminated fingermarks.

body fluids (see Chapter 3 - Hazards associated

General information:

●● Blood-contaminated surfaces are generally

encountered as a result of violent crime. Although

ACID DYES

on many articles the areas of blood contamination may be readily visible, the benefits of visualisation processes are most pronounced where faint and

imperceptible traces of blood are suspected to be

Additional considerations:

present as these can be visualised.

1

●● This chart will maximise the chances of recovering

both bloody and latent marks. If only marks in

DFO and Ninhydrin may adversely affect the performance of the Acid Dyes.

See Category B-C process options.

blood are required then processes that do not usually visualise blood can be omitted.

●● Although most latent fingermarks can be

VISUAL EXAMINATION FLUORESCENCE EXAMINATION POWDERS Black magnetic VACUUM METAL DEPOSITION Gold/zinc

SUPERGLUE FUMING

X

1

DFO

1

NINHYDRIN

POWDER SUSPENSION

easily damaged, fingermarks in blood are

particularly fragile on this substrate. If items are

+

to be transported, great care must be taken in packaging and handling.

POWDER SUSPENSION

●● Although latent fingermarks can be easily

damaged at elevated temperatures, fingermarks in

blood can flake at temperatures greater than 30°C.

PHYSICAL DEVELOPER

●● Proof of blood cannot be established by any of the

processes on the chart.

Typical items:

Miscellaneous handled items, fixed surfaces that may be contaminated with blood.

Home Office January 2014

ACID DYES

Key to additional chart symbols

Process can visualise fingermarks in blood



Process can visualise latent fingermarks

PHYSICAL DEVELOPER ENHANCEMENT

4.47

Fingermark Visualisation Manual

Chart 3A Blood Contamination

OPTIONS

4.47

Contents

4.48

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

General information:

Index

Secondary Chart

Use Chart 3 with MINOR modifications:

●● This chart will maximise the chances of

VISUAL EXAMINATION

X If grease contamination is evidently present, Powders will likely cause detrimental effects.

recovering both greasy and latent marks.

Process selections should be weighted where

Additional considerations and processes:

required, e.g. if only marks in grease are

1 Fluorescence Examination may be particularly effective with some grease contaminants.

required then processes that do not usually visualise grease can be omitted.

1

2 The gold/zinc and silver Vacuum Metal Deposition processes are both effective, but silver is more sensitive. They both visualise fingermarks in grease.

●● Common grease contamination may arise

from food products or from engineering

activities. Other possible contaminants include

3 Superglue Fuming and Powder Suspension are not effective at enhancing grease. However, Powder Suspension can be used to find latent fingermarks underneath some contaminants such as WD40 or butter.

cosmetics.

●● Food fats and oils include animal fats,

vegetable oil and fish oil. They are commonly

UVC Reflection may be of particular value for this substrate type when contaminated with grease.

encountered in areas such as kitchens (e.g. where areas around cookers may become

FLUORESCENCE EXAMINATION POWDERS

X Black magnetic

VACUUM METAL DEPOSITION 2

3

See Category B-C process options.

coated in a thin surface layer of grease), or they

POWDERS X Black magnetic

may be transferred from these environments.

POWDER SUSPENSION

SUPERGLUE FUMING

●● Natural and artificial oils that are used for

3

VACUUM METAL DEPOSITION Gold/zinc

engineering purposes include lubricants, fuels and greases. Contaminants of this type may

DFO

originate from garages or machine shops, or

vehicles. Fuels such as petrol and diesel also fall into this category.

NINHYDRIN

●● Cosmetics include soaps, moisturisers,

lipsticks and sun creams. Many of these are

applied by hand and may be readily transferred

PHYSICAL DEVELOPER

to other surfaces.

Typical items:

●● Takeaway containers and wrappings,

miscellaneous handled items and fixed

surfaces that may be contaminated with grease.

Home Office January 2014

Key to additional chart symbols

Process can visualise fingermarks in grease



Process can visualise latent fingermarks

PHYSICAL DEVELOPER ENHANCEMENT

4.48

Fingermark Visualisation Manual

Chart 3B Grease Contamination

Glossary

4.49

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Treating Items of Varying Complexity Introduction Items received for processing may vary significantly in their complexity from an evidence recovery perspective. For items where only one type

of substrate is present, the selection of the most appropriate processing chart is simple and dictated by the identification of the particular type of substrate. Others may be more complex and require reference to more than one chart and/or consultation with specialists in other types of forensic evidence.

The purpose of the next few pages is to demonstrate how to modify

charts or combine processes from multiple charts so that mark recovery is maximised. This expands on the information provided in Chapter

2 (See Section 2.3 for an introduction to sequential processing and

Section 2.4 for further information on Fingermark evidence recovery planning). Case studies can be found in Appendix 1. The section includes: ●● Items requiring additional or alternative processes ■■ ■■ ■■ ■■

Preparation processes Optical processes

Category B–C processes

Other forensic processes

●● Items requiring the use of multiple charts ■■ ■■ ■■ ■■

Substrate separation Targeted processing

Treating all areas simultaneously Targeting multiple contaminants

Home Office January 2014

4.49

4.50

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Items requiring additional or alternative processes Preparation processes

In some cases, the practitioner may need to use additional processes in order to get

access to a surface prior to using visualisation processes. For items where marks are

targeted on the outer surface only, these are used at the start of a sequence. For items where marks are also targeted on inaccessible areas, they may be used part-way through a sequence after treatment of the item as a whole first.

Preparation processes, depending upon their nature, may or may not have a

destructive effect on the mark or substrate (see Chapter 2.3: Sequential processing).

Optical processes

The practitioner may need to use

additional optical processes in order to get the best image of a mark. One or

multiple optical processes can be used at any stage of the processing sequence as they are generally non-destructive to the mark or substrate.

Reminder!* Sequential Processing: Rule 1

Optical processes should be used at the Preparation Process

Fingermark Visualisation Manual

Treating Items of Varying Complexity continued

beginning of any processing sequence (and after each process as required).

Additional Optical Processes Chart Processes 1 Additional Optical Processes Chart Processes 2 Additional Optical Processes

Chart Processes *Chapter 2.3: Sequential processing

A plastic bag coated with mud. The mud

must be removed prior to using the mark visualisation processes.

Category B–C processes Chart Processes for the outer surfaces Preparation Process

A cardboard box with adhesive tape

that can be treated as a whole before separating the layers for individual processing.

Home Office January 2014

Category B–C processes should be

considered if: Category A processes

cannot be used, or the full sequence has been used with little success and further attempts are desired. The process(es)

would normally be used as a last resort unless there is enough evidence or

Chart Processes for Surface 1

Chart Processes for Surface 2

Chart Processes

reasoning for it to be incorporated earlier

Category B–C Process (chemical or physical)

on in the sequence.

4.50

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Treating Items of Varying Complexity continued Items requiring additional or alternative processes continued Other forensic processes

Integration with other forensic evidence

Fingermark recovery

Where the recovery of multiple types of forensic evidence may be required from an item the following points should ●● the effect of fingermark processes on other forensic

Chart Process 1 (Optical)

processes and vice versa, and how recovery can be maximised. Some limited information is provided in Chapter 7;

●● the need to conduct joint examinations with

specialists in other forensic evidence types;

●● whether ‘clean’ environments are needed. This is a

requirement for certain evidence types in order to prevent cross-contamination;

●● where overlaps in recovery methods occur.

For example, Fluorescence Examination can be used to

target contact areas which may contain trace evidence, or Acid Dyes can be used to find footwear marks in blood in

Chart Process 2 (Optical)

Chart Process 3 (Physical)

Chart Process 4 (Chemical)

addition to fingermarks.

Chart Process 5 (Chemical)

Optical processes may be useful for locating other evidence types (e.g. trace evidence) or visualising other types of mark (e.g. footwear marks, blood distribution).

Some physical and chemical processes may find other marks e.g. footwear marks, although they may not be the most effective for that evidence type and this must be considered.

Evidence that is likely to be removed or destroyed (e.g. trace evidence, DNA, fibres, digital forensics etc.) should be recovered as early on in a processing sequence as possible. There should always be consultation with fingermark visualisation practitiioners as recovery methods may impact on fingermark recovery.

Decreasing chance of recovery

be considered:

Increasing destructiveness

4.51

Contents

A typical fingermark recovery sequence where processes are used in order of increasing

destructiveness to the fingermark and substrate. The schematic identifies at which point other evidence is normally recovered.

Home Office January 2014

4.51

4.52

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Items requiring the use of multiple charts At this stage it is worth remembering the rules for

sequential processing as outlined in Chapter 2, Section 2.3. This is important if a processing sequence needs to be developed based on information from more than one

chart. From this, there are some general points that may be useful during planning.

●● Using Rule 1. All of the charts have Visual and

Fluorescence Examination at the beginning of a

Substrate separation Reminder! Rules for sequential processes Rule 1 Optical processes should be used at the beginning of any processing sequence (and after each process as required).

sequence as they are generally non-destructive.

Therefore, no matter how complex an item is, these

would always appear at the top of any full sequence.

●● Using Rules 2–4. If these rules are followed, the

physical and chemical processes would be used

Rule 2

treated. The likely impact on marks through handling and separation of adjacent surfaces should be taken

into account when deciding whether or not to separate substrates.

For example, a paper document inside a plastic wallet can be easily separated with negligible impact on any marks that may be present, whilst a paper label on a cause damage to any marks.

Liquid-free processes should be used before any liquid-containing processes. Separation of Surfaces

on subsequent processes. Exposing substrates to unnecessary processes should be avoided if

Rule 3

the chart sequence have the potential to reduce

Organic solvent-based processes should be used before water-based processes.

the effectiveness to a limited extent of subsequent

substrates. In this case each substrate can be optimally

glass bottle will be difficult to remove and is more likely to

in an order that minimises the destructive effects

possible as even physical/chemical processes in

Some items can be easily split into their individual

Chart Processes for Surface 1

Chart Processes for Surface 2

processes.

●● It is possible to produce different sequential

processing routes that include the same processes

Rule 4

on the item. This depends upon the approach taken

Water-based processes should be used at the end of any processing sequence.

AND still follow the rules for each individual substrate as described in the next few pages.

Home Office January 2014

4.52

Fingermark Visualisation Manual

Treating Items of Varying Complexity continued

4.53

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Items requiring the use of multiple charts continued

Some guidance is given below: VMD: Masking is very effective at protecting specific areas as the line of sight from the evaporation boat

Targeted processing

If substrates cannot be separated, it may be possible to apply a process to a specific area by either careful application to the area and/or masking to avoid treating certain areas.

Any mask must have negligible impact on the area it is trying to protect. Silicone release paper is an example of an effective mask that can be

used to protect adhesive surfaces. It is low tack and has little impact, if

any, on processes. For non-adhesive surfaces, the mask will need to be fixed to the surface in a way that minimises damage to either the marks or the substrate.

Targeted application for some processes (such as Powders) is

straightforward. Others require more thought (such as VMD, Superglue

Fuming, Ninhydrin), whilst some are more difficult to apply locally due to their messy nature (such as Powder Suspension or any of the stains).

to the masked area is blocked and there will be no coating.

Superglue Fuming: It is possible to mask areas although success will be dependent upon having good contact between the area and mask so that fumes do not come into contact with that area. There may be other ways to prevent fumes from reaching the area.

Ninhydrin and DFO: These are two-stage processes: the first involves applying a solution to the item; the second involves heating the item in a pre-conditioned oven. It is straightforward to target areas by

applying the solution with a brush. However, it is not possible to target areas in the second stage as the whole item typically goes in the oven. The two stages can be separated within a sequence if necessary and (for Ninhydrin) the oven stage can be omitted in preference to development at room temperature over a longer period of time.

Processes requiring rinsing: Most of these processes can be applied with a brush to the area of

interest. However, it may be difficult to prevent rinse water from coming into contact with other areas. It

is up to the practitioner to decide whether they are possible to use, bearing in mind where they sit within a sequence and the nature of the item.

Chart Processes suitable for the whole item Chart Processes suitable for parts of the item (targeted processing)

A glass beer bottle with a porous paper label. In theory the label could be separated from the bottle, but this may not be desirable from a mark preservation perspective. The processing sequence must take account of these different substrates and may incorporate masking and careful application of some processes.

Home Office January 2014

A knife with a metal blade and a black plastic handle. The whole item could be treated with Powder Suspension, but for maximum effectiveness careful application of a white formulation to the handle and a black formulation to the blade would be required.

A non-porous surface with double-sided adhesive tape. The exposed adhesive surface is protected with silicone release paper so that the two types of surface can be target treated with different processes.

Chart Processes suitable for parts of the item, but applied to the whole item* *Basic Violet 3 would be an example of this. The porous/semi-porous areas would have been fully treated beforehand so any staining of these areas is not important for mark recovery on the non-porous areas.

4.53

Fingermark Visualisation Manual

Treating Items of Varying Complexity continued

4.54

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Items requiring the use of multiple charts continued Treating all areas simultaneously

Targeting multiple contaminants

Substrates on some items will use the same

On some items, such as wrapping paper or

charts may indicate that the different substrates

different porosities. In this case, it is not possible

primary chart for process selection. Secondary

require different processing. If the case dictates that only one process should be used then the

practitioner should use the information provided in the primary and secondary charts and select the most suitable process. This may not be

optimal for all substrates but is still likely to yield

magazine covers, there will be areas of vastly

to separate the areas nor is it practical to mask areas. In such cases, Chart 3 (Semi-porous)

is likely to be the most effective sequence as

it contains many of the processes on Chart 1 (Non-porous) and Chart 2 (Porous).

Items may have fingermarks of multiple types present. For grease

contamination and blood contamination, the appropriate charts take into account the recovery of latent marks and marks in contaminant. Where

marks in multiple types of contaminant may be present and both may be evidentially significant, either the compatibility between the processes

in each chart must be considered to derive a sequence for treatment of

the entire item, or areas masked and targeted sequences for the type of contamination used.

good results.

Only one process can be used and the different substrates have similar porosity

Use the most effective process from the Primary Chart

The different areas cannot be treated separately

Use Chart 3 (Semi-porous)

A wrench with both blood and grease contamination. In this case Acid Dyes (targeting blood) must be applied Examples of multiple substrate items including scissors and a knife, where the metal and rigid plastic substrates can be treated simultaneously with a single process if the case demands this.

Home Office January 2014

Wrapping paper having non-porous, porous and semi-porous areas in intimate contact, making masking or separation impossible.

before Solvent Black 3 or Basic Violet 3 (targeting grease) as blood is water-soluble.

4.54

Fingermark Visualisation Manual

Treating Items of Varying Complexity continued

4.55

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Preparation processes are required for use in circumstances where the condition of an

There are two principal scenarios that preparation processes are used to address.

be otherwise ineffective.

categories.

item or surface means that application of optical and chemical/physical processes will

Separation of surfaces

These are outlined on this page along with links to Manual processes that fall into those

Removal of contaminants/interfering substances

Surfaces of significance for fingermark recovery may be inaccessible

Surfaces of significance for fingermark recovery may be inaccessible to

situations preparation processes are required to separate the surfaces and

that has built up after deposition of the fingermark. Alternatively, the

to visualisation processes because they are stuck together. In these

expose them for subsequent treatment, whilst causing minimal damage to any fingermarks present.

visualisation processes because they are covered with a layer of contaminant substrate may include a layer of a substance that is known to react adversely with chemical processes and thus obscure fingermarks. In both cases, a preparation process will be required to remove the layer of contaminant/

interfering substance prior to the application of other visualisation processes. Adhesive Tape Removal

Chapter 5, Category A

Soot Removal

Chapter 5, Category A

Numberplate Splitting

Chapter 5, Category A

Thermal Coating Removal

Chapter 5, Category A

Adhesive Tape Removal (solvent-based)

Chapter 6, Category B

Body Decomposition Residue Removal

Chapter 6, Category B

Earth and Mud Removal

Chapter 6, Category B

Drug Removal

Chapter 6, Category C

Home Office January 2014

4.55

Fingermark Visualisation Manual

Preparation Processes Overview

4.56

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

The presence of contamination may significantly change

Schematic

process selection for fingermark visualisation. There

are many types of contamination that may be present,

ranging from dry, particulate contamination, material that

has been wet and subsequently dried on the surface and those that remain as a viscous liquid such as greases

and oils. Sometimes the contamination may be of direct

evidential importance (such as blood); in other cases it is

inhibiting forensic recovery and may need to be removed

so that fingermark visualisation processes can be applied.

Distribution of contaminants

In developing plans, practitioners should consider

whether the contaminant is likely to have been present at the time that a crime was committed or has been

Description

Possible approaches for processing

Scenario 1: Fingermarks rich in contaminants deposited on a clean surface.

Use processes specifically targeting the type of contaminant present.

Scenario 2: Latent fingermarks deposited on a layer of contaminant pre-existing on the surface.

Use processes specifically targeting latent fingermarks which do not interact with the type of contaminant present.

Scenario 3: Latent fingermarks deposited on a clean surface, and subsequently covered with a layer of contaminant.

Use processes specifically targeting latent fingermarks which do not interact with the type of contaminant present and/or remove contaminant and use standard processes for the substrate.

Scenario 4: Impression left in a thick layer of contaminant by a finger.

Use optical processes (e.g. oblique lighting) and/or use processes specifically targeting the type of contaminant present.

subsequently deposited. There are several ways in

which contaminants, surfaces and fingermarks may be distributed. Four simplified, theoretical scenarios are

shown together with possible approaches for dealing with them, although it will often be difficult to determine which is prevalent in some cases.

The next page outlines common contaminants and

how they can be removed or targeted depending on the scenario encountered.

Home Office January 2014

Contaminant

Surface

Latent fingermark

4.56

Fingermark Visualisation Manual

Contaminants Overview

4.57

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Common contaminants

Removal of contaminants

Targeting contaminants

present on an item or surface that can impact on the

type of contaminant, it may be necessary

will visualise many contaminants (e.g. Fluorescence Examination).

There are many types of contaminants that may be Fingermark Recovery Plan. They may include:

●● Body decomposition residues that arise from the

fluids released onto substrates in contact with a decomposing body.

●● Earth and mud that can be picked up either before,

Depending upon the distribution and

to remove the contaminant and prepare

the surface for subsequent visualisation processes. See also, preparation processes overview.

In some cases visualising the contaminant is desired. Some processes Specific secondary charts are given for substrates where either blood or grease is present. These charts have been designed to maximise

the number of fingermarks (both latent and contaminated) that will be visualised, and:

●● incorporate processes that target latent mark constituents only (i.e.

sweat), the contaminant only (i.e. blood or grease) and processes

Soot Removal

Chapter 5, Category A

Body Decomposition Residue Removal

Chapter 6, Category B

involved in the fire.

Earth and Mud Removal

Chapter 6, Category B

Particular care may be required when processing items and surfaces

contaminant types, from powdery coatings to oily

Drug Removal

Chapter 6, Category C

forensic importance (see Chapter 7: Body Fluids and DNA). In addition,

during or after mark deposition by exposure to muddy environments or hands.

●● Soot contamination that is found at nearly all fire

scenes and consists of a surface coating of dry particles. The nature of the soot contamination

will vary according to what substances have been ●● Drug contamination that covers a range of

residues that may be left on the packaging and

paraphernalia associated with drug manufacture, supply and abuse. Contamination may already

be present on the surface, or may be arise from

the decanting process if this is conducted prior to fingermark recovery.

●● Grease contamination that includes fats from food

and oils from cosmetics and engineering practices.

●● Blood contamination that may be encountered on

surfaces associated with crimes where an injury has

capable of visualising both (e.g. sweat and blood);

●● clearly identify the type of mark that each process in the sequence can

visualise, enabling the processing sequence to be weighted towards the type of mark of highest evidential priority (e.g. if only marks in

blood are of importance, processes targeting latent marks only can be omitted from the sequence).

where blood contamination is suspected to be present because of its

care must be taken when interpreting marks in blood (see next page). Secondary charts for contaminated items or surfaces Substrate porosity

Blood contamination

Grease contamination

Non-porous

1A

1B

Porous

2A

2B

Semi-porous

3A

3B

occurred to one or more of the parties involved.

Home Office January 2014

4.57

Fingermark Visualisation Manual

Contaminants Overview continued

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Blood Interpretation Blood is a contaminant that is generally of

high operational importance when it is encountered, because of its association with serious crimes. It is

therefore important to optimise the way in which items and scenes where blood contamination is present

are processed to maximise evidential recovery. Blood

pattern analysis and footwear mark recovery may also be

important considerations and forensic specialists in these fields should be consulted before final selection of the processes to be used.

Even without considering the other types of forensic

In scenario 3, if the blood interacts with pre-existing

evidence associated with blood contamination, in the

ridge detail it may initially appear to be integral with it

it is important to establish not only that blood is present

ridge detail could have been present on the surface

particular context of a ‘fingermark associated with blood’ within the boundaries of the mark but also to demonstrate that at least some of the blood is an integral part of

the mark and was distributed by the same action that originated the friction ridge pattern. This may require

consultation with specialists in interpretation of blood

because ridge patterns associated with blood may be formed in different ways as shown in the images.

but there is, in fact, only a coincidental association. This for seconds, weeks or months prior to the blood being

smeared over it. Unless the practitioner examining this

mark and carrying out the chemical development of it for identification purposes also considers how it has been

formed, it is likely that it will be described to the court as

a ‘fingermark in blood’ and may wrongly place the donor of that mark at the scene during the period when the blood was wet.

A palm mark formed by ridge detail wet with blood making contact with a clean surface (scenario 1).

Home Office January 2014

A palm mark formed by clean ridge detail making contact with blood already present on the surface (scenario 4).

A palm mark visualised by wiping wet blood across

ridge detail in sweat and/or another contaminant already present on the surface (scenario 3).

4.58

Fingermark Visualisation Manual

Contaminants Overview continued

© See Photo Credits

4.58

Contents

4.59

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Blood Interpretation There may be other explanations, such as combinations of the three possibilities above.

In order to attempt to understand these factors and how they influence the resultant

the distribution and amount of blood on, and around, the friction ridges along with the

across the mark and use microscopy, in addition to using case-specific contextual

In considering these possibilities it is necessary to take into account factors such as

nature of the surface on which the mark is located. Other factors will also be important in considering how the mark has been deposited, including whether blood wets the

surface, how dry the blood is when it is deposited, and what pressure is used during deposition.

Fingermarks formed by a finger coated with blood coming into contact with a surface where: (left) the blood is on the finger for only a few

seconds before a ‘light’ contact pressure is applied; (centre) same as left-

Home Office January 2014

marks, an experienced examiner may map the distribution of blood components

information. Only then can an experienced examiner form an opinion on the method of

mark formation. Blood-mark interpretation is therefore a complex process that must run alongside fingermark visualisation.

hand picture but ‘heavy’ contact pressure; and (right) same as left-hand picture but the blood is on the finger for one minute before contact.

4.59

Fingermark Visualisation Manual

Contaminants Overview continued

4.60

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Optical processes can be used at the beginning of a processing sequence to visualise marks and can also be

considered as a means of enhancing the contrast of any marks that have been visualised by chemical and physical

processes. The types of mark that may

Process

Target Any coloured fingermarks (treated or untreated) and/or marks on coloured backgrounds.

●● Untreated blood marks on surfaces of similar colour; ●● Faint Ninhydrin marks on light-coloured surfaces.

Fluorescence Examination Utilises differences in fluorescence properties between the fingermark and background.

Marks in fluorescent contaminants, or nonfluorescent contaminants on fluorescent surfaces.

●● Marks in fluorescent contaminants (e.g. oil from orange peel) on non-fluorescent backgrounds; ●● Marks in blood on fluorescent backgrounds (e.g. white paper); ●● Marks developed with processes giving fluorescent products (e.g. DFO).

IR Reflection Utilises differences in infrared reflection and absorption between the fingermark and background.

Fingermarks developed by metallic/inorganic deposition processes.

●● Marks developed using Physical Developer on highly coloured and patterned printed backgrounds.

Monochromatic Illumination Utilises colour differences between the fingermark and background.

Any coloured fingermarks (treated or untreated) and/or marks on coloured backgrounds.

●● Ninhydrin marks on coloured, patterned backgrounds of similar colour.

Multi-Spectral Imaging Utilises differences in colour and/or fluorescence spectra between the fingermark and background.

Any coloured fingermarks (treated or untreated) and/or marks on coloured backgrounds, also fluorescent marks on fluorescing backgrounds.

●● Ninhydrin marks on coloured, patterned backgrounds of multiple colours (e.g. banknotes); ●● Faint Ninhydrin marks on light-coloured surfaces; ●● Marks developed using DFO on fluorescent backgrounds.

Ultraviolet (UVC) Reflection Utilises differences in ultraviolet reflection and absorption between the fingermark and background.

Latent marks or marks developed by Superglue Fuming on smooth surfaces.

●● Untreated marks on smooth, non-porous surfaces such as glass or metal; ●● Untreated marks on glossy white paper and card.

Visual Examination Utilises differences in a range of properties between the fingermark and background including reflection, transmission, absorption, topography.

Both untreated and treated fingermarks, and marks left by many other means including impressions, surface corrosion, visible contaminants. It can be used across the full range of substrates.

●● Marks in grease on smooth opaque and transparent surfaces; ●● Impressions in soft surfaces; ●● Marks in dust; ●● A range of different light sources will be required to detect all these types of mark.

be encountered and some of the optical

processes that can be initially selected for their visualisation are summarised on this page.

See the process instruction for full details.

Home Office January 2014

Application examples (not exhaustive)

Colour Filtration Utilises colour differences between the fingermark and background.

4.60

Fingermark Visualisation Manual

Optical Processes Selection Guide

4.61

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Category B-C Process Options The table summarises Category B–C processes and where they may be considered for use. Category B process

Category C process Primary Chart 1: Non-Porous

Europium Chelate Iodine Fuming Iodine Solution Natural Yellow 3 Radioactive Sulphur Dioxide Scanning Electron Microscopy Superglue Fluorescent Dye Staining (propanol-based)

ATR-FTIR Basic Violet 2 Fluorescent Superglue Fuming MALDI-MSI Nile Red Powders (Fluorescent) SIMS Single Metal Deposition S2N2 Tagged Nanoparticles XRF

Secondary Chart 1.13: Untreated Metal Gun Blueing Palladium Deposition Scanning Kelvin Probe

CERA Electrochromic Development Electroless Silver Deposition

Secondary Chart 1A: Blood Acid Dyes (water-based) Leuco Crystal Violet Scanning Electron Microscopy

ATR-FTIR MALDI-MSI SIMS

Secondary Chart 1B: Grease Europium Chelate Iodine Fuming Iodine Solution Natural Yellow 3 Scanning Electron Microscopy

Home Office January 2014

ATR-FTIR Basic Violet 2 MALDI-MSI Nile Red SIMS

Category B process

Category C process Primary Chart 2: Porous

DMAC Indandione Iodine Fuming Iodine Solution Oil Red O Radioactive Sulphur Dioxide Scanning Electron Microscopy Silver Nitrate

Genipin MALDI-MSI Nile Red Powders (Fluorescent) SIMS S2N2 Tagged Nanoparticles Thermal Development Thermanin XRF

Secondary Chart 2A: Blood Acid Dyes (water-based) DMAC Indandione Leuco Crystal Violet Scanning Electron Microscopy

MALDI-MSI SIMS

Secondary Chart 2B: Grease Iodine Fuming Iodine Solution Oil Red O Scanning Electron Microscopy

MALDI-MSI Nile Red SIMS

4.61

4.62

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Category B-C Process Options continued The table summarises Category B–C processes and where they may be considered for use n Category B process

Category C process Primary Chart 3: Semi-Porous

DMAC Indandione Iodine Fuming Iodine Solution Oil Red O Radioactive Sulphur Dioxide Scanning Electron Microscopy

ATR-FTIR Fluorescent Superglue Fuming MALDI-MSI Nile Red Powders (Fluorescent) SIMS S2N2 Tagged Nanoparticles Thermal Development XRF

Secondary Chart 3A: Blood Acid Dyes (water-based) DMAC Indandione Leuco Crystal Violet Scanning Electron Microscopy

ATR-FTIR MALDI-MSI SIMS

Secondary Chart 3B: Grease Iodine Fuming Iodine Solution Oil Red O Scanning Electron Microscopy

Home Office January 2014

ATR-FTIR MALDI-MSI Nile Red SIMS

4.62

Chapter 5: Category A Processes

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

5 Category A Processes Contents Preparation Processes.......................................... 5.PP.1 Adhesive Tape Removal..................................5.ATR.1 Numberplate Splitting....................................... 5.NS.1 Soot Removal................................................... 5.SR.1 Thermal Coating Removal.............................. 5.TCR.1 Optical Processes.................................................5.OP.1 Colour Filtration................................................. 5.CF.1 Fluorescence Examination................................. 5.FE.1 Infrared Reflection........................................... 5.IRR.1 Monochromatic Illumination.............................. 5.MI.1 Multi-Spectral Imaging....................................5.MSI.1 Ultraviolet (UVC) Reflection......................... 5.UVCR.1 Visual Examination.............................................5.VE.1 Chemical and Physical Processes.................... 5.CPP.1 Acid Dyes.......................................................... 5.AD.1 Basic Violet 3...................................................5.BV3.1 DFO.................................................................5.DFO.1 ESDA............................................................5.ESDA.1 Lifting................................................................. 5.Lif.1 Multi-Metal Deposition................................. 5.MMD.1 Ninhydrin...........................................................5.Nin.1 Physical Developer........................................... 5.PD.1 Physical Developer Enhancement.................. 5.PDE.1 Powders.......................................................... 5.Pow.1 Powder Suspension...........................................5.PS.1 Small Particle Reagent................................... 5.SPR.1 Solvent Black 3............................................... 5.SB3.1 Superglue Fluorescent Dye Staining............ 5.SFDS.1 Superglue Fuming.............................................. 5.SF.1 Vacuum Metal Deposition.............................. 5.VMD.1

Introduction

properties of the fingermark. They can be used to

processes, it is important that they are carried out most

treated items or surfaces.

Having decided on the most appropriate process or

effectively. This chapter contains full instructions on the use of Category A preparation, optical, chemical and

physical visualisation processes which have been fully

evaluated by CAST and in most cases are routinely used for fingermark development.

A

Standard processes for routine operational use. They must be used in preference to other category processes where possible. Full process instructions are given.

It is anticipated that these instructions will be used to guide the production of local procedures to describe

how the processes will be carried out most effectively

within any limitations imposed on individual operational laboratories.

The preparation processes are used to prepare surfaces

visualise latent marks or further enhance previously Each process is presented in a consistent style making it easy for the reader to find information. (See User

Guide – Chapter 5 Process Instruction Contents). Different levels of information are available for each

process to target the information for different readers. The first page of each process instruction is intended

to be a useful starting point for all, directing access to

further information if necessary, e.g. if deciding whether scene application would be beneficial. Step-by-step

guides with health and safety considerations are provided for those carrying out the process, with supplementary information for those wishing to learn more about the

process. It is important that the processes are carried out by competent personnel, who are familiar with the entire content of the process instruction n

for subsequent application of visualisation processes and may involve the removal of contaminants or

potentially interfering substances, or separation of

attached surfaces. They may be needed before any other processes are applied or within a sequence.

The optical visualisation processes exploit the optical properties of the item or surface when illuminated or

irradiated. They can be used to visualise marks prior to any chemical or physical processes or further enhance previously treated items or surfaces.

The chemical and physical visualisation processes

target chemicals present in fingermarks or the physical Home Office January 2014

5.1

Fingermark Visualisation Manual

5.INTRO.1

CH5

5.PP.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Adhesive Tape Removal............. 5.ATR.1 Numberplate Splitting.................. 5.NS.1 Soot Removal................................ 5.SR.1 Thermal Coating Removal......... 5.TCR.1

Fingermark Visualisation Manual

Preparation Processes Introduction

The preparation processes are used to prepare surfaces for subsequent application of visualisation processes and may involve the removal of contaminants or potentially interfering substances, or separation of

attached surfaces. They may be needed before any other processes are applied or within a sequence n

Home Office January 2014

5.PP.1

5.ATR.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Sticky Tape Removal

Main Uses Separation of adhesive surfaces from nonadhesive surfaces

Contents Options........................................ 5.ATR.2 Laboratory or Scene?................ 5.ATR.3 Laboratory Use........................... 5.ATR.4 Health and Safety....................5.ATR.4 Equipment...............................5.ATR.5 Processing...............................5.ATR.6 Post-Processing......................5.ATR.7 Scene Use................................... 5.ATR.8 Additional Considerations.......5.ATR.8 Supplementary Information....... 5.ATR.9

Safety and Effectiveness Summary ✔ Non-Porous ✔ Semi-Porous ✘ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

The process separates adhesive surfaces with non-porous

(or semi-porous) backings from non-porous (or semi- porous)

substrates in order to expose the previously inaccessible internal surfaces for subsequent fingermark visualisation. The removal technique ultimately involves mechanical separation of the

surfaces by pulling and prising. For well-bonded tapes, it will be

necessary to cool the adhesive layer to make it brittle (i.e. reduce the temperature of the adhesive to below its glass transition

temperature). This makes it less adherent to the surface and separation may be easier to achieve.

It is a preparation process (physical) that involves mechanically

pulling the adhesive surface apart from the substrate it is stuck to.

More Details

Home Office January 2014

The Process

●● Adhesive Tape Removal can be used safely and effectively in

a laboratory and at scenes.

●● The effectiveness is influenced by the strength of the

adhesion between the tape and surface and how readily this can be overcome by the options presented in this process instruction.

●● If cooling is required, the effectiveness is dependent upon

being able to keep the temperature of the adhesive below the glass transition temperature so that it is brittle, whilst pulling and prising.

The Item or Surface

●● Adhesive Tape Removal is most suitable for use on bonded

surfaces that are unlikely to tear or be damaged during

pulling or prising. This is typically non-porous tapes and surfaces although it may be successful on some semiporous tapes or surfaces.

●● It is normally ineffective on tapes (of any porosity) bonded to

porous surfaces, or on tapes bonded to the adhesive side of other tapes.

Integrated Use

Adhesive Tape Removal may be detrimental to subsequent fingermark or forensic processing.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

with other forensic processes.

5.ATR.1

Fingermark Visualisation Manual

A Adhesive Tape Removal

5.ATR.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options Pulling and prising (at room temperature) ●● Pulling and prising (at room temperature) is a

simple method of removing some tapes from some surfaces.

●● It is the best option for preserving fingermarks

provided the layers can be separated without tearing or distorting.

Pulling and prising (at reduced temperatures)

●● Pulling and prising (at reduced temperatures) may enable tapes

to be separated from surfaces if pulling and prising (at room temperature) is unsuccessful.

●● It varies in complexity depending upon the level of cooling required,

but it must reach a point where the adhesive becomes brittle

enabling the tape to be fractured from the surface. Some options for cooling include the following. ■■

Freezer spray: normally capable of reducing the temperature to levels where the adhesive is brittle. The spray is directional so it can be applied only to the area of interest. It is safe and easy to use and will be described in this process instruction.

■■

Liquid Nitrogen: reaches extremely low temperatures and will make all adhesives brittle but is more difficult to use safely. Its use is not described in this process instruction, but in Numberplate Splitting.

■■

Placing the item in a conventional freezer unit may not cool the adhesive layer sufficiently.

●● Condensation may form on the cooled surfaces and reduce the

effectiveness of some subsequently visualisation processes.

Sequential use Adhesive Tape Removal ●● Pulling and prising (at room

temperature) must be attempted prior to pulling and prising (at reduced

temperatures) as it is least likely to cause damage to fingermarks on both sides of the tape and to the surface to which it is bonded.

●● If the techniques outlined in this

Category A process instruction

are unsuccessful, solvents may

be used to dissolve the adhesive

to aid separation of the surfaces. Depending upon the amount of

solvent used, this may be highly

destructive to fingermarks. Further details are given in Chapter 6: Category B: Adhesive Tape Removal (solvent-based).

●● See Chapter 4: Process Selection

for information on its sequential use with other fingermark visualisation processes.

●● See Chapter 7: Other Forensics

for information on integration of fingermark and other forensic processes.

Home Office January 2014

5.ATR.2

Fingermark Visualisation Manual

Adhesive Tape Removal

5.ATR.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Home Office January 2014

Health and Safety

Adhesive Tape Removal can be used safely in the laboratory and at the scene.

Effectiveness

Adhesive Tape Removal is equally effective if used in the laboratory or at the scene, provided the details as written in the process instruction can be followed.

Practicality

Adhesive Tape Removal can be just as practical to use at scenes as it is in the

laboratory, provided equipment can be used as described in the process instruction.

5.ATR.3

Fingermark Visualisation Manual

Adhesive Tape Removal

5.ATR.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Adhesive Tape Removal may be carried out with no known hazards to health

provided practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards

Glossary

Index

Laboratory Use Hazards associated with Adhesive Tape Removal ●● Adhesive Tape Removal is a preparation process (physical).

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS).

●● Wear Standard PPE as a minimum.

●● There are no additional hazards associated with the process.

(e.g. ‘residual processing chemicals on items are hazardous’) and/or control

measures, (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.ATR.4

Fingermark Visualisation Manual

Adhesive Tape Removal

Appendices

5.ATR.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Adhesive Tape Removal uses simple equipment for removing tape from surfaces. General laboratory equipment that may be required is outlined in Chapter 3. Equipment

Requirements

Freezer spray

The freezer spray must: ●● reduce the temperature of the adhesive within the section of tape to be separated to below that of its glass transition temperature.

Release paper

The surface of the release paper must: ●● not form strong bonds with the adhesives used on the tape (e.g. silicone or glassine); ●● be clean and free of anything (fingermarks, dust, fibres etc.) that could be transferred to the adhesive surface.

Home Office January 2014

5.ATR.5

Fingermark Visualisation Manual

Adhesive Tape Removal

Appendices

5.ATR.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Work area

a) Work in well-ventilated area if using freezer spray.

(2) Equipment

a) Follow manufacturer’s instructions for use of freezer spray.

Processing (3) Pulling and prising (at room temperature)

(4) Pulling and prising (at reduced temperatures)

Post removal

a) Using tweezers, carefully prise up the end of the adhesive tape and slowly peel it from the substrate avoiding tearing or significant stretching and distortion of the tape. b) If the tape is completely removed using this technique then proceed to step (5) or store appropriately, otherwise continue to step (4).

a) Locally apply freezer spray to the region where the tape remains stuck to the surface. Continue spraying until the surface appears frozen and ice has formed at area of interest. This only takes a few seconds. b) Immediately, using tweezers, carefully pull the tape away from the substrate. Only areas with cooled and brittle adhesive will separate. Do not force separation. c) Repeat a) and b) until the tape is fully separated from the substrate and store appropriately.

(5) Process lifted tape and underlying substrate according to appropriate charts in Chapter 4. The removal of adhesive tapes using a

combination of pulling with tweezers and localised application of a freezer spray.

Home Office January 2014

5.ATR.6

Fingermark Visualisation Manual

Adhesive Tape Removal

Appendices

5.ATR.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item

(1) Packaging and storage of adhesive tape

a) Separated adhesive tapes may be placed onto release paper to protect the adhesive coating during storage, transportation or processing of the non-adhesive side. The tape may then be easily removed prior to treatment with other processes on the adhesive side. b) Precautions must be taken to ensure that there are no pre-existing fingermarks or other potential contaminants on the paper that could be transferred to the adhesive surface.

The storage of adhesive tapes on a sheet of release paper.

Home Office January 2014

5.ATR.7

Fingermark Visualisation Manual

Adhesive Tape Removal

Glossary

5.ATR.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Scene Use

Additional Considerations If a decision has been made to apply Adhesive Tape Removal at a scene,

a number of additional considerations need to be taken into account, over

and above those given for laboratory use. The recommendations cannot be

prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make the process as effective as possible

within the constraints of the scene;

For health and safety, consider:

●● if there is adequate ventilation is using freezer spray.

For effectiveness consider:

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of the constraints posed by the scene.

For practicality, consider:

●● access to the areas to be treated.

●● present a range of practical issues that need to be overcome.

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

3, Section 3.1 - Scene use of the processes and treatment of large areas for other general information.

Home Office January 2014

5.ATR.8

Fingermark Visualisation Manual

Adhesive Tape Removal

Glossary

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Adhesive tapes, labels and films may be removed from surfaces in any of four ways: ●● pulling and prising only;

●● cooling (in conjunction with pulling and prising);

●● use of solvents (in conjunction with pulling and prising); ●● heating (in conjunction with pulling and prising).

All four techniques target the adhesive layer in one way or another to achieve separation. The adhesive layer used in nearly all tapes is polymeric in nature. The adhesive layer is

strongly bonded to a backing layer, and on being brought into contact with the substrate

it can form reasonably strong bonds with it. The objective during Adhesive Tape Removal is to break the bonds between the adhesive layer and the substrate while minimising the impact on any fingermarks that may be present.

In order to understand the techniques used to facilitate Adhesive Tape Removal, it is

Thermal expansion coefficient

Theory

Glassy state

Rubbery state

Tg

necessary to understand the concept of glass transition. Polymeric materials such

Temperature

as adhesives and rubbers undergo a transition from a rubbery, flexible state at higher

temperatures to a glass-like, brittle state as the temperature is reduced below a ‘glass

transition temperature’ (Tg). This transition can be detected in several ways, including by measuring stiffness and/or coefficient of thermal expansion with temperature, as shown

b-transition

a-transition

on the right.

At room temperature the adhesive is in a rubbery state where it has low stiffness and

a high thermal expansion coefficient, whereas if it is cooled below the glass transition

temperature it becomes stiff, glassy and brittle with a low thermal expansion coefficient. The ways in which the removal techniques utilise these properties are summarised on the following page:

Tg Glassy state

Glass transition

Rubbery state

Degradation

Temperature Home Office January 2014

5.ATR.9

Fingermark Visualisation Manual

Adhesive Tape Removal

Appendices

Stiffness

5.ATR.9

Contents

5.ATR.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Pulling and prising only

Glossary

Index

Supplementary Information

This technique utilises the properties of the adhesive in

Cooling (in conjunction with pulling and prising)

Use of solvents (in conjunction with pulling and prising)

the substrate stretches the adhesive layer until it either

temperature makes it glassy. When the backing layer is

the adhesive layer sufficiently so that the bond between

its rubbery state. Pulling the backing layer apart from

breaks or detaches itself from the substrate, snapping

back to its original dimensions. This leaves the majority of the adhesive layer attached to its original backing, with a small amount of residue left on the substrate.

Cooling the adhesive layer below its glass transition

pulled apart from the substrate, the adhesive is no longer flexible and when failure occurs, it takes place in a brittle manner with a crack running through the adhesive layer. This results in a clean separation of the backing layer

from the substrate, although more adhesive may be left on the substrate than is seen for the pulling and prising

Adhesive layer

Backing layer

method above.

This technique uses a solvent to dissolve and/or soften

the adhesive and the substrate is broken and the tape can be peeled from the surface. The use of solvents to remove adhesive surfaces should generally be discouraged as the solvents used to dissolve the adhesive can readily damage fingermarks. However, this may be the only suitable method for removing tapes and labels from

paper and card and separating adhesive from adhesive. Extreme care and minimum quantities of solvent should

be used. This method is outlined in Chapter 6: Category B: Adhesive Tape Removal (solvent-based). Adhesive layer

Backing layer

Substrate

Heating (in conjunction with pulling and prising)

Heating can also be used as a means of softening the

adhesive layer, making it even more rubbery and flexible. When the pulling and prising technique is subsequently Substrate

applied to the heated region, the tape is easier to peel

from the surface. The technique is not generally suitable

as tapes and labels may easily be damaged by the use of excessive heat n

Home Office January 2014

5.ATR.10

Fingermark Visualisation Manual

Adhesive Tape Removal

Appendices

5.NS.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Vehicle Plate Splitting

Contents Laboratory or scene?................... 5.NS.2 Laboratory Use............................. 5.NS.3 Health and Safety....................... 5.NS.3 Equipment................................... 5.NS.4 Chemicals................................... 5.NS.4 Processing.................................. 5.NS.5 Post-Processing.......................... 5.NS.6 Supplementary Information......... 5.NS.7

Main Uses Separation of adhesive surfaces from nonadhesive surfaces

Safety and Effectiveness Summary ✔ Non-Porous ✔ Semi-Porous ✘ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use only.

Process Overview

The process is used to split vehicle numberplates consisting of printed, flexible, polymer-backed adhesive surfaces stuck to a

rigid polymeric plate. This exposes the previously inaccessible

internal adhesive and non-adhesive surfaces that may have been handled during numberplate fabrication so that they are available for subsequent fingermark visualisation.

It is a preparation process (physical) that involves significantly

reducing the temperature of the adhesive layer with liquid

The Process

●● Numberplate Splitting can be used safely and effectively in a

laboratory.

●● This process requires liquid nitrogen temperatures to ensure

the adhesive becomes brittle and to maximise the thermal stresses set up between the two layers.

●● Other sources of sub-zero temperatures such as freezers and

dry ice are considerably less effective than liquid nitrogen.

The Item or Surface

●● The process is only suitable for two component polymer

numberplates and is not effective on numberplates consisting of embossed lettering on metal sheets.

Integrated Use

Numberplate Splitting may be detrimental to subsequent fingermark or forensic processing.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

with other forensic processes.

nitrogen to make it brittle and less adherent to the surface and

then applying force to introduce stresses that split the adhesive layer from the backing plate.

© See Photo Credits

More Details

Home Office January 2014

5.NS.1

Fingermark Visualisation Manual

A Numberplate Splitting

1st proof

5.NS.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Home Office January 2014

Health and Safety

Numberplate Splitting can be only be used safely in the laboratory (see Practicality).

Effectiveness

Numberplate Splitting is only effective if used in the laboratory (see Practicality).

Practicality

Numberplate Splitting is only applied to small portable items that are readily

transported to a laboratory. It is neither necessary nor practical to transport the quantities of liquid nitrogen required to a scene.

5.NS.2

Fingermark Visualisation Manual

Numberplate Splitting

5.NS.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Numberplate Splitting may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

Index

Laboratory Use Hazards associated with Numberplate Splitting

●● Numberplate Splitting is a preparation process (chemical or physical).

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and be suitably trained in the safe use of liquid nitrogen. See hazards from handling liquid nitrogen.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional Hazard

Risk

Suggested control measures

Skin exposure to liquid nitrogen or surfaces cooled with liquid nitrogen

Cryogenic burns

Wear appropriate PPE (e.g. cryo-gloves and a face shield)

Oxygen depletion in the air when using liquid nitrogen

Asphyxiation

Use liquid nitrogen in an extracted fume cupboard or well-ventilated area.

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.NS.3

Fingermark Visualisation Manual

Numberplate Splitting

Glossary

5.NS.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Equipment

Numberplate Splitting utilises simple equipment for handling and separating

numberplate layers, and some specialised equipment for containing liquid nitrogen. General laboratory equipment that may be required is outlined in Chapter 3. Equipment Processing vessel

Requirements The processing vessel must: ●● be suitably sized for Numberplate Splitting; ●● be suitable for containing liquid nitrogen i.e. be resistant to thermal shock and not become embrittled by prolonged exposure to low temperatures. The processing vessel should: ●● prevent the exterior of the vessel and surrounding surfaces from becoming unduly chilled.

Insulated flask(s)

The insulated flask must: ●● be suitable for storing liquid nitrogen including being insulated adequately and with a loose lid; ●● be suitably sized so that it contains at least the quantity of liquid nitrogen for processing (or use multiple smaller flasks). Note: details for bulk storage of liquid nitrogen are not given in this process instruction.

Release paper

The surface of the release paper must: ●● have a coating (e.g. silicone or glassine) that does not form strong bonds with the adhesives used on tape; ●● be clean and free of anything (fingermarks, dust, fibres etc.) that could be transferred to the adhesive surface.

Home Office January 2014

Index

Laboratory Use Chemicals

This table lists chemicals that are required for Numberplate Splitting. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3 safe handling of chemicals for general information. Common Name Liquid nitrogen

Alternative Name(s)

CAS Number 7727-37-9

Grade Standard

5.NS.4

Fingermark Visualisation Manual

Numberplate Splitting

Glossary

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory Use

Processing Post- removal

Preparation (1) Work area (2) Equipment

Processing (3) Expose items to liquid nitrogen

(4) Separate the layers

(5) Remove separated parts of numberplate(s) from vessel using tongs

(6) Dry item

a) Work in a fume cupboard or well-ventilated area. a) Place the processing vessel on an insulating base such as corrugated cardboard. b) Ensure that the insulated flask(s) contains at least the quantity of liquid nitrogen required for processing. a) Put the numberplate(s) into the bottom of the processing vessel. b) Slowly and carefully add liquid nitrogen to the processing vessel (liquid nitrogen will rapidly boil and evaporate until thermal equilibrium is reached). Continue to pour until the numberplate(s) are covered and/or begin to bend due to thermal stresses. (Pictures 1 and 2). c) The numberplate(s) may separate at this point without any further external application of force. If this occurs proceed to step (5). a) Increase the stress at the interface between the thin polymer layer and the backing plate by pushing down on the raised regions of the plate with plastic tongs. Applied stress from tongs may be sufficient to separate the printed polymer layer from the backing plate. This is not always possible and some plates may break into smaller fragments instead of separating cleanly. (Picture 3). b) In some cases the sheet may not come away cleanly and additional manipulation with implements such as tweezers may be required to remove it. (Pictures 4 and 5). a) Condensation may have formed on the surfaces. See

Drying of items.

Continued on next column Home Office January 2014

(7) Process separated surfaces according to appropriate charts in Chapter 4

2

1

3

4 5 5.NS.5

Fingermark Visualisation Manual

Numberplate Splitting

© See Photo Credits

5.NS.5

Contents

5.NS.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Packaging and storage of items

a) Adhesive polymer layers removed from the backing plate may be placed onto release paper to protect the adhesive coating during storage, transportation or processing of the non-adhesive side. The adhesive polymer layer may then be easily removed prior to treatment with other processes on the adhesive side. b) Precautions must be taken to ensure that there are no pre-existing fingermarks or other potential contaminants on the paper that could be transferred to the adhesive surface.

The storage of adhesive surfaces on a sheet of release paper.

Equipment and chemicals (2) Excess liquid nitrogen in the processing vessel

Home Office January 2014

a) Any remaining liquid nitrogen should be allowed to evaporate from the vessel and the vessel allowed to return to room temperature before handling.

5.NS.6

Fingermark Visualisation Manual

Numberplate Splitting

Appendices

5.NS.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Theory

Glossary

Index

Supplementary Information Room temperature

There are two principles that are used in Numberplate Splitting. Firstly, the adhesive

layer is a viscoelastic material and undergoes a transition from a glass-like, solid state

at low temperatures to a rubbery state where it can flow, deform and provide adhesion

Thin polymer layer with high thermal expansion coefficient, bonded with adhesive layer

at higher temperatures. At room temperature the adhesive is rubbery and can readily bond to other surfaces. However, when cooled to liquid nitrogen temperatures the

adhesive becomes rigid and will fracture like a glass if sufficient stress is placed on it. The principle of glass transition temperature is explained in more detail in Chapter 5: Adhesive Tape Removal.

Polymer panel with lower thermal expansion coefficient

Secondly, the polymer layer bearing the printed numbers and the backing plate that the sheet is stuck to will in almost every case have different coefficients of thermal

expansion. This means that they will contract at different rates when cooled to liquid nitrogen temperature. As a result, the plate will bend because the component of the numberplate with the higher thermal expansion coefficient shrinks more, pulling the lower thermal expansion coefficient component into a convex shape.

Liquid nitrogen temperature (before fracture) Contraction of high thermal expansion coefficient material

The bending that occurs in the numberplate as it cools sets up stresses which become concentrated along the adhesive layer, and these may be sufficient to fracture the

adhesive in its glass-like state. If the adhesive does not initially fracture, pushing down on both raised ends of the plate (or the raised centre if the plate is the other way up) increases the stresses in the adhesive layer further and may cause the fracture and separation to occur.

Liquid nitrogen is used for this process because the extremely low (-196°C) temperature of the liquid ensures that the adhesive is cooled to below its glass transition temperature. It also maximises the stresses that will build up in the adhesive due to the thermal expansion coefficient mismatch between the printed polymer layer and the backing plate because the temperature range (>200°C) that the thermal contraction occurs over is so large n

Stresses set up in lower thermal expansion coefficient material

Liquid nitrogen temperature (after fracture) Stresses relieved by fracture

Schematic diagram of the thermal stresses set up in numberplates on cooling to liquid nitrogen temperature, and how these can be used to split them. Home Office January 2014

5.NS.7

Fingermark Visualisation Manual

Numberplate Splitting

Appendices

5.SR.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Contents Definitions..................................... 5.SR.2 Options.......................................... 5.SR.3 Laboratory or Scene?.................. 5.SR.5 Laboratory Use............................. 5.SR.6 Health and Safety........................5.SR.6 Equipment....................................5.SR.7 Chemicals....................................5.SR.7 Solutions......................................5.SR.8 Processing ................................5.SR.9 Scene Use................................... 5.SR.16 Additional Considerations..........5.SR.16 Supplementary Information....... 5.SR.17

Main Uses Removal of dry soot

Safety and Effectiveness Summary ✔ Non-Porous ✔ Semi-Porous ✔ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for four Soot

Removal techniques: ■■ ■■ ■■ ■■

brushing; lifting;

rubbing with soft, friable materials; washing with acids and alkalis.

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

The Process

●● Soot Removal techniques can be used safely and effectively

in a laboratory and at scenes.

●● Effectiveness may be variable as it depends on the

constituents of the soot and how strongly they interact with the substrate it has been deposited on.

●● Effectiveness is also influenced by selection and application

of the most appropriate removal technique.

The Item or Surface

●● Soot removal techniques can be used on all surfaces covered

in a layer of dry soot.

●● Soot removal is not effective on surfaces: ■■

that have burnt, bubbled or melted due to the action of heat;

■■

coated with tarry residues of a fire.

Integrated Use

Soot Removal may be detrimental to subsequent fingermark or forensic processing.

This process physically removes and reduces layers of soot from

●● See Chapter 4 for information on its sequential use with other

processes to fully interact with the surface. The process may

●● See Chapter 7 for information on integration of fingermark

surfaces, hence enabling subsequent fingermark visualisation

also improve the clarity of any marks which are covered in soot by selectively removing the soot which is not adhering to the

fingermark visualisation processes. with other forensic processes.

fingermark ridges.

It is a preparation process (chemical or physical) involving the

application of a solid or liquid medium to the surface to either wash away or physically remove loose soot residue. More Details

Home Office January 2014

5.SR.1

Fingermark Visualisation Manual

A Soot Removal

1st proof

5.SR.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Definitions Types of soot

Dry soot deposit

Sticky (tar-like) deposit

Charring

after exposure to the conditions

the underlying substrate. Suitable for

the substrate. Not suitable for brushing/

heat. Original surface no longer present

The dark colouration left on surfaces experienced in a fire may differ

considerably in nature. Of the possible

Dry, fine particulates deposited on

brushing/lifting/rubbing and washing.

scenarios outlined below, the Soot

Resinous, tacky material deposited on rubbing/lifting, may be removed by solvents.

Physical damage caused to substrate by and any marks destroyed.

Removal process is only suitable for removal of dry soot.

Levels of soot coverage

Light soot deposit

Medium soot deposit

Heavy soot deposit

significantly on items recovered from the

surface, underlying substrate clearly

surface, but underlying substrate still

surface, underlying substrate no longer

The level of soot build-up may vary

same scene, and the level of adhesion

of the soot to the surface will also vary.

Discontinuous deposits across the visible.

Continuous deposit of soot across visible.

Continuous deposit of soot across visible.

The processing options for soot removal outlined overleaf are described in terms of their ability to lift light, medium and heavy deposits of soot, which are defined on the right.

Home Office January 2014

5.SR.2

Fingermark Visualisation Manual

Soot Removal

5.SR.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options Brushing (low impact technique)

●● Suitable for use on porous and non-porous

substrates to remove unattached soot.

●● Using a sweeping effect with a soft brush (to

Lifting (medium impact technique)

●● Used for removal of light to medium soot deposits. ●● A range of lifting media can be used. ■■

minimise damage to marks) some surface deposits will be removed enabling other removal techniques

Adhesive tape – for flat, simple shaped nonporous surfaces.

■■

to be more effective.

Silicone rubber casting compound – for complex shaped non-porous surfaces.

■■

Liquid latex – for treatment of small or large areas, applicable to most types of surface

(porous, non-porous, flat and complex shapes).

Rubbing (high impact technique)

●● Used for removal of heavy soot deposits on non-

porous surfaces, and light to medium deposits on porous surfaces.

●● This process involves rubbing soft, friable materials

(Absorene® or pencil erasers) gently across the layer of soot.

●● The soot is picked up on the surface of the ‘eraser’,

which then crumbles to expose a fresh surface capable of picking up more soot.

●● Lifting media are applied to the surface, then

●● This process is repeated until all loosely adhering

●● The theory of the lifting techniques is described in

●● Pencil erasers are more aggressive and potentially

removed after an appropriate time. the Lifting process section.

material is removed.

more damaging than Absorene®, and use should be restricted to localised removal of heavy soot around marks that may be partially visible.

Home Office January 2014

5.SR.3

Fingermark Visualisation Manual

Soot Removal

5.SR.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Soot Removal Options continued Washing (high-impact technique)

●● Used on non-porous substrates to remove heavy,

tenacious soot deposits.

●● Items are immersed in acid and alkali solutions

which causes a reaction at the interface between the soot and the surface loosening the deposits.

●● Also, the reaction between any residual acid trapped

in the soot when the item is transferred to the alkali solution can act to loosen deposits or make the wetted soot more transparent for imaging.

Sequential use of Soot Removal

●● Soot Removal techniques are chosen depending on

the amount of soot present and the substrate type, and can be used sequentially. If a Soot Removal technique does not remove enough soot from a

mark, the technique can be repeated or a higher impact technique may be considered. Note that

it is unlikely that all soot will be removed from the

surface, even if all processes are used. The objective of Soot Removal is to achieve a condition where residual material will have minimal detrimental

impact on subsequent application of visualisation

processes, and any resultant marks will be readily visible.

●● For the sequential application of Soot Removal

treatments a ‘minimal damage’ philosophy should be adopted. The sequential use of Soot Removal

techniques should start with low-impact techniques that can remove large quantities of loosely adhering

material, progressively moving to medium- and highimpact processes that remove more tenacious soot deposits until the surface is sufficiently clean. Soot Removal should stop at the point that the surface is regarded as being sufficiently clean rather than

carrying out every available technique in every case.

●● See Chapter 4: Process Selection for information on

its sequential use with other fingermark visualisation processes.

●● See Chapter 7: Other Forensics for information

on integration of fingermark and other forensic processes.

Home Office January 2014

5.SR.4

5.SR.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Health and Safety

Soot Removal can be used safely in the laboratory and at the scene.

Effectiveness

Soot Removal is equally effective if used in the laboratory or at the scene, provided the details as written in the process instruction can be followed.

Practicality

Most options for Soot Removal can be just as practical to use at scenes as they

are in the laboratory, provided equipment can be used as described in the process instruction.

Non-removable or large surfaces (especially horizontal surfaces) may be more difficult to process than smaller items and application methods for some techniques may be more complex.

Applying washing processes at scenes needs to be contained to minimise surface water contamination and damage to other areas not being directly treated.

Home Office January 2014

5.SR.5

Fingermark Visualisation Manual

Soot Removal

5.SR.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Soot Removal may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

Laboratory Use Hazards associated with Soot Removal

●● Soot Removal is a preparation process (chemical or physical).

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions or mixtures.

●● Wear Standard PPE as a minimum.

●● There are no additional hazards associated with the process.

Labelling solutions While the hazards associated with the chemicals used can be found on the SDS, those associated with the solutions need to be calculated from their percentages in the final solution. To assist in this, in 2011, CAST commissioned work to calculate the risks

associated with the solutions it was using at the time. The results of those calculations are given here for guidance only to those responsible for risk assessments of

solutions used locally.

The calculations are not shown for Alkali Wash Solution. Hazards* typically associated with prepared Soot Removal Solutions (CLP) Solution

Symbols

Acid Wash Solution

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Index

Signal Word and Hazard Statements ‘WARNING’ H315 ‘Causes skin irritation’ H319 ‘Causes serious eye irritation’

Hazards* typically associated with prepared Soot Removal Solutions (CHIP) Solution Acid Wash Solution

Symbols None required

Hazard Statements None required

* Solution hazards based on CAST’s solutions and calculated by ChemLaw UK.

Flammability classifications assessed either theoretically or by measurement by Hazard Evaluation Laboratory (HEL).

Home Office January 2014

5.SR.6

Fingermark Visualisation Manual

Soot Removal

Glossary

5.SR.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Laboratory Use

Equipment

Soot Removal (in particular brushing, lifting and rubbing) uses a range of equipment and

consumables, some of which are used in other processes such as Lifting and Powders. General laboratory equipment that may be required is outlined in Chapter 3. Equipment

Index

Requirements

Soft brush

The brush must: ●● be clean and soft. A suitable example would be a squirrel hair mop-shaped brush.

Lifting tape

The lifting tape should: ●● have a degree of elasticity. Such tapes deform better into irregularities in surface texture, and are less prone to splitting on removal. See Lifting for further details on lifting tapes.

Silicone rubber casting compound*

The silicone rubber casting compound should: ●● have a quality similar to that used for forensic applications such as casting of toolmark impressions. See Lifting for further details on silicone rubber casting compounds.

Liquid latex*

Liquid latex products marketed specifically for soot removal are commercially available. In practice standard liquid latex sold for theatrical make-up is also suitable.

Absorene ®*

Absorene® is a commercial product that consists of a soft, dough-like material that is wiped across a surface and removes soot as it forms granules. Putty (e.g. Blu-Tak) or the specialised types of kneaded gum eraser used by artists may also be suitable.

Chemicals

This table lists chemicals that are required for Soot Removal. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

Unless specified, water used for making solutions or for rinsing items is purified. See Chapter 3 safe handling of chemicals for general information. Common Name

Alternative Name(s)

CAS Number

Grade

Sodium hydroxide

Caustic soda

1310-73-2

Reagent grade*

5-Sulphosalicylic acid, dehydrate

5-SSA dehydrate

5965-83-3

Laboratory

* Sodium Hydroxide solutions can also be purchased at a range of concentrations.

* For convenience this consumable is listed on the ‘Equipment’ page alongside other lifting media. However, the general information on the ‘Chemicals’ page also applies specifically with regards to Safety Data Sheets.

Home Office January 2014

5.SR.7

Fingermark Visualisation Manual

Soot Removal

Glossary

5.SR.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Solutions

Consult Chapter 3 for general information on solution preparation, safe storage of chemicals, solutions and mixtures (which includes information on packaging and labelling), management of waste for disposal of solutions and guideline expiry periods. This page gives additional information relevant to this process.

Solutions Acid Wash Solution

23 g 5-sulphosalicyclic acid dihydrate 1 L Water

Alkali Wash Solution

5 g Sodium hydroxide 1 L Water

(1) Prepare solutions

a) Acid Wash and Alkali Wash Solutions are colourless.

(2) Label appropriately

a) The Acid Wash and Alkali Wash Solutions should be labelled in line with the guidance in Soot Removal Health and Safety.

(3) Store appropriately

a) The Acid Wash and Alkali Wash Solutions have guideline expiry dates of 12 months after preparation if stored at room temperature.

(4) Dispose of appropriately

For other quantities see Ready Reckoner.

Ready Reckoner Quantity of Acid Wash Solution Chemical

500 mL

1L

2L

5-sulphosalicyclic 11.5 g acid, dehydrate

23 g

46 g

Distilled water

1L

2L

500 mL

Quantity of Alkali Wash Solution

Home Office January 2014

Chemical

500 mL

1L

2L

Sodium hydroxide

2.5 g

5g

10 g

Distilled water

500 mL

1L

2L

5.SR.8

Fingermark Visualisation Manual

Soot Removal

Appendices

5.SR.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Brushing) Preparation (1) Work area

a) Work in an extracted powdering cabinet or on a downdraft bench where possible.

(2) Item

a) Consider imaging any visible marks that may have been developed by soot deposition in situ where possible.

Processing (3) Gently brush across the surface to remove loose soot particles

(4) Examine item

a) Use a gentle sweeping motion similar to that used for developing marks by powdering. Clean excess soot and debris from the brush at regular intervals by tapping the handle of the brush gently.

a) Observe level of soot removal. If sufficient, proceed to post-removal stage. If insufficient, re-treat using the same technique or proceed to a higher impact soot removal technique. See Options.

The removal of soot and ash using a light brushing

Post-removal (5) Process according to the appropriate chart for the surface in Chapter 4

Home Office January 2014

method. In this case, marks have been revealed by this a) Consideration should be given to the effect of heat or any extinguishing methods (such as water) on the effectiveness of visualisation processes within the chart.

process alone.

5.SR.9

Fingermark Visualisation Manual

Soot Removal

Appendices

5.SR.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Lifting – Lifting tape)

A

Removing soot from non-porous surfaces is similar to lifting marks developed with

Powders, although there is likely to be more material to lift and the quality of the lift is not important. See Lifting for additional information on lifting marks.

Preparation (1) Item

a) Consider imaging any visible marks that may have been developed by soot deposition in situ where possible.

Processing (2) Apply the lifting tape to the surface

(3) Remove the lifting tape from the surface

(4) Examine both item and tape lift

Post-removal (5) Process according to the appropriate chart for the surface in Chapter 4

Home Office January 2014

a) Apply the tape to the surface and smooth it in place using suitable means such as a roller or tissue (picture A). b) Eliminate air bubbles where possible. Use of a roller may assist to ensure good adhesion across the entire area of application (picture B).

B

C

a) Peel the tape off the substrate, removing any loose soot from the surface (picture C). a) Observe the level of soot removal. If sufficient, proceed to the post-removal stage. If insufficient, re-treat using the same technique or proceed to a higher-impact soot removal technique. See Options. b) Lifting tape can be reapplied to the same area by repeating steps 3–4, but in general most of the soot that can be removed in this way will have been removed after the third application of tape (picture D). c) Examine both the cleaned surface and the tape lift for evidence of fingermarks before chemical treatment.

D

a) Consideration should be given to the effect of heat or any extinguishing methods (such as water) on the effectiveness of visualisation processes within the chart.

The removal of soot using lifting tape.

5.SR.10

Fingermark Visualisation Manual

Soot Removal

Appendices

5.SR.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Laboratory Use

Processing (Lifting – Silicone rubber casting compound) Removing soot from

non-porous surfaces is similar to lifting

marks developed with Powders, although

Preparation (1) Equipment (2) Item

there is likely to be

more material to lift and the quality of the lift

is not important. See Lifting for additional

information on lifting marks.

Index

A

a) Thoroughly mix component parts of the casting compounds together, ensuring they are free of air bubbles. Use mixing ratios outlined in manufacturer’s instructions.

B

a) Consider imaging any visible marks that may have been developed by soot deposition in situ where possible.

Processing (3) Apply the casting compound to the surface

a) Apply the silicone rubber casting compound directly to the surface using an appropriate applicator, eliminating air bubbles from the layer formed where possible (picture A).

C

(4) Allow casting compound to set in place on surface (picture B) (5) Peel casting compound from the surface (picture C) (6) Examine both item and silicone rubber moulding

Post-removal (7) Process according to the appropriate chart for the surface in Chapter 4 Home Office January 2014

a) Observe the level of soot removal. If sufficient, proceed to the post-removal stage. If insufficient, re-treat using the same technique or proceed to a higher-impact soot removal technique. See Options (picture D). b) Examine both the cleaned surface and the surface of the silicone rubber mould for evidence of fingermarks before chemical treatment. a) Consideration should be given to the effect of heat or any extinguishing methods (such as water) on the effectiveness of visualisation processes within the chart.

D

The removal of soot using silicone casting compound.

5.SR.11

Fingermark Visualisation Manual

Soot Removal

Glossary

5.SR.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

(1) Equipment

a) Follow manufacturer’s instructions. It may be necessary to add thickening agents to some types of liquid latex prior to use in this application.

(2) Item

a) Consider imaging any visible marks that may have been developed by soot deposition in situ where possible.

Processing (3) Apply the liquid latex to the surface

(4) Allow liquid latex to set in place on surface

Index

Laboratory Use

Processing (Lifting – Liquid latex) Preparation

Glossary

a) Apply the liquid latex directly to the surface using an appropriate applicator such as a sponge or brush. Minimise the presence of bubbles in the layer deposited (picture A). b) Repeat applications of liquid latex if it is necessary to build up a thicker coating. However, excessive application may give prolonged drying times and ‘skinning over’ (where the top layers are dry, but the bottom layer still wet).

A

B

C

a) This normally takes approximately 5-10 minutes but may vary depending upon the thickness of the latex and the ambient temperature (picture B).

(5) Peel the dried latex from the surface (picture C)

(6) Examine surface

Post-removal (7) Process according to the appropriate chart for the surface in Chapter 4

Home Office January 2014

a) Observe the level of soot removal. If sufficient, proceed to the post-removal stage. If insufficient, re-treat using the same technique or proceed to a higher-impact soot removal technique. See Options. b) Examine the cleaned surface for evidence of fingermarks before chemical treatment.

The removal of soot using liquid latex.

a) Consideration should be given to the effect of heat or any extinguishing methods (such as water) on the effectiveness of visualisation processes within the chart.

5.SR.12

Fingermark Visualisation Manual

Soot Removal

Appendices

5.SR.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Rubbing – Absorene® dough) Preparation (1) Equipment

a) Take a handful of the dough, work it between the hands until it is soft and pliable.

(2) Item

a) Consider imaging any visible marks that may have been developed by soot deposition in situ where possible.

Processing (3) Gently wipe the dough across the sootcovered surface

(4) Examine item

a) Lightly wipe in one direction on the surface, brushing clear all crumbs of dough. Continue until the entire area of interest has been covered.

a) Observe the level of soot removal. If sufficient, proceed to the post-removal stage. If insufficient, re-treat using the same technique or proceed to a higher-impact soot removal technique. See Options. b) Examine the cleaned surface for evidence of fingermarks before chemical treatment.

Post-removal (5) Process according to the appropriate chart for the surface in Chapter 4

a) Consideration should be given to the effect of heat or any extinguishing methods (such as water) on the effectiveness of visualisation processes within the chart.

The removal of soot using Absorene® dough, and an example of adjacent areas showing level of soot coverage before and after cleaning.

Home Office January 2014

5.SR.13

Fingermark Visualisation Manual

Soot Removal

Appendices

5.SR.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Processing (Rubbing – Pencil eraser) Preparation (1) Equipment

(2) Item

a) Ensure the eraser is clean of any pre-existing soot or other contaminants.

a) Consider imaging any visible marks that may have been developed by soot deposition in situ where possible.

Processing (3) Gently rub the eraser across the sootcovered surface

(4) Examine item

a) Gently brush loose granules from the surface and clean surface of eraser as soon as it becomes heavily coated with soot.

a) Observe the level of soot removal. If sufficient, proceed to the post-removal stage. If insufficient, apply eraser again. The process should be stopped as soon as the ridge detail appears to start degrading.

The removal of soot using a pencil eraser.

Post-removal (5) Process according to the appropriate chart for the surface in Chapter 4

Home Office January 2014

a) Consideration should be given to the effect of heat or any extinguishing methods (such as water) on the effectiveness of visualisation processes within the chart.

5.SR.14

Fingermark Visualisation Manual

Soot Removal

Glossary

5.SR.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Washing – Acid-Alkali solutions) Preparation (1) Equipment (2) Item

Processing (3) Expose the surface to Acid Wash Solution (4) Expose the surface to Alkali Solution

a) Fill a dish or beaker with an appropriate quantity of Acid Wash Solution. b) Fill a separate dish or beaker with an appropriate quantity of Alkali Wash Solution. a) Consider imaging any visible marks that may have been developed by soot deposition in situ where possible.

a) Apply the Acid Wash Solution to the item for a maximum of 30 s using suitable means, such as immersion or pouring. Cease treatment immediately if application of either acid or alkali causes noticeable damage to the surface. a) Apply the Alkali Wash Solution to the item for approximately 15 s using suitable means, such as immersion or pouring.

(5) Rinse item under running water to remove loosened soot (6) Dry item

Post-removal (7) Process according to the appropriate chart for the surface in Chapter 4

a) Observe the level of soot removal. If sufficient, proceed to post-removal stage. If insufficient, re-treat using the same technique or try an alternative high-impact soot removal technique, see Options. b) See drying of items. c) Examine the cleaned surface for evidence of fingermarks before chemical treatment. a) Consideration should be given to the effect of heat or any extinguishing methods (such as water) on the effectiveness of visualisation processes within the chart.

The removal of soot using sodium hydroxide solution. Home Office January 2014

5.SR.15

Fingermark Visualisation Manual

Soot Removal

Appendices

5.SR.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Additional Considerations If a decision has been made to apply Soot Removal at a scene, a number of additional considerations need to be taken into account, over and

above those given for laboratory use. The recommendations cannot be

prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make the process as effective as possible

within the constraints of the scene;

●● present a range of practical issues that need to be overcome.

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

3, Section 3.1 - Scene use of the processes and treatment of large areas for other general information.

Index

Scene Use The techniques outlined for Soot Removal differ significantly. Although it is possible

to use all of the techniques at scenes, the additional considerations do vary and may

only apply to a limited number of techniques. Where such differences do exist they are highlighted in the information below.

For health and safety, consider:

●● there are no additional considerations with regard to brushing and rubbing

techniques at scenes;

●● there are no additional considerations with regard to lifting using adhesive tape or

silicone rubber casting compound at scenes;

●● the spray application of liquid latex at scenes may require provision of additional

respiratory protective equipment;

●● application of washing using Acid–Alkali Solutions may generate gaseous products

and should be conducted in well-ventilated areas. Minimise splashing of solutions and use containment methods.

For effectiveness consider:

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of the constraints posed by the scene. This is equally valid for all Soot Removal techniques outlined.

For practicality, consider:

●● access to the areas to be treated (valid for all Soot Removal techniques);

●● for lifting of soot from large areas, liquid latex is generally the only practical

technique; it may be necessary to add a colourant to the latex to enable areas where the latex has been applied to be discriminated;

●● additional equipment such as a compressor with air regulator and a spray gun unit

may be required for the application of liquid latex at scenes;

●● for the application of washing using Acid–Alkali Solutions, a means of applying and

containing the liquids used will be required.

Home Office January 2014

5.SR.16

Fingermark Visualisation Manual

Soot Removal

Glossary

5.SR.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Theory

Soot refers to dry, solid particulates that are formed as the product of combustion,

carried into the air as smoke and then deposited onto surfaces. The majority of these particulates are essentially amorphous carbon, but because combustion is likely to

be incomplete and the substances being burnt may vary significantly in composition, soot particles are likely to contain a number of other impurities. The dry particulates

Glossary

Index

Supplementary Information the successive exposure of the soot to an acid and an alkali solution may result in chemical reactions within the soot layer that may act to loosen the soot.

It may be necessary to apply a soot removal technique more than once, or to use several soot removal techniques in sequence to achieve a sufficiently clean surface for mark visualisation n

deposited in this way are essentially similar to some of the fine powders deposited on fingermarks during use of the Powders process.

Combustion may also result in the formation of vapours of higher melting point

hydrocarbon materials, which may condense on surfaces they come into contact with

to form a ‘tarry’ deposit. Deposits of this type are not compatible with the Soot Removal techniques outlined in this section. It may be possible to dissolve tarry deposits using solvents, but this has not been extensively researched.

Soot Removal is used as a preparation step for dry soot-covered items recovered from

scenes and fixed surfaces such as walls, doors, windows and large furniture at a scene. Soot Removal is used to clean the surface. Cleaning the surface enables the fingermark visualisation processes to interact more effectively with any fingermark residues that

may remain, and allows any marks that are visualised to be more readily visible on the surface. Because soot can preferentially adhere to fingermark ridges, marks may be revealed by the cleaning process itself.

The theory behind the lifting processes (tape lifting, silicone rubber casting compound, liquid latex) for soot removal is the same as that outlined in the section on the Lifting process.

The theory for the rubbing processes is similar to that for lifting, except that the loose soot from the surface is picked up by friction between the rubbing medium and the surface. The friction also sets up stresses in the rubbing medium which results in it breaking up and shedding granules from the surface. This in turn exposes a fresh surface which can pick up more soot.

More than one mechanism may operate for washing processes. The exposure of soot to a liquid may loosen the soot sufficiently for it to float away from the surface. In addition, Home Office January 2014

5.SR.17

Fingermark Visualisation Manual

Soot Removal

Appendices

5.TCR.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Contents Laboratory or Scene? ............... 5.TCR.2 Laboratory Use........................... 5.TCR.3 Health and Safety..................... 5.TCR.3 Equipment ................................ 5.TCR.4 Chemicals ................................ 5.TCR.4 Processing................................ 5.TCR.5 Post-Processing ....................... 5.TCR.6 Troubleshooting ......................... 5.TCR.7 Supplementary Information ...... 5.TCR.8

Main Uses Removal of thermal coatings

Safety and Effectiveness Summary ✘ Non-Porous ✘ Semi-Porous ✔ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for one Category A

method (acetone).

●● Full process details are given for laboratory use only.

Process Overview

This process is used on porous substrates with thermally activated layers (such as till receipts ), which may darken

during the subsequent application of fingermark visualisation

The Process

●● Thermal Coating Removal can be used safely and effectively

in a laboratory.

●● Thermal Coating Removal can be applied before DFO

and Ninhydrin to prevent the formation of dark layers on

thermal receipts. It can also be applied to remove any dark

layers that form during the application of DFO or Ninhydrin. It is generally more effective if used as a pre-treatment as opposed to a post-treatment.

The Item or Surface

●● The use of the process is limited to items that have a

thermally activated surface layer. It is not suitable for other types of coated porous substrate such as carbon paper.

Integrated Use

Thermal Coating Removal may be detrimental to subsequent fingermark or forensic processing.

techniques. Removal of the constituents of the thermally

●● See Chapter 4 for information on its sequential use with other

visualisation processes to be used without producing interfering

●● See Chapter 7 for information on integration of fingermark

activated layer produces a clean surface enabling subsequent black or grey backgrounds.

fingermark visualisation processes. with other forensic processes.

It is a preparation process (chemical) that involves dissolving

and removing the constituents of the thermally activated layer using a solvent. More Details

Home Office January 2014

5.TCR.1

Fingermark Visualisation Manual

A Thermal Coating Removal

5.TCR.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Health and Safety

Thermal Coating Removal uses a highly flammable solvent and can be only be used safely in the laboratory (see Practicality).

Effectiveness

Although, in theory, Thermal Coating Removal could be equally effective if used in the laboratory or at a scene, for health and safety and practical reasons it would only be used in a laboratory.

Practicality

Thermal Coating Removal is only applied to small portable items that are readily

transported to a laboratory. It is not necessary to transport the highly flammable solvent and processing equipment required to a scene.

Home Office January 2014

5.TCR.2

Fingermark Visualisation Manual

Thermal Coating Removal

5.TCR.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Thermal Coating Removal may be carried out with no known hazards to health

provided practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

Glossary

Index

Laboratory Use Hazards associated with Thermal Coating Removal ●● Thermal Coating Removal is a preparation process (chemical).

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS).

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional hazard

Creation of a flammable atmosphere when using acetone.

Risk Fire

Suggested control measures ●● Use acetone in a fume

cupboard. See working with flammable liquids for further information.

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.TCR.3

Fingermark Visualisation Manual

Thermal Coating Removal

Appendices

5.TCR.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Equipment

Thermal Coating Removal utilises only simple equipment. General laboratory equipment that may be required is outlined in Chapter 3. Equipment Suitable vessel

Home Office January 2014

Requirements Processing troughs used in DFO and Ninhydrin are suitable and convenient for the application of acetone during Thermal Coating Removal. Other vessels can be used.

Index

Laboratory Use Chemicals

This table lists chemicals that are required for Thermal Coating Removal. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3 safe handling of chemicals for general information. Common Name Acetone

Alternative Name(s) Propanone

CAS Number 67-64-1

Grade Analytical

5.TCR.4

Fingermark Visualisation Manual

Thermal Coating Removal

Glossary

5.TCR.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Work area

a) Processing must be carried out in a fume cupboard.

(2) Equipment

a) Pour the acetone into an appropriate clean, dry processing trough.

(3) Item

(4) Expose item to solvent

(5) Remove item from solvent and allow to dry

a) Ensure that images of the information present on the item(s) have been captured before proceeding because the Thermal Coating Removal process will remove all pre-existing text. a) Immerse the item in the solvent until printing and/ or dark colouration is removed. It may take many minutes and more than one wash to remove chemicals responsible for blackening from the heat sensitive coatings on some papers. b) The solvent wash must be discarded after use. A clean dry processing trough with fresh solvent must be used if the wash becomes badly contaminated and ceases to remove the dark colouration of the item. a) Allow the solvent to evaporate from the item before removing from fume cupboard. If the items remain free of dark colouration, proceed to Post-Removal. b) If the item turns grey/black as it dries, repeat steps 4 and 5 until dried papers no longer show any residual dark colouration.

Post-Removal (6) Process according to appropriate charts in Chapter 4

a) In cases where it is necessary to recover the text, it may be possible to use the Category B Iodine Fuming process for this purpose.

The removal of thermal

coatings using acetone solvent.

Home Office January 2014

5.TCR.5

Fingermark Visualisation Manual

Thermal Coating Removal

Appendices

5.TCR.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Equipment and Chemicals (1) Acetone

Home Office January 2014

a) Acetone used for Thermal Coating Removal should not be re-used or poured back into its container and should be disposed of as flammable waste.

5.TCR.6

Fingermark Visualisation Manual

Thermal Coating Removal

Appendices

5.TCR.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Darkening of Processed Items on Drying or after Processing Recognition

The porous substrate becomes grey or black on drying following Thermal Coating Removal, or subsequently darkens during DFO or Ninhydrin.

A thermal receipt after processing with

Thermal Coating Removal followed by

Ninhydrin where (left) shows a darkening

of the paper due to inadequate removal of

the thermal coating and (right) shows the successful removal of this layer once the error is recognised.

Cause The substrate has not been immersed in the solvent long enough to fully dissolve the active thermal layer.

Home Office January 2014

Effect

Prevention

Correction

The residual active layer reacts with the Ensure that the item has been exposed to Repeat the Thermal Coating Removal polar solvent (and/or heat) and a grey/ the solvent long enough for all the active process by re-immersing in solvent. black background colouration appears on thermal layer to be dissolved. drying.

5.TCR.7

Fingermark Visualisation Manual

Thermal Coating Removal

Appendices

5.TCR.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

(acetone being recommended) that dissolves the thermal coating and has a minimal

application. The active coat is the layer in which the desired printed image is created

allowing the item to dry and then processing it in a conventional way. If treated in this

Thermal papers have a multi-layered construction, with each layer having its own unique through applied heat from a separate thermal print head. Dyes, co-reactant, sensitisers and stabilisers are all present within this layer. With the application of heat, the above

components react with each other in the specific areas where heat is applied to give a

black reaction product, permanently preserving a printed image within the active thermal

layer. Depending on the type of thermal paper and the manufacturer, the number of other layers can vary considerably; however, every thermal paper will contain an active coat, a

substrate (the paper or base that coatings are applied to) and a base coat that is used as a primer to seal the substrate and provide a surface that the thermal coating will adhere to.

effect on fingermarks. This is used to dissolve the thermal coating entirely before

way, thermal papers will first blacken on contact with the solvent before the thermal

layer dissolves entirely and the paper becomes clear of printed text. It is still possible to develop fingermarks on such items because the thermal coating is very thin and

the fingermark deposits migrate through it into the paper substrate, where the mark is developed.

Although Thermal Coating Removal is recommended as a pre-treatment, if thermal

papers are processed in error and turn black during processing it is possible to use the solvent wash as a post-treatment to remove the black layer and reveal any marks that may have developed.

Active coat (leuco-dye)

Thermal Coating Removal describes only one option (acetone). There may be other suitable processes that have not been fully evaluated by CAST n

Base coat

Substrate Schematic diagram showing the structure of thermal paper. The presence of the active thermal layer in thermal receipts and papers can cause

problems for some fingermark visualisation processes, in particular DFO and Ninhydrin. The solvents used in these processes partially dissolve the thermal layer, turning items of this type completely black. In addition, the high temperatures which are used in the DFO and Ninhydrin processes also have an obvious effect on the thermal layer. This

blackening of the paper can obscure any developed marks, the fluorescence of DFO

being absorbed by the black coating and the coloured Ninhydrin products being difficult to see.

The principle used in Thermal Coating Removal is to utilise a pre-wash with a solvent

Home Office January 2014

5.TCR.8

Fingermark Visualisation Manual

Thermal Coating Removal

Appendices

5.OP.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Colour Filtration............................. 5.CF.1 Fluorescence Examination........... 5.FE.1 Infrared Reflection....................... 5.IRR.1 Monochromatic Illumination........ 5.MI.1 Multi-Spectral Imaging...............5.MSI.1 Ultraviolet (UVC) Reflection.... 5.UVCR.1 Visual Examination........................5.VE.1

Home Office January 2014

Fingermark Visualisation Manual

Optical Processes Introduction

The optical visualisation processes exploit the optical properties of the item or surface when illuminated or irradiated. They can be used to

visualise marks prior to any chemical or physical processes or further enhance previously treated items or surfaces n

5.OP.1

5.CF.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Contents Options........................................... 5.CF.2 Laboratory or Scene?................... 5.CF.3 Laboratory Use.............................. 5.CF.4 Health and Safety...................... 5.CF.4 Equipment................................. 5.CF.5 Colour Selection........................ 5.CF.6 Processing................................. 5.CF.7 Scene Use...................................... 5.CF.8 Additional Considerations......... 5.CF.8 Supplementary Information.......... 5.CF.9

Main Uses ✘ Latent ✔ Blood ✘ Grease ✔ Other*

It is an optical process that involves simultaneously

✔ Non-Porous ✔ Semi-Porous ✔ Porous

*Any coloured fingermarks (treated or untreated) and/or marks on coloured backgrounds.

Key Information

●● Competent personnel specialising in fingermark

visualisation, in particular imaging, must be

consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use and

additional considerations are given for scene use.

Process Overview

Colour Filtration is used to enhance fingermarks that

are already visible in situations where the fingermark, the

background, or both are coloured. The process utilises the

colour characteristics of the mark and/or surface and involves selection of appropriately coloured filters and/or light sources

illuminating the mark and surface with an appropriate lowpowered light source and viewing the outcome. A suitable

viewing filter may also be required to obtain optimum results (see Options). More Details

Safety and Effectiveness Summary The Process

●● Colour Filtration can be used safely and effectively in the

laboratory and at scenes.

●● Process effectiveness will be determined by the range of

coloured filters (or light sources) available.

The Item or Substrate

●● Process effectiveness is influenced by the colour of the

mark, the colour of the surface and to a lesser extent the distribution of the colours present.

Integrated Use

Colour Filtration is non-contact, non-destructive and has no

detrimental impact on any subsequent fingermark or forensic processing.

to alter the contrast of the mark relative to the background.

●● See Chapter 4 for information on its sequential use with other

to increase contrast of marks with surfaces of a single colour;

●● See Chapter 7 for information on integration of fingermark

Two principal approaches can be used: colour enhancement

and colour cancellation to reduce unwanted contrast between different regions of multi-coloured surfaces. Monochromatic

fingermark visualisation processes. with other forensic processes.

Illumination is also described as a separate process because

the colour filtration condition can be dynamically controlled over a broad wavelength range and the narrower bandwidths used allow greater colour discrimination.

Home Office January 2014

5.CF.1

Fingermark Visualisation Manual

A Colour Filtration

5.CF.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options

There are three approaches to achieving the desired enhancement effects with Colour Filtration. These are described below and they are all equally effective.

White light source and a coloured filter on the viewing system

Coloured filter in front of white light source

●● A white light source is used to provide even spectral

●● An appropriately coloured filter is placed in front of a

illumination of the surface being examined.

●● An appropriately coloured filter is placed in front of

the imaging system.

Colour Filtration using white light illumination with a green filter placed in front of the camera.

white light source to provide coloured illumination of the surface being examined.

●● Enhanced effects can be obtained using

Monochromatic Illumination, where a variable

wavelength filter is placed in front of the light source instead of a single colour filter.

Colour Filtration using white light illumination with a green filter placed in front of the light source.

Coloured light source

●● An appropriately coloured light source is used to

illuminate the surface.

●● Although not strictly Colour Filtration, the effect

achieved is similar to the approach of placing

a coloured filter in front of a white light source, outlined above.

●● It is usually more practical to keep a selection of

coloured filters than low-powered coloured light sources but where the latter are available they should be considered.

Colour Filtration using green light illumination to provide both lighting and colour contrast.

Home Office January 2014

5.CF.2

Fingermark Visualisation Manual

Colour Filtration

5.CF.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Home Office January 2014

Health and Safety

Colour Filtration can be used safely in the laboratory and at the scene.

Effectiveness

Colour Filtration is equally effective if used in the laboratory or at the scene, provided the details as written in the process instruction can be followed.

Practicality

Colour Filtration can be just as practical to use at scenes as it is in the laboratory, provided equipment can be used as described in the process instruction.

5.CF.3

Fingermark Visualisation Manual

Colour Filtration

5.CF.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Colour Filtration may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is

Index

Laboratory Use Hazards associated with Colour Filtration ●● Colour Filtration is an optical process.

●● Practitioners must be aware of the hazards associated with the particular radiation

sources they plan to use. (See hazards associated with the use of light sources).

●● Wear Standard PPE as a minimum.

●● Hazards associated with the use of the process are identified below but those cited

must not be regarded as exhaustive, nor the control measures prescriptive. Hazard

Risk

Hazardous dust or nuisance odours from items previously treated with a chemical or physical process.

See specific process instruction for possible adverse effects to eyes, skin and respiratory system.

Radiation emitted from source in: Visible range (380-780 nm)

Negligible risk as long as a low-powered source is selected and used appropriately.

Suggested control measures Follow recommendations for examination of items in process instructions for the physical or chemical process used.

carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.CF.4

Fingermark Visualisation Manual

Colour Filtration

Glossary

5.CF.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

Colour Filtration uses a selection of simple optical equipment (low-powered light

sources, filters). General laboratory equipment that may be required is outlined in Chapter 3.

Equipment White light source

Requirements The white light source must: ●● be low-powered to avoid hazards associated with eye damage. The white light source should:

●● have a relatively even spectral output across the visible

region of the spectrum, although this is less important than for Monochromatic Illumination.

A selection of coloured filters

The selection of coloured filters should: ●● include a broad range of filters for colour enhancement and colour cancellation. Each filter must: ●● be of optical quality if used in front of an imaging

system or the eye (this is less important if it is to be used over the light source).

A selection of coloured light sources

The selection of coloured light sources should: ●● include a broad range of light sources for colour enhancement and colour cancellation.

Each light source must: ●● be low-powered to avoid hazards associated with eye damage.

Home Office January 2014

5.CF.5

Fingermark Visualisation Manual

Colour Filtration

Appendices

5.CF.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Colour Selection The Colour Wheel

Examples of Colour Enhancement Contrast enhancement of coloured marks against neutral backgrounds

most appropriate coloured filters or light sources (whichever is used).

Black 1) and Solvent Black 3 are all within the magenta to blue colour range. By using

The colour wheel is a useful quick reference tool to assist the practitioner in selecting the

Red

Marks developed with Ninhydrin, Basic Violet 3, Acid Dyes (Acid Violet 17 and Acid

complementary coloured light sources or filters (yellow to green), the marks will appear darkened.

Contrast enhancement of marks against coloured backgrounds

The contrast between white marks on a red surface can be enhanced by using

Magenta

Yellow

surface complementary coloured light sources or filters (in this case, cyan) to give the appearance of a darkened background.

Example of Colour Cancellation Contrast enhancement of marks against multi-coloured backgrounds A purple mark developed with Ninhydrin on a white envelope is obscured by a red

postal stamp. By colour matching the postal stamp with a red light source or filter, the background interference appears to be eliminated.

For a more detailed explanation, see Supplementary Information.

Blue

Green

Cyan For colour enhancement, complementary coloured light sources or filters should be used (i.e. the opposite colour on the colour wheel).

For colour cancellation, the colour of the light source or filter should match one of the colours on the surface that is interferring with the visualisation of the mark.

The practitioner should select the light source or filter to be used according to the colours present in both the mark and the background. Home Office January 2014

5.CF.6

Fingermark Visualisation Manual

Colour Filtration

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Work area

(2) Equipment

a) Follow manufacturer’s instructions. b) Select appropriate equipment (see Options and Wavelength Selection) Consider whether colour enhancement or colour cancellation is required.

Processing (3) Mark up any visible marks

(4) Capture reference images using white light illumination, if necessary

a) As Colour Filtration enhances marks developed with other processes, they may already be marked up (and imaged).

a) See Visual Examination.

Sample images of marks enhanced using Colour Filtration: (top) colour enhancement of Ninhydrin fingermarks on white paper

with a green filter; (bottom) colour cancellation of Black Powder

Suspension marks on a multi-coloured drink can with a red filter. (5) View item using selected Colour Filtration equipment

(6) Mark up any additional viable marks that may have been revealed and capture image(s)

Home Office January 2014

a) Repeat process with different wavelength selection, if necessary.

5.CF.7

Fingermark Visualisation Manual

Colour Filtration

Appendices

© See Photo Credits

5.CF.7

Contents

5.CF.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Scene Use

Additional Considerations If a decision has been made to apply Colour Filtration at a scene, a number of additional considerations for the scene use of Colour Filtration need to be taken into account, over and above those given for laboratory use. The

recommendations cannot be prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make the process as effective as possible

within the constraints of the scene;

●● present a range of practical issues that need to be overcome.

For health and safety:

●● there are generally no additional considerations with regard to the use of the

process at scenes.

For effectiveness, consider:

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of the constraints posed by the scene.

For practicality, consider:

●● access to the areas to be treated;

●● provision of a suitable power source, if needed.

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter 3, Scene use of the processes and treatment of large areas for other general information.

Home Office January 2014

5.CF.8

Fingermark Visualisation Manual

Colour Filtration

Appendices

5.CF.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

White light sources are often composed of all colours of the spectrum (red, orange,

Colour Filtration utilses this surface property in a way that maximises the contrast

will vary resulting in some light sources appearing ‘warmer’ or ‘cooler’ than others.

filters instead of white light.

yellow, green, blue, indigo and violet). The relative amounts of each wavelength (colour) When white light falls upon a surface, some wavelengths (colours) are absorbed

whilst other wavelengths (colours) are reflected. This property of the surface dictates its colour under white light illumination. The schematic below (and other schematics within supplementary information) demonstrates this point with the white light being represented by the three primary colours (red, blue and green) for simplicity.

between the colour of the mark and the colour of the surface by using coloured lights or There are three elements that are important for Colour Filtration: ●● the colour of the light used to illuminate the surface, or the colour of the filter used to

view the reflections;

●● the colour of the surface;

●● the colour of the fingermark.

In order to understand how these elements influence Colour Filtration, knowledge of the

White light emission

Surface reflects red, green, blue

Surface appears white

White light emission

Surface absorbs red, green, blue

Surface appears black

White light emission

Surface reflects red, blue and absorbs green

Surface appears magenta

Home Office January 2014

colour wheel is required.

5.CF.9

Fingermark Visualisation Manual

Colour Filtration

Appendices

5.CF.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

The Colour Wheel

When considering the use of Colour Filtration to alter the contrast between differently coloured regions (e.g. the surface and the fingermark), it is useful to understand the

relationship between different colours. A useful tool to illustrate this is the colour wheel (see below).

The colours of the spectrum are arranged in a circle so that colours are opposite their complementary colours.

If a surface is illuminated with its complementary colour (e.g. if a blue surface is

illuminated with yellow light), then the surface would strongly absorb that colour and appear dark. If a surface is illuminated with the same colour as the surface (e.g. if a

blue surface is illuminated with a blue light) then it would strongly reflect and appear

Red

bright. In fact, any coloured lights or filters will appear to lighten colours that are close to that colour on the wheel and darken colours that are opposite. The darkening or

lightening effect is relative to other colours, rather than absolute (i.e. using filters of

a complementary colour to a mark or surface will make it appear darker rather than making it appear black).

Magenta

Yellow

By observing the colours present in the mark and the surface, light sources or filters can be selected using the colour wheel to give the desired lightening or darkening effect. There are two principal ways in which Colour Filtration is used to enhance contrast between the mark and background: ●● colour enhancement; ●● colour cancellation.

Both of these are described in more detail in the following pages.

Blue

Green

Cyan A colour wheel, showing the relationship between primary and complementary colours.

Home Office January 2014

5.CF.10

Fingermark Visualisation Manual

Colour Filtration

Appendices

5.CF.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Contrast enhancement of coloured marks against neutral backgrounds Description and principles

Where the fingermark visualisation process produces

Example

Colour enhancement of Ninhydrin

fingermarks on white paper with a green filter.

coloured marks, the contrast of these marks with a

neutral background can usually be enhanced by the use

of a filter of a complementary colour giving contrast with the mark, making it darker in relation to the background.

This increase in contrast may sometimes reveal detail that is not clear under normal, white lighting. The visualisation process for which this is most applicable is Ninhydrin, where the contrast of the purplish-red marks can be

Lighting diagram and additional notes

camera. This is an example of colour enhancement.

green filter blocks all other colours from reaching the imaging system, and the resultant colour-filtered image therefore

enhanced by using a green contrast filter in front of the

The purple mark absorbs green wavelengths of light, whereas the other regions of the surface reflect it. The use of a appears dark where green light is absorbed and light where it is reflected, thus darkening the mark relative to the background.

White light source outputting all wavelengths

Green wavelengths reflected by surface regions and transmitted by filter

Green light source

Reduced amount of light passing through filter in region of fingermark

Reduced amount of light passing through filter in region of fingermark

Pale coloured surface reflecting most wavelengths

Green filter blocking all wavelengths except green

Fingermark absorbing green wavelengths

Home Office January 2014

Green wavelengths reflected by surface regions and transmitted by filter

Pale coloured surface reflecting most wavelengths

Green filter blocking all wavelengths except green

Fingermark absorbing green wavelengths

5.CF.11

Fingermark Visualisation Manual

Colour Filtration

Appendices

5.CF.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Contrast enhancement of marks against plain coloured backgrounds

Example

Colour enhancement of white powder

suspension fingermark on a semi-porous

Description and principles

box with a green filter.

In other cases the opposite effect to that shown on

the previous page may be utilised. For example, the contrast between a fingermark visualised using a

process giving light-coloured marks (e.g. Superglue

Fuming or White Powder Suspension) and a coloured surface could be enhanced by using a coloured filter

to darken the background in relation to the mark. This is an example of colour enhancement.

Lighting diagram and additional notes

The white mark reflects all wavelengths of light, whereas the other regions of the surface absorb green and blue and

reflect red. The use of a green filter blocks all other colours from reaching the imaging system, and the resultant colourfiltered image therefore appears dark where green light is absorbed and light where it is reflected, thus darkening the background relative to the mark.

White light source outputting all wavelengths

Coloured surface reflecting mostly red wavelengths and absorbing others

Green wavelengths reflected by fingermark and transmitted by filter Reduced amount of light passing through filter in regions of coloured surface

Green filter blocking all wavelengths except green

Fingermark reflecting all wavelengths

Home Office January 2014

Green light source

Green wavelengths reflected by fingermark and transmitted by filter Reduced amount of light passing through filter in regions of coloured surface

Coloured surface reflecting mostly red wavelengths and absorbing others

Green filter blocking all wavelengths except green

Fingermark reflecting green wavelengths

5.CF.12

Fingermark Visualisation Manual

Colour Filtration

Appendices

5.CF.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Contrast enhancement of marks against multi-coloured backgrounds

Example

Colour cancellation of Black Powder

Suspension marks on a multi-coloured

Description and principles

drinks can with a red filter.

The background itself may have adjacent regions of

contrasting colour and it is often worth attempting to suppress contrast within the background. In these

circumstances there may be benefit in using coloured filters to ‘cancel’ one of the background colours and

make it appear a more uniform colour (either lighter or

Lighting diagram and additional notes

discriminated as it crosses colour boundaries. This is an

absorb green and blue and reflect red. The use of a red filter blocks all other colours from reaching the imaging system,

darker than the mark) so that the mark can be more easily

The black mark absorbs all wavelengths of light, the white regions of the surface reflect all colours and the red regions

example of colour cancellation.

White light source outputting all wavelengths

and the resultant colour filtered image therefore appears light where red light is reflected, thus making the background lighter and more uniform relative to the mark n

Red wavelengths reflected by both surface regions and transmitted by filter

Red light source outputting all wavelengths

Reduced amount of light passing through filter in regions of fingermark

Coloured surface reflecting mostly red wavelengths and absorbing others

Red filter blocking all wavelengths except red White surface reflecting all wavelengths Fingermark absorbing all wavelengths

Home Office January 2014

Red wavelengths reflected by both surface regions and transmitted by filter Reduced amount of light passing through filter in regions of fingermark

Coloured surface reflecting red wavelengths and absorbing others

Red filter blocking all wavelengths except red White surface reflecting all wavelengths

Fingermark absorbing all wavelengths

5.CF.13

Fingermark Visualisation Manual

Colour Filtration

Appendices

5.FE.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

High Intensity Light Source (HILS) Examination

Contents Options........................................... 5.FE.2 Laboratory or Scene?................... 5.FE.3 Laboratory Use.............................. 5.FE.4 Health and Safety ....................... 5.FE.4 Equipment ................................... 5.FE.6 Wavelength Selection.................. 5.FE.8 Processing ................................ 5.FE.12 Scene Use.................................... 5.FE.14 Additional Considerations ......... 5.FE.14 Troubleshooting .......................... 5.FE.15 Supplementary Information ....... 5.FE.23

Main Uses ✔ Latent ✔ Blood ✔ Grease ✔ Other*

Safety and Effectiveness Summary ✔ Non-Porous ✔ Semi-Porous ✔ Porous

*Marks in fluorescent contaminants, or in absorbing contaminants on fluorescent surfaces.

Key information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

Fluorescence Examination utilises differences in the fluorescent properties between the fingermark and the background to

The Process

●● Fluorescence Examination can be used safely and effectively

in a laboratory and at scenes provided the guidance in this process instruction is followed.

●● Its effectiveness is influenced by the quality of the equipment;

the surrounding environment; the skill, expertise, patience and other human factors associated with the operator.

The Item or Surface

●● Fluorescence Examination can be effective on all surfaces,

but is dependent on the relative fluorescent properties of the fingermark and surface.

●● It is most useful for visualising marks from processes that

yield fluorescent products, or non-fluorescing marks that utilise background fluorescence.

●● Fluorescence Examination of untreated items or surfaces

is typically less productive than subsequent chemical or

physical processing, but it will find many marks that other processes will not detect.

produce fingermarks visible to either the eye or an imaging

Integrated Use

(mostly from contaminants rather than natural sweat), some

detrimental impact on any subsequent fingermark or forensic

system. Chemical constituents within unprocessed fingermarks processed fingermarks and some surfaces may fluoresce, whilst others may absorb light but do not fluoresce. Fingermarks that have been subjected to processes to make them fluoresce are usually brighter and easier to see than those found during an

initial examination prior to any chemical processing, which may be extremely faint.

It is an optical process that uses specialist high-intensity light

Fluorescence Examination is normally non-destructive with no evidence recovery processes provided that excessive surface heating does not occur.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

with other forensic processes

sources (visible and UV) to excite fluorescence and specialist filters to enable the practitioner to view it. More Details Home Office January 2014

5.FE.1

Fingermark Visualisation Manual

A Fluorescence Examination

5.FE.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options Initial examination ●● Initial

examination refers to

the use of

Fluorescence Examination on items or

surfaces prior to the use of

any chemical or physical processes.

●● It is effective at visualising marks in some

contaminants that are not targeted by subsequent chemical or physical processes.

●● The fluorescent properties of the mark and surface

are often unknown. This lack of knowledge makes an initial examination for latent marks time-consuming as multiple searches with different excitation light sources and viewing filters will be required.

●● Many fingermarks do not fluoresce (e.g. blood),

but marks can still be visualised with Fluorescence

Examination by utilising the fluorescence of the item or surface (known as background fluorescence).

●● However, a competent practitioner will be able to

maximise mark recovery and minimise the amount

of searches by making informed decisions based on experience, observation during initial examination

Examination of processed fingermarks ●● Some

processes yield fingermarks

that fluoresce. In this case,

Sequential use of Fluorescence Examination ●● It is possible to use any of the light source–filter

combinations in sequence with each other. The light source–filter combinations can be used in any order in such a sequence.

the excitation

●● See Chapter 4 for information on its sequential use

characteristics

●● See Chapter 7 for information on integration of

and emission of the

chemicals

with other fingermark visualisation processes. fingermark with other forensic processes.

are known and initial

selection of light source and filter combinations is straightforward.

●● It may still be necessary to modify the initial selection

based on further information obtained during

examination, for example if the background gives unwanted, high levels of fluorescence.

●● Some processes yield fingermarks that do not

fluoresce, but marks can still be visualised

with Fluorescence Examination by utilising the fluorescence of the item or surface (known as background fluoresence).

See Wavelength Selection for Examination of Processed Fingermarks.

and a few known facts.

See Wavelength Selection for Initial Examination.

Home Office January 2014

5.FE.2

Fingermark Visualisation Manual

Fluorescence Examination

5.FE.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical

Health and Safety

issues associated with the use of this process. Those responsible for deciding

Fluorescence Examination can be carried out safely both in the laboratory and at the

or investigators, must consider in addition to the information below:

taken against the optical hazards. Laboratories typically have a specially designed safe

whether to process items in the laboratory or at the scene, e.g. crime scene managers ●● the detailed process instructions; and

●● other factors dictated by the investigation

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

scene, provided this process instruction is followed and appropriate precautions are

working environment for Fluorescence Examination, whilst it may be more difficult to create a safe working environment at scenes.

Effectiveness

Fluorescence Examination is equally effective if used in the laboratory or at the

scene, provided the details as written in the process instruction can be followed. This

includes having access to the most appropriate equipment; being able to black out the environment; and having adequate space to work.

Practicality

Optimal environmental parameters are easy to achieve in a laboratory, but may be

more challenging to achieve at scenes. A means of providing a darkened environment

is essential and this is critical for initial examinations. For this reason, small, removable items are probably best examined in a well-equipped laboratory.

Home Office January 2014

5.FE.3

Fingermark Visualisation Manual

Fluorescence Examination

5.FE.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Fluorescence Examination may be carried out with no known hazards to health

provided practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.FE.4

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety continued Hazards associated with Fluorescence Examination

●● Fluorescence Examination is an optical process.

●● Practitioners must be aware of the hazards associated

with the particular radiation sources they plan to use.

●● (See hazards associated with the use of artificial

optical radiation).

●● Wear Standard PPE as a minimum in addition to that

identified below.

●● Hazards associated with the use of the process are

identified below but those cited must not be regarded as exhaustive, nor the control measures prescriptive.

Home Office January 2014

Glossary

Index

Laboratory Use

Hazard

Risk

Suggested control measures

Hazardous dust or nuisance odours from items previously treated with a chemical or physical process.

See specific process instruction for possible adverse effects to eyes, skin and respiratory system.

Follow recommendations for examination of items in process instructions for the physical or chemical process used.

Hazardous visible and non-visible radiation emitted from highintensity light sources in: Visible range (380–780 nm) or UVA range (315–400 nm)

Damage to eyes and skin from the high power density and/or wavelength of excitation radiation, even with very short exposure times.

Apply engineering controls: ●● wherever possible use enclosed or semi-enclosed housings as this obviates the requirement for operator-worn eye protection, which can be uncomfortable, especially if used for long periods; ●● work in a facility, such as a fluorescence examination room, equipped with suitable engineering controls; ●● where possible, purchase and use light sources that have integrated safety features such as fail-safe light emission. This may include: ■■ incorporation of a ‘dead-man’s switch’ into handheld units. This is usually a button that the practitioner must press for light emission. Once this is released then the light source will fail in a safe mode; ■■ incorporation of a facility that will allow integration with door interlock systems. This will protect anyone without appropriate PPE who inadvertently interrupts the examination. Apply administrative controls: ●● ensure light sources and viewing filters are clearly labelled; ●● work to a safe method recorded in the risk assessment to include: ■■ use of the equipment limited to trained and competent personnel ensuring that they understand their responsibilities to others in the vicinity; ■■ if using light sources in open-beam mode always direct the excitation light away from viewers; ■■ use of well-maintained light sources in accordance with the manufacturer’s instructions, taking account of any guidelines for safe use; ■■ indication by warning signs when high-intensity light sources are being used. Provide personal protective equipment: ●● ensure suitable PPE is provided, such as: ■■ appropriate eye protection, as supplied or recommended by the light source manufacturer, checked that it is not damaged and worn at all times during light emission; ■■ ensure that skin is covered adequately when using ultraviolet (UVA) emissions.

5.FE.5

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Equipment

Fluorescence Examination requires the use of some process-specific equipment. This

includes a range of specialist light sources* and viewing filters. If equipment is to meet the requirements as outlined below, it must be well maintained and, if appropriate, serviced regularly in accordance with the manufacturer’s instructions. General laboratory equipment that may be required is outlined in Chapter 3.

In order to get the most benefit from Fluorescence Examination, an understanding of the

information contained within Supplementary Information is required prior to purchasing and using equipment.

* By definition, non-visible radiation such as UVA should be referred to as radiation rather than light, and rather than surfaces being illuminated by such, they may be irradiated. However, within this process instruction the general term light source is adopted.

Index

Laboratory Use Equipment

Requirements

Highintensity light source

The high-intensity light source must: ●● emit wavelengths of illumination to excite fluorescence within either the mark or background. Consideration must be given to the type of mark (chemically enhanced, latent etc.) and the surface being examined in order to determine appropriate wavelengths. See Wavelength Selection; ●● not emit perceptible stray light at the wavelengths at which the fluorescence is being viewed; ●● produce an intensity of illumination (i.e. power) at the surface that is high enough to produce a level of fluorescence that can be effectively observed; (high power densities of 10–100 mW cm-2 are necessary to detect some fingermarks. This equates to a light source with an output power of 1–10 W across a search area 10 cm × 10 cm.); ●● be maintained in accordance with manufacturer’s instructions, ensuring in particular that the output power is maintained within acceptable limits; ●● be clearly labelled with enough information to inform the user of output wavelengths and any associated hazards. The high-intensity light source should: ●● deliver an even beam of light covering an acceptable search area, enabling the user to effectively observe marks of typical size and contrast from a practical distance. It is essential for optimum light source operation that any userserviceable parts (e.g. filters) are kept in good condition. Some surfacecoated items may be permanently damaged by fingermarks or other contamination left on them by inappropriate cleaning. Some optical components gradually degrade by exposure to the intense radiation and this causes a reduction in output power. Some high-intensity light sources (and light guides) have limited lifetimes and their performance will decrease with time. It is good practice to keep records of light source usage where a component has a stated service life (e.g. discharge lamps).

Home Office January 2014

5.FE.6

Fingermark Visualisation Manual

Fluorescence Examination

Glossary

5.FE.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Equipment continued Equipment Viewing filters for the eyes (goggles or glasses)

Viewing filter for imaging systems (imaging filters)

Requirements The goggles or glasses must: ●● protect the eyes against the output illumination of the highintensity light source whilst transmitting fluorescence from the item. This usually means that transmission of the filter over the wavelength range of the illumination should be less that 10 -4 (or OD4 where OD = optical density); ●● be maintained in accordance with manufacturer’s instructions, ensuring that they are kept clean and damage free – damaged viewing goggles must not be used; ●● be clearly labelled with enough information to inform the user of the transmission properties and/or which specific light source they must be used with. The goggles or glasses should: ●● be supplied by the manufacturer of the high-intensity light or ultraviolet radiation source, or be recommended by them as appropriate for use with it; ●● fit to the face such that the amount of scattered light entering the eye is limited as this will affect dark adaptation; ●● not fluoresce when illuminated at the examination wavelengths. Note: see health and safety for PPE requirements for the eyes and skin. Full-face shields may be required if using a UVA light source.

Equipment

Requirements

Enclosed or semienclosed system

There are several commercially available systems that enable the user to conduct Fluorescence Examination within an enclosed or semienclosed space. Manufacturers’ instructions must be followed for the safe use of such equipment.

Torch

The torch should: ●● be dull red for use when some light is essential in the examination room and dark adaptation needs to be maintained.

Dark adaptation goggles

Dark adaptation goggles should: ●● allow the eyes of the user to adapt to low light levels prior to beginning a Fluorescence Examination search by cutting down the amount of light entering the eye, in particular light of wavelengths < 600 nm; ●● allow the user to carry on with other tasks during the adaptation period.

The imaging filters must: ●● comply with all requirements outlined for viewing filters for the eyes above except that relating to fitting the face; ●● fit to the imaging system such that no light can enter it except by passing through the imaging filter.

Home Office January 2014

5.FE.7

Fingermark Visualisation Manual

Fluorescence Examination

Glossary

5.FE.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Wavelength Selection General principles

Wavelength selection for Fluorescence Examination should take into consideration three main factors:

●● the output characteristics of the light source;

●● the transmission characteristics of the viewing filter;

●● the excitation and emission characteristics of the substrate and the mark being

examined (if known).

These are explained further in Supplementary Information whilst the requirements for high-intensity light sources and viewing filters are outlined in Equipment. For maximum fluorescence, it is important that: 1. the light source output spectra overlaps as much as possible with the excitation spectra of the fluorescent mark or surface;

2. the power of the light source is such that the intensity of illumination at the surface is high enough to produce sufficient fluorescence to be effectively observed;

3. the viewing filter transmission spectra overlaps as much as possible with the emission spectra of the fluorescent mark or surface;

Glossary

Index

Laboratory Use Guidance

Initial guidance for selection of output wavelengths for light sources and appropriate

viewing filters both for searching for latent marks and for examining marks visualised with processes giving known excitation and emission spectra, are given on the following pages:

Wavelength Selection for Initial Examination Wavelength Selection for Examination of Processed Fingermarks With so many high-intensity light sources and viewing filters available to the

practitioner, it is not possible to give specific guidance for the use of certain light sources. The guidance is therefore generic and relies on the competence of the practitioner to ensure that appropriate equipment is used. Also, experienced

practitioners, who fully understand the principles of Fluorescence Examination,

may be able to maximise the detail in faint marks via adjustments to the illumination wavelengths and viewing filters based on observations during examination.

There is also limited guidance on some of the labelling systems adopted by

manufacturers for light sources and viewing filters enabling compatible combinations for a given scenario to be rapidly identified.

4. the eyes are protected against the output illumination as outlined in Equipment. Failure to optimally match the light source and viewing filter to the item or surface being examined will result in lower-contrast marks caused by either weaker fluorescence or less discrimination between mark and substrate fluorescence. Although this may be

acceptable for brightly fluorescing marks, weakly fluorescing marks will almost certainly be missed.

Home Office January 2014

5.FE.8

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Wavelength Selection continued Initial Examination

The high-intensity light source and viewing filter should be selected to provide maximum fluorescence contrast between the mark and the background. For initial examination it may be difficult to determine the best combination straightaway as the fluorescent properties of the mark and surface are often unknown. The following offers some guidance.

In general, the more light source and viewing filter combinations that are used in an initial examination, the more productive it will be. However, there are practical

limitations on the time available to conduct searches and the number of light sources available to the practitioner. The practitioner should use their competence and all

available information to inform which wavelengths are likely to be most productive for any particular scenario encountered.

The general information below may assist in the selection of light sources and filters for initial examination:

●● latent marks composed solely of sweat fluoresce extremely weakly, if at all;

●● some contaminants do fluoresce (although the nature of the contaminant and its

excitation wavelengths is unknown in most cases) and the intensity can vary from faint through to bright;

●● in most cases, blood does not fluoresce;

●● some body fluids (e.g. semen, urine) fluoresce when excited by shorter wavelengths

(UVA-Violet-Blue);

●● background fluorescence often decreases as excitation wavelength increases.

Home Office January 2014

This knowledge can be exploited during initial examination by: ●● selecting shorter wavelength illumination (e.g. Violet-Blue) to increase background

fluorescence, thus enabling any potentially absorbing fingermark contaminants (such as blood) to be visualised;

●● selecting shorter wavelength illumination (e.g. UVA-Violet-Blue) to visualise marks in

certain fluorescing body fluids (e.g. semen, urine), although it should be considered

that any background fluorescence promoted by these wavelengths may interfere with visualisation;

●● selecting longer wavelength illumination (e.g. Green-Yellow) to reduce background

fluorescence so that any weakly fluorescent marks can be visualised against a dark background.

From light sources available at the time of publication, the green laser (532 nm) may

be the most productive for finding weakly fluorescing marks during initial examination, (although it will not find all marks and other light sources should still be used).

For most latent marks where composition is unknown, a systematic approach should

be taken, initially searching using two or three different wavelengths widely spaced from each other and known to be generally productive (e.g. blue or green). The selection

can be modified based on further information obtained during initial examination, for

example if the background gives unwanted, high levels of fluorescence other light source and filter combinations may yield improved results, or if faint marks are observed their intensity may be increased by use of illumination of a slightly different wavelength.

5.FE.9

Fingermark Visualisation Manual

Fluorescence Examination

Glossary

5.FE.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Wavelength Selection

Application

The high-intensity light source and viewing filter should be selected to provide

maximum fluorescence contrast between the mark and the background. For the

examination of processed fingermarks,

Laboratory Use

Nominal wavelength range/nm

Examples of light sources and viewing filters/goggles (not exhaustive)

Excitation

Emission

Excitation source (colour)

Background fluorescence for absorbing processes

350-500

400-600

Short wavelength illumination (UVA-Violet-Blue) may increase background fluorescence, thus enabling any potentially absorbing processed fingermarks (such as Ninhydrin, Acid Black 1, Acid Violet 17 and Powders) to be visualised.

Acid Dyes (Acid Yellow 7)

400-480

450-600

Laser (Blue) LED (Blue) Filtered arc or discharge lamp (Blue) Filtered arc or discharge lamp (Blue)

460 420-470 385-509 400-519

451-460 OD6+ GG495 519 529

3 2 1 1

Basic Violet 3

500-650

570-720

Laser (Yellow) LED (Orange) Filtered arc or discharge lamp (Green-Yellow)

577 570-610 503-591

…575-579 OD5+ RG645 593

3 2 1

DFO

520-590

540-620

Laser (Green) LED (Green) Filtered arc or discharge lamp (Green)

532 500-560 473-548

190-532 OD7+ OG590 549

3 2 1 1

continued

Examination of Processed Fingermarks

the fluorescent properties of the mark are

known and the surface typically unknown. This table provides details to assist with selection.

Index

Excitation wavelength range/nm

Viewing filter wavelength/nm

Labelling system number

DFO fluorescence can sometimes be difficult to visualise due to background fluorescence of some papers. This interference can often be reduced by using excitation sources with little output at the lower wavelengths. Moving to longer wavelengths will reduce the intensity of DFO fluorescence as well as that of the background, but this action may still give better overall contrast. Examples are given below.

Home Office January 2014

Laser (Yellow) Filtered arc or discharge lamp (Green-Yellow)

577 503-591

…575-579 OD5+ 593

3 1

Superglue dyed with Basic Red 14

450-600

530-650

Laser (Green) LED (Green) Filtered arc or discharge lamp (Green)

532 490-560 473-548

190-532 OD7+ OG590 549

3 2 1

Superglue dyed with Basic Yellow 40

360-490

450-550

Laser (Blue) LED (Blue) Filtered arc or discharge lamp (Violet)

460 420-470 400-469

…451-460nm OD6+ GG495 476

3 2 1

5.FE.10

Fingermark Visualisation Manual

Fluorescence Examination

Glossary

5.FE.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Wavelength Selection continued Labelling Light Sources and Viewing Filters Light sources and viewing filters must be clearly labelled so that:

●● the practitioner can easily select safe viewing filters for they eyes and protect their

skin (for UV only) for the high-intensity light source output;

●● the practitioner can easily tailor their search in order to be most effective.

The viewing filter must transmit most of the fluorescence but not a significant amount of the incident illumination so that adequate protection for the eyes is provided.

This usually means that transmission of the filter over the wavelength range of the

illumination should be less that 0.01% of the total power (or Optical Density (OD) 4). More Details There are many commercially available light sources used for Fluorescence

Examination. Most are supplied with their own viewing filters. This page outlines some of the labelling systems, but is not exhaustive.

(1) The 1% transmission point for light source outputs and viewing filters Example:

illumination light source viewing filters

400-469 nm (1% transmission points)* 476 nm (1% transmission point )**

* The lower and upper 1% transmission points are referred to as the excitation filter cuton and cut-off points respectively.

** The point at which the transmission rises above 1% in the direction of increasing wavelength is referred to as the viewing filter cut-on point.

This labelling system has one simple rule for both safety and effectiveness:

Glossary

Index

Laboratory Use If this is followed, less than 0.01% of the total power will be transmitted through the

filters. This rule also gives flexibility as other longer wavelength viewing filters can be used to improve mark-to-background contrast whilst remaining safe. (2) Mixed labelling systems Example:

illumination light source

420-470 nm (‘rough’ cut-on and cut-off points rounded to

viewing filters

GG 495 nm (colour designation letters and 50%



the nearest 10 nm)

transmission point)

In this case the light source and viewing filters are manufactured by different

companies and so have different labelling systems. The supplier of this equipment has

determined this to be a safe and effective combination. The practitioner must follow the manufacturer’s instructions on which viewing filters to use with which light source. (3) Labelling systems for laser light sources and laser viewing filters Example:

illumination light source viewing filters

460 nm

190-450 nm OD5+ 451-460 nm OD6+

Laser light sources emit a single wavelength and are labelled accordingly. The viewing

filters can be either long-pass or band-pass filters and are labelled accordingly. Viewing

filters supplied with lasers are often labelled with their optical density (OD) across broad ranges of the spectrum as opposed to having a single transmission cut-on value. The above example shows that the 460 nm laser light is blocked by the filters to a level

of OD6 (equivalent to 10-6 transmission or 0.0001% total power transmission). The

practitioner must follow the manufacturer’s instructions on which viewing filters to use with the laser.

The viewing filter 1% point (the cut-on point) must be greater than or equal to the upper excitation filter 1% point (the cut-off point).

Home Office January 2014

5.FE.11

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation

(1) Work area

(2) Equipment

(3) Item

continued on next column

Home Office January 2014

a) If necessary, clean the examination benching by wiping down with a suitable product such as detergent or ethanol to remove visible and/or fluorescent contaminants. Replace disposable bench covering if it has become too contaminated, scratched or difficult to clean. b) If not using an enclosed or semi-enclosed viewing system, ensure that the room is suitably blacked out. See Fluorescence Examination room requirements. a) Select light source(s) and viewing filters appropriate to task. See Wavelength Selection. b) Check that any accessible filters such as goggles or excitation filters are in good condition. See Equipment requirements. c) Follow manufacturer’s instructions and local safe working procedures. If working in openbeam mode and if practical, connect the light source to a door interlock system. If using an enclosed or semi-enclosed system and eye protection is not normally required the operator must not be exposed to hazardous levels of light. d) Position the equipment so that it is easily and safely accessible from the examination area, bearing in mind that open-beam examination will be done with the lights off. e) If necessary, prepare the light source so that it is ready to use, but do not allow light to be emitted. a) Transparent or semi-transparent items, such as some carrier bags, should be prepared in such a way that fluorescence from the underlying surfaces will not interfere with the examination of the top surface. It may be necessary to cut and flatten such articles or use a barrier, such as non-fluorescent card, between the layers.

(4) Operator

(5) Safety checks

Processing (6) Turn on light source

(7) Illuminate item with appropriate wavelengths

a) If viewing items with the eye, the operator must be suitably dark adapted before beginning fluorescence examination. This step is not necessary if viewing items through a live capture imaging system.

a) For open-beam examination, prepare local access restrictions such as signs and door interlocks. b) Light from high-intensity light and UVA sources may be hazardous to skin and eyes depending on the wavelength and power density. Whilst light is being emitted appropriate protection for eyes and, where necessary, skin must be used if not already provided by means of an enclosed or semi-enclosed system. c) It is the responsibility of the operator of the light source to check that all personnel within the room are aware of, and appropriately protected against, the light source/UVA hazard, prior to high-intensity light or UVA emission. It must be made clear to all personnel that it is not safe to remove goggles or other PPE until told to do so by the operator. Good communication is essential.

a) Always direct the excitation beam towards the examination bench area. Never point it towards the eyes of anyone! a) Take care not to overheat surfaces. Be prepared to remove or reduce the illumination immediately should any damage to the fingermark or substrate due to overheating be apparent.

continued on next page

5.FE.12

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing continued continued from previous page

(8) Observe item through appropriate viewing filter

(9) Mark up viable marks appropriately and capture image

a) Illuminate the item with the excitation beam. Closely, slowly and methodically search the item whilst observing the fluorescent response. Fingermarks are often very faint and careful, patient observation is necessary. Marks may be fluorescent against a dark background, or absorbing against a fluorescent background. b) Focusing at short distances in low light levels is extremely tiring on the eyes and regular breaks must be taken.

a) Practitioners may prefer to find the optimal illumination wavelength and viewing filter combination prior to image capture.

(10) Turn off light source

(11) Repeat with other combinations of illumination wavelengths and viewing filters as appropriate

Home Office January 2014

a) Items can be re-examined with alternative light sources and viewing filters if required and this is essential for initial examination. This may be necessary if marks are faint, or unwanted background fluorescence occurs.

Fluorescent DFO mark on paper. Absorbing mark in a contaminant on paper exhibiting background fluorescence.

5.FE.13

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Scene Use

Additional Considerations If a decision has been made to apply Fluorescence Examination at a scene,

a number of additional considerations need to be taken into account, over and above those given for laboratory use. The recommendations cannot be

prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make the process as effective as possible

within the constraints of the scene;

●● present a range of practical issues that need to be overcome.

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter 3, Section 3.1 – Scene use of processes and treatment of large areas for other general information.

Home Office January 2014

For health and safety, consider:

Minimising the risks of exposing practitioners and the public to the optical hazards by: ●● enforcing exclusion zones around areas being examined, e.g. by using warning

signs and personnel outside doors;

●● use of protective measures such as mobile door interlock systems and blacking out

externally facing windows.

For effectiveness, consider:

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of the constraints posed by the scene;

●● how the lighting environment at the scene can be properly controlled or blacked out

to enable faint fluorescence to be detected.

For practicality, consider:

●● access to the areas to be treated;

●● provision of a suitable power source, if needed.

5.FE.14

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Troubleshooting

Faint Fluorescent Marks Recognition

The mark detected by Fluorescence Examination is very faint and difficult to detect.

A plastic bag processed with Superglue Fuming and stained with Basic

Yellow 40 viewed with a 460 nm blue laser with an output power of (left)

1W and (right) 2W. The images were taken with the same camera settings to highlight differences in the brightness of the fluorescence. Cause

Effect

Prevention

Correction

Faint fluorescence of marks can occur if: ●● the illumination light is not optimised for the excitation band of the fluorescent mark; ●● the viewing filter blocks most of the fluorescent light; ●● the excitation and emission spectra of the fluorescent material overlap so much that light sources and viewing filters only excite or view part of the band; ●● the light source is under-powered.

Weakly fluorescent marks may be difficult to visualise or may be missed altogether.

Ensure that: ●● where possible, the appropriate light source and viewing filter are used. See Wavelength Selection; ●● equipment is serviced and maintained; ●● regular power checks are carried out.

There are no corrective measures for marks that have been missed. Weakly fluorescent marks may be re-examined using a light source of higher power output if available, or using a light source with an excitation wavelength which is more appropriate to the fluorescent material present.

Faint fluorescence of marks can occur if the mark does not contain strongly fluorescent components.

Weakly fluorescent marks may be difficult to visualise or may be missed altogether.

Not applicable.

There are no corrective measures for marks that have been missed. Weakly fluorescent marks may be re-examined using a light source of higher power output if available, or using a light source with an excitation wavelength which is more appropriate to the fluorescent material present.

Home Office January 2014

Other methods of increasing fluorescence intensity can be considered in addition to those above.

Other methods of increasing fluorescence intensity can be considered in addition to those above.

5.FE.15

Fingermark Visualisation Manual

Fluorescence Examination

Glossary

5.FE.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Troubleshooting

Distortion of the Surface (and Mark) Recognition

Whilst conducting a Fluorescence Examination, the surface (and mark) starts to distort.

A dark plastic bag viewed using a 532 nm green laser showing (left) no distortion, and (right) distortion.

Cause

Effect

The illumination light is absorbed by the surface causing localised heating effects. This heating effect may be exacerbated by: ●● an increase in the power density of the excitation beam (e.g. by light source being brought too close to the surface); ●● the colour, material and thickness of the substrate (e.g. black materials absorb more strongly).

In extreme cases heating may cause irreversible damage to the surface (e.g. melting) which may distort, obscure or destroy marks present.

Home Office January 2014

Prevention These notes are particularly important for thin, dark materials such as bin bags. Ensure that: ●● the tolerance of the material to the light source power is assessed prior to carrying out Fluorescence Examination. Ideally, this should be done on a similar, non-operational sample; ●● when a mark is found, the practitioner does not automatically ‘zoom-in’ with the light source and/or continuously illuminate the mark for a period of time as this intense illumination will increase the temperature on the surface considerably. If examining a mark, periodically illuminate the area instead.

Correction There are no corrective measures.

5.FE.16

Fingermark Visualisation Manual

Fluorescence Examination

Glossary

5.FE.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Background Fluorescence Recognition

Background fluorescence from the

substrate has made the fluorescence from the fingermark difficult to detect using

the illumination and filtration conditions originally selected.

Effect of increasing excitation wavelength and viewing filter cut-on: A paper label processed with DFO and illuminated with (a) a 532 nm green laser with a 190-532 OD7+ viewing filter and (b) a 577 nm yellow laser with a …575-579 OD5+ viewing filter.

Effect of increasing excitation wavelength and viewing filter cut-on, and narrowing excitation wavelength range: A yellow ‘postit‘ note processed with DFO and illuminated with (left) a 473-548 nm filtered arc or discharge lamp with a 549 nm (1%) viewing filter,

(centre) a 503-591 nm filtered arc or discharge lamp with a 593 nm (1%) viewing filter, and (right) a 532 nm green laser with a 549 nm (1%) viewing filter. Home Office January 2014

5.FE.17

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Troubleshooting

Background Fluorescence continued

Effect of using a band-pass filter: A

paying-in slip processed with DFO and

illuminated with (left) a 532 nm laser and viewed using a 549 nm (1%) viewing

filter, (centre) a 577 nm laser and viewed using a 593 nm (1%) viewing filter, and

(right) a 532 nm laser and viewed using an appropriate band-pass filter. Cause

Effect

Prevention

Correction

Pigments and dyes present within substrates are also excited by the illumination wavelengths. In some cases this effect may persist or increase at higher wavelengths.

The background fluorescence may partially obscure marks or, in extreme cases, totally swamp fluorescence from marks causing them to be missed.

Not applicable.

There are several ways to attempt to reduce background fluorescence, which generally decreases at higher wavelengths. They are: ●● narrow the excitation wavelengths used and maintain the cut-on transmission value of the viewing filter (e.g. use a laser in place of an LED or filtered white light source); ●● use the same excitation wavelength of the light source but increase the cut-on transmission value of the viewing filter; ●● use a light source of a higher excitation wavelength with the appropriate higher cut-on viewing filter. In cases where background fluorescence persists or increases at higher wavelengths: ●● use the same excitation wavelength of the light source but use an appropriate band-pass viewing filter instead of, or in combination with, a long-pass filter. This may restrict the transmission of fluorescence to a narrow portion of the spectrum where the intensity of fluorescence emitted from the fingermark is significantly greater than that from the substrate. Note: success cannot be guaranteed with any method.

Home Office January 2014

5.FE.18

Fingermark Visualisation Manual

Fluorescence Examination

Glossary

5.FE.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Seeing Illumination Light through Viewing Goggles Recognition

Light of the same colour as the illuminating light source can be seen in the background, swamping fluorescence from any fingermarks.

White photocopier paper processed with DFO and

enhanced with two different green light sources and filters

as recommended by manufacturers where (a) clearly shows green reflected light in the background of the

image compared to (b) which has no perceptible green

light in the image.

Cause

Effect

Some of the illumination light is transmission through the viewing filter.

Depending on the amount of incident light transmitted, marks may be obscured making visualisation and imaging more difficult. In some circumstances, marks may be missed. In extreme circumstances, there may be an optical hazard.

Home Office January 2014

Prevention

Correction

Ensure that: Re-image the mark using ●● the light source and viewing filter meet the requirements as outlined mitigating measures outlined in Equipment; in ‘Prevention’. ●● the light source and viewing filter are correctly selected for compatibility; ●● the viewing filters are not damaged in any way; ●● the viewing filters are assembled correctly (some can be taken apart for cleaning and if not re-assembled correctly may have gaps).

5.FE.19

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Low Contrast or ‘Foggy’ Appearance of the Item during Examination or on the Resultant Image Recognition

The image captured of the fingermark is of lower contrast than expected, and/or the glass of the viewing goggles appears ‘foggy’ when light of the illumination wavelengths falls on it.

Viewing goggles with fluorescing glass (left) and non-fluorescing glass

(right), and the corresponding images of the same mark viewed through imaging filters of the same types of glass. Left, mark viewed through

fluorescing glass, right, mark viewed through non-fluorescing glass.

Cause

Effect

Some viewing filters contain fluorescent substances and the viewing filter itself fluoresces under the illumination wavelengths used.

Reduction in the perceived intensity and contrast of fluorescent fingermarks, possibly resulting in marks being missed.

Home Office January 2014

The effect may not be immediately apparent and only seen in the captured image, because the viewing goggles and imaging filter are not necessarily made from the same glass (though they may be visually indistinguishable in normal light). The effect increases with increasing proximity to the light source or item.

Prevention

Correction

Ensure that: Re-examine the item and/or re-image ●● viewing filters (for the eye and camera) are made the mark using mitigating measures of low-fluorescence glass. outlined in ‘Prevention’. If this is not possible: ●● the effect may be reduced by directing the excitation light away from the viewing filter; ●● the effect may be partially prevented by choosing a longer working distance (with a longer focal length lens to maintain image magnification) and shielding the filter from as much reflected light as possible (using lens hood, black card, etc.)

5.FE.20

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.21

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Troubleshooting

Additional Fluorescent Contamination on the Item Recognition

Fluorescent contaminants have been picked up on the surface of the

item and appear as fluorescent particles or, in extreme circumstances, fluorescent streaks.

Mark developed on a transparent sandwich container using Superglue

Fuming followed by staining with Basic Yellow 40. The surface has picked up fluorescent particles from a powder that was previously being used in the area and has not been properly cleaned up.

Cause Benches used for Fluorescence Examination become covered in fluorescent contaminants which are not visible to the eye but may be picked up on the surface of items during subsequent examination.

Home Office January 2014

Effect Loose contaminants picked up on items may create unwanted artefacts in marks and/or obscure ridge detail.

Prevention Ensure that examination benches are cleaned regularly by wiping down with a suitable product such as detergent or ethanol to remove visible and/or fluorescent contaminants.

Correction Re-examine the item and/or re-image the mark using mitigating measures outlined in ‘Prevention’. It may be possible to remove contaminants picked up on the item by blowing gently with compressed air. If contaminants interfere with mark detail and cannot be removed with compressed air, gentle brushing may be used although this could destroy detail of the mark and any other latent marks present but not yet visualised.

5.FE.21

Fingermark Visualisation Manual

Fluorescence Examination

Glossary

5.FE.22

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Fluorescence Interference whilst Examining Transparent Items Recognition

Fluorescence from both sides or layers of a transparent item and/or the examination bench are viewed simultaneously when examined.

A transparent plastic bag processed using Superglue

Fuming and stained with Basic Yellow 40, resulting in

marks being visualised on both outside surfaces, where

(left) shows fluorescence from both surfaces, and (right) fluorescence from the top surface only. The removal of

the interfering fluorescence from the bottom surface was

achieved by blocking this fluorescence by placing a piece of black card between the layers.

Cause The item is transparent, and illuminating light passes through it and is able to interact with any fluorescent substances that are present, regardless of whether these are on the surface of the item, underlying regions of the item, or the examination bench.

Home Office January 2014

Effect ●● Marks on the top surface

may be obscured by other fluorescent marks or regions of contamination not associated with that surface. ●● If there are fluorescent marks on both sides of a transparent material, it is not obvious which side the mark is actually on. This may cause interpretation problems associated with its orientation.

Prevention

Correction

Ensure that: ●● examination benches are cleaned regularly by wiping down with a suitable product such as detergent or ethanol to remove visible and/or fluorescent contaminants. Replace disposable bench covering if it has become too contaminated, scratched or difficult to clean; ●● for transparent items such as plastic bags, fluorescence from the other layers does not interfere with the examination. This can be achieved by cutting and flattening such items so that they are a single layer or by placing a light-blocking material, such as non-fluorescent card, between the layers.

Re-examine the item and/or re-image the mark using mitigating measures outlined in ‘Prevention’. If marks are on both sides of the same layer UVC Reflection or Lifting may help to resolve the detail although success in not guaranteed.

5.FE.22

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Supplementary Information

Theory

Fluorescence

Anti-Stokes fluorescence

specific colour is first absorbed and then, after a very short time delay (less than

materials may also exhibit ‘Anti-Stokes’ fluorescence where the electron absorbs energy

Fluorescence is the property that some substances possess whereby light of a

10-8 seconds), light is emitted. The emitted light is of a different colour from that

of the absorbed colour. The time delay is so short that it appears that the emission stops as soon as the illuminating light is removed.

For a substance to fluoresce, it must have a chemical structure that has a series of energy states to which electrons can be excited from the normal, ‘ground state’.

In addition to the fluorescence mechanism outlined above, a very limited number of

from two photons of lower energy (higher wavelength) to reach the higher energy level,

and emits a single higher energy (lower wavelength) photon of light to return to the lower energy level. Typically, radiation in the infrared region of the spectrum is used to excite Anti-Stokes fluorescence which may result in the emission of light in the red, green or blue regions of the spectrum.

Excitation is provided by electromagnetic radiation (in this case UVA or visible light) that

Anti-Stokes fluorescence is considerably less efficient than conventional fluorescence,

light is sufficient to promote the electron to one of the excited states, the energy is

eliminated. Until recently Anti-Stokes fluorescence has not been utilised for fingermark

absorbed by the electron and it enters a higher energy state. The electron then seeks

to return to the ground state by losing energy, some of which can be lost by dropping to the lowest energy level within the excited state. To return to the ground state the

light will be of lower energy and correspondingly longer wavelength than the incident light. (The energy of electromagnetic

Higher energy and vibration state

radiation is inversely proportional to its wavelength, hence shorter

and longer wavelengths possess

lower energy. This accounts for the difference in colour between the

illuminating light and the emitted light.)

+hν

Loss of energy

wavelengths possess higher energy

Lowest singlet excited state

visualisation but some powders

and light sources have now been

Higher energy and vibration state

However, these have not yet been

Lowest singlet excited state

developed for this application.

investigated in detail and therefore the remainder of this section will

consider conventional fluorescence only.

-hν

Schematic diagram showing the

mechanism by which Anti-Stokes

Loss of energy

electron loses the remaining excess energy in the form of a photon of light. The emitted

but has the potential advantage that interfering background fluorescence can be

Absorption

is incident upon the fluorescent substance. Provided that the energy of the incident

+hν

fluorescence occurs.

Ground state

-hν

Schematic diagram showing the

mechanism by which fluorescence occurs.

Ground state

Home Office January 2014

5.FE.23

Fingermark Visualisation Manual

Fluorescence Examination

Absorption

5.FE.23

Contents

5.FE.24

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory continued Time resolved fluorescence

Although most fluorescent materials exhibit a very short time delay (less than 10-8 seconds) before light is emitted, there are some substances (in particular those

incorporating rare earth elements such europium or terbium) for which this delay can be significantly longer (greater than 10-6 seconds).

This difference in fluorescent decay times has been considered as a means of

discriminating different substances, in particular where one of these substances may be strongly fluorescent. By labelling the substance of interest with a taggant with a

longer fluorescent decay time, it becomes possible to discriminate the two fluorescent

substances by adjusting the illumination and imaging conditions so that only the regions

with the longer fluorescent decay time are detected. This can be achieved by means of a pulsed light source and a controllable shutter in front of the imaging system. The relative timings of the laser pulses and shutter can then be adjusted to block the signal from the regions with rapid decay times and pass that from regions with extended fluorescent decay times.

Several chemical systems producing extended fluorescent decay times have been proposed for fingermark enhancement, but none is currently in widespread use. Advances in the imaging technology for conducting time resolved fluorescence

examination may lead to an increase in the use of processes based on these chemicals in future.

Home Office January 2014

5.FE.24

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.25

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Index

Supplementary Information

Fingermark detection by Fluorescence Examination

The intensity of the light emitted as fluorescence is usually significantly less than that of the incident light. Most illumination light is reflected from the surface and the fluorescence is usually swamped by this reflected light. In order to see the fluorescence, it is necessary to view the surface through a filter that blocks the wavelengths of the reflected light and enables the wavelengths of the fluorescence to pass. When Fluorescence Examination is being used to detect fingermarks, two principal

Glossary

●● fingermarks may fluoresce and the background absorb and/or reflect the illuminating

wavelengths;

●● fingermarks may absorb the illuminating wavelengths and the background fluoresces.

Both of these are shown schematically. In both cases, fluorescence examination is used as a method of improving the contrast of fingermarks against the background surface.

situations may be encountered:

Background fluorescence

Fluorescent fingermarks Light source

Observer’s eye

Light source

Viewing filter

Observer’s eye Viewing filter

Fluorescence (longerwavelength) transmitted by filter Incident light (shorter wavelength)

Reflected/scattered light

Fluorescence (longer wavelength) transmitted by filter Incident light (shorter wavelength)

Reflected/scattered light

Fluorescence from surface

Surface under examination

Home Office January 2014

Fingermark ridges (containing fluorescent substances)

Surface under examination

Fingermark ridges (containing absorbing substances)

5.FE.25

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.26

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination continued The ability to detect fingermarks by fluorescence is dependent upon four principal factors.

1. The mark or substrate must be fluorescent. 2. The light source must emit the appropriate wavelength(s) and have sufficient power to excite the fluorescent chemical within the mark or substrate.

3. The viewing filters must protect the eyes against the output illumination of the high-intensity light source whilst transmitting fluorescence from the item, and where appropriate, separate the background and fingermark fluorescence.

4. The practitioner must be competent in viewing fluorescent marks, have good

eyesight and be suitably prepared, or utilise an appropriate detection system other than the eye.

The remainder of this theory section will expand on these requirements.

Home Office January 2014

5.FE.26

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.27

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Mark Marks may fluoresce for a number of reasons, including: 1. they contain naturally secreted constituents or contaminants that are fluorescent; 2. they have been exposed to environments that make constituents in them fluorescent;

3. they have been treated with chemical or physical processes that make them fluorescent.

Marks in the first two categories are most likely to be detected during initial

examination of items or surfaces, and marks in the third category will be deliberately

targeted during the examination of items or surfaces previously treated with chemical or physical processes.

There are several approaches that can be used to increase intensity of fluorescent marks if they appear faint when initially visualised.

Examples of fluorescent marks found during initial examination:

Marks of these types could potentially be composed of any constituent/contaminant.

Fingermarks may be detected or

enhanced due to the fluorescence of some of the constituents of

Fingermarks contaminated with materials such as

of background materials such as

than those consisting of sweat alone.

sweat. Often the fluorescence

paper or plastic obscures the weak

ink, drugs or grease may fluoresce more strongly

fluorescence of these fingermarks.

Different fluorescent compounds will absorb and emit light at different wavelengths (and

with different efficiencies). Ideally, this information would be known to the practitioner so that light sources and viewing filters most suited to maximise contrast of the fingermark can be used, but in reality this is often not possible and little is known about its

fluorescent properties prior to commencing examination. In addition, marks found vary greatly in intensity and colour. They are often extremely faint.

Some constituents of fingermarks may be

broken down to fluorescent products by the action of heat. This has occasionally been noted on paper items recovered from fire scenes.

Home Office January 2014

5.FE.27

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.28

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Requirements for Fluorescence Examination: The Mark continued Examples of fluorescent marks on items or surfaces previously treated with chemical or physical processes:

Glossary

Index

Supplementary Information

Basic Violet 3

DFO

Several visualisation processes are used to deliberately make marks fluoresce, in most cases brightly. Five commonly used fluorescent processes are shown.

Superglue Fluorescent Dye Staining (Basic Yellow 40)

Superglue Fluorescent Dye Staining (Basic Red 14)

DFO reacts with some of the constituent Basic Violet 3 fluoresces and some marks developed with it which are faint or even

invisible during Visual Examination can be detected and enhanced.

chemicals of latent fingermarks to produce fluorescent products. This is particularly useful on dark or patterned porous surfaces.

Acid Dyes (Acid Yellow 7)

White fingermarks developed with Superglue Fuming can be difficult to see, especially on light-coloured surfaces. By staining the deposited superglue with a Superglue

Fluorescent Dye Stain (such as Basic Yellow 40 or Basic Red 14) and viewing with

Acid Yellow 7 is a

Examination alone.

that stains proteins in

Fluorescence Examination considerably more marks will be seen compared to Visual

fluorescent Acid Dye

blood and other proteinrich contaminants. It is particularly useful on dark surfaces.

Home Office January 2014

5.FE.28

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Mark continued

Basic Yellow 40

For fluorescent marks of this type, the fluorescent properties (excitation and emission

spectra) have been well characterised and are illustrated on the right*. This knowledge

Excitation spectra

enables manufacturers of light sources to tailor their equipment (where possible) to these

Emission spectra

processes so that maximum efficiency is achieved. They also provide an initial reference point for the practitioner for establishing whether any particular light source or viewing

Acid Yellow 7

filter may be suitable for use in enhancing marks of these types.

*The spectra presented are for marks produced under ideal conditions. There may be

some variation in the exact spectra of fluorescence from realistic items due to variability in conditions such as blood thickness (for Acid Yellow 7).

DFO

Basic Red 14

Basic Violet 3

400 400

450

500 500

550

600 600

650

700 700

Wavelength / nm Home Office January 2014

5.FE.29

Fingermark Visualisation Manual

Fluorescence Examination

Intensity (normalised)

5.FE.29

Contents

5.FE.30

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Mark continued Increasing intensity of fluorescence from the mark

In addition to increasing the power and changing the wavelength of illumination, there are several methods that may be attempted to increase the intensity of fluorescence from fluorescent marks. These are described below.

Low temperature fluorescence enhancement

The intensity of fluorescent emission may sometimes be increased by cooling the item to very low temperatures such as that of liquid nitrogen (-196°C). Cooling to these

temperatures stops energy dissipation mechanisms such as sidegroup rotation or bond bending occurring within fluorescent molecules and means that more incident energy is

used in exciting electrons to higher energy states. The fluorescence mechanism at these temperatures is therefore more efficient. Cooling of items to these low temperatures can result in condensation of water from the air unless precautions are taken. Condensation

may cause the diffusion of water-soluble components from fingermarks and prevent the

subsequent visualisation of the mark. This is particularly important to note in the case of articles to be subsequently treated with DFO, Ninhydrin or Superglue Fuming.

Drying the item

Where water molecules are present, they can become associated with the molecules of fluorescent substances and provide additional mechanisms by which energy can

be dissipated. By drying the item and removing the water, the fluorescent molecules

become more rigid and more energy is dissipated via fluorescence. Ensuring the item is

fully dry is most important when Fluorescence Examination is used to visualise marks on adhesive tapes processed using Basic Violet 3. In this particular situation, the adhesive contributes to holding the fluorescent molecules rigid, and it is equally important to remove the water from the adhesive as it is from the fingermark.

Home Office January 2014

5.FE.30

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.31

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Substrate Substrates may fluoresce for a number of reasons, including: 1. they are naturally fluorescent substances;

2. they are loaded with fluorescent additives or printed with inks containing fluorescent pigments;

3. they have absorbed or become covered in contaminants that are fluorescent.

Examples of background fluorescence during initial examination or on items or surfaces treated with a chemical or physical process that yields non-fluorescing marks Blood on a fluorescent wood surface

Ninhydrin-developed marks on paper

The fluorescence of background surfaces

The background surface may fluoresce

may improve the contrast of fingermarks

the incident light and appear black, for

detected during initial examination.

printed with fluorescent ink.

Background fluorescence from the substrate may enable marks to be detected if the fingermark has been deposited in an absorbing contaminant such as blood or dirt. Background fluorescence from the substrate can also be detrimental if it obscures fluorescence from a fingermark.

The number of fluorescent substances that may be present in, or on, a substrate is

almost limitless. Different fluorescent compounds will absorb and emit light at different wavelengths (and with different efficiencies). Ideally, this information would be known to the practitioner so that light sources and filters most suited to maximise contrast

can be used, but in reality this is rarely possible and little is known about a substrate’s fluorescent properties before commencing examination. It is possible to build a

knowledge of how commonly encountered substrates (e.g. gloss paint, matt paint,

varnished wood) are likely to respond from ongoing experience in examining multiple items and scenes.

such as paper, wood and cardboard

contaminated with materials such as

blood or dirt which will absorb the incident light and appear dark against a light

and the fingermark may absorb or reflect example Physical Developer and some Ninhydrin fingermarks on paper.

background.

The excitation and emission spectra of the surface are very rarely known before

Fluorescence Examination commences and it is not possible to reliably predict how a particular surface will behave.

Home Office January 2014

5.FE.31

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.32

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Substrate continued The images below illustrate how a typical range of items fluoresce under various lighting conditions*. Often white items fluoresce strongly when illuminated with UVA or violet

light due to the presence of optical brighteners. Overall fluorescence of surfaces typically reduces with increasing illumination wavelength.

* The relative brightness when viewed with the eye will differ to that shown in these images. See detection systems for fluorescence.

UVA illumination

Blue illumination

Green illumination

Yellow illumination

White light reference image

Home Office January 2014

5.FE.32

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.33

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Substrate continued The images below illustrate another example of how

a typical surface (in this case fixtures and fittings on a

wall) fluoresce under various lighting conditions*. In this

UVA illumination

Blue illumination

Green illumination

Yellow illumination

case the background fluorescence across all surfaces

has diminished significantly at longer wavelengths (green and yellow illumination). Fluorescent contact areas and marks are revealed at these wavelengths (note that the fluorescent areas are different for the two illuminations

indicating that they are composed of different fluorescent contaminants).

* The relative brightness when viewed with the eye will differ to that shown in these images. See detection systems for fluorescence.

White light reference image

Home Office January 2014

5.FE.33

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.34

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Light Source The light source is required to excite fluorescence within the mark or substrate. There are many types of light source available for use in Fluorescence Examination. The

principal features of the main types are given on the following pages. These include: ●● Lasers

●● Light emitting diodes (LEDs)

●● Filtered arc or discharge lamps ●● UVA mercury vapour lamps ●● Photographic flash

Whichever light source is used, it must emit the appropriate wavelength(s) and have sufficient power to excite the fluorescent chemical within the mark or substrate. This is more important than the source of the light.

Wavelength

As seen on previous pages, the mark and the substrate can fluoresce across a broad wavelength range. Thus, light source(s) should be capable of operating across the

range from approximately 350 nm to 600 nm or even longer wavelengths if IR-sensitive imaging systems are used to detect the fluorescence. This may be achieved with one light source that allows the practitioner to select the suitable wavelength band, or it could achieved with several single wavelength or waveband light sources.

Power

High power densities of 10–100 mW cm-2 are necessary to detect some fingermarks. This equates to a light source with an output power of 1–10 W across a search area 10 cm × 10 cm.

Home Office January 2014

5.FE.34

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Lasers Output characteristics

Index

If the light guide is severely damaged and the optical fibre(s) broken, light transmission will stop completely. Minor damage to the protective sleeve may not cause a drop in

output power but should be avoided. Lasers may also require occasional realignment to maintain peak performance.

Modern lasers used for fingermark detection emit light of one discrete wavelength only (unique to the type of laser). All of the output power is at this wavelength.

The coherence and collimation, uniquely characteristic of laser light, have no beneficial effect for Fluorescence Examination. Therefore, the beam must be divergent in order

to give an acceptable illumination area and speckle effects must be reduced to a point where they do not interfere with the examination.

Lasers outputting in the UV, blue, green, yellow, red and infrared parts of the spectrum

are available, although those currently available for fingermark detection are green (532

nm), yellow (577 nm) and blue (460 nm). Blue/green lasers (514 nm) have also been used

in these applications. Current lasers have a high power output (typically in excess of 2 W and in some cases up to 8 W).

Light guides are

normally used to direct the illumination from a

laser to the item being examined. For lasers,

these may be bundles

under development.

Benefits and limitations

The output characteristics of lasers have many benefits for visualising fingermarks, in particular:

500

wavelength, ensures that viewing filters can be selected to more closely match the excitation wavelength than for other broad-band light sources, and thus maximise the amount of fluorescence transmitted whilst still protecting the eyes of the operator;

●● the absence of light emission at shorter wavelengths, relative to the output

wavelength, may result in reduced background fluorescence for some substrates;

●● the output power of lasers is typically higher than that of other types of light sources.

This typically results in marks that appear brighter with greater contrast than those found with other light sources. This is most noticeable for the green (532 nm) and yellow (577

nm) lasers although the latter finds marks that are more

difficult to see with the eye. The technology is currently

in a protective sleeve.

options, limiting versatility.

Typical spectral output Wavelength / nm

search most rooms without the need to move equipment. Smaller, handheld units are

of optical fibres or

single fibres encased

450

Current lasers are bulky, although light guides are normally long enough to be able to

●● the absence of light emission at longer wavelengths, relative to the output

Equipment availability

Home Office January 2014

Glossary

Supplementary Information

Requirements for Fluorescence Examination: The Light Source continued

400

Appendices

from a laser light

limited to a few wavelength Examples of scene portable laser systems.

source.

5.FE.35

Fingermark Visualisation Manual

Fluorescence Examination

Intensity

5.FE.35

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Light Source continued Light Emitting Diodes (LEDs) Output characteristics

They are generally compact and lightweight. Most are battery operated, with the

batteries being either an integral part of the torch or as a pack that the operator carries. Battery life can vary considerably. Alternatively, many can be plugged into an electricity supply.

LEDs have a broad output roughly centred on a particular peak wavelength. The output may continue at a low level over a broad wavelength range. LED torches used for

fingermark detection should contain suitable filtering to ensure that this low level does not interfere with examinations.

The output power quoted for LEDs refers to the combined power across all of the output wavelengths.

Although there are some very effective LED light sources available, there are also many that have insufficient power outputs and poor filtering.

Benefits and limitations

A full set of the most advanced LED torches (with appropriate filtering and power) are

versatile, convenient to use and effective (although some wavelength ranges are more effective than others).

They do not have the benefits associated with the narrow bandwidth and high output

Equipment availability

LED light sources for fingermark detections normally come in the form of a set of

handheld torches. Each torch emits light over a certain wavelength range from the UVA and across the visible parts of the electromagnetic spectrum. Modern LEDs have high power efficiency and produce reasonably

power of lasers and marks visualised using LEDs generally will not have the same level of contrast between the mark and background as those visualised by lasers (although the gap is narrowing as power densities and filtration are improved). However, they

are one of the best options for Fluorescence Examination in wavelength regions where lasers do not operate.

high power densities

(although not as high as lasers).

Some LED torches allow the user to narrow the output waveband by supplying additional

filters that can be placed in front of the light source.

400

450 Wavelength / nm

Home Office January 2014

500

Typical spectral output

from an LED light source.

Examples of a set of LED torches.

5.FE.36

Fingermark Visualisation Manual

Fluorescence Examination

Intensity

5.FE.36

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Light Source continued Filtered arc or discharge lamps Output characteristics

depend critically on the specification of the filters used. The filter sets used for filtration of arc or discharge lamps typically contain combinations of short-pass and long-pass

filters so that the cut-on and cut-off wavelengths can be tightly controlled. Some models allow the output wavelength for filters to be ‘tuned’ by rotating them in the light path.

Arc or discharge lamps produce a continuous spectral output from UV through the

visible and into the IR. The power intensity at each wavelength will depend on the type of bulb used.

When used for Fluorescence Examination, part of the spectrum may be selected by filtration. A narrow band of wavelengths may be selected although, for many

applications, broader bands transmitting higher powers have proved to be very effective. The output power quoted for filtered arc or discharge lamps refers to the combined power across all of the output wavelengths.

Light guides are normally used to direct the illumination from a filtered arc or discharge

lamp to the item being examined. These may be bundles of optical fibres, single fibres,

or, more commonly, liquid light guides. The liquid light guides used on most systems are very easily damaged by bending or crushing resulting in transmission losses. They must be handled carefully and the output power monitored. A sudden increase in exposure times required during image capture may indicate significant damage.

Benefits and limitations

Filtered arc or discharge lamps are the single most versatile type of light source, with a range of selected output wavelengths being provided from a single unit.

Equipment availability

In common with LEDs, the broader band output of filtered arc or discharge lamps means

lamps are commonly

low power efficiency compared to lasers and more advanced types of LEDs in certain

Xenon-filled discharge employed. Spectral output may include

UVA and infrared as

well as the full visible

that visualised marks may have less contrast between the mark and the background

than those visualised using lasers. Filtered arc or discharge lamps also have relatively

wavelength ranges, and the bulbs used in this type of light source have a relatively short lamp life (compared to LEDs).

spectrum. When

used for fluorescence examination, part of

the spectrum may be selected by filtration

and performance will

400

450 Wavelength / nm

Home Office January 2014

500

Typical spectral output

Examples of different

discharge lamp.

or discharge lamps.

from a filtered arc or

generations of filtered arc

5.FE.37

Fingermark Visualisation Manual

Fluorescence Examination

Intensity

5.FE.37

Contents

5.FE.38

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Light Source continued Other UVA mercury vapour lamps

The output power (typically 2–8 W) quoted for tubes refers to the combined power

(‘Woods glass’) generally provide a peak output at 365 nm; they are excellent sources for

Photographic flash

surfaces that do not contain optical brighteners.

standard photographic flash is a xenon discharge tube and has similar spectral

across all of the output wavelengths, and is emitted in all directions rather than being

High-pressure mercury vapour discharge lamps combined with a UV transmitting filter

UVA and particularly suitable for fluorescence of untreated fingermarks and fluorescent

Low-pressure mercury vapour lamps emit less intense UVA

making them less suitable for initial

examination where

focused. As a consequence, power density on the surface may be relatively low.

Although not suitable for detection of fluorescence it is worth noting here that the properties to continuously emitting xenon discharge lamps. Photographic flash may find uses in image capture of fluorescence. Flash tubes may be modified to increase their

UVA output, and filtration can be used in front of flash guns to produce different coloured outputs.

Examples of photographic flash units.

mark fluorescence may be weak, but

they are suitable for

promoting background fluorescence in items Examples of a handheld UVA lamp and ‘black light’ tubes of the type used within it.

containing optical

brighteners because these fluoresce strongly. Low-

pressure mercury vapour lamps are sometimes referred to as ‘black lights’ and have an appearance and operation similar to domestic fluorescent tube lamps. The tube has an

internal coating of a phosphor material that converts the incident short-wave ultraviolet

(UVC) radiation to UVA. Different phosphors can be used to produce different wavelength UVA outputs, for example europium-doped strontium borate gives a peak output ~370 nm, whereas lead-doped barium silicate gives a peak output ~350 nm.

UVA mercury vapour lamps usually produce a broad output spectrum very similar to that of LEDs, with a single peak output wavelength. Home Office January 2014

5.FE.38

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.39

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Viewing Filter Viewing filters are used in Fluorescence Examination to block out most of the

The optical density of a material is given by:

illumination wavelengths output by the light source and to transmit the longer

wavelengths emitted by the fluorescent components of the mark or substrate. They

serve two main purposes: to protect the eyes from optical hazards and to enable the fluorescence to be discriminated by the detection system. The detection system

could be the eye or the imaging system, and appropriate goggles/glasses or imaging filters (used in front of the sensor on the imaging system) should be used respectively. The principal features of the main types are given on the following pages. For the eye, these include:

OD = log10[1/transmission] For light sources with power outputs less than 10 W, the transmission of the filter

over the wavelength range of the illumination should be less that 10-4 (OD4 or 0.01%). This level of protection is adequate for all-day operational use since there is no risk of the operator looking directly into the beam for extended periods. However, sufficient

protection is provided for repeated short periods of exposure. Practitioners should still carry out their own assessment to ensure they are properly protected from the light source being used. Optical Density

transmission

% transmission

●● Band-blocking filters

0

1

100

Specialist imaging filters can also be used in combination with other filters on imaging

1

0.1

2

0.01 (10 )

●● Long-(wave)-pass filters

systems only:

●● Short-(wave)-pass filters ●● Band-pass filters

Optical density

It is most important that any viewing filters used with the eye provide adequate

protection from the optical hazard associated with the light source. The concept of

optical density (OD) is a means used to describe the protection level provided by a filter and is outlined below.

10 1

-2

(10-3)

3

0.001

4

0.0001 (10 )

0.01 (10-2)

5

0.00001 (10-5)

0.001 (10-3)

6

10-6

0.0001 (10-4)

7

10-7

0.00001 (10-5)

-4

0.1

Relationship between optical density, transmission and % transmission. Red text

indicates viewing filters that would be unsafe for use in Fluorescence Examination.

To protect the eyes a protective filter of sufficient optical density must be used and this information must be provided by the light source manufacturer. Optical density defines the ability of the filter to block transmission and is directly related to the proportion of incident light transmitted through the filter.

Home Office January 2014

5.FE.39

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Viewing Filter continued Long-(wave)-pass filter

Band-blocking filter

transmission increases rapidly over a short wavelength range until most energy is

Like long-pass filters the transition from blocking to full transmission occurs over a

Long-pass edge filters block all wavelengths of light below a certain value after which transmitted through the filter. This rapid change in transmission properties is important in Fluorescence Examination in order to transmit maximum fluorescence.

They are typically used with LED light sources or filtered arc or discharge lamp light sources, but can also be used with laser light sources.

narrow wavelength range.

These viewing filters are sometimes used with laser light sources as they only need to block a single wavelength. Specialist laser filters (sometimes described as notch

filters) are therefore designed and manufactured for use with lasers with known output

wavelengths.

This is the type of filter most often used when imaging fluorescence.

400

Band-blocking (notch) filters block wavelengths over a limited region of the spectrum.

Transmission 500

600

700

400

500

600

700

Wavelength / nm

Wavelength / nm

Typical transmission characteristics for a long-pass filter transmitting light in the yellow,

Typical transmission characteristics for a band-blocking pass filter designed to block the

orange, red and near infrared region of the spectrum.

Home Office January 2014

illuminating wavelength from a 532 nm laser.

5.FE.40

Fingermark Visualisation Manual

Fluorescence Examination

Transmission

5.FE.40

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Viewing Filter continued

Band-pass filters

Short-(wave)-pass filters

shorter wavelengths.

Band-pass filters transmit in a particular region of the spectrum and reject longer and

These are edge filters which reject the longer wavelengths and transmit shorter

wavelengths. These filters are referred to by the wavelength at which this change in transmission occurs, in the same way as long-(wave)-pass filters.

Filters of this type are generally used as part of excitation filter systems in filtered

light sources and are not often used in imaging applications. They can also be used

in combination with long-(wave)-pass filters to produce a similar effect to band-pass (notch) filters.

They are not generally used in protective eyewear and tend to be used during image capture as a method of reducing background fluorescence. Band-pass filters may be produced by doping clear glass with additives to give the desired transmission characteristics, or by deposition of thin films on the surface of glass to produce a

dichroic (or interference) filter. The thin films deposited on the surface are carefully

controlled to transmit a small portion of the electromagnetic spectrum and reflect others. The dichroic type of band-pass filters are more selective in terms of the part of the

spectrum that is transmitted than doped filters, but are more susceptible to damage. Similar types of filter may also be used in other optical processes including Colour

Filtration. In some cases the coloured filters used for Colour Filtration are long-pass

filters (e.g. yellow and red filters), in

other cases bandpass filters are

400

used (e.g. green Transmission

500

600

700

Wavelength / nm

Transmission characteristics for a theoretical short-pass filter designed to block the illuminating wavelengths above the mid-red region of the spectrum. Home Office January 2014

filters).

400

500

600

700

Wavelength / nm

Transmission characteristics for a band-pass filter with a broad

transmission range centred on the green region of the spectrum.

5.FE.41

Fingermark Visualisation Manual

Fluorescence Examination

Transmission

5.FE.41

Contents

5.FE.42

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Viewing Filter continued Practical implementation of viewing filters

The form in which viewing filters are used is determined by whether the eye or a live

view imaging system is being used to detect the fluorescence. This can be summarised below:

Detection system

Eye

Live view imaging system

Principal form of viewing filter

Protective eyewear

Camera filter

Purpose of viewing filter

Protection from optical hazard Maximising effectiveness

Maximising effectiveness

There may still be a requirement for other forms of viewing filter in addition to the principal types identified above. Marks detected by eye still require images to be

captured of them and therefore camera filters will also be required. Similarly, use of a

live view imaging system may not preclude a requirement to provide goggles to protect those in the vicinity from the optical hazard.

Home Office January 2014

5.FE.42

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.43

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Viewing Filter continued Protective eyewear design

Flexible plastic goggles

into, including flexible plastic goggles that can form to the face, rigid heavy duty goggles

a single flat piece of filter glass or two separate circular filters for the eyes. The flexible

There are several types of protective eyewear that the viewing filter can be incorporated and glasses fitted with viewing filters as lenses.

All of these types of goggles can be used for viewing fluorescence. Whichever type is

This type of goggles is based on technology used during welding, and may incorporate plastic allows the goggles to form to the face and an elasticated band allows to user to adjust the fitting.

ultimately selected it is important to ensure that they fit the face, are comfortable to wear

Flexible plastic goggles are usually fitted with glass, long-pass filters protected by a

Examination. The principal types that may be encountered are:

fluorescence of the glass used.

and are securely fixed in place so that they do not slip from the face during Fluorescence

clear plastic layer. Additional films may be used to overcome issues associated with

●● Flexible plastic goggles

The benefits of this type of goggles are that the tight fit to the face prevents leakage of

●● Laser glasses

throughout examination. Limitations are that the tight fit may cause the goggles to steam

●● Rigid, heavy duty goggles ●● Coloured plastic glasses ●● Full-face visors

light and therefore process effectiveness is maximised and dark adaptation is maintained up relatively quickly.

All of these are described in more detail below.

Home Office January 2014

5.FE.43

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.44

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Viewing Filter continued Rigid, heavy duty goggles

Laser glasses

plastic frame is designed to resist penetration by a focused laser beam. They incorporate

in a number of different designs based on standard glasses. The normal clear lenses

This type of goggles is generally used for working with focused lasers, where the rigid

two separate filters for the eyes. An elasticated band allows the user to adjust the fitting. Rigid, heavy duty goggles are usually fitted with band-blocking pass filters or long-pass filters.

The benefits of this type of goggles are that the tight fit to the face prevents leakage of

light and therefore process effectiveness is maximised and dark adaptation is maintained

Laser glasses are generally used for working with focused lasers, and are manufactured are replaced with an appropriate viewing filter. The glasses may allow some adjustment by the user, and cords can be fitted to prevent the glasses slipping from the face accidentally.

Laser glasses are usually fitted with lenses of band-blocking (notch) filters or long-pass filters providing protection from a particular laser wavelength.

throughout examination. Limitations are that the tight fit may cause the goggles to

The benefits of this type of glasses are that they can be more comfortable to wear

goggles for long periods of time may be uncomfortable.

sealed to the face the user may be aware of diffuse reflected light during examination.

steam up relatively quickly. The rigid frame may not fit well to every face and wearing the

than goggles and are not so prone to steaming up. However, because they are not fully Although not dangerous, this may affect dark adaptation and the ability to detect faint fluorescence.

Home Office January 2014

5.FE.44

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.45

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Viewing Filter continued Coloured plastic glasses

Full-face visors

dye added to the clear polymer to give the desired characteristics.

clear visors used to protect the eyes and face whilst maximising visibility, e.g. during use

This type of glasses is based on the design used for laboratory safety glasses, with a Coloured plastic glasses are usually designed and manufactured so that the resultant dyed polymer has the transmission characteristics of a long-pass filter.

The benefits of this type of glasses are that they can be more comfortable to wear

than goggles and are not so prone to steaming up. However, because they are not fully sealed to the face the user may be aware of diffuse reflected light during examination. Although not dangerous, this may affect dark adaptation and the ability to detect faint fluorescence.

Coloured plastic glasses can be the cheapest type of eyewear but they can also vary in quality (including the transmission characteristics) and level of protection offered.

Full-face visors may be based on either the types of visor used during welding, or the

of a chain saw. A flat glass filter may be used fitted to a welding mask, or a dye added to the clear polymer visor material to impart the desired transmission characteristics.

Both types of visor are designed to provide protection to the exposed skin of the face in addition to the eyes, which becomes an important consideration when using ultraviolet radiation during Fluorescence Examination. They incorporate an adjustable band that can be used to ensure a good fit to the head.

Full-face visors are either fitted with long-pass filter glass, or the clear polymer dyed to give the transmission characteristics of a long-pass filter.

The benefits of visors are that they provide the additional skin protection required for

fluorescence using ultraviolet radiation. However, they are more bulky than other types of eyewear.

Home Office January 2014

5.FE.45

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.46

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: The Viewing Filter continued Camera filter design

Camera filters may either be fitted to a live view imaging system during detection of

marks, or to an imaging system such as a digital SLR camera during the capture of an image of a mark initially detected by eye.

In both cases the requirement is for the camera filter to fit securely in a position in front of the sensor so that no light can reach the sensor without first passing through the

camera filter. Filters are usually cut to a circular shape and mounted in a metal fitting with a screw thread. This enables the filter to be fitted to the end of a lens attached to the imaging system, ensuring that no stray, unfiltered light can reach the sensor.

Most camera filters will be of the long-pass type, although camera filters incorporating the same band-blocking filters used in laser glasses are also available.

In general, where the eye is used to initially detect marks, the camera filters used during

subsequent imaging are selected to be equivalent to that in the protective eyewear used during searching.

A selection of long-pass filters (top); a band-blocking filter (bottom left: a band-pass filter (bottom right).

Home Office January 2014

5.FE.46

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.47

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: Detection Systems Fluorescence Examination often involves working in medium to low light levels and

looking for fine detail in coloured fingermarks. All of the guidelines for optimising light source and viewing filter combinations become irrelevant if a potentially identifiable fingermark is missed because it has not been picked up by the detection system

used. It is therefore important to optimise the use of the particular detection system

being employed. Two types of system may be used in the detection of fluorescence associated with fingermarks:

●● live view imaging systems; ●● the human eye.

Each of these detection systems has its own advantages and disadvantages, and

in practice the two may be used in combination (for example the eye used for initial

location of a faintly fluorescing mark and an imaging system to capture an image of it). The principal features of each of these systems are outlined below.

Live view imaging systems

Live view imaging systems utilise arrays of sensors that are capable of detecting

radiation over the approximate wavelength range 320–1100 nm. Unmodified cameras

are usually fitted with UV/IR blocking filters over the imaging sensor and do not record incident UVA or near IR radiation. However, conventional digital cameras and imaging

optics are suitable for use in visible and UVA Fluorescence Examination because it is the fluorescence in the visible region of the spectrum that is being recorded.

Imaging systems generally have a spectral response and a spatial resolution that is

independent of light level. Under low light levels imaging systems may be able to detect

and capture fine detail, contrast and colour better than a human observer can see them. It may be advantageous to err on the side of caution and capture images of marks

that, during Fluorescence Examination, initially appear to contain insufficient detail for comparison.

Imaging systems with spectral responses broader than the visible spectrum are

available. For a full discussion of imaging systems see Chapter 3: Imaging. (See also Infrared Reflection and Ultraviolet (UVC) Reflection)

Home Office January 2014

5.FE.47

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.48

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: Detection Systems continued The human eye

Factors affecting detection using the human eye

photoreceptors. There are two types of photoreceptor: rods and cones.

and there are many factors affecting their performance including:

The light sensitive surface at the back of the eye, the retina, consists of millions of

The effectiveness of the human observer in conducting examinations will be variable,

It is the cones that are responsible for colour vision because there are three types of

●● eyesight;

allow us to see the finest detail because of their close spatial arrangement in the retina

●● visual attention;

cone, each of which responds to a different part of the visible spectrum. Cones also

but they only function at relatively high light levels (e.g. daylight and normal room light). We do not perceive all colours of the visible spectrum as equally bright even when the

●● dark adaptation; ●● fatigue.

radiation that is responsible is equally intense. For example, if we had three lights of

equal power output, one blue, one yellow and one red, the yellow light would appear brighter than the blue or red lights.

Both the rods and the cones respond at a medium light level (e.g. twilight), where we can see some colour but not the finest detail.

When light levels are low (e.g. moonlight), the cones do not respond; it is then the rods

that are responsible for allowing us to see. Rods are not colour-sensitive and they do not allow us to see fine detail.

It can therefore be seen that the eye will need to adapt to the particular environment it is working in, in this case the low light levels required for Fluorescence Examination. It will also find it easier to detect certain colours of fluorescence (such as green) than others (such as red).

Home Office January 2014

5.FE.48

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.FE.49

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Requirements for Fluorescence Examination: Detection Systems continued Eye sight: There are a number of potential eye problems that could impact on a person’s

Usefully, the dark adapted eye is insensitive to deep red light. It is therefore possible to

(nyctalopia), colour blindness, age-related degeneration.

during the examination period. Red goggles can also be used for dark adaptation.

ability to perform a visual search task in low light conditions, including: night blindness

use a red torch, very low level room lighting or a red safe light to maintain the sensitivity

In order to see the sometimes very faint fluorescence, it is essential for the person

The speed of dark adaptation depends on a number of factors including, but not limited

normal nearpoint, i.e. approximately 25 cm from the eyes. If the operator cannot focus

illuminated, viewer’s age and eye condition.

carrying out the examination to work very closely to the surface with the surface at the comfortably at this distance spectacles must be worn, otherwise fingermarks may be missed. Most personnel become progressively longsighted with age and it is more

likely that older members of staff will require glasses to correct this in order to operate efficiently during Fluorescence Examination. It is recommended that the eyesight of those regularly employed for fingermark examination work is regularly checked.

Detection of fingermarks may be improved by the use of a good quality hand magnifier. This must only be used between the eyes and the surface; it must not be used to focus the beam from high-intensity light sources.

Colour vision is impaired in a significant proportion (approximately 10%) of males and in a very small proportion of females. Minor colour deficiency is unlikely to seriously

reduce the capacity to detect fingermarks; serious colour deficiency may, however, make the detection of fingermarks, selection of filters and image capture very difficult. It is

recommended that the colour vision of those employed for fingermark examination work is checked before work commences.

Dark adaptation (and light adaptation): The ability to see faint fluorescence arising

from treated and untreated fingermarks is a critical factor in the successful execution

of Fluorescence Examination. The sensitivity of the eye increases in the dark. In order

to, wavelength of light, viewing time in brighter ‘pre-dark adaptation’ light, area of retina Visual attention: Visual attention is an ‘enabler’. It enables the visual system to bring its considerable identification, feature association and recognition powers to bear on an

object or special location. The implications of this on forensic examinations are that if

the observer is familiar with the colour and shape of fingermarks, the visual system will prioritise features of this type during the search and thus be more likely to find them quickly.

Fatigue: Visual fatigue is a long-recognised problem for those whose occupation

involves a lot of close work, with the effects observed including blurred vision, eyestrain and headaches. Tests have indicated that observers may show a loss in sensitivity as

time engaged in the visual activity increases, and that the symptoms of visual fatigue are

much more marked in the periphery of vision. These results highlight the need for regular rest breaks during any activity that requires the maximum sensitivity of the eye to be harnessed.

In the context of forensic examinations it may become evident that certain individuals are more suited to carrying out particular types of examination, and efforts should be made to use personnel known to be most effective wherever possible n

to detect very faint fluorescence it is necessary to allow time (15–30 minutes) for

the eyes to become sufficiently dark adapted (full dark adaptation can take up to 40

minutes). Light adaptation, on the other hand, is very quick (full light adaptation takes only five minutes). If the dark adaptation of the examiner is not maintained then it will be necessary, once again, to allow sufficient time for dark adaptation to be restored. Home Office January 2014

5.FE.49

Fingermark Visualisation Manual

Fluorescence Examination

Appendices

5.IRR.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

IR Imaging; Near IR imaging; Short wave IR imaging

Contents Laboratory or Scene?................. 5.IRR.2 Laboratory Use............................ 5.IRR.3 Health and Safety.....................5.IRR.3 Equipment................................5.IRR.4 Processing................................5.IRR.5 Scene Use.................................... 5.IRR.6 Additional Considerations........5.IRR.6 Supplementary Information........ 5.IRR.7

Main Uses ✘ Latent ✘ Blood ✘ Grease ✔ Other*

Safety and Effectiveness Summary ✔ Non-Porous ✔ Semi-Porous ✔ Porous

*Fingermarks developed by metallic/inorganic deposition processes

Key Information

●● Competent personnel specialising in fingermark

visualisation, in particular imaging, must be

consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

Infrared Reflection is used to enhance fingermarks that are

The Process

●● Infrared Reflection can be used safely and effectively in the

laboratory and at scenes.

●● Appropriate selection of infrared long-pass and/or band-pass

filters is required to obtain optimum results.

●● An infrared sensitive imaging device must be used.

●● A light source outputting in the infrared region of the

spectrum is required.

The Item or Substrate

●● Process effectiveness is influenced by the reflectivity of the

surface in the infrared region of the spectrum. The process

will not be effective on substrates that strongly and uniformly absorb infrared radiation.

●● Process effectiveness is influenced by the ability of the

mark to either absorb or strongly scatter infrared radiation.

It is most effective for marks visualised by processes giving selective deposition of metallic or inorganic material.

already visible in situations where the fingermark is obscured

Integrated Use

significantly darkened due to the action of heat. The process

detrimental impact on any subsequent fingermark or forensic

by coloured, patterned backgrounds or where the surface has utilises differences in the infrared reflectivity of the mark and surface to provide additional contrast between them.

It is an optical process that involves simultaneously illuminating the mark and surface with a source outputting infrared radiation and viewing the effect using an infrared sensitive imaging

system fitted with a filter that blocks visible light and transmits

Infrared Reflection is non-contact, non-destructive and has no processing.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

with other forensic processes.

infrared.

More Details

Home Office January 2014

5.IRR.1

Fingermark Visualisation Manual

A Infrared Reflection

5.IRR.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Home Office January 2014

Health and Safety

Infrared Reflection can be used safely in the laboratory and at the scene.

Effectiveness

Infrared Reflection is equally effective if used in the laboratory or at the scene, provided the details as written in the process instruction can be followed.

Practicality

Infrared Reflection can be just as practical to use at scenes as it is in the laboratory, provided equipment can be used as described in the process instruction.

5.IRR.2

Fingermark Visualisation Manual

Infrared Reflection

5.IRR.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Infrared Reflection may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

Index

Laboratory Use Hazards associated with Infrared Reflection ●● Infrared Reflection is an optical process.

●● Practitioners must be aware of the hazards associated with the particular radiation

sources they plan to use. (See hazards associated with the use of artificial optical radiation).

●● Wear Standard PPE as a minimum.

●● Hazards associated with the use of the process are identified below but those cited

must not be regarded as exhaustive, nor the control measures prescriptive. Hazard

Risk

Suggested control measures

Hazardous dust or nuisance odours from items previously treated with a chemical or physical process.

See specific process instruction for possible adverse effects to eyes, skin and respiratory system.

Follow recommendations for examination of items in process instructions for the physical or chemical process used.

Non-visible optical radiation emitted from source in: Infrared range (>780 nm)

Negligible risk as long as a low output-power source is selected and used appropriately, although the risk increases if people are unaware of the hazard (IR emissions are non-visible).

●● Do not view the

infrared source directly from short distances or point it towards the eyes. ●● Wear eye protection that blocks infrared wavelengths output by the infrared source to safe levels.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.IRR.3

Fingermark Visualisation Manual

Infrared Reflection

Glossary

5.IRR.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

Infrared Reflection uses a selection of specialist optical equipment (infrared radiation sources, infrared filters, infrared sensitive imaging systems). General laboratory equipment that may be required is outlined in Chapter 3. Equipment Infrared radiation source(s)

Requirements The infrared radiation source must: ●● Have output in the near infrared region of the spectrum in the

wavelength range 700-1100 nm Options include:

●● a white light source with a relatively even spectral output

across the visible region of the spectrum which extends into the near infrared region (up to 1100 nm) (e.g. incandescent bulb);

●● a broadband infrared source or set of infrared sources (e.g.

infrared LEDs) allowing similar infrared spectral output(s) covering the wavelength range 700-1100 nm;

●● photographic flash guns.

Infrared imaging system

The infrared imaging system must: ●● be capable of directly detecting radiation in the near infrared

region of the electromagnetic spectrum (e.g. CCDs with the

OR

IR blocking filter removed);

●● be capable of converting radiation in the near infrared region

of the electromagnetic spectrum (700-1100 nm) to a visible output (e.g. image converters).

Infrared filter

The infrared filter must: ●● block all visible radiation and transmit in the near infrared

region of the spectrum. Band-pass and long-pass filters are appropriate, filters with cut-on wavelengths of 750 nm or greater generally give the best results.

Home Office January 2014

5.IRR.4

Fingermark Visualisation Manual

Infrared Reflection

Appendices

5.IRR.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Processing Preparation (1) Work area (2) Equipment

Processing (3) Mark up any visible marks (4) Capture reference images using white light illumination, if necessary

a) Follow manufacturer’s instructions and local safe working procedures. b) Remove UV/IR blocking filter (if present) from imaging equipment so that it is sensitive to infrared radiation.

a) As Infrared Reflection enhances marks developed with other processes, they may already be marked up (and imaged). a) See Visual Examination.

enhanced by Infrared Reflection.

(5) If applicable, turn off any light sources not being used for Infrared Reflection

a) Only required where infrared filtration is being used in front of the light source instead of placed in front of the imaging system.

(6) Expose item to infrared radiation

a) Expose surface to radiation in the near infrared region of the spectrum using selected infrared radiation source.

(7) View item under appropriate infrared filtered conditions

(8) Mark up any additional viable marks that may have been revealed appropriately and capture image

Home Office January 2014

Sample images of a Physical Developer fingermark on a cheque

a) Introduce a long- or band-pass filter transmitting solely in the infrared region of the spectrum in front of the viewing/ imaging system (if not using a filtered infrared radiation source). b) Re-focus imaging equipment to an appropriate focal point for infrared radiation, if this is not automatically corrected by the imaging/viewing system. c) Observe irradiated item using appropriate infrared sensitive viewing equipment.

Sample images of a Physical Developer fingermark on charred paper enhanced by Infrared Reflection.

a) Image may be captured directly if using infrared imaging equipment. Alternatively, conventional imaging equipment may be used to indirectly capture images displayed by an image converter system. b) Repeat process with different wavelength infrared filters/ light sources if necessary.

5.IRR.5

Fingermark Visualisation Manual

Infrared Reflection

Glossary

5.IRR.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Scene Use

Additional Considerations If a decision has been made to apply Infrared Reflection at a scene, a

number of additional considerations need to be taken into account, over

and above those given for laboratory use. The recommendations cannot be

prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make the process as effective as possible

within the constraints of the scene;

●● present a range of practical issues that need to be overcome.

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

For health and safety:

●● there are no additional considerations with regard to the use of the process at

scenes.

For effectiveness, consider:

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of the constraints posed by the scene;

●● how the lighting environment at the scene, in particular sources of infrared radiation,

can be properly controlled.

For practicality, consider:

●● access to the areas to be treated;

●● provision of a suitable power source, if needed.

3, Section 3.1 - Scene use of the processes and treatment of large areas for other general information.

Home Office January 2014

5.IRR.6

Fingermark Visualisation Manual

Infrared Reflection

Appendices

5.IRR.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

In the near (700-1100 nm) region of the infrared (IR) spectrum, the mechanisms

available for fingermark visualisation are essentially the same as those used in the

visible and ultraviolet (UV) regions, namely fluorescence and absorption/reflection.

Infrared fluorescence is not yet widely exploited for fingermark enhancement although

this may become an area of interest in future. The process currently used in fingermark enhancement is Infrared Reflection.

The principal difference between Infrared Reflection and viewing an item in the visible region is that infrared is invisible and therefore the item must be viewed indirectly: an

imaging system must be used in order to provide a visible image. Conceptually Infrared Reflection is otherwise very similar to Colour Filtration.

Infrared Reflection is particularly useful for examining materials that are coloured by pigments and dyes. Many of the organic pigments used in printing inks are infrared

transparent or reflective, and surfaces that appear highly patterned and/or coloured

under ‘daylight’ conditions may appear devoid of printing when viewed in the infrared spectral region, as illustrated in the example on the next page.

The potential ability of Infrared Reflection to remove background colours can be a

significant advantage when trying to resolve ridge detail in fingermarks developed on items like banknotes, which have complex multi-coloured and patterned designs. Its

success relies on the chemical or physical process (used to visualise the mark in the first

place) giving a product that is either absorbing or strongly scattering of infrared radiation. Visualisation processes resulting in selective deposition of metallic or inorganic material

on the mark (Powders, Powder Suspension, Small Particle Reagent, Physical Developer,

Vacuum Metal Deposition) produce marks of this type. Untreated marks in contaminants such as blood, paint, ink and engine oil may also be revealed by Infrared Reflection,

although generally the process is not used for speculative searching for these types of mark.

Home Office January 2014

5.IRR.7

Fingermark Visualisation Manual

Infrared Reflection

Appendices

5.IRR.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

Example: IR absorbing mark on a multi-coloured background

Visual Examination

Infrared Reflection

region of the spectrum, the pigments in the

pigments in the inks appear transparent. The

When illuminated with light in the visible

When illuminated with infrared radiation, the

inks selectively absorb certain wavelengths

radiation passes through the pigments and

and reflect others, and the surface therefore

is reflected by the substrate. The surface

appears as different coloured regions. The

therefore appears uniformly light when

fingermark absorbs most wavelengths

viewed on an infrared imaging system. The

of light and may also scatter visible

fingermark absorbs and may also scatter

wavelengths. It therefore appears dark grey/

infrared radiation. It therefore appears dark

black although contrast may be poor.

White light source outputting all wavelengths

Surface printed with inks containing different pigments

grey/black against a light background when viewed on an infrared imaging system.

Reflected wavelengths of light producing different surface colours

Absorption of certain wavelengths by pigments in inks

Absorption/scattering of light by fingermark Home Office January 2014

Radiation source outputting infrared wavelengths

Pigments in inks transmit infrared radiation

Reflected infrared radiation varying in intensity from different surface regions

Reflection of infrared radiation by substrate

Absorption/scattering of infrared radiation by fingermark

5.IRR.8

Fingermark Visualisation Manual

Infrared Reflection

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Supplementary Information

Equipment

Infrared radiation sources

120

must output in the near infrared region. Tungsten lamps and xenon discharge lamps

100

An appropriate source of infrared must be used. For Infrared Reflection the light source (including photographic flash) are suitable for this purpose. Infrared light-emitting diodes (LEDs) outputting in various regions of the near infrared may be suitable. White LEDs,

coloured LEDs and fluorescent tubes are not suitable. Output spectra typical of some of

these different types of light source are illustrated on the right for comparative purposes. The broad, even, output spectrum for tungsten is independent of any particular model

or make of lamp and demonstrates why it is such a useful infrared source: any portion of the near infrared region may be isolated with an appropriate filter. The infrared

LED spectrum is particular to a type of LED and demonstrates why a set of different

infrared LEDs may be useful. The spectra for the white LED and white fluorescent tubes

80

Sunlight Infrared LED White LED White fluorescent tube Tungsten lamp

60 40 20

demonstrate they do not provide any significant output at wavelengths much above 700 nm, making them unsuitable for this purpose.

0

400

500

600 700 Wavelength (nm)

800

900

Normalised output spectra for a range of light sources, showing that not

all will have sufficient emission in the infrared region to be suitable for the Infrared Reflection process.

Home Office January 2014

5.IRR.9

Fingermark Visualisation Manual

Infrared Reflection

Intensity

5.IRR.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

0.9

For Infrared Reflection to be effective, imaging devices that are sensitive in the near infrared region of the spectrum must be used. Conventional charge coupled device

(a UV/IR blocking or ‘hot mirror’ filter) bonded to them to block radiation outside the

visible region, ensuring better colour reproduction in the visible region of the spectrum.

Specialist models of camera are available for infrared imaging with this filter removed or

replaced with one or another type of infrared transmitting filter, and specialist equipment used for document examination will also include infrared sensitive imaging devices.

0.8 0.7 0.6

0.4 0.3 0.2

must be given to factors affecting image quality including focus, magnification, contrast,

0.1

brightness and spatial resolution. Consideration must be given to both the viewed image and the captured image. Some discussion is given in Chapter 3, Section 3.3: Working Effectively - Imaging.

Focusing reflected infrared images

With conventional optics, infrared wavelengths are focused to a plane behind that at

which the wavelengths of visible light are normally focused. This presents a practical

CCD 1 CCD 2

0.5

Camera systems offering a ‘live view’ or ‘real time’ image have an obvious advantage over cameras that require an image to be captured before it is viewed. Consideration

Index

1

Imaging system technologies

cameras are inherently sensitive in this region (see below) but they usually have a filter

Glossary

Supplementary Information

Infrared imaging systems

(CCD) and complementary metal-oxide-semiconductor (CMOS) sensors used in digital

Appendices

0 400

500

600

700 800 Wavelength (nm)

900

1000

1100

Quantum efficiency curves for two types of CCD sensor, showing that in the unmodified state this type of sensor is sensitive to near IR radiation.

difficulty. If the lens is focused manually under white light conditions before the infrared

filter is placed over the lens the resulting infrared image may be out of focus. In addition, manual focus will not be possible with the filter attached to the lens because infrared

filters are visually opaque (attaching the filter to the light source will not overcome this problem). Infrared focus correction may be achieved if the lens is suitably marked (as was common on old lenses but is less common today), by calculation, or by trial and error.

The problem may be avoided by use of specialist lenses designed for near infrared

imaging, cameras specially modified for near infrared imaging, cameras employing edgecontrast based auto focus and cameras offering manual focus via a live view image.

Home Office January 2014

5.IRR.10

Fingermark Visualisation Manual

Infrared Reflection

Quantum efficiency

5.IRR.10

Contents

5.IRR.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Infrared filters

An alternative to fitting the infrared filter in front of the

infrared region of the spectrum. This can be achieved

advantage is that when using an imaging system that

by using a radiation source with an output solely in the infrared, but it is more common to use a light/radiation source with a broadband output in conjunction with infrared filters.

Infrared long-pass filters are generally used in front of

imaging system is to fit it in front of the light source. An does not provide a live view it is possible to see through

the lens to compose the image. The disadvantage is that

the working area must be darkened prior to imaging. This disadvantage may be overcome if a filtered photographic flash is used as the light source.

the imaging system to block the visible region of the

Band-pass interference filters can also be used, but are

A range of Schott and Hoya long-pass glass filters are

use in some circumstances but in general long pass filters

spectrum when broad output radiation sources are used. available giving transmission cut-on wavelengths between 645 and 1000 nm.

Index

Supplementary Information

Infrared Reflection requires a means of restricting the

wavelengths reaching the imaging system to the near

Glossary

considerably more expensive. Band-pass filters may be of will be best suited to this application n

Although the lower wavelength filters do have some use in document examination, those of most use in Infrared

Reflection applications such as suppression of patterned/ coloured backgrounds and enhancing marks on charred substrates are those with transmission cut-on points in the range 715-1000 nm.

Home Office January 2014

5.IRR.11

Fingermark Visualisation Manual

Infrared Reflection

Appendices

5.MI.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Monochromator; Quaserchrome

Contents Laboratory or Scene?................... 5.MI.2 Laboratory Use.............................. 5.MI.3 Health and Safety................. 5.MI.3 Equipment............................ 5.MI.4 Processing........................... 5.MI.5 Scene Use...................................... 5.MI.6 Additional Considerations......... 5.MI.6 Supplementary Information.......... 5.MI.7

Main Uses ✘ Latent ✔ Blood ✘ Grease ✔ Other*

It is an optical process that involves simultaneously illuminating

✔ Non-Porous ✔ Semi-Porous ✔ Porous

*Any coloured fingermarks (treated or untreated) and/or marks on coloured backgrounds

Key Information

●● Competent personnel specialising in fingermark

visualisation, in particular imaging, must be

consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

Monochromatic Illumination is used to enhance fingermarks

that are already visible in situations where the fingermark, the background, or both are coloured. The process utilises the

colour characteristics of the mark and/or surface and involves

the use of a filter capable of giving narrow band illumination from

the mark and surface with a low-intensity light of an appropriate narrow wavelength range and observing the outcome as the illumination wavelength is adjusted. More Details

Safety and Effectiveness Summary The Process

●● Monochromatic Illumination can be used safely and

effectively in the laboratory and at scenes.

●● Process effectiveness will be determined by the properties

of the adjustable filter, in particular the bandwidth of illumination.

The Item or Surface

●● Process effectiveness is influenced by the colour of the

mark, the colour of the surface and to a lesser extent the distribution of the colours present.

Integrated Use

Monochromatic Illumination is non-contact, non-destructive

and has no detrimental impact on any subsequent fingermark or forensic processing.

any portion of the visible spectrum that is adjusted to alter the

●● See Chapter 4 for information on its sequential use with other

a sub-process of Colour Filtration, but is described separately

●● See Chapter 7 for information on integration of fingermark

contrast of the mark relative to the background. It is essentially because the colour filtration condition can be dynamically

controlled over a broad wavelength range and the narrower

fingermark visualisation processes. and other forensic processes.

bandwidths used allow greater spectral discrimination of colours. The optimum discrimination of the mark may be obtained using conditions intermediate between the colour enhancement and colour cancellation conditions described for Colour Filtration.

Home Office January 2014

5.MI.1

Fingermark Visualisation Manual

A Monochromatic Illumination

1st proof+

5.MI.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Health and Safety

Monochromatic Illumination can be used safely in the laboratory and at the scene.

Effectiveness

Monochromatic Illumination is equally effective if used in the laboratory or at the scene, provided the details as written in the process instruction can be followed.

Practicality

Monochromatic Illumination can be just as practical to use at scenes as it is in the

laboratory, provided equipment can be used as described in the process instruction. This can be readily achieved for purpose-built linear variable filter – adjustable slit

combinations that can be attached to the end of light guides, whereas it will not be practical where the linear variable filter is integrated into larger items of laboratory imaging equipment.

Home Office January 2014

5.MI.2

Fingermark Visualisation Manual

Monochromatic Illumination

5.MI.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Monochromatic Illumination may be carried out with no known hazards to health

provided practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measure, (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

Laboratory Use Hazards associated with Monochromatic Illumination ●● Monochromatic Illumination is an optical process.

●● Practitioners must be aware of the hazards associated with the particular radiation

sources they plan to use. (See hazards associated with the use of light sources).

●● Wear Standard PPE as a minimum.

●● Hazards associated with the use of the process are identified below but those cited

must not be regarded as exhaustive, nor the control measures prescriptive. Hazard

❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants present.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness;

Risk

Suggested control measures

Hazardous dust or nuisance odours from items previously treated with a chemical or physical process.

See specific process instruction for possible adverse effects to eyes, skin and respiratory system.

Follow recommendations for examination of items in process instructions for the physical or chemical process used.

Hazardous radiation emitted from high-intensity white light sources in: Visible range (380–780 nm)

Damage to eyes from the high power density and/ or wavelength of excitation radiation, even with very short exposure times.

Engineering controls must be in place so that the operator never views the white light emission. The risk is then reduced to negligible.

Filtered radiation emitted from source in: Visible range (380–780 nm)

Negligible risk as long as the light filtration (i.e. the linear variable filter) is effective in reducing the power of the emission (from the white light source) to a safe level.

Ensure the filters used are not damaged and are effective at reducing the power of the emissions to a safe level.

a responsible person will carry out a risk assessment before the process is carried out to include at least:

Index

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.MI.3

Fingermark Visualisation Manual

Monochromatic Illumination

Glossary

5.MI.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

Monochromatic Illumination requires a white light source and a specialist filter to

produce the desired illumination conditions. General laboratory equipment that may be required is outlined in Chapter 3.

Equipment

Requirements

White light source

The white light source should: ●● have an even spectral output across the visible region of the spectrum; ●● have an output of an intensity such that image capture can be achieved using relatively short exposure times (but without representing an optical hazard to unprotected eyes).

Linear variable filter - adjustable slit combination

The linear variable filter - adjustable slit combination

must: ●● allow narrow portions of the full range of the visible spectrum to be selected. Approximately 25 nm bandwidths are typical but this can vary; ●● allow the transmission of the selected narrow bandwidth portions of the visible spectrum onto the surface.

The linear variable filter - adjustable slit combination may: ●● be incorporated into commercially produced equipment such as document examination stations.

Home Office January 2014

5.MI.4

Fingermark Visualisation Manual

Monochromatic Illumination

Appendices

5.MI.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Processing

Glossary

Index

Laboratory Use Sample images of a Vacuum Metal

Preparation

Deposition fingermark

on a coloured, patterned

background revealed

(1) Work area

(2) Equipment

by Monochromatic

a) Follow manufacturer’s instructions. b) Place linear variable filter - adjustable slit combination in front of light source output, if not already integrated into illumination source or imaging equipment.

Illumination vs. white diffuse lighting.

Processing (3) Mark up any visible marks

(4) Capture reference images using white light illumination, if necessary

(5) Observe item using Monochromatic Illumination and adjust colour as required

a) As Monochromatic Illumination enhances marks developed with other processes, they may already be marked up (and imaged).

a) See Visual Examination.

a) Vary illumination colours by adjusting the linear variable filter - adjustable slit combination, whilst observing the effect until optimum contrast is obtained between mark and background.

(6) Mark up any additional viable marks that may have been revealed appropriately and capture image(s)

Home Office January 2014

5.MI.5

Fingermark Visualisation Manual

Monochromatic Illumination

Appendices

5.MI.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Scene Use

Additional Considerations If a decision has been made to apply Monochromatic Illumination at a scene, a number of additional considerations need to be taken into account over and above those given for laboratory use. The

recommendations cannot be prescriptive since every scene will be different and: ●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

For health and safety:

●● there are generally no additional considerations with regard to the use of the

process at scenes.

For effectiveness, consider:

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of the constraints posed by the scene.

●● different approaches may be needed to make the process as effective as possible

For practicality, consider:

●● present a range of practical issues that need to be overcome.

●● provision of a suitable power source, if needed.

within the constraints of the scene;

●● access to the areas to be treated;

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

3, Section 3.1 - Scene use of the processes and treatment of large areas for other general information.

Home Office January 2014

5.MI.6

Fingermark Visualisation Manual

Monochromatic Illumination

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Supplementary Information

Theory

The theory of Monochromatic Illumination is essentially that already described in Colour Filtration (Supplementary Information). The principal advantages of Monochromatic Illumination over the basic principles described for Colour Filtration are that the linear

variable filter can be tuned to illuminate the surface with light from any narrow portion

of the visible spectrum, and the narrow bandwidth means that it is more discriminating

between similarly coloured regions. This means that the optimum illumination condition to discriminate the mark from the background may be in a portion of the spectrum

Image of a mark developed using

where pure colour enhancement or contrast cancellation are not effective, but the

Ninhydrin against a red printed

tunable nature of the illumination means that colour discrimination can still be achieved.

background pattern viewed under white

However, Monochromatic Illumination is not effective where complex combinations of

light, and corresponding reflectance

multiple background colours are present and in such situations Multi-Spectral Imaging

spectra for Ninhydrin and red ink.

should be considered instead.

In Monochromatic Illumination, the colour of light produced is controlled by a slit placed

80

in front of the linear variable filter that only allows light to fall on a section of the filter corresponding to approximately a 25 nm range of wavelengths (i.e. bandwidth). The

70

position of the slit is adjusted to select the colour of light that will be output as a result of transmission of light through it.

60

The principles of how the linear variable filter makes it possible to achieve discrimination between regions of the mark and background that are spectrally very similar can be

demonstrated for the following scenario with marks developed using Ninhydrin on a

background printed with patterns in a red ink. In this case the purple ridges in the marks on the regions printed with red ink cannot easily be resolved under white light.

50 Ninhydrin

40

(reflection) Red ink

30

(reflection)

20 10 0 420

Home Office January 2014

470

520 570 620 Wavelength (nm)

670

720

5.MI.7

Fingermark Visualisation Manual

Monochromatic Illumination

Intensity

5.MI.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Supplementary Information

Viewing the surface using a narrow, green region of the spectrum to

Tuning the filter to illuminate in the red region of the spectrum means that although both mark and ink

mark and ink absorb strongly in this region and appear dark.

for the Ninhydrin mark to be more easily discerned because it reflects less red light than the ink and the

increase contrast by colour enhancement is ineffective because both

Image of a mark developed

reflect red light, the spectral differences between the ink and Ninhydrin in this region are still sufficient white background.

Image of a mark developed using Ninhydrin against a red

using Ninhydrin against a

printed background pattern viewed under red monochromatic

red printed background

light, and corresponding reflectance spectra for Ninhydrin

pattern viewed under green

and red ink with output band of monochromator overlaid.

monochromatic light, and

corresponding reflectance spectra for Ninhydrin and

red ink with output band of monochromator overlaid.

Linear filter

Linear filter

Band pass ‘slot’

Band pass ‘slot’ 80

70

70

60

60

50

50

Ninhydrin

40

(reflection)

30

Red ink

(reflection)

20

Intensity

80

0

420

470

520

570

620

Wavelength (nm)

Home Office January 2014

670

720

for Colour Filtration,

Monochromatic Illumination Ninhydrin (reflection) Red ink (reflection)

20

0

simple one and is essentially described in the theory

30

10

illustrated here is a relatively ‘colour cancellation’ as

40

10

Although the scenario

has advantages over

Colour Filtration where the reflectivity spectra of the

mark and surface resemble

each other even more closely and may only differ over very

420

470

520

570

620

Wavelength (nm)

670

720

narrow wavelength ranges.

5.MI.8

Fingermark Visualisation Manual

Monochromatic Illumination

Intensity

5.MI.8

Contents

5.MI.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Equipment

The presence of the slit in combination with the linear variable filter is essential to the

Light sources with an even output across the entire visible spectrum are required. If any

reaching unused parts of the linear filter and only allows white light to fall on the filter in

Light sources

gaps in the spectrum occur in the light source output, it becomes difficult to discriminate between colours of marks or backgrounds that fall in this region of the spectrum. For example, the output from fluorescent tubes contains many gaps in the spectrum and

light sources based on this technology should not be used as the primary illumination source in Monochromatic Illumination. Arc lamps are generally most suitable.

implementation of Monochromatic Illumination. The slit blocks the white light from

the required spectral range. For this reason it is advisable to purchase pre-integrated linear filter - slit combinations for this process n

An example of a linear variable filter - adjustable slit combination integrated into a single unit.

Linear variable filters

Monochromatic Illumination uses a linear, variable, narrow band-pass filter that is placed in front of the light source.

This filter consists of glass coated with a range of coatings of different refractive indices that are applied to produce a continuously variable interference filter. The resultant

filter is therefore capable of producing all colours of the visible spectrum when light is transmitted through it.

Multiple metallised layers Glass substrate Appearance in transmission Schematic diagram of a linear variable filter. Several suppliers produce linear variable filters in a range of lengths. Longer filters make it easier to fine tune the wavelength band that is output because the region of the filter

associated with each part of the spectrum is physically longer, making it easier to select the required spectral range using a fine slit.

Home Office January 2014

5.MI.9

Fingermark Visualisation Manual

Monochromatic Illumination

Appendices

5.MSI.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Hyperspectral imaging

Contents Laboratory or Scene?.................5.MSI.2 Laboratory Use............................5.MSI.3 Health and Safety ..................... 5.MSI.3 Equipment ................................. 5.MSI.4 Processing ................................ 5.MSI.6 Scene Use....................................5.MSI.8 Additional Considerations ......... 5.MSI.8 Supplementary Information .......5.MSI.9

Main Uses ✘ Latent ✔ Blood ✘ Grease ✔ Other*

and Monochromatic Illumination, especially where multiple

✔ Non-Porous ✔ Semi-Porous ✔ Porous

*Any coloured fingermarks (treated or untreated) and/or marks

on coloured backgrounds; also fluorescent marks on fluorescing backgrounds

Key Information

●● Competent personnel specialising in fingermark

visualisation, in particular imaging, must be

consulted if considering the use of this process.

●● Multi-Spectral Imaging uses commercial equipment and

software and specialist training will be required on its use in addition to the detail given in this process instruction.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

Multi-Spectral Imaging is used to enhance fingermarks that are already visible in situations where the fingermark, the

with both Visual Examination and Fluorescence Examination. It is an optical process that involves illuminating the area with a light outputting an appropriate wavelength range and collecting a series of images at different wavelengths. These images are

then combined and analysed using computer software to extract the relevant information. More Details

Safety and Effectiveness Summary The Process

●● Multi-Spectral Imaging can be used safely and effectively

in the laboratory and at scenes although it is normally considered impractical to use at scenes.

●● The effectiveness of the process is dependent on: the

filtration bandwidth achievable by the imaging system; the software available for separating colour spectra; and the expertise of the operator.

The Item or Surface

●● Process effectiveness is influenced by the colour/

fluorescence of the mark, the reflection and/or fluorescence

spectra of the surface and to a lesser extent the number and distribution of the colours present.

background, or both are coloured. The process utilises the

Integrated Use

are obtained for each region of interest and software used to

no detrimental impact on any subsequent fingermark or forensic

colour characteristics of the mark and/or surface. Colour spectra discriminate the characteristic spectrum of the mark from that of the background. Because the process analyses the colour spectra of mark and surface across the visible spectrum,

it is potentially capable of achieving greater discrimination between marks and backgrounds than Colour Filtration

Home Office January 2014

background colours are present. It can be used in conjunction

Multi-Spectral Imaging is non-contact, non-destructive and has processing.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

with other forensic processes.

5.MSI.1

Fingermark Visualisation Manual

A Multi-Spectral Imaging

5.MSI.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Health and Safety

Multi-Spectral Imaging can be used safely in the laboratory and at the scene.

Effectiveness

Multi-Spectral Imaging is equally effective if used in the laboratory or at the scene, provided the details as written in the process instruction can be followed.

Practicality

The specialist equipment used for image collection and analysis in Multi-Spectral

Imaging is generally located in a laboratory. It may be significantly less practical to relocate such equipment to scenes.

Home Office January 2014

5.MSI.2

Fingermark Visualisation Manual

Multi-Spectral Imaging

5.MSI.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Multi-Spectral Imaging may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’).These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

Index

Laboratory Use Hazards associated with Multi-Spectral Imaging ●● Multi-Spectral Imaging is an optical process.

●● Practitioners must be aware of the hazards associated with the particular radiation

sources they plan to use. (See hazards associated with the use of Artificial Optical Radiation).

●● Wear Standard PPE as a minimum.

●● Hazards associated with the use of the process are identified below but those cited

must not be regarded as exhaustive, nor the control measures prescriptive. Hazard

Risk

Hazardous dust or nuisance odours from items previously treated with a chemical or physical process.

See specific process instruction for possible adverse effects to eyes, skin and respiratory system.

Reflection mode Radiation emitted from source in: Visible range (380–780 nm)

Negligible risk as long as a low-powered source is selected and used appropriately.

Fluorescence mode Hazardous visible and nonvisible radiation emitted from high-intensity light sources in: Visible range (380–780 nm) or UVA range (315–400 nm)

Damage to eyes and skin from the high power density of excitation radiation, even with very short exposure times.

Suggested control measures Follow recommendations for examination of items in the process instructions for the physical or chemical process used.

See Fluorescence Examination for control measures needed when using high-intensity light sources.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.MSI.3

Fingermark Visualisation Manual

Multi-Spectral Imaging

Glossary

5.MSI.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Equipment

Multi-Spectral Imaging uses specialist multi-spectral imaging equipment with

appropriate lighting depending on whether it is being used in reflection or fluorescence mode. General laboratory equipment that may be required is outlined in Chapter 3.

Equipment MultiSpectral imaging system

Requirements The Multi-Spectral imaging system should: ●● allow the capture of multiple images of the surface at different wavelength ranges over a broad region of the visible spectrum.

Equipment

Requirements Imaging system Range of different coloured LEDs

Several appropriate technologies are available commercially including liquid crystal tunable filters, acousto-optical filters, prisms and systems with multiple integrated LED light sources. All will require specialist training.

Light tight enclosure

Imaging system

Fingermark

Broad output white light source Tunable filter

Fingermark

Substrate

Schematic diagram for a system based on multiple sets of coloured LEDs.

Substrate

Schematic diagram for system based on a turnable filter.

Home Office January 2014

5.MSI.4

Fingermark Visualisation Manual

Multi-Spectral Imaging

Glossary

5.MSI.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Equipment continued Equipment

Requirements

Equipment

White light source OR Series of narrow spectral output coloured light sources

The white light source (used as illustrated above) should: ●● have an even spectral output across the visible region of the spectrum; ●● have an output that is consistent in intensity and output profile each time that it is used; ●● have an output power sufficiently high so that image capture can be carried out using relatively short exposure times (but without representing an optical hazard to unprotected eyes).

High-intensity coloured light source

The high-intensity coloured light source must: ●● promote fluorescence in the mark being imaged.

Analysis software

This is usually supplied with commercial imaging systems and specialist training on its use will be required. The analysis software should: ●● enable characteristic colour spectra to be obtained from the fingermark and relevant regions of background; ●● allow the regions where these spectra are present to be clearly defined and separated from each other; ●● allow the saving of information relevant to the creation of an audit trail for any enhancements carried out.

White tile

The white tile should: ●● be of a uniform white colour to allow the capture of a ‘white cube’ that can be used as a reference for normalisation of spectral information.

The series of coloured light sources (used as illustrated above) should: ●● have a means of ensuring that the coloured light is the sole illumination source incident on the sample surface; ●● provide outputs at a set of wavelengths that evenly cover the spectral range being examined; ●● have an output power sufficiently high so that image capture can be carried out using relatively short exposure times (but without representing an optical hazard to unprotected eyes).

Home Office January 2014

Requirements

Consult Fluorescence Examination for advice on suitable light sources.

5.MSI.5

Fingermark Visualisation Manual

Multi-Spectral Imaging

Glossary

5.MSI.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Processing (Reflection) Preparation (1) Work area

(2) Equipment

a) Follow manufacturer’s instructions for set-up and use of equipment.

Processing (3) Mark up any visible marks

(4) Illuminate item and focus imaging system

(5) Set Multi-Spectral imager to collect images over selected spectral range

(6) Obtain individual colour spectra for mark and background(s)

a) As Multi-Spectral Imaging enhances marks visualised with other processes they may already be marked up (and imaged).

Glossary

Index

Laboratory Use (7) Use analysis software to enhance contrast between mark and background

(8) Capture appropriate image(s) of enhanced marks. Mark up positions of any additional marks revealed by enhancement and capture appropriate image(s)

a) The means of contrast enhancement will vary between different manufacturers’ software. Several enhancement methods may be available on the same system. Different combinations of methods should be investigated for extracting colour spectra and for contrast enhancement until the optimum image is obtained. a) These may include a series of images and associated data that provide an audit trail from the original colour image to the enhanced image e.g. a normal colour reference image, an ‘unmixed’ false colour image, individual colour spectra and distribution maps for individual spectral components.

Sample images of Ninhydrin fingermarks obscured by coloured patterns on wrapping paper (left) and faintly

developed on white paper (right) then enhanced by MultiSpectral Imaging (bottom) vs. diffuse lighting (top).

a) Ensure that the mark is in focus and exposure settings are correct for all regions of the spectrum being captured. Some systems may calculate exposure times automatically. a) If a white tile is being used to colour balance the data obtained, collect a reference spectrum from the white tile over the wavelength range of interest. b) Collect images and data from the item over the entire spectral range initially. It may be possible to obtain more detailed data for specific regions of the spectrum once individual spectra for the mark and background(s) have been obtained and the wavelength ranges of most interest identified. a) The means of extracting the required spectra from the ‘image cube’ will vary between different manufacturers’ systems. Different extraction methods may be available on the same system.

Continued on next column Home Office January 2014

5.MSI.6

Fingermark Visualisation Manual

Multi-Spectral Imaging

Appendices

5.MSI.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Processing (Fluorescence) The practitioner must be competent in the use of Fluorescence Examination if using high-intensity light sources an part of Multi-Spectral Imaging. They must

be aware of the hazards and follow the Fluorescence Examination process instruction (where applicable) as full details will not be repeated here.

Preparation (1) Work area (2) Equipment

a) Follow manufacturer’s instructions for set-up and use of equipment.

Processing (3) Mark up any visible marks

a) As Multi-Spectral Imaging enhances marks developed with other processes they may already be marked up (and imaged).

(4) Illuminate item and focus imaging system

a) Ensure that the mark is in focus and exposure settings are correct for all regions of the spectrum being captured. Some systems may calculate exposure times automatically.

(5) Set multispectral imager to collect images over selected spectral range

a) Collect images and data from the cut-on wavelength of the filter normally used to view fluorescence from the mark up to the highest wavelength available on the imaging system. It may be possible to obtain more detailed data for specific regions of the spectrum once individual spectra for the mark and background(s) have been obtained and the wavelength ranges of most interest identified.

(6) Obtain individual colour spectra for mark and background(s)

Glossary

Index

Laboratory Use (7) Use analysis software to enhance contrast between mark and background

a) The means of contrast enhancement will vary between different manufacturers’ software. Several enhancement methods may be available on the same system. Different combinations of methods should be investigated for extracting colour spectra and for contrast enhancement until the optimum image is obtained.

(8) Capture appropriate image(s) of enhanced marks. Mark up positions of any additional marks revealed by enhancement and capture appropriate image(s)

a) These may include a series of images and associated data that provide an audit trail from the original colour image to the enhanced image e.g. a normal colour reference image, an ‘unmixed’ false colour image, individual colour spectra and distribution maps for individual spectral components.

Sample images of fluorescent DFO fingermarks on

background fluorescing yellow paper enhanced by Multi-

Spectral Imaging (right) vs. fluorescence examination (left).

a) The means of extracting the required spectra from the ‘image cube’ will vary between different manufacturers’ systems. Different extraction methods may be available on the same system.

Continued on next column Home Office January 2014

5.MSI.7

Fingermark Visualisation Manual

Multi-Spectral Imaging

Appendices

5.MSI.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Scene Use

Additional Considerations If a decision has been made to use Multi-Spectral Imaging at a scene, a

For health and safety, consider:

number of additional considerations need to be taken into account, over

if using the process in fluorescence mode, see additional considerations in

be prescriptive since every scene will be different and:

For effectiveness, consider:

and above those given for laboratory use. The recommendations cannot ●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make the process as effective as possible

within the constraints of the scene;

●● present a range of practical issues that need to be overcome.

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

3, Section 3.1 – Scene use of the processes and treatment of large areas for other general information.

Fluorescence Examination.

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of the constraints posed by the scene;

●● whether power is available to run the equipment, otherwise light sources may be

restricted to those using battery power.

For practicality, consider: ●● access to the areas;

●● the additional constraints of using the process at the scene, including: ■■ ■■

transportation costs;

additional equipment to mount Multi-Spectral imaging systems, which may include tripods;

■■

running the software on a laptop (only an issue if normally run from a desktop computer);

●● provision of a suitable power source.

Home Office January 2014

5.MSI.8

Fingermark Visualisation Manual

Multi-Spectral Imaging

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Supplementary Information

Theory

Imaging is that some visible marks have a characteristic colour of reflection and/

or fluorescence spectrum associated with them, and that the differences between

Magenta pixel

Reflectance

The theory used by Multi-Spectral

Green pixel

this spectrum and that of the background can be exploited to discriminate the

mark. Multi-Spectral Imaging describes a range of techniques that all ultimately

400

500 600 700 Wavelength (nm)

400

500 600 700 Wavelength (nm)

result in the capture of a digital image with each pixel of that image having spectral information associated with it.

When carrying out Multi-Spectral Imaging a series of monochrome images are

captured at set wavelength intervals

Reflectance

over the selected wavelength range. The series of monochrome images collected is known as an ‘image cube’ (or ‘image

stack’) and can be interpreted by software to give a red-green-blue (RGB, i.e. colour)

An example of data collected by a Multi-Spectral imaging system,

illustrated right.

spectral information associated with it.

representation of the item. An example is

Home Office January 2014

showing how each pixel on the colour representation of the item has

400

White pixel

500 600 700 Wavelength (nm)

5.MSI.9

Fingermark Visualisation Manual

Multi-Spectral Imaging Reflectance

5.MSI.9

Contents

5.MSI.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory continued Once the ‘image cube’ has been collected, every area of the surface can be defined in terms of a characteristic

colour spectrum. In some areas this will be a ‘pure’ colour spectrum associated with a single component of the

image (e.g. a particular colour of printed ink), and in other areas this will be a mixed colour spectrum (e.g. where

a coloured fingermark passes over a coloured surface

660 nm

region).

620 nm

Multi-Spectral Imaging relies on the subsequent

580 nm

application of analysis software to the image cube to

extract the characteristic colour (or fluorescence) spectra

540 nm

for regions of particular interest (such as the fingermark

‘Image cube’

500 nm

and any interfering background colours). Once these

460 nm

spectra have been extracted, the software can be used to generate images that boost the signal from the spectral

RGB representation

regions of interest and suppress the signal from regions

of background, thus enabling the fingermark to be better discriminated.

The spectra obtained from the fingermark and

background may vary only imperceptibly from each other,

Unmixed image

but are still capable of being distinguished using MultiSpectral Imaging. This gives a power of discrimination that is considerably greater than that achievable using alternative processes such as Colour Filtration and

Monochromatic Illumination and also allows multiple

An example of an‘image cube’ collected by a Multi-

Spectral imager, the corresponding colour representation and a false colour ‘unmixed’ image.

background spectra to be identified and suppressed simultaneously, again not achievable using other processes.

Home Office January 2014

5.MSI.10

Fingermark Visualisation Manual

Multi-Spectral Imaging

Appendices

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Equipment

Multi-Spectral imaging systems

Several different technologies are commercially available for use in Multi-Spectral

Imaging. Multi-Spectral information may be obtained using a single sensor which is scanned across the area of interest capturing spectral information at each point, or by an array of such sensors capable of capturing spatial and spectral information

simultaneously. Both of these approaches are more commonly used for Multi-Spectral

Imaging in the near to mid-infrared region of the spectrum (not described in this Manual). Multi-Spectral imaging systems operating in the visible region of the spectrum generally use a monochrome sensor array in combination with a tunable filter, or a monochrome sensor array with a series of light sources with different output wavelengths. Several

different tunable filter technologies are available, including liquid crystal and acousto-

Image  1   Image  2   Image  3   Image  4   Image  5   Image  6  

optical systems, but both types operate in essentially the same way. The tunable filter

is a narrow bandwidth band-pass filter (typically with bandwidth in the range 2–20 nm)

Image  7  

for which the peak of the band-pass can be controlled to any point within the selected

Image  8  

wavelength range. The narrower the bandwidth of the filter, the better the spectral

resolution that can be achieved, although less light will be transmitted and light source output may need to be increased to compensate for this. The bandwidths used in

Multi-Spectral Imaging are generally narrower than the 25 nm used in Monochromatic Illumination, which makes Multi-Spectral Imaging more discriminating between subtle colour differences.

The tunable nature of the filter means that it can be tuned to a particular wavelength, an

image captured, the filter tuned to the next wavelength, another image captured, and so

400  

450  

500   550   Wavelength  (nm)  

600  

Example showing how the band-pass filter of the Multi-Spectral imaging system can be tuned to collect a series of images across the visible spectrum.

on. Equivalent information can be obtained by systems that capture a series of images as the article is progressively exposed to a series of controlled lighting conditions at different wavelengths.

Home Office January 2014

5.MSI.11

Fingermark Visualisation Manual

Multi-Spectral Imaging

Appendices

Transmission  

5.MSI.11

Contents

5.MSI.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Equipment continued Analysis software

Regardless of which technology the Multi-Spectral imaging system uses, once the series of images has been captured and stored in the form of the image cube the analysis software becomes more critical to the successful implementation of the process.

The analysis software supplied with the Multi-Spectral Imaging system provides the

means of extracting the characteristic colour spectra and discriminating the mark from the background. It should be easy to use and provide several options for the operator

to discriminate the required spectrum of the fingermark from the unwanted spectra from the background. The operator should ensure that this is the case before purchasing any system.

In the simplest form of analysis, regions with the desired colour spectrum (e.g. the purple of Ninhydrin) can be identified, as can regions of unwanted background colour/pattern.

These can be assigned false colours and the image ‘unmixed’ to show the fingermark in greater contrast with the background.

Alternatively, the regions corresponding to each colour channel can be viewed

individually to see if any of these shows the fingermark more clearly than the unmixed image.

Marks developed using Ninhydrin over a background containing printed ink of a similar

colour, (top) standard colour reference image, and (centre) unmixed image after assigning false colours to different spectra (Ninhydrin = black, purple ink = pale pink, white paper = white).

Same marks as illustrated above, but after selection of an image showing the distribution of pixels having the Ninhydrin colour spectrum only (bottom). Home Office January 2014

5.MSI.12

Fingermark Visualisation Manual

Multi-Spectral Imaging

Appendices

5.MSI.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Equipment continued Analysis software continued

For items with multiple background colours where a fingermark crosses several colour

boundaries, other approaches such as Principal Component Analysis can be adopted to separate out the major spectral responses from the image. The spectral responses from the principal components identified can be separated into those associated with the

fingermark and those associated with the background colours and this may enable the mark to be discriminated.

A pure spectrum can also be calculated by selecting a region known to contain mixed spectra from the background and the fingermark (i.e. where the mark passes over a

coloured region), and a region containing the background spectrum only. By subtracting the pure background spectrum from that of the mixed spectrum, the spectrum

associated with the fingermark alone can be extracted. This ‘pure’ fingermark spectrum

can then be use to highlight regions where this spectral response is present, and regions exhibiting the spectral response of the background can be suppressed.

It is recommended that the operator try a number of different approaches for discriminating each mark so that the optimum image can be obtained n

Home Office January 2014

5.MSI.13

Fingermark Visualisation Manual

Multi-Spectral Imaging

Appendices

5.UVCR.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Short Wave UV Imaging

Contents Laboratory or Scene?............. 5.UVCR.2 Laboratory Use........................ 5.UVCR.3 Health and Safety.................5.UVCR.3 Equipment............................5.UVCR.5 Processing ...........................5.UVCR.6 Scene Use................................ 5.UVCR.8 Additional Considerations....5.UVCR.8 Supplementary Information.... 5.UVCR.9

Main Uses ✔ Latent ✘ Blood ✘ Grease ✔ Other*

●● Although it can be used at scenes this is generally less

✔ Non-Porous ✔ Semi-Porous ✔ Porous

*Fingermarks developed by Superglue Fuming

Key Information

●● Competent personnel specialising in fingermark

visualisation, in particular imaging, must be

consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

Ultraviolet (UVC) Reflection utilises differences in the level of

absorption and/or scattering of UVC radiation between the mark and the surface.

It is an optical process that involves simultaneously irradiating the mark and surface with a source outputting UVC radiation and viewing the effect using an ultraviolet sensitive imaging

system fitted with a filter that blocks visible light and transmits ultraviolet.

More Details

Safety and Effectiveness Summary The Process

effective and safety measures are more difficult to achieve.

●● The process will only be effective if an imaging device

sensitive to UVC, specialist optics transmitting UVC and a radiation source outputting UVC are used in combination.

●● Appropriate selection of UV bandpass filters is required to

obtain optimum results.

●● The angle of the radiation source with relation to the surface

is important in optimising the effectiveness of the process on smooth non-porous surfaces.

The Item or Surface

●● Process effectiveness is influenced by the reflectivity of the

substrate in the UVC region of the spectrum.

●● Surface texture influences effectiveness. As roughness

increases, scattering of UVC by the surface will increase and

any scattering from the mark becomes difficult to distinguish.

●● High surface reflectivity is desirable on smooth porous

substrates and high surface absorption is desirable to give improved contrast on smooth non-porous substrates.

Integrated Use

Ultraviolet (UVC) Reflection is non-contact, and mostly non-

destructive to subsequent fingermark or forensic processing but

prolonged use will have a detrimental effect on subsequent DNA recovery.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

with other forensic processes.

●● Ultraviolet (UVC) Reflection can be used safely and effectively

in the laboratory.

Home Office January 2014

5.UVCR.1

Fingermark Visualisation Manual

A Ultraviolet (UVC) Reflection

2nd proof

5.UVCR.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical

Health and Safety

issues associated with the use of this process. Those responsible for deciding

There is a hazard during Ultraviolet (UVC) Reflection associated with exposure of the

or investigators, must consider in addition to the information below:

be mitigated in a laboratory environment by the use of engineering control measures

whether to process items in the laboratory or at the scene, e.g. crime scene managers ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

eyes and skin to UVC radiation and practitioners. The risk of accidental exposure must such as only using in safe viewing enclosures. The risk increases at scenes where safe viewing enclosures cannot be used and additional administrative and PPE controls

must be used. Safe systems of work must take into account the control measures that can be used at a scene and ensure they are properly implemented.

Effectiveness

Ultraviolet (UVC) Reflection is likely to be less effective at a scene than in a laboratory.

This is because UVC-compatible imaging systems available for scene use are generally less sensitive than laboratory-based systems.

Practicality

Ultraviolet (UVC) Reflection can be less practical to use at scenes compared to in the laboratory. It may be necessary to work in pairs or use additional tripods or mounting

systems to hold UVC sources at the angles required for optimum image capture. This is generally not required for fixed laboratory systems.

Home Office January 2014

5.UVCR.2

Fingermark Visualisation Manual

Ultraviolet (UVC) Reflection

5.UVCR.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Ultraviolet (UVC) Reflection may be carried out with no known hazards to health

provided practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.UVCR.3

Fingermark Visualisation Manual

Ultraviolet (UVC) Reflection

Appendices

5.UVCR.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety Hazards associated with Ultraviolet (UVC)

●● Ultraviolet (UVC) Reflection

is an optical process.

●● Practitioners must be

aware of the hazards associated with the

particular radiation sources they plan to use. (See

hazards associated with

the use of light sources).

●● Wear Standard PPE as a

Hazard

Laboratory Use Risk

Suggested control measures

Hazardous dust or nuisance odours from items previously treated with a chemical or physical process.

See specific process instruction for possible adverse effects to eyes, skin and respiratory system.

Follow recommendations for examining items in process instructions for the physical or chemical process used.

Hazardous, nonvisible radiation emitted from highintensity light sources in: UVC range (100280 nm).

Damage to eyes and skin from UVC radiation.

Apply engineering controls: ●● It is highly recommended that a fully enclosed housing is used to contain the UVC radiation as this obviates the need for eye and skin protection which can be uncomfortable, especially if used for long periods. ●● Work in a facility, such as a fluorescence examination room, equipped with suitable engineering controls. ●● Prevent anyone not fully protected from coming into contact with ultraviolet (UVC) radiation. Apply administrative controls: ●● Work to a safe method recorded in the risk assessment to include: ■■ use of the equipment limited to trained and competent personnel ensuring that they understand their responsibilities to others in the vicinity; ■■ use of well-maintained light sources in accordance with the manufacturer’s instructions, taking account of any guidelines for safe use; ■■ indication by warning signs when high-intensity ultraviolet light sources are being used. Provide personal protective equipment: ●● to completely block ultraviolet (UVC) radiation, such as: ●● full faceshield, suitably filtered; ●● gloves (tight weave cotton or polymeric laboratory gloves) suitable for use within the housing if items need to be handled during examination; ●● long-sleeved laboratory coat (tight weave cotton) or equivalent.

Ozone generated when UVC ( 17˚C prior to mixing and processing; ●● labware that is contaminated, scratched or dusty is not used; ●● the solution is prepared and used in a room with subdued lighting and away from direct sunlight.

Correction There are no corrective measures.

5.MMD.13

Fingermark Visualisation Manual

Multi-Metal Deposition

Glossary

5.MMD.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

Multi-Metal Deposition is a two-solution visualisation process. The first solution, a modified version of a long-established biochemical technique, contains gold

Colloidal gold in solution

nanoparticles which bind to proteins and some peptides in fingermark ridges. This process yields marks with very little contrast at best, pale pink in colour, so an

enhancement process is required to visualise fingermarks. The second solution, a

Gold particles binding to ridges

modified Physical Developer process, preferentially deposits on the gold particles

making them much easier to see, giving dark-grey-coloured fingermarks although they can appear gold-coloured at certain angles of illumination.

The negatively charged colloidal gold particles (the negative charge is thought to

be because of adsorption of the citrate ions) are attracted to the proteins and some peptides which are positively charged at the low pH. The pH of the colloidal gold

Substrate Fingermark ridges

Working Solution is therefore kept low (pH 2.5–3) to facilitate this. The size of the gold

particles is also regarded as important, with smaller particles claimed to result in higher

Micelles around silver particles in ‘physical developer’ solution

specificity to the proteins.

The colloidal silver Working Solution is effectively a modification of the Physical

Developer process used to visualise fingermarks on paper, containing surfactant

stabilised silver ions in the presence of a reducing system. The gold particles act to

Silver particles precipitating on gold

catalyse the reduction of the silver ions to silver metal and also act as a nucleation site for the silver metal to deposit, making them visible n

Substrate Fingermark ridges

Schematic diagrams illustrating the stages in the Multi-Metal Deposition process (top)

colloidal gold binding to ridges (centre) preferential deposition of silver particles on pre-

Substrate Fingermark ridges

existing gold and (bottom) dried mark with contrast provided by silver particles. Home Office January 2014

5.MMD.14

Fingermark Visualisation Manual

Multi-Metal Deposition

Appendices

5.MMD.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

High magnification scanning electron micrographs of part of a ridge developed with (top left) colloidal gold only and (top right) subsequently enhanced with silver. (Bottom left) and (bottom right) show progressively lower magnifications of a mark developed using Multi-Metal Deposition. Home Office January 2014

5.MMD.15

Fingermark Visualisation Manual

Multi-Metal Deposition

Appendices

5.Nin.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Nin

Contents Laboratory or Scene?..................5.Nin.2 Laboratory Use.............................5.Nin.3 Health and Safety..................... 5.Nin.3 Equipment................................ 5.Nin.5 Chemicals................................. 5.Nin.7 Solutions................................... 5.Nin.8 Processing................................ 5.Nin.9 Post-Processing..................... 5.Nin.11 Scene Use...................................5.Nin.12 Additional Considerations...... 5.Nin.12 Troubleshooting..........................5.Nin.13 Supplementary Information.......5.Nin.19

Main Uses ✔ Latent ✔ Blood ✘ Grease

Safety and Effectiveness Summary ✘ Non-Porous ✔ Semi-Porous ✔ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

Ninhydrin reacts with amino acids and possibly other

components in latent fingermarks to give a purple product. It

also reacts with amine-containing compounds (mainly proteins) in blood.

It is a chemical process that involves the application of a

solution to the item or surface followed by use of a specialist

oven (if possible) to increase the speed and effectiveness of the reaction.

More Details

The Process

●● Ninhydrin can be used safely and effectively in a laboratory. ●● The process can be used at scenes but precautions are

required to mitigate the asphyxiate nature of the solvent and the effectiveness is significantly reduced with processing times being considerably increased.

●● The effectiveness may be influenced by the method of

applying the solution.

●● The effectiveness is linked to the ability to control the

temperature and relative humidity of the item or surface postapplication. This requires the use of specialist equipment to carry out successfully.

The Item or Surface

●● The process is most effective at developing both latent and

bloody fingermarks on porous surfaces although it can also be used on semi-porous surfaces.

●● Ninhydrin is not effective on items or surfaces that have been

wetted, even if they have been subsequently dried.

●● It is effective on items or surfaces that have been soaked

with petrol or paraffin.

Integrated Use

Ninhydrin may be detrimental to subsequent fingermark or forensic processing.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

and other forensic processes.

Home Office January 2014

5.Nin.1

Fingermark Visualisation Manual

A Ninhydrin

5.Nin.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Ninhydrin can be used both in the laboratory and at scenes, although it is safer, and significantly more effective to treat removable items with Ninhydrin in a laboratory.

Health and Safety

The carrier solvent is a heavier-than-air asphyxiate and build-up of vapours must be avoided as it displaces air.

●● In a laboratory, this is easy to achieve as processing can be carried out in an

extracted fume cupboard.

●● At scenes, there is a much increased risk of asphyxiate build-up where ventilation

is variable and additional equipment, such as specialist RPE, may be required.

Effectiveness

Ninhydrin produces consistently good results if used in the laboratory compared to at

scenes where development is variable. For scenes, it is not possible to follow all of the details as written in the process instructions, predominantly due to the environmental conditions required for optimal development, which can only be achieved and controlled in a Ninhydrin development oven.

Practicality

This will depend upon the size of the item or surface to be treated and whether or not it can be readily removed to a laboratory.

●● In a laboratory, the process has few practicality issues provided the item fits into

the Ninhydrin humidity oven.

●● At scenes, application is less practical than in a laboratory due to: the added health

and safety requirement during application; the added steps required to increase the humidity and temperature within the area; the longer processing time and associated scene monitoring; and the added complexity of scene clean-up.

Home Office January 2014

5.Nin.2

Fingermark Visualisation Manual

Ninhydrin

5.Nin.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Ninhydrin may be carried out with no known hazards to health provided practitioners

are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards

(e.g. ‘residual processing chemicals on items are hazardous’) and/or control

measures, (e.g. ‘work within a fume cupboard’).These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and

Hazards associated with Ninhydrin ●● Ninhydrin is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions or mixtures.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below, but those

cited must not be regarded as exhaustive, nor the control measures prescriptive.

Additional hazard

Risk

Air depletion Asphyxiation when preparing and using Ninhydrin Working Solution.

instructions must be provided locally.

❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants present;

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness;

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

Solution in an extracted fume cupboard.

HFE7100 is not absorbed by the activated carbon filters found in recirculating fume

cupboards and organic vapour respirators. It

laboratory or the scene it will displace the air

from the ground up as it is much heavier than

a responsible person will carry out a risk assessment before the process is ❍❍

●● Prepare and apply Ninhydrin Working

the HFE7100 vapour is extracted from the

the process will be carried out in a laboratory that can provide a safe working

carried out to include at least:

Suggested control measures

passes through them unaffected and unless

environment; ■■

Index

Laboratory Use

●● In providing the Category A process instructions it is assumed that: ■■

Glossary

air. Creation of a flammable atmosphere when preparing and diluting Ninhydrin Concentrated Solution.

Fire

●● Prepare and dilute Ninhydrin

Nuisance odour from processed items.

Some individuals may experience watery eyes and sneezing.

●● Examine treated items in a well-

Concentrated Solution in an extracted fume cupboard. See working with flammable liquids for further information.

ventilated area or preferably on a downdraught bench.

5.Nin.3

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Health and Safety: Labelling Solutions While the hazards associated with the chemicals used can be found on the SDS,

those associated with the solutions need to be calculated from their percentages in the final solution. To assist in this, in 2011, CAST commissioned work to calculate the risks associated with the solutions it was using at the time. The results of

Hazards* typically associated with prepared Ninhydrin Solutions (CLP) Solution

Symbols

Ninhydrin Concentrated

‘WARNING’ H225 ‘Highly Flammable liquid and vapour’ H315 ‘Causes skin irritation‘ H319 ‘Causes serious eye irritation’

those calculations are given here for guidance only to those responsible for risk assessments of solutions used locally.

Ninhydrin Working

Signal Word and Hazard Statements

None Required None

Hazards* typically associated with prepared Ninhydrin Solutions (CHIP) Solution

Symbols

Ninhydrin Concentrated Ninhydrin Working

Hazard Statements R11 ‘Highly Flammable’ R36 ‘Irritating to eyes

None required

None

* Solution hazards based on CAST’s solutions and calculated by ChemLaw UK

Flammability classifications assessed either theoretically or by measurement by Hazard Evaluation Laboratory (HEL)

Home Office January 2014

5.Nin.4

Fingermark Visualisation Manual

Ninhydrin

Glossary

5.Nin.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Ninhydrin requires the use of some process-specific equipment for the application of

Ninhydrin Working Solution and for creating the environmental conditions required for

Ninhydrin development oven

A Ninhydrin development oven must: ●● maintain air temperature within the oven whilst at equilibrium at 80 ± 2˚C; maintain relative humidity of 62 ± 5%RH within the oven whilst at equilibrium; ●● provide close control and rapid recovery of temperature and humidity across all shelves (see calculating the oven recovery time and treatment time); ●● not have air flow so strong as to blow normal paper casework items around within the oven; ●● have an over-temperature safety cut-out; ●● have a way of monitoring items and observing mark development whilst in the oven; solutions may include multi-glazed windows with a wiper or heated glass and with suitable lighting; ●● have an adjustable airflow inlet; ●● be able to be connected to a negative pressure exhaust system (see Extraction for Ninhydrin development oven); ●● have a drain-pipe to remove condensed water, which must be connected with a continuous downward slope to a suitable outlet, such as an open drain and be resistant to acetic acid; ●● not allow condensation to drip onto the item. In addition, a Ninhydrin development oven should: ●● not exceed 80% RH for more than a few seconds in the usable part of the oven; ●● have a working capacity of at least 150 L; ●● have interior and shelves, resistant to acetic acid vapour; ●● incorporate an automatic timer that begins the cycle when the oven door is closed.

Extraction for Ninhydrin development oven

Extraction for a Ninhydrin development oven must: ●● be connected to the oven via an extraction pipe with a continuous upward slope; ●● be a negative pressure exhaust system which provides a continuous extraction rate of between five and ten times the total volume of the oven per hour; ●● have an extraction pipe that is able to resist the temperature being used and acetic acid vapour mixed with steam at that temperature. In addition, there should: ●● be an extraction hood over the oven extending in front to beyond the door end when it is fully opened.

development.

If equipment is to meet the requirements as outlined below, it must be well maintained

and, if appropriate, serviced regularly in accordance with the manufacturer’s instructions. General laboratory equipment that may be required is outlined in Chapter 3.

Processing trough

Requirements A processing trough must: ●● be made of a material compatible with solvents used in the Ninhydrin Working Solution such as polypropylene. In addition, a processing trough should: ●● be of suitable length to accommodate the size of items being processed; ●● be shallow with a curved, corrugated bottom surface. A processing trough that meets all of the above requirements allows Ninhydrin Working Solution to be applied in such a way as to minimise wastage without compromising the effectiveness of the process. The curved, corrugated surface enables small quantities of solution to be used at one time, whilst preventing paper ‘sticking’ due to surface tension effects if the surface were smooth. Other designs can be used effectively, but they may generate additional waste Ninhydrin Working Solution.

Examples of processing troughs produced for use with Ninhydrin solutions.

Home Office January 2014

Index

Laboratory Use

Equipment

Equipment

Glossary

5.Nin.5

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment - Ninhydrin Development Oven Set-up Calculating the Oven Recovery Time and Treatment Time

The following procedure is applicable to all versions of the FDC018 (185 litre Weiss Gallenkamp Chamber) including those with wet/dry bulb and direct measuring systems.

It is essential that when the oven is serviced and calibrated the engineer is asked to apply an offset so that the sensors display the temperature and relative humidity from the centre of the oven rather than where

they are situated. This will standardise the displayed readings as there are at least two different locations for the sensors.

(1) Turn on oven and let it stabilise

(2) Open oven door fully

a) The display on the oven should read 80+ 2˚C and 62 ± 5% RH [69 + 1˚C wet bulb). Once the oven has reached these values it should be left to stabilise for at least 30 minutes. a) When the door of a pre-heated and humidified oven is opened the temperature and humidity will decrease. Variations in the performance of ovens, even those of the same nominal specifications, and variations in extraction rates, will significantly affect the relative humidity and temperature recovery rates.

(3) Load shelves and close oven door

a) Ensure the shelves are loaded as they would be when the oven is in full use, then close the door after it has been open for approximately one minute.

(4) Monitor recovery time

a) Measure the longer of the times it takes the display to read 76˚C or 58% RH [64˚C wet bulb] and round this time up to the nearest minute. This is the recovery time and should be between two and five minutes if the oven is functioning correctly.

(5) Calculate treatment time

a) The treatment time is the recovery time + 2 minutes and should be between four and seven minutes. This treatment time is then used for all normal Ninhydrin treatment as described.

Once established the treatment time should not change, unless changes are made to the Ninhydrin

development oven or extraction system. However, it is good practice to re-measure the recovery time after each service and calibration on the oven. Home Office January 2014

5.Nin.6

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists chemicals that are required for Ninhydrin. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3 safe handling of chemicals for general information. Common Name

Alternative Name(s)

CAS Number

Grade

Ninhydrin

2,2-Dihydroxy1,3-indandione, 1,2,3-indantrione

485-47-2

Analytical

Acetic acid

Ethanoic acid

64-19-7

Analytical ≥ 99.7%

Ethanol

Ethyl alcohol Absolute ethanol

64-17-5

Analytical ≥ 99.7%

Ethyl acetate

Ethyl ethanoate

141-78-6

Analytical

HFE7100

Methyl nonafluorobutyl ether, 1 Methoxy nonafluorobutane

HFE7100 is only available as a mixture of two isomers. The isomers are inseparable but have essentially identical properties. Each isomer has its own CAS number (163702-08-7 and 163702-07-6). The isomeric mixture within HFE7100 does not have its own unique CAS number.

As supplied

Home Office January 2014

5.Nin.7

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Solutions

Consult Chapter 3 for general information on solution preparation, safe storage of chemicals, solutions and mixtures

a) Ninhydrin Concentrated and Working Solutions must be prepared in an extracted fume cupboard. b) Ninhydrin solutions are yellow. c) Solutions with a separate ‘oily’ layer should not be used.

(1) Prepare solutions

(which includes information on packaging and labelling), management of waste

for disposal of solutions and guideline

(2) Label appropriately

a) Ninhydrin Concentrated and Working Solutions should be labelled in line with the guidance in Ninhydrin Health and Safety.

(3) Store appropriately

a) Ninhydrin Concentrated and Working Solutions have guideline expiry dates of 12 months after preparation if stored at room temperature.

expiry periods. This page gives additional information relevant to this process.

Solutions Ninhydrin Working Solution

(4) Dispose of appropriately

52 mL Ninhydrin Concentrated Solution 1 L HFE7100

Ninhydrin Concentrated Solution

5 g Ninhydrin 5 mL Acetic acid 45 mL Ethanol 2 mL Ethyl acetate

Final solutions ready for use are identified by a red border See Ready Reckoners for other quantities of solution

Home Office January 2014

Ready Reckoner Quantity of Ninhydrin Concentrated Solution Chemical

260 mL

520 mL

1040 mL

Ninhydrin

25 g

50 g

100 g

Acetic acid

25 mL

50 mL

100 mL

Ethanol

225 mL

450 mL

900 mL

Ethyl Acetate

10 mL

20 mL

40 mL

Quantity of Ninhydrin Working Solution Chemical

1L

2L

5L

Ninhydrin concentrated solution

52 mL

104 mL

260 mL

HFE7100

1L

2L

5L

5.Nin.8

Fingermark Visualisation Manual

Ninhydrin

Glossary

5.Nin.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation

Processing

(1) Items

a) Carefully unpack and organise casework prior to pouring out the Ninhydrin Working Solution.

(2) Work area

a) Ninhydrin Working Solution must be used in an extracted fume cupboard.

(3) Equipment

a) For most items, the Ninhydrin development oven should be pre-conditioned to 80 ± 2oC and 62 ± 5% relative humidity. This may take many minutes to achieve. For solid items (i.e. those with a greater thermal mass than paper such as wood, plasterboard etc.) or cellophane, the oven must be pre- conditioned to 80 ± 2˚C at ambient humidity to avoid condensation. b) Pour the Ninhydrin Working Solution into a suitable clean, dry vessel such as a processing trough. Small quantities should be used to minimise waste. Proceed immediately to processing in order to prolong the lifetime of the solution in the vessel.

condensation on them when transferred to the oven. c) If it is not possible to immerse the item, carefully apply the solution with a soft brush. The surface must be ‘wetted’ evenly. d) If the item turns grey/black during processing see Thermal Coating Removal process instruction. e) Items contaminated with blood must be treated with utmost care so as not to damage fragile deposits of blood. Items should be treated by immersion. If this is not possible then the solution should be gently directed over the area to be treated using a wash bottle. f) Ninhydrin Working Solution must be discarded if it changes in appearance (turns cloudy, forms ‘oily’ droplets, or becomes contaminated). Provided there is no sign of contamination or precipitation, the trough may be replenished with fresh solution, but if changes in appearance occur, a clean dry trough must be used. There should be very little (if any) solution remaining in the trough at the end of the processing session, minimising wastage.

Processing (4) Apply Ninhydrin Working Solution

Continued on next column

Home Office January 2014

a) Draw the item through the Ninhydrin Working Solution allowing excess to drain back into the trough. Alternatively, quickly immerse and remove the item. It is necessary only to wet the surface with the solution. Prolonged immersion is undesirable. b) Place the item onto a suitable surface to ‘dry’ within the fume cupboard. A suitable surface could be cardboard or stiff card which can later be transferred into the oven with the items in order to keep the time of loading to a minimum enabling the oven to recover temperature and humidity faster. Avoid solid surfaces that are likely to form

(5) ‘Dry’ item

a) Allow the solvent to completely evaporate from the item before removing it from the fume cupboard.

Continued on next page

5.Nin.9

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing continued Processing (6) Transfer item to a pre- conditioned Ninhydrin development oven

(8) Examination a) Minimise the time the oven door is open during transfer. This reduces the likelihood of exceeding 80% RH within the oven. In any case, 1 minute should not be exceeded. b) If the oven is loaded with solid items (i.e. those with a greater thermal mass than paper, such as wood, plasterboard etc.) or cellophane, the oven should be held at 80 ± 2˚C and ambient humidity for up to an hour (or the time for the temperature of the item and oven to equilibrate). Only then should the humidity be increased to 62 ± 5%. c) Some items such as envelopes with plastic windows or plastic bottles with paper labels may be damaged at 80˚C. Most plastics will tolerate a temperature of 50˚C but samples of items should be tested if possible to determine the maximum temperature to which they can be subjected without damage. d) The item is heated and humidified for the treatment time. The treatment time is determined according to oven performance. e) Some types of paper, such as amine-rich papers or items that are handled regularly, may give an intense purple background staining if heated and humidified.

Primary: Visual Examination

Secondary: Fluorescence Examination

a) Items should be examined in a well-ventilated area preferably on a down-draught bench. b) Extraneous fingermarks may develop if items are handled after processing. c) Although most visible fingermarks are purple, the colour can vary from orange to purple. d) Most fingermarks are expected to develop during treatment, although further development may occur with time. The item should be kept in the dark if awaiting additional development. e) Ninhydrin developed fingermarks can fade over time so it is important to image all fingermarks found immediately. f) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination and Fluorescence Examination, particularly for low contrast marks or marks on dark or patterned surfaces. g) Mark up viable fingermarks appropriately and capture image. h) After examination, items can be re-treated if necessary, but this is only worthwhile if there is very little background development.

(7) Remove item from Ninhydrin development oven

Continued on next column

Home Office January 2014

5.Nin.10

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of items, and

management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item

(1) Residual processing chemicals

a) Items treated with Ninhydrin may emit a nuisance odour comprising of acetic acid vapour. Its concentration is likely to be below the workplace exposure limit.

(2) Cleaning processed items

a) It may not be possible to return items to their original state. If possible, items may be thoroughly wiped or washed with soap and water.

(3) Disposal or return of processed items

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (4) Disposal of used Ninhydrin Solution

Home Office January 2014

a) Used Ninhydrin Working Solution must not be poured back into a container for re-use at a later date as the effectiveness and solution lifetime are significantly reduced.

5.Nin.11

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Scene Use

Additional Considerations If a decision has been made to apply

Ninhydrin at a scene, a number of additional considerations need to be taken into

account over and above those given for laboratory use.

For health and safety, consider:

●● minimising the risk of asphyxiation by reducing the

hazard by: ■■

The recommendations below cannot be prescriptive since every scene will be different and:

area, e.g. by opening doors and windows; ■■

●● each must be subject to a local risk assessment and

targeted application; ■■

safely and in compliance with the requirements of

the process as effective as possible within the constraints of the scene;

●● present a range of practical issues that need to be

overcome.

This page must be read in conjunction with the laboratory process instruction.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter 3, Section 3.1 -

Laboratory or scene use of Category A processes for other

general information.

providing additional PPE to protect practitioners, such as breathing apparatus and oxygen

the Health and Safety at Work Act (1974);

●● different approaches may be needed to make

limiting the area treated and restricting the

amount of Ninhydrin Working Solution used by

will require different control measures to mitigate

any risks identified before work can be carried out

ensuring adequate ventilation of the processing

monitors; ■■

damaging items, surfaces and fingermarks;

●● how to protect surfaces from direct sunlight after

treatment.

For practicality, consider:

●● access to the areas to be treated;

●● the additional time, staffing and costs of applying the

process at the scene, including: ■■ ■■

humidifiers;

and the vapours are allowed to build up in a confined

❍❍

space, lack of oxygen will cause those in close proximity

application; one must be away from the

treatment area, in fresh air and able to monitor

●● what additional packaging and labelling will be

that supplied air is fresh and the other is safe;

■■

days or weeks unless it is possible to increase

to a scene to inspect for fingermark development.

applied to larger items and non-removable horizontal and vertical surfaces;

keeping the scene isolated for the time it takes for fingermarks to develop; this may be many

●● what residual hazard might be present when returning

For effectiveness consider:

if using breathing apparatus there is a

requirement for two staff to be present during

to feel faint then blackout and asphyxiate.

laboratory) to the scene;

additional equipment to make the process

breathing apparatus, oxygen monitor, heaters and

If even relatively small quantities of HFE7100 are used

needed for transporting the solutions (made in the

transport costs;

safe and effective and to minimise mess, e.g.

not spraying solutions;

●● how Ninhydrin Working Solution can be evenly

Home Office January 2014

●● how to raise temperature and humidity without

temperature and relative humidity; ■■

scene clean-up, which may involve washing and sealing surfaces followed by complete redecoration.

5.Nin.12

Fingermark Visualisation Manual

Ninhydrin

Glossary

5.Nin.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Separate Layer or Droplets on the Surface of Ninhydrin Working Solution Recognition

A separate layer and/or ‘oily’ droplets have formed on the surface of the Ninhydrin Working Solution.

Ninhydrin Working

Ninhydrin Working

Solution with thin ‘oily’

Solution with ‘oily’

layer floating on the

droplets floating on the

surface.

Cause The separate layer and/or ‘oily’ droplets is actually water. Water and HFE7100 are immiscible so when Ninhydrin Working Solution becomes contaminated with water a two-phase solution is formed. The specific gravity of water is less than that of HFE7100 so it is the water that floats, but has the appearance of ‘oil floating on water’. This can occur when water gets into the solution.

Home Office January 2014

surface. Effect

Prevention

Ninhydrin is considerably more soluble in Ensure that: the water phase than the HFE phase and it ●● absolute ethanol ≥99.7% is used becomes more concentrated there. Therefore (Ethanol 96 contains about 4% water); the Ninhydrin Working Solution becomes less ●● all equipment is thoroughly dried concentrated than intended. As a consequence: before use. In addition, some porous ●● processed fingermarks may appear lighter items naturally have a high water and weak fingermarks may be missed; content as they absorb water from the ●● processed fingermarks may be blurred as air, especially on humid days. In this the amino acids within fingermarks are water case preventing the layer or droplets soluble and if the water layer comes into from forming may prove difficult but contact with amino acids they will dissolve the use of small fresh quantities of or be diffused from ridge; solution will help. ●● the ‘oily’ layer can be transferred and leave stains which may obscure fingermarks.

Correction There are no corrective measures. Dispose of solutions appropriately. Note: Do not Filter two-phase Ninhydrin Working Solution. Although it may remove the ‘oily’ layer or water phase it leaves a Working Solution that contains much less Ninhydrin as that dissolved within the water phase will have been removed along with it.

5.Nin.13

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Cloudy Working Solution Recognition

The Ninhydrin Working Solution has turned cloudy.

Clear Ninhydrin Working

Cloudy Ninhydrin Working

Solution.

Solution.

Cause

Effect

Cloudy Ninhydrin Working Solution occurs when the dissolved Ninhydrin separates from the solvent - a process known as precipitation. This can be caused by: ●● evaporation of the solvent; ●● contaminants present in papers or the processing trough promoting precipitation of Ninhydrin.

Ninhydrin Working Solution will be less concentrated than intended. Processed fingermarks may appear lighter and weakly developed fingermarks may be missed.

Home Office January 2014

Prevention It is difficult to eliminate this problem, but steps can be taken to ensure that the solution lasts as long as possible. ●● Reduce the time the Working Solution is in the trough prior to treatment which minimises the opportunity for solvent evaporation. Unpacking and organising casework prior to pouring out the Ninhydrin Working Solution will help. ●● Minimise the volume of solution poured into the trough at a time to reduce wastage.

Correction There are no corrective measures. Dispose of solutions appropriately. Note: Do not filter cloudy Ninhydrin Working Solution as this removes precipitated Ninhydrin reducing its concentration in the Working Solution and resulting in weaker and fewer marks being developed.

5.Nin.14

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

High Background Development Recognition

High background development has occurred across the entire surface, reducing the contrast between fingermark and background and obscuring developed fingermarks.

White writing paper treated

with Ninhydrin and imaged

Same piece of paper imaged

under white light. Cause

using the multispectral imager. Effect

Prevention

Correction

The substrate has been exposed to higher levels of heat and humidity or for a longer time than those recommended, resulting in excess water in the substrate and uncontrolled reactions.

High background development occurs Ensure that more stringent control of which may significantly reduce the contrast temperature, humidity and treatment time of developed fingermarks or mean that is implemented. they are completely obscured.

It may be possible to improve the contrast of the developed fingermarks by using specialist optical processes such as MultiSpectral Imaging.

Amine-rich fillers are present in the substrate. Amines are the target fingermark component for Ninhydrin, therefore reactions occur with both fingermark and substrate.

High background development occurs which may significantly reduce the contrast of developed fingermarks or mean that they are completely obscured.

It may be possible to improve the contrast of the developed fingermarks by using specialist optical processes such as MultiSpectral Imaging.

Home Office January 2014

Consider alternative processes that do not target amino acids if it is not possible to reduce the effect by varying the processing parameters.

5.Nin.15

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Patchy Background Development Recognition

Ninhydrin Working Solution has been applied to the surface with a soft-

haired brush. Uneven areas of development are visible after processing.

Cardboard box processed with Ninhydrin. Cause Ninhydrin solution has been unevenly applied to the surface, contributing factors including: ●● rapid solvent evaporation making it difficult to see where the solution has previously been applied and when brush is exhausted of solution; ●● non-systematic application methods. Home Office January 2014

Effect Uneven/patchy development on the surface, including: ●● areas of heavy development where fingermarks may be obscured; ●● areas that have not been treated with the solution where fingermarks have not developed and will be missed.

Prevention

Correction

Ensure that: ●● the solution is applied quickly and systematically to avoid complete solvent evaporation in the area being treated and that areas are not missed.

Selectively re-treat areas where the solution has not been applied, avoiding areas already enhanced which can develop high backgrounds with re-treatment.

5.Nin.16

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Poor Development on Solid Items Recognition

Little or no fingermark development has occurred on a substrate placed directly into a Ninhydrin oven set at

elevated temperature and humidity.

Ninhydrin-treated wood

maintained at ambient

Ninhydrin-treated wood

temperature then placed

pre-heated to elevated

directly into a hot humid

temperature prior to

oven and processed. There

exposure to humid

is no or very little mark

atmosphere . There is good

development.

Cause Placing a cool item with high thermal mass such as wood, plasterboard etc. directly into the humid oven has resulted in the formation of a thin, virtually invisible layer of condensation on the surface of the item which may have washed away or diffused any amino acids present. Home Office January 2014

mark development. Effect Removal and/or diffusion of amino acids means that any fingermarks that would have been developed by Ninhydrin may now be blurred or obliterated.

Prevention Ensure that items with a high thermal mass are pre-heated at 80˚C until they reach that temperature prior to introducing humidity to the oven.

Correction There are no corrective measures.

5.Nin.17

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Blackening of Thermal Receipts Recognition

A black coating has appeared on thermal receipts after processing with Ninhydrin.

A receipt processed with Ninhydrin

showing (a) blackening post-processing,

(b) the removal of the blackening, and (c)

the revealed marks after the blackening has been removed.

Cause The black coating is caused by chemical and physical interactions between the thermal layer within the receipt and the process. In particular, acetic acid in the Ninhydrin Working Solution and high temperature within the oven cause blackening. Home Office January 2014

Effect The black layer obscures the purple developed fingermarks making them difficult to see and they are likely to be missed.

Prevention

Correction

Ensure that: ●● the receipt is treated by the Thermal Coating Removal process prior to treatment with Ninhydrin; items are imaged prior to use of the pre-dipping method as text will be removed by the solvent.

It is possible to treat with the Thermal Coating Removal process to remove the black coating after Ninhydrin has been used. However, pre-dipping is the preferred method for the removal of thermal coatings from receipts.

5.Nin.18

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

of the Ninhydrin process as there will be temperature

contained in amino acids and possibly other components

the oven chamber, with larger chambers having greater

Ninhydrin reacts with primary and secondary amines

variations and hence relative humidity differences across

in fingermarks to form a characteristic purple-coloured

variations. To ensure even and effective development of

compound called ‘Ruhemann’s Purple’. Intermediate

marks these variations need to be kept to a minimum.

products can also be formed and will vary in colour from

For example, in fully loaded ovens (at 80oC) with

orange to purple depending upon the constituents of

horizontal laminar flow and a plenum chamber the

the mark and the development conditions. Ruhemann’s

temperature can vary 3-5˚C within the oven which means

Purple consists of two Ninhydrin molecules linked by

a variation in relative humidity of 10-14% RH. Fully loaded

a nitrogen bridging atom (originally part of the amine).

Blood and some other body fluids such as semen and

convection ovens by their nature take longer to recover

vaginal fluid contain a high concentration of proteins

High magnification image of a fingermark developed

react strongly with Ninhydrin.

around edges of pores, where eccrine sweat (and amino

which are made up from amino acids so these will also The reaction between Ninhydrin and amines is catalysed

using Ninhydrin. Image shows more intense development acids) are excreted.

by hydrogen ions (acid) and water, whilst the reaction rate

be faint and difficult to see.

When using Ninhydrin to develop fingermarks the

acetic acid in the formulation ensures the presence of

hydrogen ions and the water and heat are provided via

a specially designed humidity oven so that the majority

of fingermarks will be visualised within a few minutes. A

small percentage of fingermarks will continue to develop after treatment and may take several weeks to develop fully.

Temperature, relative humidity and time of exposure

Home Office January 2014

relative humidity differences, often more than 10oC

and 30% RH making it more difficult to ensure the best development conditions for each item within the oven.

reach significantly higher levels in some parts of the oven

the reaction does not go to completion and intermediate

orange to magenta, are produced. These fingermarks can

greater variations in temperature and therefore greater

It should be noted that the relative humidity is likely to

is increased with heat. If either of the catalysts are lacking pale-coloured compounds (aldimines), which vary from

after door opening and have been seen to have much

are critical factors for the effectiveness of the Ninhydrin process, with each dependent on the others. Porous surfaces exposed for a short time (4-7 minutes) to a

temperature of 80 ± 2˚C and a relative humidity of 62 ± 5%RH will give effective development. Although other values of temperature, relative humidity and exposure time may be used, in practice their interdependency makes this difficult to easily determine alternative

settings. However, poorly selected settings may lead to

undesirable effects such as weak mark development, high background development or mark diffusion.

during the recovery period to that indicated after the door has been opened and closed but should not exceed 80% for more than a few seconds in any usable part of the

oven during the treatment cycle. If the time the oven door is open for is minimised the likelihood of overshoot of relative humidity is also minimised.

The conditions used within a specialist humidity oven

are extremely difficult to achieve at scenes as controlling relative humidity in open systems is more complicated

and without this a longer development time for marks is inevitable.

Oven design can also be crucial to the effectiveness

5.Nin.19

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.Nin.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory continued

Ninhydrin and DFO

Ninhydrin and DFO are both ‘amino-acid reagents’ and DFO is the most sensitive. However Ninhydrin is used in sequence after DFO as it finds additional marks. There are several theories for this.

1. There may not be sufficient DFO to completely react in a 2:1 ratio with all amino acids present.

2. That Ninhydrin reacts with a wider range of amino acids than DFO and also some non-amino- containing compounds.

3. The reaction between DFO and some amino acids may not proceed to completion n

Home Office January 2014

5.Nin.20

Fingermark Visualisation Manual

Ninhydrin

Appendices

5.PD.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names PD

Contents Laboratory or Scene?.................. 5.PD.2 Laboratory Use............................. 5.PD.3 Health and Safety......................5.PD.3 Equipment.................................5.PD.5 Chemicals..................................5.PD.6 Solutions....................................5.PD.7 Processing.................................5.PD.9 Post-Processing......................5.PD.10 Troubleshooting.......................... 5.PD.11 Supplementary Information....... 5.PD.19

Main Uses ✔ Latent ✘ Blood ✘ Grease

Safety and Effectiveness Summary ✘ Non-Porous ✔ Semi-Porous ✔ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use only.

Process Overview

Physical Developer works by preferentially depositing silver

The Process

●● Physical Developer can be used safely and effectively when

used in a laboratory.

●● The effectiveness depends on close observation of

fingermark and background development and the condition of the processing solutions.

●● Developed fingermarks may be faint or obscured by the

surface colour or pattern; use of subsequent Physical

Developer Enhancement or IR Reflection may improve contrast.

The Item or Surface

●● The process is most effective at developing latent

fingermarks on porous and semi-porous surfaces.

metal onto fingermark ridges resulting in grey/silver-coloured

●● It can be used on surfaces that are wet, or have been wetted

trapped eccrine constituents which assist deposition of silver

●● It can be used on surfaces that have been subjected to

It is a chemical process that involves exposing the item or

Integrated Use

fingermarks. It is believed to detect the presence of sebaceous during development of the fingermark.

surface to three solutions in sequence. More Details

and subsequently dried. moderate levels of heat.

Physical Developer may be detrimental to subsequent fingermark or forensic processing.

●● See Chapter 4: Process Selection for information on its

sequential use with other fingermark visualisation processes.

●● See Chapter 7: Other Forensics for information on integration

of fingermark and other forensic processes.

Home Office January 2014

5.PD.1

Fingermark Visualisation Manual

A Physical Developer

2nd proof

5.PD.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Home Office January 2014

Health and Safety

Not applicable (see Practicality).

Effectiveness

Not applicable (see Practicality).

Practicality

Achieving the sequence of chemical conditions required for use of Physical Developer at scenes is extremely difficult and usually considered impractical.

5.PD.2

Fingermark Visualisation Manual

Physical Developer

5.PD.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Physical Developer may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

Index

Laboratory Use Hazards associated with Physical Developer ●● Physical Developer is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions.

●● Wear Standard PPE as a minimum.

●● There are no additional hazards associated with the process.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

■■

All control measures identified will be put in place, including the wearing of appropriate PPE, and reviewed for their effectiveness.

■■

Where information is included for scene use of the processes, the considerations are over and above those for laboratory applications of the processes.

Home Office January 2014

5.PD.3

Fingermark Visualisation Manual

Physical Developer

Glossary

5.PD.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Physical Developer Health and Safety: Labelling Solutions While the hazards associated with the chemicals used can be found on the SDS, those associated with the solutions need to be calculated from their percentages in the final solution. To assist in this, in 2011, CAST commissioned work to calculate the risks

associated with the solutions it was using at the time. The results of those calculations are given here for guidance only to those responsible for risk assessments of solutions used locally.

Hazards* typically associated with prepared Physical Developer Solutions (CLP) Solution

Symbols

Signal Word and Hazard Statements

Hazards* typically associated with prepared Physical Developer Solutions (CHIP) Solution

Symbols

Hazard Statements

Maleic acid

‘WARNING’ H317 ‘May cause an allergic skin reaction’

Maleic acid

R43 ‘May cause sensitisation by skin contact’

Physical Developer Working

‘WARNING’ H315 ‘Causes skin irritation’, H319 ‘Causes serious eye irritation’ H410 ‘Very toxic to aquatic life with long-lasting effects’

Physical Developer Working

R36 ‘Irritating to eyes’ R50-53 ‘Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment’

Physical Developer Redox Physical Developer Stock Detergent

‘WARNING’ H315 ‘Causes skin irritation’ H319 ‘Causes serious eye irritation’ H335 ‘May cause respiratory irritation’ None required

Silver Nitrate

None required

Physical Developer Redox

None required

None required

Physical Developer Stock Detergent

None required

None required

Silver Nitrate ‘DANGER’ H314 ‘Causes severe skin burns and eye damage’ H410 ‘Very toxic to aquatic life with long-lasting effects’

R34 ‘Causes burns’ R50-53 ‘Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment’

* Solution hazards based on CAST’s solutions and calculated by ChemLaw UK.

Flammability classifications assessed either theoretically or by measurement by Hazard Evaluation Laboratory (HEL).

Home Office January 2014

5.PD.4

5.PD.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

Physical Developer requires the use of some process-specific equipment for the

preparation and application of the solutions. General laboratory equipment that may be required is outlined in Chapter 3. Equipment

Requirements

Glassware for solutions containing silver nitrate Glassware for solutions containing silver nitrate must: ●● be thoroughly clean; ●● be scratch free. Processing dishes for Physical Developer Working Solution and Maleic Acid Solution

The processing dish must: ●● be non-metallic; ●● be scratch free (for Physical Developer Working Solution only); ●● be large enough to process the item without folding. Use-once disposable plastic liners may be considered to line damaged processing dishes.

Implement to move items during processing, such as forceps, tongs or fish slice

The implement must: ●● be smooth and non-metallic; ●● not have serrated or sharp edges or have ridges.

Equipment that will deliver an indirect source of The equipment should: fresh running water, such as a print-washer ●● be capable of being attached to a regulated flow of water, such as a tap; ●● be designed so that items stay within the confines of the equipment and not damaged by water flow.

Home Office January 2014

5.PD.5

Fingermark Visualisation Manual

Physical Developer

Appendices

5.PD.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Chemicals

This table lists chemicals that are required for Physical Developer. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified

chemicals. Unless specified, water used within the solutions or for rinsing is purified. See Chapter 3 safe handling of chemicals for general information.

Index

Laboratory Use Common Name

Alternative Name(s)

CAS Number

Grade

Ammonium iron (II) sulphate hexahydrate

Ferrous ammonium sulphate, Ammonium iron sulphate

7783-85-9

Analytical

Citric acid anhydrous

2-hydroxypropane-1,2,3 tricarboxylic acid

77-92-9

Analytical

n-Dodecylamine acetate

Laurylamine acetate

2016-56-0

See note*

Iron (III) nitrate nonahydrate

Ferric nitrate nonahydrate; iron nitrate; ferric nitrate

7782-61-8

Analytical

Maleic acid

cis-butenedioic acid; malenic acid; toxilic acid

110-16-7

Laboratory

Silver nitrate

Silver (I) nitrate

7761-88-8

Laboratory

Synperonic N*

Isononylphenol ethoxylate

9016-45-9

As supplied

* Both n-Dodecylamine acetate and Synperonic N are constituents within Physical

Developer Stock Detergent Solution. This solution is currently prepared and supplied to UK police forces by CAST for two reasons:

●● The purity of n-Dodecylamine acetate varies considerably from batch to batch. The

formulation given in this Manual has been developed for the batch of n-Dodecylamine acetate that CAST currently holds stocks of. This formulation may have to be re-

adjusted if, when measured, the purity of any further batches of this chemical varies.

●● Synperonic N is being phased out of production in many parts of the world and may

be difficult to purchase in the future.

CAST holds a limited stock of each chemical. When current stocks are exhausted, an alternative formulation of Physical Developer will be required.

Home Office January 2014

5.PD.6

Fingermark Visualisation Manual

Physical Developer

Glossary

5.PD.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Solutions

Consult Chapter 3 for

general information on

solution preparation, safe storage of chemicals,

solutions and mixtures

(which includes information on packaging and

labelling), management

of waste for disposal of solutions and guideline expiry periods. This

page gives additional

information relevant to this process.

Glossary

Index

Laboratory Use Solutions

Maleic Acid Solution

25 g Maleic acid 1 L Water

(1) Prepare solutions

Physical Developer (PD) Working Solution

900 mL Physical Developer Redox Solution 40 mL Physical Developer Stock Detergent Solution 50 mL Silver Nitrate Solution

Physical Developer Redox Solution

30 g Iron(III) Nitrate nonahydrate 80 g Ammonium iron(II) sulphate hexahydrate 20 g Citric acid anhydrous 900 mL Water

(2) Label appropriately

(3) Store appropriately

Physical Developer Stock Detergent Solution

2.8 g n-Dodecylamine acetate 2.8 g Synperonic N 1 L Water

Silver Nitrate Solution

10 g Silver nitrate 50 mL Water

a) All solutions must be thoroughly mixed and all solid components dissolved. Physical Developer Stock Detergent Solution may require stirring for several hours. b) Water and solutions used within Physical Developer Redox and Working Solution must be >17˚C prior to mixing. c) See Physical Developer Equipment for glassware requirements for solutions containing silver nitrate. In addition all labware must be scrupulously clean and dust free. d) Silver Nitrate Solution must be kept in the dark until use. e) Maleic Acid, Physical Developer Stock Detergent and Silver Nitrate Solutions are colourless. f) Physical Developer Redox and Physical Developer Working Solutions may vary in appearance from a yellow/brown to a brown/green colour. a) All solutions should be labelled in line with the guidance in Physical Developer Health and Safety. a) Maleic Acid Solution, Physical Developer Stock Detergent Solution and Physical Developer Redox Solution have guideline expiry dates of 12 months after preparation if stored at room temperature. b) Silver Nitrate Solution must be stored in the dark until use. This process requires that the solution is made and used fresh. c) PD Working Solution has a guideline expiry date of five days after preparation if stored at room temperature and in the dark. It must be stored in a vessel that is clean and scratch free. A small amount of white sediment may appear but this does not affect performance. If sediment is silver/ grey, do not use.

(4) Dispose of appropriately

Final solutions are identified by a red border See Ready Reckoners for other quantities of solution Home Office January 2014

5.PD.7

Fingermark Visualisation Manual

Physical Developer

Appendices

5.PD.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Solutions Ready Reckoner - Maleic Acid Solution

Ready Reckoner - PD Working Solution

Quantity Chemical

0.5 L

Quantity of PD Working Solution

1L

2L

Solution

0.5 L

1L

2L

Maleic acid

12.5 g

25 g

50 g

PD Redox Solution

450 mL

900 mL

1800 mL

Water

500 mL

1L

2L

PD Stock Detergent Solution

20 mL

40 mL

80 mL

Silver Nitrate Solution

25 mL

50 mL

100 mL

Quantity of PD Redox Solution Chemical

450 mL

900 mL

1800 mL

Iron (III) nitrate nonahydrate

15 g

30 g

60 g

Ammonium iron (II) sulphate hexahydrate

40 g

80 g

160 g

Citric acid anhydrous

10 g

20 g

40 g

Water

450 mL

900 mL

1800 mL

Quantity of Silver Nitrate Solution Chemical

Home Office January 2014

25 mL

50 mL

100 mL

Silver Nitrate

5g

10 g

20 g

Water

25 mL

50 mL

100 mL

5.PD.8

Fingermark Visualisation Manual

Physical Developer

Glossary

5.PD.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Processing Preparation (1) Work area

(2) Equipment

Processing

(3) Immerse item in Maleic Acid Solution

(4) Immerse item in Physical Developer Working Solution Continued on next column Home Office January 2014

a) Room temperature should be greater than 17˚C. The speed of silver deposition is likely to be considered too slow at temperatures lower than this. b) The work area should not be in direct sunlight. c) There should be sufficient space available to accommodate all dishes and the print-washer or equivalent (if used). This is typically 4-6 vessels.

a) Pour Maleic Acid Solution into one dish; Physical Developer Working Solution into another dish; water into the remaining dishes. Add sufficient solution to immerse the item. Attach the print-washer, or equivalent, to a tap for the final continuous wash. In addition to the equipment requirements for the dishes used for Physical Developer Working Solution, the internal surfaces must be scrupulously clean and dust free before use. a) Immerse the item for ten minutes or until bubble evolution from the item ceases, whichever is the longer. Occasionally agitate the dish. b) This step can be omitted for wood and fragile papers such as tissue or charred paper. c) Multiple items may be treated in the same dish throughout processing, although they must not overlap or be folded. d) Physical contact with the item should be kept to a minimum throughout processing. e) Replenish the solution as necessary. Discard if the solution becomes exhausted or badly contaminated with debris. a) Immerse the item and occasionally agitate the dish. b) Replace the solution as necessary. Discard if the solution becomes badly contaminated with debris or if dark grey/silver particles are observed at the bottom of the dish or floating on the surface of the Physical Developer Working Solution.

Processing (5) Observe mark development

(6) Once optimal contrast is achieved immerse item in water

(7) Leave to dry

(8) Examination Primary: Visual Examination Secondary: Fluorescence Examination; IR Reflection

a) Grey-coloured marks will be developed which gradually darken with development. b) As more items are treated the development time increases. Eventually development time will become unacceptable and the solution must be discarded, the dish rinsed with water and refilled.

a) Immerse the item in water wash dishes, each for about five minutes with occasional agitation, until all Physical Developer Working Solution has been removed. Change the wash water when it appears yellow. b) Finally, wash for at least ten minutes in a print-washer or equivalent.

a) See Drying of items.

a) Visible marks are grey/silver in colour when the item has dried. b) Weak marks may only be seen when the paper is completely dry. c) If washing has not been thorough the background can discolour so it is important to image all fingermarks found immediately. d) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination, Fluorescence Examination and IR Reflection, particularly for lowcontrast marks or marks on dark or patterned surfaces. e) Mark up viable fingermarks appropriately and capture image. f) After examination, items with light-coloured marks and little background development can be re-treated if necessary but immersion in maleic acid is not required.

5.PD.9

Fingermark Visualisation Manual

Physical Developer

Glossary

5.PD.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Cleaning processed items

(2) Disposal or return of processed items

a) It is not possible to return items to their original state.

a) Residual processing chemicals that are present are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (3) Disposal of used Physical Developer Working Solution

(4) Cleaning of processing dishes

(5) Cleaning of laboratory surfaces

Home Office January 2014

a) Used Physical Developer Working Solution must not be poured back into a container for re-use at a later date as the effectiveness and solution lifetime are significantly reduced.

a) Processing dishes must be thoroughly washed and dried with a soft cloth or tissue. Stubborn stains may be removed with a neutral detergent, never abrasive cleaning products, then dishes must be thoroughly rinsed to remove any remaining detergent before drying.

a) It is not normally possible to remove silver stains from laboratory coats, balances, benching, flooring etc. so care should be taken when handling solutions containing silver.

5.PD.10

Fingermark Visualisation Manual

Physical Developer

Appendices

5.PD.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Grey Deposition on Labware Recognition

A grey deposit has appeared on labware that has come in contact with the Physical Developer Working Solution.

Silver from the Physical Developer Working Solution

depositing on the sides and bottom of the dish.

Cause

Effect

Prevention

Correction

Imperfections on the surface of processing equipment causes silver deposition from solution.

The working solution becomes depleted of silver ions. This may result in slow and/or weak development of marks.

Ensure that labware used for processing is scrupulously clean and free of scratches. Use-once disposable plastic liners may be considered to line damaged dishes.

Items with weak or apparently no development can be re-treated using fresh Physical Developer Working Solution.

Home Office January 2014

5.PD.11

Fingermark Visualisation Manual

Physical Developer

Appendices

5.PD.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Troubleshooting

Cloudy Working Solution Recognition

The Physical Developer Working Solution is cloudy in appearance.

Physical Developer Working Solution of

‘Cloudy’ Physical Developer Working

correct appearance.

Solution.

Cause

Effect

Some components within the solution have not dissolved or have precipitated out from solution causing loss of clarity and change in colour of the Physical Developer Working Solution.

The working solution does not have the fine chemical balance required for optimum mark development. This may result in: ●● marks not being developed; ●● marks only being developed very faintly and being missed during examination.

Home Office January 2014

Prevention Ensure that: ●● the purity of chemicals and water are the recommended grades; ●● the temperature of all of the solutions is >17˚C prior to mixing and during processing; ●● the solution is thoroughly mixed between the addition of each solution when making Physical Developer Working Solution; ●● processing is carried out away from direct sunlight to avoid photodegradation.

Correction There are no corrective measures.

5.PD.12

Fingermark Visualisation Manual

Physical Developer

Glossary

5.PD.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Localised Areas of High Background Development Recognition

There are localised areas of high background

development, sometimes appearing within folds or areas that have been abraded or handled.

Porous items treated with Physical

Developer showing silver deposition

on marks and (left) scrapes caused by incorrect handling and (right) creases and abrasions.

Cause Imperfections on the surface of the item cause preferential silver deposition from solution onto these areas.

Home Office January 2014

Effect Marks may be obscured or obliterated.

Prevention Ensure that items are handled carefully, avoiding creasing, and minimising any abrasion of the surface with gloves. Smooth tongs and fish slices may be used where handling is required.

Correction There are no corrective measures.

5.PD.13

Fingermark Visualisation Manual

Physical Developer

Appendices

5.PD.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Uniform High Background Development Recognition

The porous item appears uniformly grey either across the whole area or in uniform patches.

White writing paper processed with

Physical Developer showing high background development.

Cause

Effect

Prevention

Correction

Filler particles in the substrate have not fully reacted in the maleic acid pre-wash, and react directly with the Physical Developer Working Solution. This reaction acts as nucleation sites for silver deposition.

High background development occurs across the whole surface, giving a dark grey background which may obscure developed marks.

Ensure that: ●● the item remains in the maleic acid pre-treatment until bubbles are no longer emitted from the surface; ●● items don’t overlap during treatment; ●● air is not trapped between the item and the solution.

There are no corrective measures.

The substrate and working solution have been exposed to excessive light/sunlight during processing.

High background development occurs across the whole surface, giving a dark grey background which may obscure developed marks.

Ensure that: ●● the item remains fully immersed in the working solution during processing; ●● the processing area is protected from direct sunlight; ●● items don’t overlap during treatment.

There are no corrective measures.

Home Office January 2014

5.PD.14

Fingermark Visualisation Manual

Physical Developer

Appendices

5.PD.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Substrate Damage from Maleic Acid Solution Recognition

The porous item breaks up or blisters when immersed in Maleic Acid Solution.

Paper substrates have been detrimentally affected by the

maleic acid pre-wash, including signs of (left) physical

degradation and (right) blistering of the surface.

Cause

Effect

Prevention

Heavily recycled papers (and some other substrates) may contain short fibres and high quantities of filler used for binding. The binding between the short fibres is easily disrupted during the reaction of the filler with maleic acid.

The substrate becomes fragile and/or breaks up while immersed in solution, destroying any marks that may be present.

Consider omitting the maleic acid prewash stage (especially for fragile materials such as tissue paper). If the issue cannot be overcome by omitting the pre-wash, consider alternative processes for this substrate.

There are no corrective measures.

Surface coatings or calendared layers present on some papers can inhibit the release of bubbles formed when the item is immersed in maleic acid.

Localised ‘blisters’ form within the substrate which may act as preferential nucleation sites for silver. Both preferential silver deposition and the blisters themselves may obscure or obliterate marks.

Consider omitting the maleic acid prewash stage. If the issue cannot be overcome by omitting the pre-wash, consider alternative processes for this substrate.

There are no corrective measures.

Home Office January 2014

Correction

5.PD.15

Fingermark Visualisation Manual

Physical Developer

Appendices

5.PD.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Under-Developed Mark Recognition

After processing with Physical Developer the developed mark is very faint.

Cause

Effect

Prevention

Correction*

The item has not been exposed to Physical Developer Working Solution for long enough to allow adequate development.

Lower than optimum amounts of silver are deposited on the mark. Developed marks are faint and difficult to detect, weaker marks may not be developed.

Ensure that items are exposed to the working solution for a sufficiently long period of time (~10-15 minutes for fresh solution, longer for older solutions).

Re-treat with Physical Developer.

The Physical Developer Working Solution has become exhausted and insufficient silver is present to fully develop marks.

Lower than optimum amounts of silver are deposited on the mark. Developed marks are faint and difficult to detect, weaker marks may not be developed.

Continuously monitor for signs of solution depletion such as deposition of silver in the processing dish. Use test spots if available.

Replace used solution with a fresh batch and re-treat item.

The item has been left without occasional agitation of the Physical Developer Working Solution, resulting in local depletion of silver ions.

Lower than optimum amounts of silver are deposited on the mark. Developed marks are faint and difficult to detect, weaker marks may not be developed.

Ensure that the solution is gently agitated at regular intervals to maintain a uniform distribution of chemicals within the solution.

Replace used solution with a fresh batch and re-treat item.

The mark contains limited constituents suitable for visualisation with Physical Developer.

Developed marks are faint and difficult to detect.

There are no preventative measures.

There are no corrective measures.

Paper packaging processed with Physical

Developer showing weakly developed marks.

* Any weak marks can be processed with Physical Developer Enhancement or viewed using IR Reflection.

Home Office January 2014

5.PD.16

Fingermark Visualisation Manual

Physical Developer

Appendices

5.PD.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Colour Change to the Substrate Post-Processing Recognition

The processed porous item appears ‘rusty’ in areas. This colour change has occurred over time.

White photocopier paper treated with Physical Developer with areas of strong discoloration after one month.

Cause Incomplete washing of the item during the final stages of processing has resulted in iron salts and other trace chemicals still being present in the substrate after processing. Home Office January 2014

Effect Subsequent oxidation reaction of the residual iron salts over time results in localised areas of discolouration. These may progressively obscure or obliterate developed marks.

Prevention Ensure that the item is washed for a sufficiently long period after processing and immediately photograph any useful marks.

Correction There are no corrective measures.

5.PD.17

Fingermark Visualisation Manual

Troubleshooting

Physical Developer

5.PD.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

A Swirly Pattern is Deposited on the Item Recognition

The item develops a ‘marbling’ pattern during processing.

A yellow post-it-note paper treated with Physical

Developer where silver has deposited in a swirly pattern,

also known as ‘marbling’.

Cause The ‘marbling’ effect is caused by either: ●● the presence of dust left on the internal surfaces of the dish used for Physical Developer Working Solution; ●● or dust from the laboratory settling onto the surface of the Physical Developer Working Solution during processing. Home Office January 2014

Effect Any dust in the Physical Developer Working Solution or on the surface can adhere to the surface of the item being treated. These dust particles disrupt the silver micelles and act as seeds for silver deposition. The result can be seen as a swirly pattern or ‘marbling’.

Prevention

Correction

Ensure that the dish used for Physical There are no corrective measures. Developer Working Solution is scrupulously clean and dust free and that the laboratory is free from floating dust.

5.PD.18

Fingermark Visualisation Manual

Physical Developer

Appendices

5.PD.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

It is unknown

depositing silver metal onto fingermark ridges.

the fingerprint

Development relies on a balanced electrochemical

reaction which can be affected by ions present from contamination, temperature and surface defects on

labware and on the item being treated. Therefore, for

successful implementation of this process, it is important to use chemicals of the correct grade, scratch-free

labware and to ensure minimal handling of items prior to treatment.

The Physical Developer Solution is a modified

photographic developer that contains silver ions, a

ferrous/ferric oxidation/reduction system that acts as a

reducing agent for the silver ions and a citric acid buffer. The reversible reaction below is set up: Ag+

+

Fe2+

Ag +

Fe3+

The formulation is stabilised by the inclusion of a cationic surfactant which acts to surround the particles of silver as they are formed by enveloping them in a positively

charged shell which is known as a micelle. These micelles repel the positively charged silver ions thereby preventing growth of the silver particles when in solution.

The relative concentrations of each component are in

balance so that the Physical Developer Solution remains fairly stable until items to be treated for fingermarks

are introduced into the solution. The silver micelles are

then disrupted by fingermark components, some other

contaminants or damage to the surface of the item and the tiny silver particle is deposited onto the surface.

Home Office January 2014

Index

Supplementary Information

Theory

The Physical Developer process works by preferentially

Glossary

what it is within that causes the

disruption to the

silver micelles nor its mechanism

but studies have

shown that they are probably water-

soluble components that are trapped within a water-

Scanning electron micrographs of silver particles deposited on fingermark ridges on a paper substrate.

insoluble emulsion

of sebaceous material. Once a particle of silver has deposited on the surface

it acts as a seed growing by interaction with silver ions. Where there is a large amount of contamination, for

example along fingermark ridges, many silver particles

are deposited and as they grow they will become visible as grey-/silver-coloured marks.

When treating porous items for fingermarks with Physical Developer, some papers have alkaline binders and fillers that react directly with the acidic Physical Developer

Solution. This reaction destabilises the silver micelles

and silver is rapidly deposited at the reaction sites and unable to develop fingermarks. Therefore, included in

the process is a maleic acid pre-wash, for papers that

require it, where the maleic acid reacts with the alkaline

binders and fillers to neutralise them, forming an insoluble

These papers can then be treated normally with Physical Developer.

The maleic acid pre-wash may cause some damage to certain types of paper and for this reason it may

be omitted for fragile papers such as tissue which are unlikely to have a high filler content. Other types of

porous surface such as wood contain no alkaline fillers so there is no need to use a maleic acid pre-wash.

As items are processed, silver is removed from the

Physical Developer Working Solution and there is less to deposit on the next items. With every item that is

put through the process the longer it takes to develop fingermarks until the process becomes unacceptably

slow. The Physical Developer Working Solution can then be replaced and the item continued being treated until

mark-to-background contrast is judged to be optimal n

salt and generally carbon dioxide gas will be evolved.

5.PD.19

Fingermark Visualisation Manual

Physical Developer

Appendices

5.PDE.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names PD toning

Contents Options........................................ 5.PDE.2 Laboratory or Scene? ............... 5.PDE.3 Laboratory Use........................... 5.PDE.4 Health and Safety .................... 5.PDE.4 Equipment................................. 5.PDE.5 Chemicals ................................ 5.PDE.6 Solutions .................................. 5.PDE.8 Processing ............................. 5.PDE.11 Post-Processing...................... 5.PDE.13 Supplementary Information .... 5.PDE.14

Main Uses ✘ Latent ✘ Blood ✘ Grease ✔ Other*

Safety and Effectiveness Summary ✘ Non-Porous ✔ Semi-Porous ✔ Porous

* Enhancement of marks visualised with Physical Developer

Key Information

●● Competent personnel specialising in fingermark

enhancement must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for three Category

A Physical Developer (PD) Enhancement methods: ■■ ■■ ■■

Blue Toning

Iodide Toning

Sulphide Toning

●● Full process details are given for laboratory use only.

Process Overview

Physical Developer Enhancement converts the grey-coloured

The Process

●● Physical Developer Enhancement can be used safely and

effectively in a laboratory.

●● It is only effective at enhancing marks previously treated with

Physical Developer.

●● The effectiveness of the process depends on close

observation of the contrast between the fingermark and the

background, as any silver deposited on the background will also be enhanced.

The Item or Surface

●● The process is only effective at enhancing marks visualised

using Physical Developer on semi-porous and porous surfaces.

●● Using one of the three formulations it is possible to enhance

the contrast of PD marks on coloured, dark and light surfaces.

Integrated Use

Physical Developer Enhancement may be detrimental to subsequent fingermark or forensic processing.

fingermarks visualised using Physical Developer to a colour

●● See Chapter 4: Process Selection for information on its

between the developed mark and the background. All three

●● See Chapter 7: Other Forensics for information on integration

(black, blue or cream/white) that provides greater contrast chemical processes detailed in this section are based on traditional wet photographic techniques.

sequential use with other fingermark visualisation processes. of fingermark and other forensic processes.

These are chemical processes that involve exposing the item or

surface to solutions in sequence. More Details

Home Office January 2014

5.PDE.1

Fingermark Visualisation Manual

A Physical Developer Enhancement

5.PDE.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options Blue Toning

●● The blue toner will change the colour of the grey

marks visualised by Physical Developer to deep blue.

●● The density of the blue colour can be varied by

length of exposure.

Iodide Toning

●● Iodide toning will change the colour of the grey marks

visualised by Physical Developer to cream/white.

●● It is most effective where marks are present on dark

backgrounds.

●● Iodide-toned marks will darken over time especially if

Sulphide Toning

●● Sulphide toning will change the colour of the grey

marks visualised by Physical Developer to black.

●● It is most effective when used to darken faint marks

that are present on light-coloured backgrounds.

they are exposed to strong lighting.

●● The process is most effective where marks are

present on coloured backgrounds and converting

marks to blue can provide increased colour contrast.

Sequential Use of Physical Developer Enhancement ●● Optical processes should be considered for

enhancing marks visualised with Physical Developer before proceeding to the chemical methods summarised above.

●● It is believed that no advantage would be gained

by using the Physical Developer Enhancement

techniques in sequence as each has a different use.

●● See Chapter 4: Process Selection for information on

its sequential use with other fingermark visualisation processes. Physical Developer Enhancement will

normally be the last fingermark visualisation process used in sequences on porous and semi-porous substrates.

●● See Chapter 7: Other Forensics for information

on integration of fingermark and other forensic processes.

Home Office January 2014

5.PDE.2

Fingermark Visualisation Manual

Physical Developer Enhancement

5.PDE.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Home Office January 2014

Health and Safety

Not applicable (see Practicality).

Effectiveness

Not applicable (see Practicality).

Practicality

Achieving the sequence of chemical conditions required for use of Physical Developer Enhancement at scenes is extremely difficult and usually considered impractical.

5.PDE.3

Fingermark Visualisation Manual

Physical Developer Enhancement

5.PDE.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Physical Developer Enhancement may be carried out with no known hazards to

health provided practitioners are trained and competent, if appropriate control

measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’).These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

Glossary

Index

Laboratory Use Hazards associated with Physical Developer Enhancement ●● Physical Developer Enhancement is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional hazard

Strongly exothermic reaction on addition of water to thiourea and sodium hydroxide to make Thiourea Stock Solution.

Risk Localised heating glassware, with risk of causing cracks and leaks.

Suggested control measures Stir constantly to prevent sodium hydroxide collecting in one place and concentrating heating in a single area.

CAST has not had any of the Physical Developer Enhancement Solutions assessed for labelling. The practitioner must do this before making and using any of the solutions.

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.PDE.4

Fingermark Visualisation Manual

Physical Developer Enhancement

Appendices

5.PDE.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

Physical Developer Enhancement requires the use of some process-specific equipment

for the preparation and application of the solutions. General laboratory equipment that may be required is outlined in Chapter 3. Equipment

Requirements

Processing dish for PD Enhancement Solution(s)

The processing dish must: ●● be non-metallic; ●● be large enough to process without folding the item.

Implement to move and transfer items during processing, such as forceps or tongs

The implement must: ●● be smooth and non-metallic; ●● not have serrated edges.

Equipment that will deliver an indirect source of fresh running water, such as a print-washer

The equipment should: ●● be capable of being attached to a regulated flow of water, such as a tap; ●● be designed so that items stay within the confines of the equipment and not damaged by water flow.

Home Office January 2014

5.PDE.5

Fingermark Visualisation Manual

Physical Developer Enhancement

Appendices

5.PDE.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Chemicals

The table below lists chemicals that are required for Physical Developer Enhancement. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

Sodium Hypochlorite

Bleach

Potassium Iodide

CAS Number

Grade

7681-52-9

10–15% Available chlorine

7681-11-0

Laboratory

Ammonium iron (II) sulphate hexahydrate

Ferrous ammonium 7783-85-9 sulphate; Ammonium iron sulphate

Analytical

Citric acid anhydrous

2-hydroxypropane-1,2,3 tricarboxylic acid

77-92-9

Analytical

Iron (III) nitrate nonahydrate

Ferric nitrate nonahydrate; iron nitrate; ferric nitrate

7782-61-8

Analytical

7758-02-3

Laboratory

Potassium Bromide Potassium Ferricyanide

Potassium hexacyanoferrate (III), Prussian Red

13746-66-2

Analytical

Thiourea

Sulfourea, Thiocarbamide

62-56-6

Analytical

Sodium hydroxide

Caustic soda

1310-73-2

Reagent grade

Home Office January 2014

The table below lists commercial Blue Toning products that CAST has evaluated for

use*. Other products may be available but their effectiveness will have to be evaluated before operational use.

Common Name

See Chapter 3 safe handling of chemicals for general information. Alternative Name(s)

Laboratory Use

Refer to supplier’s Information and Safety Data Sheet (SDS) for further information.

Unless specified, water used within the solutions or for rinsing is purified.

Common Name

Index

Blue Toner

Alternative Name(s) BT20, iron Blue Toner

Manufactured by Fotospeed

Use Use as supplied

* The batch quality of commercially available Blue Toner cannot be guaranteed by CAST.

5.PDE.6

Fingermark Visualisation Manual

Physical Developer Enhancement

Glossary

5.PDE.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Solutions (Iodide Toning) Consult Chapter 3 for

general information on

solution preparation, safe storage of chemicals,

solutions and mixtures

(which includes information on packaging and

labelling), management

of waste for disposal of solutions and guideline expiry periods. This

page gives additional

information relevant to this process.

Index

Laboratory Use

Solutions Hypochlorite Bleach Solution

1.5 g Sodium Hypochlorite 500 mL Water

(1) Prepare solutions

Iodide Toning Solution

475 mL Physical Developer Redox Solution 25 mL Potassium Iodide Solution

Potassium Iodide Solution

5 g Potassium Iodide 25 mL Water

(2) Label appropriately

(3) Store appropriately

Physical Developer Redox Solution

30 g Iron(III) Nitrate nonahydrate 80 g Ammonium iron(II) sulphate hexahydrate 20 g Citric acid anhydrous 900 mL Water

(4) Dispose of appropriately

a) As for Physical Developer, all solutions must be thoroughly mixed and all solid components dissolved. b) Water and solutions used for Iodide Toning must be >17˚C prior to mixing. c) Solutions containing potassium iodide should be prepared in subdued light. d) The Hypochlorite Bleach Solution and Potassium Iodide Solution are colourless. The Physical Developer Redox Solution and Iodide Toning Solution may vary in appearance from a yellow/brown to a brown/green colour.

a) All solutions should be labelled as determined by a local hazard assessment.

a) Hypochlorite Bleach Solution and Physical Developer Redox Solution have guideline expiry dates of 12 months after preparation if stored at room temperature. b) Potassium Iodide Solution must be stored in the dark until use. This process requires that the solution is used immediately. c) Iodide Toning Solution has a guideline expiry date of five days after preparation if stored at room temperature and in the dark.

Final solutions are identified by a red border. See Ready Reckoners for other quantities of solution. Home Office January 2014

5.PDE.7

Fingermark Visualisation Manual

Physical Developer Enhancement

Glossary

5.PDE.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Solutions (Iodide Toning) continued Ready Reckoner – Hypochlorite Bleach Solution Quantity Solution

0.5 L

1L

2L

Sodium Hypochlorite

1.5 g

3.0 g

6.0 g

Water

500 mL

1000 mL

2000 mL

Ready Reckoner – Iodide Toning Solution Quantity Chemical

0.5 L

1L

2L

Physical Developer Redox Solution

475 mL

950 mL

1900 mL

Potassium Iodide Solution

25 mL

50 mL

100 mL

Quantity of Physical Developer Redox Solution Chemical

450 mL

900 mL

1800 mL

Iron (III) nitrate nonahydrate

15 g

30 g

60 g

Ammonium iron (II) sulphate hexahydrate

40 g

80 g

160 g

Citric acid anhydrous

10 g

20 g

40 g

Water

450 mL

900 mL

1800 mL

Quantity of Potassium Iodide Solution Chemical

25 mL

50 mL

100 mL

Potassium Iodide

5g

10 g

20 g

Water

25 mL

50 mL

100 mL

Home Office January 2014

5.PDE.8

Fingermark Visualisation Manual

Physical Developer Enhancement

Appendices

5.PDE.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Solutions (Sulphide Toning)

Consult Chapter 3 for

general information on

solution preparation, safe storage of chemicals,

solutions and mixtures

(which includes information on packaging and

labelling), management

of waste for disposal of solutions and guideline expiry periods. This

page gives additional

information relevant to this process.

Solutions

(1) Prepare solutions

FerricyanideBromide ‘Bleach’ Solution

5 g Potassium Bromide 15 g Potassium Ferricyanide 500 mL Water

(2) Label appropriately

Index

Laboratory Use a) The Ferricyanide-Bromide ‘Bleach’ Solution should be prepared in subdued light. b) Whilst making Thiourea Stock Solution continuously agitate the flask to prevent sodium hydroxide collecting in one place and concentrating excessive heat in a single area. c) Ferricyanide-Bromide ‘Bleach’ Solution is pale yellow coloured. Thiourea Stock Solution and Sulphide Toning Solution are colourless. a) All solutions should be labelled as determined by a local hazard assessment.

Sulphide Toning Solution

25 mL Thiourea Stock Solution 500 mL Water

Thiourea Stock Solution

5 g Thiourea 20 g Sodium hydroxide 50 mL Water

(3) Store appropriately

a) Ferricyanide-Bromide ‘Bleach’ Solution has a guideline expiry date of 12 months after preparation if stored at room temperature in an opaque container. b) Thiourea Stock solution and Sulphide Toning solution should be used immediately.

(4) Dispose of appropriately

Final solutions are identified by a red border. See Ready Reckoners for other quantities of solution.

Home Office January 2014

5.PDE.9

Fingermark Visualisation Manual

Physical Developer Enhancement

Glossary

5.PDE.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Solutions (Sulphide Toning) continued Ready Reckoner – Ferricyanide-Bromide ‘Bleach’ Solution Quantity Solution

0.5 L

1L

2L

Potassium Bromide

5g

10 g

20 g

Potassium Ferricyanide

15 g

30 g

60 g

Water

500 mL

1000 mL

2000 mL

Ready Reckoner – Sulphide Toning Solution Quantity Chemical

525 L

1.05 L

2.10 L

Thiourea Stock Solution

25 mL

50 mL

100 mL

Water

500 mL

1000 mL

2000 mL

Quantity of Thiourea Stock Solution Chemical

25 mL

50 mL

100 mL

Thiourea

2.5 g

5g

10 g

Sodium Hydroxide

10 g

20 g

40 g

Water

25 mL

50 mL

100 mL

Home Office January 2014

5.PDE.10

Fingermark Visualisation Manual

Physical Developer Enhancement

Appendices

5.PDE.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Blue Toning) Preparation (1) Work area

a) There should be sufficient space available to accommodate all dishes and the print-washer or equivalent (if used). This is typically 3-4 vessels.

(2) Equipment

a) Lay out dishes and ensure print-washer or equivalent is working.

Processing (3) Immerse item in water

a) Immerse the item in water until it is completely wetted.

(4) Immerse item in Blue Toner

a) Immerse the item in Blue Toner (green-coloured solution) and occasionally agitate the dish.

(5) Observe mark development

a) The marks will change quickly to a dark blue colour normally in about 10 – 20 seconds. The intensity of the blue will increase the longer the item is left in the toning solution.

(6) Once optimal contrast is achieved, wash item in water

a) Immerse the item in water wash dishes, each for about five minutes with occasional agitation, until all the Blue Toning Solution has been removed. Change the wash water when it appears yellow. b) Finally, wash for at least 5 minutes in a print-washer or equivalent.

(7) Leave to dry

(8) Examination Primary: Visual Examination

a) Visible marks are coloured blue. b) Weak marks may only be seen when the paper is completely dry. c) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination. d) Mark up viable fingermarks appropriately and capture image. e) After examination, items can be re-treated if necessary. This will intensify the blue colour further.

a) See Drying of items.

Continued on next column Home Office January 2014

5.PDE.11

Fingermark Visualisation Manual

Physical Developer Enhancement

Appendices

5.PDE.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Processing (Iodide Toning and Sulphide Toning) Preparation (1) Work area

(2) Equipment

a) If using Iodide Toning, room temperature should be greater than 17˚C. The speed of iodide reaction is likely to be considered too slow at temperatures lower than this. b) The work area should be under subdued lighting. c) There should be sufficient space available to accommodate all dishes and the print-washer or equivalent (if used). This is typically 3-4 vessels. a) Lay out the dishes and ensure that the print-washer or equivalent is working.

(5) Immerse item in Toning Solution (6) Observe mark development

a) For Iodide Toning the marks will gradually lighten to a cream/white colour. This may take between 15 minutes and 2 hours. b) For Sulphide Toning the marks will very quickly darken to black. This should take between 15 and 30 seconds.

(7) Once optimal contrast is achieved, wash item in water

a) Immerse the item in two water wash dishes, each for about 5 minutes with occasional agitation. Change the wash water regularly. b) Finally, wash for at least 10 minutes in a print-washer or equivalent.

Processing (3) Immerse item in the ‘Bleach’ Solution

(4) Immerse item in water

Continued on next column

Home Office January 2014

a) If using Iodide Toning, the item should be immersed in the Hypochlorite Solution for approximately 3–5 minutes. Marks will darken and the background lighten although this may be difficult to observe especially on patterned surfaces. b) If using Sulphide Toning, the item should be immersed in the Ferricyanide-Bromide ‘Bleach’ Solution for approximately for 5–10 minutes. Marks will be seen to lighten, maybe to the point of invisibility and paper may take on a blue colouration. a) If using Iodide Toning, immerse the item in either a series of two water wash dishes, each for approximately 5–10 minutes with occasional agitation, or wash for at least 10 minutes in a print-washer or equivalent. b) If using Sulphide Toning, wash the item in either a series of water washes or wash in a print-washer or equivalent until all trace of Ferricyanide-Bromide ‘Bleach’ Solution has been removed.

a) Immerse the time in the Toning Solution and occasionally agitate the dish.

(8) Leave to dry

(9) Examination Primary: Visual Examination

a) See Drying of items.

a) Visible marks are coloured cream/white (Iodide Toning) or black (Sulphide Toning). b) Weak marks may only be seen when the paper is completely dry. c) Iodide-toned fingermarks will darken with exposure to light so it is important to image all fingermarks found immediately. d) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination. e) Mark up viable fingermarks appropriately and capture image.

5.PDE.12

Fingermark Visualisation Manual

Physical Developer Enhancement

Glossary

5.PDE.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Cleaning processed items

a) It is not possible to return items to their original state.

(2) Disposal or return of processed items

a) Residual processing chemicals that are present are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (3) Disposal of used Physical Developer Enhancement Solutions

Home Office January 2014

a) Used Physical Developer Enhancement Solutions must not be poured back into a container for re-use at a later date as the effectiveness and solution lifetime are significantly reduced.

5.PDE.13

Fingermark Visualisation Manual

Physical Developer Enhancement

Appendices

5.PDE.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Theory

The Physical Developer process results in deposition of microscopic silver particles on

fingermark ridges, producing marks of a light grey colour. On some substrates, the light grey colour may not produce sufficient contrast for the ridge detail in the fingermark

to be fully visualised. In such circumstances it is desirable for practitioners to darken,

lighten or change the colour of these fingermarks chemically to increase contrast with the background.

All of the processes outlined for Physical Developer Enhancement utilise chemical

reactions with the silver particles deposited on the fingermark ridges to convert them to compounds that have a different colour than light grey elemental silver. They have

been derived from the photographic industry where a multitude of coloured toners have

Glossary

Index

Supplementary Information ferric ammonium citrate, which reacts with the silver ferrocyanide to form the blue compound ferric ferrocyanide, commonly known as Prussian Blue.

Iodide Toning:

Iodide Toning is a two-stage process that first uses a hypochlorite bleach solution

that oxidises the silver to its oxide which is a darker grey than the silver deposits from Physical Developer. At the same time, the bleach may also lighten the substrate.

While any soluble halide salts (iodides, chlorides, bromides), could be used to react with the silver oxide and produce a cream/white silver halide salt, it is the silver iodide that

has been seen to give the best contrast. This may be helped as the papers that contain starch will darken as this reacts with tri-iodide ions.

been utilised. However, using one of the three toning solutions presented here should

Silver halides are light sensitive so subdued lighting must be used when carrying out this

cases. Blue Toning for the most part gives good colour contrast, whilst the other two

Sulphide Toning:

give good results in enhancing marks developed using Physical Developer in almost all toning methods offer excellent differences in luminance (light and dark contrast) between mark and background.

In addition, it is expected that these methods could be applied to increase contrast of MMD-developed fingermarks as they are also composed of silver particles.

process.

Sulphide Toning is a two-stage process that uses a ferricyanide-bromide ‘bleach’

solution that reacts with silver Physical Developer marks and turns them into silver

bromide. Items are then exposed to an alkaline solution of thiourea which changes the silver bromide in the fingermark to black-coloured silver sulphide.

The three methods of silver toning recommended use similar chemistry in that they use

A variation of this process using radioactive thiourea containing 35S has been

which lightens either the mark or the background. This reaction turns silver metal into a

then visualised by autoradiographical methods, i.e. placing the treated item in a press

a ‘bleach’ (which is generally not household bleach, although in one instance here it is) salt. A second reaction is then carried out which changes either the anion in the silver

salt or the silver. The reactions used in each Physical Developer Enhancement process

successfully used to label marks on dark and heavily patterned backgrounds which were between two layers of x-ray sensitive film n

are outlined below.

Blue Toning:

Commercially available photographic blue toners are generally single-bath (‘bleach’ and

toner in one process) and consist of a combination of chemicals that undergo a series of reactions which ultimately replaces the silver with a blue-coloured iron compound. Blue toners commonly contain potassium ferricyanide, which reacts with silver to

produce silver ferrocyanide, an almost colourless compound. Blue toners also contain Home Office January 2014

5.PDE.14

Fingermark Visualisation Manual

Physical Developer Enhancement

Appendices

5.Pow.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Powdering; Dusting

Contents Options ....................................... 5.Pow.2 Laboratory or Scene? ............... 5.Pow.5 Laboratory Use........................... 5.Pow.6 Health and Safety .................... 5.Pow.6 Equipment ................................ 5.Pow.7 Powders ................................... 5.Pow.9 Processing ............................. 5.Pow.10 Post-Processing ..................... 5.Pow.13 Scene Use................................. 5.Pow.14 Additional Considerations ...... 5.Pow.14 Troubleshooting........................ 5.Pow.15 Supplementary Information .... 5.Pow.18

Main Uses ✔ Latent ✘ Blood ✘ Grease ✔ Other*

Safety and Effectiveness Summary ✔ Non-Porous ✔ Semi-Porous ✘ Porous

* Enhancement of marks visualised using Superglue Fuming

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for four generic

types of powders: ■■ ■■

flake powders (magnetic and non-magnetic);

granular powders (magnetic and non-magnetic);

●● Powders can be used safely and effectively at scenes and in

a laboratory.

●● There are many types of powder and several methods of

application. The effectiveness of the various combinations

differs considerably and is dependent upon the chemical and physical properties of the powder, the type of applicator and

the competence of the operator (including the use of suitable illumination). If used optimally, it is still one of the most productive fingermark visualisation processes.

The Item or Surface

●● Powders are most effective on clean, smooth, non-porous

surfaces which have less affinity for the particles and no surface features to trap them.

●● Some types of powders perform better than others on semi-

porous or textured surfaces.

It does not include Lifting.

●● On highly textured or heavily contaminated surfaces Powders

additional considerations are given for scene use. Powders

●● Powders are not effective on surfaces which are wet although

●● Full process details are given for laboratory use and

are more likely to be used at scenes.

Process Overview

Powders develop fingermarks by preferential adhesion of fine particles to the deposited ridge detail. The adhesion of the

particles is influenced by the presence of aqueous and/or fatty components in sweat, or by ‘sticky’ contaminants in the mark. It is a physical process that involves applying a dry powder to the item or surface using an appropriate applicator and observing how the deposition of powder progresses. More Details

Home Office January 2014

The Process

are generally ineffective.

they can be used once the item or surface has thoroughly dried.

●● The effectiveness of Powders decreases with the age of the

mark.

Integrated Use

Powders may be detrimental to subsequent fingermark or forensic processing.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

and other forensic processes.

5.Pow.1

Fingermark Visualisation Manual

A Powders

5.Pow.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Powders Options

A wide range of powders are available, although most comparisons have been

conducted between four generic types of powder: metal flake, granular, magnetic flake and magnetic granular. All of these types of powder differ in terms of the way in which

they adhere to the marks and are lifted from the surface. Some further information about these generic powder types and where each powder type may be most applicable is

given below. Details of the most appropriate brushes and magnetic powder applicators

are given in Equipment. See Further Reading for details of CAST research on Powders.

Metal flake powders

Metal flake powders include aluminium powder and brass alloy powder. The latter is more commonly called ‘bronze’ or ‘gold’ powder due to its colour.

●● On clean, smooth surfaces metal flake powders are one of the most effective

powder types.

●● Their effectiveness drops considerably as surface texture increases and they must

not be used on textured surfaces.

●● Aluminium powder is safer to use than brass alloy powders and is the most

commonly used metal flake powder. Marks developed with aluminium powder can be difficult to see and appropriate illumination is essential.

●● Brass powder may prove useful on surfaces where aluminium powder is difficult to

see (e.g. silver cars).

●● In general fingermarks developed with aluminium powder lift well and imaging in situ

is unnecessary. However, the quality of the lift will be dependent on the type of lifting material (see Lifting). If in doubt, image marks before lifting.

Home Office January 2014

Scanning electron micrograph of aluminium flake powder (left). A mark visualised with aluminium powder (right).

5.Pow.2

5.Pow.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options continued Granular powders

There are many granular powders commercially available. CAST have fully evaluated

black and white granular powders across a range of surfaces based on UK usage. Other granular powders (e.g. fluorescent powders) have not been fully tested but may prove beneficial if coloured developed marks are desired.

●● Granular powders are most suited for use on smooth surfaces although they

are generally not as sensitive as other types of powder.

●● Their effectiveness drops as surface texture increases and they should not be used

on textured surfaces.

●● Black granular powder is more sensitive than white granular powder and should be

used in preference unless the colour of the surface prohibits its use. In this case other types of powder might be more effective.

●● Marks developed with granular powders may not lift as well as flake powders and

preferably should be imaged on the surface. The quality of the lift will be dependent on the type of lifting material (see Lifting).

Scanning electron micrograph of black granular powder (left).

Magnetic flake powders There are few commercially available magnetic flake powders available. CAST have evaluated ‘magneta flake’ only.

●● Magneta flake is generally effective across a range of surfaces of varying

porosity and texture. It is slightly less effective than magnetic granular

powders (black) on textured surfaces but may offer a good alternative to them on dark textured surfaces.

●● Application can be difficult and inconsistent compared to non-magnetic powders,

especially on vertical surfaces.

●● In general fingermarks developed with magneta flake lift well and imaging in situ is

unnecessary. However, the quality of the lift will be dependent on the type of lifting material (see Lifting). If in doubt, image marks before lifting.

Scanning electron micrograph of magneta flake powder (left). A mark visualised with magneta flake powder (right).

A mark visualised with black granular powder (right).

Home Office January 2014

5.Pow.3

Fingermark Visualisation Manual

Powders

5.Pow.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options continued Magnetic granular powders

There are many magnetic granular powders commercially available. CAST have fully evaluated black and white magnetic granular powders across a range of surfaces.

Others (e.g. fluorescent powders) have not been fully tested but may prove beneficial if coloured developed marks are desired.

●● Although effective across a range of surfaces of varying porosity and texture,

on textured surfaces and u-PVC black magnetic powders are one of the most effective powders.

●● Black magnetic powder is considerably more sensitive than white magnetic powder

Sequential use of Powders ●● Although not extensively researched, Powders can be used in sequence with other

powders to find additional marks. The optimum order is not known, although using granular powders after flake powders has proved beneficial in some cases.

●● See Chapter 4: Process Selection for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7: Other Forensics for information on integration of fingermark and

other forensic processes.

and should be used in preference unless the colour of the surface prohibits its use (e.g. dark, textured surfaces).

●● Application can be difficult compared to non-magnetic powders, especially on

vertical surfaces.

●● Marks developed with magnetic granular powders may not lift as well as flake

powders and preferably should be imaged on the surface. The quality of the lift will be dependent on the type of lifting material (see Lifting).

Scanning electron micrograph of black magnetic granular powder (left). A mark visualised with magnetic granular powder (right).

Home Office January 2014

5.Pow.4

Fingermark Visualisation Manual

Powders

5.Pow.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical

In contrast to most other processes, Powders is more likely to be used at scenes than

whether to process items in the laboratory or at the scene, e.g. crime scene managers

few health and safety considerations; and requires less handling and packaging (for

issues associated with the use of this process. Those responsible for deciding or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’

in the laboratory as it: is normally the most practical option; is just as effective; has removable items).

Health and Safety

Powders can be used safely at the scene and in the laboratory. Additional protective

equipment (e.g. dust masks) may be required when applying Powders in uncontrolled, confined environments, depending on the particular powder being used. See Health

and Safety for further guidance.

Effectiveness

Powders is equally effective if used in the laboratory or at the scene, provided the details as written in the process instruction can be followed.

Practicality

For large or non-removable surfaces, it is considerably more practical to use Powders at the scene – often removal to the laboratory is not an option. Even for small,

removable items, the process can be just as practical to use at scenes as it is in the

laboratory, provided equipment can be used as described in the process instruction.

Home Office January 2014

5.Pow.5

Fingermark Visualisation Manual

Powders

5.Pow.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Powders may be carried out with no known hazards to health provided practitioners

are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

Index

Laboratory Use Hazards associated with Powders ●● Powders is a physical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS).

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional hazard

Exposure to airborne dust or fibres from powders and/or brushes.

Risk Adverse health effects associated with breathing in dust or fibres whilst powdering (main risk) and examining items (negligible risk).

Suggested control measures ●● Apply powders in a

powdering cabinet.

●● Examine items treated

with powders in a well-ventilated area or preferably on a downdraught bench.

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.Pow.6

Fingermark Visualisation Manual

Powders

Glossary

5.Pow.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Equipment

Powders uses a selection of simple equipment. General laboratory equipment that may be required is outlined in Chapter 3. Equipment Brushes

Requirements There are many commercially available brushes, of varying quality,

made from a range of natural and synthetic fibres or hairs. They are

typically mounted in one of two ways: ‘Zephyr’ style; or ‘Artist’ or ‘mop’ style (see images below). It is important to use good quality brushes to achieve the best results with Powders.

Brushes must: ●● not cause damage to latent marks during use; ●● not shed excessively; ●● hold and transfer an appropriate amount of powder during use.

Equipment

Requirements Animal hair brushes: There are many animal hair brushes available offering different types of hair, mounting and size. Some animal hair is coarser than others and any brush used for powdering must be soft. They typically don’t retain powder as well as glass-fibre brushes and are more suited for use with granular powders. Artist-style, soft squirrel hair brushes are commonly used for granular powders, whilst zephyrstyle squirrel hair brushes may be used to apply aluminium flake powder on contaminated surfaces where glass-fibre brushes may clog up.

The types of brush found most suitable for use with Powders at the time of publication include: Glass-fibre brushes: Good quality glass-fibre brushes are constructed of very fine fibres (zephyr-style mount) and if properly used may cause less damage to latent marks than those constructed of animal hair. They hold powder well, allowing for marks to be built up gradually and are particularly effective at applying metal flake powders (e.g. aluminium powder). They can clog easily and are best used on clean surfaces. Their performance improves over the first few hours of use.

A squirrel hair, mop-style brush. Tapered polyester brushes: This specific type of polyester brush can be used as an alternative to a glass-fibre brush. It is also mounted zephyr style and may be used to apply aluminium flake powder on contaminated surfaces where glass brushes may clog up. This brush is washable. The tapered end to the fibres causes less damage to marks than other non-tapered polyester-fibre brushes. There are many other synthetic and natural hair brushes available, but they must be fully assessed prior to use.

A glass fibre, zephyr-style brush.

Home Office January 2014

5.Pow.7

Fingermark Visualisation Manual

Powders

Glossary

5.Pow.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment continued Equipment Magnetic powder applicators (‘wands’)

Requirements There are several commercially available magnetic powder applicators, of varying quality, size and magnetic field strength.

Magnetic powder applicators must: ●● contain magnets strong enough to pick up an appropriate amount of magnetic powder – applicators with stronger magnets produce larger powder ‘brushes’ minimising risk of contact between the metal applicator and the surface; ●● have a powder release mechanism – most contain retractable magnets and some have a non-magnetic sheath to contain powder to the tip of the applicator.

A magnetic applicator and the ‘brush’ formed by magnetic powder being attracted to it. White light source

To maximise visualisation of powdered fingermarks it is essential that good light sources are available which provide a high level of even illumination e.g. good scene lamps or torches. Examples of suitable light sources are listed under Equipment for Visual Examination.

Lifting media

There are many types of lifting media available, which should be selected according to the type of surface present and the type of powder use. See Lifting for details on options.

Home Office January 2014

5.Pow.8

Fingermark Visualisation Manual

Powders

Appendices

5.Pow.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Powders

This table lists powders that are required for this process. Unlike chemicals used in other process instructions, CAS Numbers are not given for the individual powders as they are

Black granular powder

Granular powder

●● The composition of black granular powders is variable

Black magnetic and white magnetic powders

Magnetic granular powders

●● Often referred to as ‘magna powders’. Many different

normally purchased from forensic equipment suppliers rather than chemical suppliers. The description of each powder given below is taken from research conducted by

CAST from 2002 to 2007. To the best of our knowledge, this information is still current, but powders should be tested for suitability when new batches are purchased as their chemical and/or physical properties may have changed without notice.

There may be other powders that have benefits for use in certain situations that are not listed on this page. In this case, it is the responsibility of the practitioner to ensure that the powder is fit for purpose.

Refer to supplier’s Safety Data Sheet (SDS) for further information on specified

depending on supplier and there is no standard specification for particle size, although: ■■ nearly all powders consist of some form of carbon black; ■■ powders typically contain fine granular particles (5–10 µm)

compositions of magnetic granular powder are available and there is no standard specification. During use, the powder should re-form back into its original shape when the applicator is removed from the surface as shown below:

chemicals.

See Chapter 3 safe handling of chemicals for general information. Name

Type of Powder

Description

Aluminium flake powder

Metal flake powder

●● Aluminium flake powder consists of jagged-edged

Bronze and gold powders (brass)

Metal flake powder

●● Bronze and gold powders are named according to

Home Office January 2014

✔

components: ■■ large magnetic carrier particles (for black magnetic: iron, particle size 20–200 µm); and ■■ smaller non-magnetic particles (for black magnetic: iron oxide, particle size 3-12 µm).

flakes of aluminium metal.

●● Typical particle diameter falls within the range

4–10 µm. ●● Each flake is coated in a thin layer of stearic acid and this typically makes up 3 to 5% w/w of the powder. their colour rather than their chemical composition. They are both brass, which is a copper-zinc alloy, and the variation in colour is due to the difference in the ratio of copper to zinc. ●● Brass powders with similar particle size and levels of stearic acid coating to that of aluminium flake powder should be used.

✘

●● Magnetic powders of this type generally have two

Magneta flake powder

Magnetic flake powder

●● Magneta flake is a single component magnetic powder

where the powder serves as both the carrier and developing medium. ●● It consists of smooth-edged flakes. ●● Typical particle diameter falls within the range 10–60 µm. ●● Each flake is coated in a thin layer of stearic acid and this typically makes up 3 to 5% w/w of the powder.

5.Pow.9

Fingermark Visualisation Manual

Powders

Glossary

5.Pow.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Metal flake powders) Preparation (1) Equipment

Processing (2) Load brush with powder

(3) Apply powder to the item

Continued on next column Home Office January 2014

a) Powders should be applied in a powdering cabinet. b) Select the type of metal flake powder (see Options) and brush (see Equipment) most appropriate to item/ surface being powdered. c) Place a small amount of the selected powder into an appropriate deep container. a) Carefully dip the brush into the container of powder. Glass-fibre brushes must be only lightly loaded with powder. Sufficient powder may usually be picked up from the inside walls of the container rather than dipping the brush into the bulk of the powder. b) It is good practice to test the amount of powder on the brush by applying it to a small test area away from the area of interest. If a heavy deposit appears, stop applying powder and remove excess powder from the brush by tapping the handle against the inside of the rim of the container or other hard surface.

(4) Examination Primary: Visual Examination Secondary: Lifting

a) Visible marks are metallic pale grey (aluminium) and metallic pale brown/yellow (brass). b) There are many non-destructive optical processes that can be considered when examining and imaging marks. c) Mark up viable marks appropriately and capture image. d) Metal flake powders lift well, but a competent photographer in the controlled environment of a optical examination room should have little trouble imaging marks on the surface in most cases. For difficult-toimage marks, lifting may be the best option. e) After examination, items can be re-treated if necessary, either with the same powder or with a different type. f) Lifting may have a detrimental effect on subsequent processing.

a) Practitioners must maintain a good application technique when applying powders. Powders must be applied evenly and in such a way as to minimise damage to fingermarks. b) Apply the powder to the surface with a light brushing action and build up the fingermark gradually*. If excess powder is applied removing it may damage the fingermark. * Powder can be applied to the surface using a ‘spinning’ technique although this offers no advantage in terms of mark development and may increase the amount of airborne particles. c) If too much powder has been applied it may be possible to reduce this by brushing out with a clean glass-fibre brush. Brushing out with other brushes may be necessary although this is more likely to damage the fingermark. d) If high background development cannot be removed, stop application and consider the use of alternative powders and/or alternative processes.

5.Pow.10

Fingermark Visualisation Manual

Powders

Appendices

5.Pow.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Granular powders) Preparation (1) Equipment

Processing (2) Load brush with powder

(3) Apply powder to the item

Continued on next column

Home Office January 2014

a) Powders should be applied in a powdering cabinet. b) Select the type of granular powder (see Options) and brush (see Equipment) most appropriate to the item/ surface being powdered. c) If necessary, place a small amount of the selected powder into an appropriate deep container. a) Carefully dip the brush into the container of powder. Glass-fibre brushes should be lightly loaded with powder, picking up powder from the walls of the container rather than dipping the brush into the bulk powder. Animal-hair brushes should be well loaded with powder. Other brushes should be tested and loaded appropriately. b) It is good practice to test the amount of powder on the brush by applying it to a small test area away from the area of interest. If a heavy deposit appears, stop applying powder and remove excess powder from the brush by tapping the handle against the inside of the rim of the container or other hard surface.

(4) Examination Primary: Visual Examination Secondary: Lifting

a) The colour of the visible marks is dependent on the particular powder used although black is the most common. b) There are many non-destructive optical processes that can be considered when examining and imaging marks. c) Mark up viable marks appropriately and capture image. d) Granular powders do not lift as well as metal flake powders and results can be variable depending on the type of powder and type of lifting media. Therefore, imaging of marks in situ is strongly recommended. e) After examination, items can be re-treated if necessary, either with the same powder or with a different type. f) Lifting may have a detrimental effect on subsequent processing.

a) Practitioners must maintain a good application technique when applying powders. Powders must be applied evenly and in such a way as to minimise damage to fingermarks. b) Apply the powder to the surface with a light brushing action. If a glass-fibre brush is used the fingermarks may be built up gradually*. If an animal-hair brush is used the powder should be liberally applied to the item and the excess removed with a few light strokes, although care must be taken as it is possible to damage fingermarks with this type of brush. * Powder can be applied to the surface using a ‘spinning’ technique although this offers no advantage in terms of mark development and may increase the amount of airborne particles. c) If high background development cannot be removed, stop application and consider the use of alternative powders and/or alternative processes.

5.Pow.11

Fingermark Visualisation Manual

Powders

Appendices

5.Pow.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Magnetic granular and flake powders) Preparation (1) Equipment

Processing (2) Load magnetic applicator with powder

(3) Apply powder to the item

Continued on next column

Home Office January 2014

a) Powders should be applied in a powdering cabinet. b) Magnetic powders must be applied with a magnetic applicator wand. a) Dip the magnetic applicator into the container of powder and withdraw, shaking slightly to remove excess powder. A brush-like clump of powder should have adhered to the applicator. b) It is good practice to test the suitability of the powder for the surface by applying it to a small test area away from the area of interest.

a) Practitioners must maintain a good application technique when applying powders. Powders must be applied evenly and in such a way as to minimise damage to fingermarks. b) Pass the applicator over the surface to be examined taking care not to let the head of the applicator touch the surface otherwise damage to fingermarks may occur. In most cases, marks should be visualised by a single pass of the applicator as multiple passes may either fill in the mark, or remove powder from it. In some cases multiple passes are required to build up the mark. c) If necessary, replenish the applicator as described in 2a. d) Hold the applicator over the powder container and release the powder back into the container by withdrawing the magnet to deactivate it. e) Pass the clean applicator over the surface as closely as possible without touching it. Excess powder should be removed from the mark and surface by these passes. It may be necessary to repeat this several times. f) If high background development cannot be removed, stop application and consider the use of alternative powders and/or alternative processes.

(4) Examination Primary: Visual Examination Secondary: Lifting

a) The colour of the visible marks is dependent on the particular powder used although metallic grey (magneta flake) and black (black magnetic) are the most common. b) There are many non-destructive optical processes that can be considered when examining and imaging marks. c) Mark up viable marks appropriately and capture image. d) Magnetic granular powders do not lift as well as metal flake powders and results can be variable depending on the type of powder and type of lifting media. Therefore, imaging of marks in situ is strongly recommended. e) Magnetic flake powders lift well, but a competent photographer in the controlled environment of an optical examination room should have little trouble imaging marks on the surface in most cases. For difficult-to-image marks lifting may be the best option. f) After examination, items can be re-treated if necessary, either with the same powder or with a different type. g) Lifting may have a detrimental effect on subsequent processing.

5.Pow.12

Fingermark Visualisation Manual

Powders

Appendices

5.Pow.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed Item (1) Cleaning processed items

a) Powdered items may be scrubbed with detergent and water although it may not be possible to return them to their original state. b) Powders are generally harder to remove from surfaces if left for a period of time. They should therefore be cleaned as soon as possible.

(2) Disposal or return of processed items

a) Provided items have been cleaned, they may be returned to the owner or discarded with ordinary waste.

Equipment and Chemicals (3) Disposal of powders

Home Office January 2014

a) Excess quantities of powders may be returned to large pots after use, but the possibility of DNA crosscontamination must be considered if powders are to be used in multiple locations.

5.Pow.13

Fingermark Visualisation Manual

Powders

Appendices

5.Pow.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Scene Use

Additional Considerations If a decision has been made to use Powders at a scene, a number

of additional considerations need to be taken into account, over and

above those given for laboratory use. The recommendations cannot be

prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make the process as effective as possible

within the constraints of the scene;

●● present a range of practical issues that need to be overcome.

This page must be read in conjunction with the laboratory process instruction.

For health and safety, consider:

●● provision of appropriate protective equipment (such as dust masks) if powders are

being applied in situations that would generate high concentrations of airborne powder, for example in confined and/or poorly ventilated spaces.

For effectiveness consider:

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of constraints posed by the scene.

As there are very few constraints posed by the scene, removable items to be treated

with Powders only (i.e. not part of a processing sequence) are normally treated in situ.

This is just as effective as laboratory processing and also eliminates the likelihood of damage caused to marks from any packaging.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

For practicality, consider:

general information.

●● the benefits of imaging powdered marks directly versus lifting them;

3, Section 3.1 – Scene use of the processes and treatment of large areas for other

●● access to the areas to be treated;

Although imaging marks prior to attempting to lift them is encouraged, this may not be

practical in all situations. If a decision has already been made to only use Powders then it may be acceptable to omit direct imaging and lift instead. This is particularly relevant for aluminium powder which is highly reflective and often difficult to image on some surfaces without the controlled lighting conditions that a laboratory would offer.

●● scene clean-up – powders should be removed from surfaces as soon as possible.

Home Office January 2014

5.Pow.14

Fingermark Visualisation Manual

Powders

Glossary

5.Pow.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Troubleshooting

Damage to Mark by Brush or Applicator Recognition

Damage has been caused to fingermarks during application of Powders.

Marks on glossy cardboard

(left) damaged by contact with an applicator.

Brush damage to marks (right) on a ceramic tile.

Cause

Effect

Prevention

Correction

If using magnetic powders, the solid metal head of the magnetic applicator has come into contact with the surface when being passed across it.

This has resulted in localised areas of physical damage that may destroy ridge detail or obliterate developed marks.

Ensure that the applicator does not scrape across the surface when used. This can be achieved by: ●● using an applicator with a strong enough magnet so that enough powder can be lifted to form a usable ‘brush’; ●● re-loading the brush regularly so that the ‘brush’ head remains fully loaded; ●● using a good quality powder that does not permanently flatten to produce a ‘hard pad’ after making contact with the surface. The ‘brush’ head should easily regain its shape. Practitioners must receive suitable training in powder application techniques.

There are no corrective measures.

If using non-magnetic powders, the brush has been applied to the surface with excessive force, and/or the fibres of the brush being used are too stiff.

This has resulted in localised areas of physical damage that may destroy ridge detail or obliterate developed marks.

Ensure that appropriate, soft brushes are selected and used to apply the powder. Practitioners must receive suitable training in powder application techniques.

There are no corrective measures.

Home Office January 2014

5.Pow.15

Fingermark Visualisation Manual

Powders

Glossary

5.Pow.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Uneven Powder Application Recognition

Fingermarks have been developed in some areas but limited or no development is observed in others.

A ceramic tile powdered with black magnetic powder.

Cause

Effect

Not all regions of the surface receive the same Marks may be missed in areas that have level of exposure to the powder. This may be not been properly exposed to the powder. due to: ●● the brush or magnetic applicator not being passed evenly across all areas of the surface; ●● powder becoming depleted from the brush/ applicator during processing. Home Office January 2014

Prevention Ensure that: ●● the brush/applicator is applied to the surface in a methodical manner to avoid missing areas; ●● the brush/applicator is kept appropriately loaded with powder throughout.

Correction It may be possible to re-treat the surface where the powder has not been applied. Consideration should be given to imaging already enhanced marks as they may over-develop or be damaged by further brushing.

5.Pow.16

Fingermark Visualisation Manual

Powders

Appendices

5.Pow.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

High Background Development Recognition

Areas of high background development have occurred during powdering that partly or totally obscure marks.

Contaminated ceramic tile treated with

black magnetic powder (left).

Textured vinyl wallpaper treated with

aluminium flake powder (right).

Cause

Effect

Prevention

Correction

Sticky/greasy contaminants are present on the surface and can act as preferential deposition sites for powders.

Powders adhere to both the mark and Ensure that powders are not used on surfaces surface contaminants, producing areas where there is known or suspected to be of high background development contamination. which may obscure marks. Another process more suitable for the surface and contamination present should be used for any similarly contaminated areas (see Chapter 4: Process Selection).

There are no corrective measures, although obscured marks may subsequently be visualised during sequential processing as the powder adhering to the background is removed.

The surface is highly textured and traps fine particles in its troughs.

The particles trapped in the troughs on the surface make those adhering to ridges difficult to see resulting in obscured marks.

There are no corrective measures, although obscured marks may subsequently be visualised during sequential processing as the powder adhering to the background is removed.

The brush was too heavily loaded The brush deposits too much powder with powder. onto the surface and obscures marks. Home Office January 2014

Another powder more suited to textured surfaces should be selected, or a another process more suitable for the type of substrate present should be used (see Chapter 4: Process Selection).

Ensure that the process instruction is followed It may be possible to remove excess powder with a for loading the brush and applying the powder. clean brush although this cannot be guaranteed.

5.Pow.17

Fingermark Visualisation Manual

Powders

Appendices

5.Pow.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

of auto-adhesion (the interaction between individual particles) becomes important. In the

powder particles to fingermark ridges, with significantly less particles adhering to the

to ‘build up’ the mark, indicating that strong auto-adhesive bonds do exist between

The development of fingermarks by Powders occurs by preferential adhesion of solid substrate. There are many factors that can affect the adhesion mechanism, some of which are outlined below.

case of aluminium powders it is observed that repeated passes of the brush are used

aluminium flakes. During powdering with magnetic flake powders, a single sweep of the

applicator is suggested, with further passes thought to ‘fill in’ or reduce the quality of the

Chemical and Physical Nature of the Powder

fingermark. This indicates that auto-adhesive forces between magnetic flake particles

smooth, clean surfaces because their shape gives them a higher surface area in intimate

Electrostatic charge: This can potentially make a large contribution to adhesion if

Particle shape: Flake powders may be more sensitive than granular powders on contact with the fingermark deposits where they lie flat.

Surface chemistry: Adhesion of a particle to a solid surface in air is partly due to molecular forces. Changing the molecules on the surface of the solid particle will

therefore have an effect on the interaction between that particle and the substrate it adheres to.

For example, surface coatings have been shown to play a role in the effectiveness of metallic flake powders for fingermark development. The stearic acid coating

(applied during the milling process and common to many flake powders) preferentially adheres the powder particles to fingermark ridges instead of the background surface.

Fingermarks contain similar chemical compounds and so the particles have an affinity for them and less of an affinity for clean surfaces, irrespective of flake diameter.

Once the initial layer of solid particles has adhered to the fingermark ridge, the process

are weak, and there is a possibility that the magnetised particles may repel each other. the particles are highly charged and the associated attractive force exceeds that of

other attractive forces. Various ways of utilising this effect for enhancing fingermark

development have been studied, but it is not the major mechanism employed by any of the powder types widely used at crime scenes.

Chemical and Physical Nature of the Mark and Substrate

Chemical constituents: Components of fingermarks or surface contamination, such as

water or grease, will promote adhesion of the powder to it for two principal reasons. The first is that the liquid is able to wet the surfaces, thus giving a greater contact area for

the particles. The second is the capillary force of the liquid caused by surface tension. In atmospheres of relative humidity in excess of 70% the increase observed in the adhesion of microscopic particles is due to capillary forces.

With fresh fingermarks the aqueous component of the fingermark contributes

significantly to the adhesion of powders. With older fingermarks, when most of the water has evaporated, powders adhere principally to the fatty deposit of the sebaceous sweat content.

In dry climates or for fingermarks that have dried out, anecdotal evidence suggests

that ‘huffing’ (blowing warm, humid air or breath over the mark) or re-humidification prior to powdering may improve the quality of the developed mark. This is because water may be re-absorbed by some constituents of the fingermark, making their

subsequent interaction with the particles in the powder stronger. This practice is difficult High magnification images of (left) fingermark ridges developed using black granular powder, and (right) fingermark ridges developed using a magnetic flake powder. Home Office January 2014

to control and should be considered with caution as it may also cause high background development. Breathing on marks must not be carried out if DNA recovery is a priority.

5.Pow.18

Fingermark Visualisation Manual

Powders

Appendices

5.Pow.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory continued The potentially strong interaction between solid particles and liquids and greases means that Powders should not be used where surfaces are sticky or heavily contaminated.

This is because the particles will not be able to discriminate between the constituents in the fingermark residues and the contaminant, and will adhere across the entire surface.

Surface morphology: Textured or porous surfaces can physically trap powder particles and lead to high background development. This is less of a problem for magnetic powders as the applicator can help remove trapped particles. However, trapped particles are difficult to remove with a brush.

Lifting of powdered marks

Developed marks may be either photographed in situ on the surface or recovered by

lifting. Potential advantages of lifting include the fact that it enables a large number of marks developed using powder to be rapidly collected from a scene, it removes the

powdered mark from the background environment it has been developed on and thus

makes imaging of the marks in isolation easier, and it removes many issues associated

with the level of skill of the crime scene photographer in capturing a good quality image. Disadvantages are that lifting may remove contextual information about the environment the mark was found in, and the quality of the lifted mark is potentially degraded from the mark developed in situ because some powder remains on the surface while the

remainder adheres to the lifting medium. Lifting is most compatible with flake powders; it is less appropriate for granular and magnetic powders and may cause greater

degradation to the quality of the lifted mark for these powder types. If it has been

decided that the developed mark is to be lifted there are several types of material that can be used as lifting media, see the Lifting process for further details.

Home Office January 2014

5.Pow.19

Fingermark Visualisation Manual

Powders

Appendices

5.Pow.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Further Reading

From 2004 to 2007 the Home Office produced a series of newsletters on Powders.

Although the main findings are incorporated in this process instruction, those requiring further information should read the newsletters:

Home Office Publication 54/04 (August 2004); Helen L Bandey. The Powders Process, Study 1: Evaluation of Fingerprint Brushes for use with Aluminium Powder.

Home Office Publication 08/06 (February 2006); Helen L Bandey, Andrew P Gibson. The Powders Process, Study 2: Evaluation of Fingerprint Powders on Smooth Surfaces.

Home Office Publication 67/06 (October 2006); Helen L Bandey, Thomas Hardy. The

Powders Process, Study 3: Evaluation of Fingerprint Powders on Textured Surfaces and U-PVC.

Home Office Publication 09/07 (March 2007); Helen L Bandey. Fingerprint Powders Guidelines n

Home Office January 2014

5.Pow.20

Fingermark Visualisation Manual

Powders

Appendices

5.PS.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Wet Powders

Contents Options...........................................5.PS.2 Laboratory or Scene?...................5.PS.3 Laboratory Use..............................5.PS.4 Health and Safety......................5.PS.4 Equipment.................................5.PS.5 Chemicals..................................5.PS.6 Solutions and Mixtures .............5.PS.7 Processing.................................5.PS.9 Post-Processing......................5.PS.10 Scene Use....................................5.PS.11 Additional Considerations.......5.PS.11 Troubleshooting...........................5.PS.12 Supplementary Information........5.PS.17

Main Uses ✔ Latent ✔ Blood ✔ Grease*

More Details

✔ Non-Porous ✔ Semi-Porous ✘ Porous

* targets latent marks in a greasy contaminant

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

Safety and Effectiveness Summary The Process

●● Powder Suspension can be used safely and effectively in a

laboratory and at scenes.

The Item or Surface

●● Effectiveness improves with the age of the fingermark, over a

period of several weeks.

●● The effectiveness of Powder Suspension decreases with

increased surface texture.

this process for the first time.

●● Powder Suspension is effective on items/surfaces that have

A Powder Suspension formulations:

●● Powder Suspension is effective on items/surfaces that have

●● This section contains process instructions for three Category ■■ ■■ ■■

Iron oxide-based Carbon-based

Titanium dioxide-based

●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

Powder Suspension consists of a fine powder dispersed through a concentrated detergent and wetting agent solution. This

process was initially used for treating adhesive surfaces such as tapes; however, Powder Suspension is also effective on general non-porous and semi-porous substrates. When applied, the

powder is selectively deposited along fingermark ridges but the

been wetted.

been subjected to moderate heating.

●● Powder Suspension can stain the background of some

substrates, most notably semi-porous items, causing developed fingermarks to be obscured.

Integrated Use

Powder Suspension may be detrimental to subsequent fingermark or forensic processing.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

and other forensic processes.

mechanism is unknown. Iron oxide and Carbon-based Powder

Suspension yield black fingermarks and Titanium dioxide-based Powder Suspension produces white marks.

It is a chemical process that involves applying the Powder

Suspension to the item or surface followed by a water wash. Home Office January 2014

5.PS.1

Fingermark Visualisation Manual

A Powder Suspension

2nd proof

5.PS.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options Iron oxide-based

●● Iron oxide-based Powder Suspension is generally

the most effective black Powder Suspension on

light, non-porous and semi-porous substrates (nonadhesive).

●● It gives less background staining on these substrates

than Carbon-based Powder Suspension so marks are easier to visualise.

●● It gives similar performance to Carbon-based

Powder Suspension on rubber-based adhesive surfaces but should not be used on acrylic-

based adhesives. It would not normally be used

Carbon-based

●● Carbon-based Powder Suspension is generally the

most effective black Powder Suspension on nonporous-backed, light-coloured adhesive surfaces and backings.

●● It may be effective on some light-coloured non-

porous and semi-porous substrates; however, it

Titanium dioxide-based

●● Titanium dioxide-based Powder Suspension can

be used on dark, non-porous and semi-porous substrates, and dark adhesive surfaces and backings.

●● The process produces visible, light fingermarks.

is less sensitive than Iron oxide-based Powder

Suspension and more prone to background staining in this use.

●● The process produces visible, dark fingermarks.

for this application due to the difficulty in quickly determining the type of adhesive.

●● Iron oxide-based Powder Suspension is the only

Powder Suspension formulation recommended

for adhesive surfaces with semi-porous backings (excluding cellulose-backed adhesives).

●● The process produces visible, dark fingermarks.

Sequential Use of Powder Suspension ●● Additional marks may be developed if Powder

Suspension mixtures are used in sequence with one another (and in any order). This is most relevant for non-porous items.

●● Powder Suspension can be reapplied, if necessary. ●● See Chapter 4 for information on its sequential use

with other fingermark visualisation processes.

●● See Chapter 7 for information on integration of

fingermark and other forensic processes.

Home Office January 2014

5.PS.2

Fingermark Visualisation Manual

Powder Suspension

5.PS.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Powder Suspension Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Health and Safety

Powder Suspension can be used safely in the laboratory and at the scene.

Effectiveness

Powder Suspension is equally effective if used in the laboratory or at the scene, provided the details as written in the process instruction can be followed.

Practicality

Powder Suspension is a messy process if not contained and it is generally considered more practical to remove items back to a laboratory for treatment. Processing large items may require additional considerations to avoid run-off of Powder Suspension and rinse water into areas not requiring treatment.

●● In a laboratory it should be possible to contain the Powder Suspension and rinse

water.

●● At scenes, the containment of Powder Suspension may be problematic when it is

rinsed off larger fixed surfaces, as copious amounts of water will be required. This

must be considered before the process is used, and additional equipment may be required to minimise the mess and contain rinse water.

Home Office January 2014

5.PS.3

5.PS.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Powder Suspension may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards

(e.g. ‘residual processing chemicals on items are hazardous’) and/or control

Index

Laboratory Use Hazards associated with Powder Suspension ●● Powder Suspension is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions or mixtures (including the ready-to-use Powder Suspension).

●● Wear Standard PPE as a minimum.

●● There are no additional hazards associated with the process.

measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.PS.4

Fingermark Visualisation Manual

Powder Suspension

Glossary

5.PS.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Equipment

Powder Suspension requires very little process-specific equipment. General laboratory equipment that may be required is outlined in

While the hazards associated with the chemicals used can be found on the SDS, those associated with the

Chapter 3.

solutions need to be calculated from their percentages

Equipment

in the final solution. To assist in this, in 2011, CAST

Brush

commissioned work to calculate the risks associated

with the solutions it was using at the time. The results

of those calculations are given here for guidance only to those responsible for risk assessments of solutions used locally.

Hazards* typically associated with prepared Iron oxide-based Powder Suspension (CLP) Symbols

Index

Laboratory Use

Health and Safety: Labelling Solutions and Mixtures

Solution

Glossary

Requirements The brush must:

●● be soft, and capable of being well loaded with

Powder Suspension. A suitable example would be a squirrel-hair mop-shaped brush; ●● be dedicated for use with one type of Powder Suspension (e.g. a brush used for Titanium dioxidebased Powder Suspension should not be used for Iron oxide-based Powder Suspension).

Signal Word and Hazard Statements

Powder Suspension Stock Detergent

‘DANGER’ H302 ‘Harmful if swallowed’ H318 ‘Causes serious eye damage’

Iron oxide-based Powder Suspension

‘DANGER’ H302 ‘Harmful if swallowed’ H318 ‘Causes serious eye damage’

Hazards* typically associated with prepared Iron oxide-based Powder Suspension (CHIP) Solution

Symbols

Hazard Statements

Powder Suspension Stock Detergent

R22 ‘Harmful if swallowed’ R41 ‘Risk of serious damage to eyes’

Iron oxide-based Powder Suspension

R22 ‘Harmful if swallowed’ R41 ‘Risk of serious damage to eyes’

* Solution hazards based on CAST’s solutions and calculated by ChemLaw UK. Flammability classifications assessed either theoretically or by measurement by Hazard Evaluation Laboratory (HEL).

Home Office January 2014

5.PS.5

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.PS.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Chemicals The table below lists chemicals that are required for Iron oxide-based Powder Suspension.

Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

Unless specified, water used for making solutions or for rinsing is purified.

Alternative Name(s)

CAS Number

has evaluated for use*. Other products may be available but their effectiveness will have to be evaluated before operational use.

Refer to supplier’s Information and Safety Data Sheet (SDS) for further information. Common Name

See Chapter 3 safe handling of chemicals for general information. Common Name

The table below lists commercial, ready-to-use Powder Suspension products that CAST

Grade

Ethylene glycol

Ethane-1,2-diol

107-21-1

> 99%

Triton® X-100

There are many alternative names

9002-93-1

Laboratory

Iron (II/III)oxide

Iron Oxide (FeO. Fe2O3), Magnetite, Pigment black 11 (CI77499)

1317-61-9

Precipitated (synthetic), magnetic, particle size: 200nm - 1µm.

Alternative Name(s)

Manufactured by

Use

Black Wet PowderTM

Carbon-based Kjell Carlsson Powder Suspension Innovation

Use as supplied

Black WetwopTM

Carbon-based Forensics Source Powder Suspension (formerly Armor Forensics)

Use as supplied

White Wet PowderTM

Titanium dioxidebased Powder Suspension

Kjell Carlsson Innovation

Use as supplied

White WetwopTM

Titanium dioxidebased powder suspension

Forensics Source (formerly Armor Forensics)

Use as supplied

* The batch quality of commercially available Powder Suspension cannot be guaranteed by CAST.

Home Office January 2014

5.PS.6

Fingermark Visualisation Manual

Powder Suspension

Glossary

5.PS.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Solutions and Mixtures (Iron oxide-based Powder Suspension) Consult Chapter 3 for general information on solution preparation, safe storage of chemicals, solutions and mixtures (which includes information on packaging and labelling), management of waste for disposal of solutions and guideline expiry periods. This page gives additional information relevant to this process.

Solutions and Mixtures Iron oxide-based Powder Suspension

50 g Iron (II/III) oxide 50 mL Powder Suspension Stock Detergent Solution

Powder Suspension Stock Detergent Solution

(1) Prepare Powder Suspension Stock Detergent Solution

a) Triton®X-100 should be be mixed with ethylene glycol before water, or with the ethylene glycol and water already mixed together. When the three components have been combined, stir for approximately ten minutes to ensure thorough mixing. b) Powder Suspension Stock Detergent Solution is colourless.

(2) Prepare Powder Suspension

a) Powder Suspension should be prepared in a wellventilated area. b) Mix iron (II/III) oxide powder with the Powder Suspension Stock Detergent Solution in a suitable vessel, such as a glass or plastic beaker, until a smooth paste is formed. c) Iron oxide-based Powder Suspension is black.

(3) Label appropriately

a) Powder Suspension Stock Detergent Solution and Iron oxide-based Powder Suspension should be labelled according to the information provided in Powder Suspension Health and Safety.

350 mL Ethylene glycol 250 mL Triton® X-100 400 mL Water

The working mixture is identified by a red border For other quantities see Ready Reckoner

(4) Store appropriately

a) Powder Suspension Stock Detergent Solution has a guideline expiry date of 12 months after preparation if stored at room temperature. b) Iron oxide-based Powder Suspension has a guideline expiry date of one month after preparation if stored at room temperature, and in a container with lid (a suitable plastic cover film may fulfill this requirement).

(5) Dispose of appropriately

Home Office January 2014

5.PS.7

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.PS.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Solutions and Mixtures (Iron oxide-based Powder Suspension) Ready Reckoner Quantity of Powder Suspension Stock Detergent Solution Chemical

500 mL

1L

2L

Ethylene glycol

175 mL

350 mL

700 mL

Triton® X-100

125 mL

250 mL

500 mL

Water

200 mL

400 mL

800 mL

Ready Reckoner Quantity of Iron oxide-based Powder Suspension Chemical

50 mL

100 mL

200 mL

Iron (II/III) oxide

50 g

100 g

200 g

Powder Suspension Stock Detergent Solution

50 mL

100 mL

200 mL

Home Office January 2014

5.PS.8

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.PS.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Processing

(2) Items

(3) Powder Suspension

Processing (4) Wet the item

(5) Expose item to Powder Suspension

(6) Rinse item

(7) Dry item

Home Office January 2014

Index

Laboratory Use Continued from previous column

Preparation (1) Work area

Glossary

a) Powder Suspension should be used at a sink or wet bench. a) If necessary, prepare item so that processing is practical to carry out (e.g. some items may need to be cut and/or pinned to a backing board), whilst considering effective handling of items. a) Ensure the Powder Suspension is well mixed. b) If applicable, decant an appropriate amount into a suitable vessel. a) For non-adhesive surfaces only: gently pre-rinse with cold tap water. The concentration of Powder Suspension may vary due to the addition of water to the surface. This has very little effect on the number of fingermarks developed.

(8) Examination Primary: Visual Examination

Secondary: Fluorescence Examination

a) Visible marks are coloured black (Carbon-based or Iron oxide-based Powder Suspension) or white (Titanium dioxide-based Powder Suspension). b) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination and Fluorescence Examination, particularly for low-contrast marks or marks on dark or patterned surfaces. c) Mark up viable fingermarks appropriately and capture image. d) After examination, items can be re-treated if necessary.

a) The brush head should be pre-moistened with tap water (but not dripping wet). The brush head must then be saturated with Powder Suspension. b) Brush the Powder Suspension onto the surface ensuring an even distribution. The brush should be re-saturated with Powder Suspension during application as required. The surface should be exposed to the Powder Suspension for approximately 10-20s (less time may be required for some semi-porous substrates). c) Cellulose-based tapes only: take particular care not to wet or apply the Powder Suspension to the nonadhesive side. a) Rinse the item with cold running tap water until the excess Powder Suspension has been removed from the background. b) Cellulose-based tapes only: remove excess Powder Suspension by floating the item on the surface of a large dish of tap water. a) See Drying of items.

5.PS.9

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.PS.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Cleaning processed items

(2) Disposal or return of processed items

a) It may not be possible to return items to their original state. If possible, items may be thoroughly wiped or washed with soap and water.

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals

(3) Continued use of Prepared Powder Suspensions

Home Office January 2014

a) Decanted Powder Suspension can be used to process further items provided it is not contaminated. Consideration must be given to the impact of continued Powder Suspension use on other forensic evidence types.

5.PS.10

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.PS.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Scene Use

Additional Considerations If a decision has been made to apply Powder Suspension at a scene, a

number of additional considerations need to be taken into account over and above those given for laboratory use. The recommendations below

cannot be prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make the process as effective as possible

within the constraints of the scene;

●● present a range of practical issues that need to be overcome.

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

For health and safety, consider:

●● what additional packaging and labelling will be needed for transporting the mixtures

(made in the laboratory) to the scene.

For effectiveness consider:

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of the constraints posed by the scene.

For practicality, consider:

●● access to the areas to be treated;

●● the additional time and costs of applying the process at the scene, including: ■■ ■■

3, Section 3.1 - Scene Use of the processes and treatment of large areas for other

transport costs;

additional equipment to apply, rinse and contain Powder Suspension so that

mess is minimised. This includes preventing wash water/Powder Suspension

general information.

run-off from contaminating areas not requiring treatment. It should not come in contact with porous surfaces (such as grouting between tiles) as it cannot be removed; ■■

scene clean-up, which may involve dismantling badly stained surfaces for disposal.

Home Office January 2014

5.PS.11

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.PS.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Incorrect Preparation of Powder Suspension Stock Detergent Solution Recognition

During the preparation of Powder Suspension Stock Detergent Solution, a solid, gelatinous mass has formed.

Left: Adding chemicals in the incorrect order.

Right: Adding chemicals in the correct order.

Cause The Triton® X-100 was added directly to the water (or vice versa). Triton® X-100 preferentially associates with itself rather than dissolving in water.

Home Office January 2014

Effect A viscous layer of solid Triton® X-100 forms at the base of the beaker.

Prevention Ensure that Triton® X-100 is mixed with the required volume of ethylene glycol before adding water, or alternatively, add the Triton® X-100 to a solution of the required amounts of water and ethylene glycol.

Correction The Triton® X-100 will dissolve in the water slowly, over a period of several hours. More rapid dissolution may be facilitated by the addition of the required amount of ethylene glycol.

5.PS.12

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.PS.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Inconsistent Mixing of Iron Oxide-Based Powder Suspension Recognition

Clumps of black powder have been deposited, obscuring some areas of the mark.

Powder Suspension on a glossy

cardboard box showing localised

areas of high deposition.

Cause Clumps of dry iron (II/III) oxide powder were present in the Powder Suspension during application.

Home Office January 2014

Effect The dry clumps of powder can lead to: ●● localised deposition of dry powder clumps, obscuring mark detail; ●● physical damage to marks caused by the brushing of abrasive dry powder across the surface.

Prevention Ensure that the iron (II/III) oxide powder is fully mixed with the Powder Suspension Stock Detergent Solution to form a smooth paste before application.

Correction Re-apply fully mixed Powder Suspension then rinse to reduce background staining. Note: Success cannot be guaranteed.

5.PS.13

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.PS.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Troubleshooting

High Background Development

a

Recognition

b

c

Brush marks and other areas of background staining are present post-rinsing.

Powder Suspension on uPVC. There

are three areas with varying amounts

of background staining; a) minimal, b) moderate, c) heavy.

Cause

Effect

The Powder Suspension mixture on the surface is too dry prior to rinsing.

The Powder Suspension is difficult to rinse off the surface leading to high background staining that may obscure or obliterate developed marks. Attempts to remove the staining with aggressive rinsing may also cause damage to marks.

Ensure that: ●● non-porous surfaces are pre-wetted; ●● the application brush is moistened with tap water prior to processing; ●● the brush is saturated with Powder Suspension; ●● Powder Suspension is rinsed from the surface approximately 10-20 seconds following application (less time may be required for some semi-porous substrates). Do not allow the suspension to dry out.

Re-apply Powder Suspension then rinse to reduce background staining. Note: Success cannot be guaranteed.

The surface is not suitable for treatment with Powder Suspension. It may be: ●● too porous; ●● or contaminated with a material that has an affinity for Powder Suspension.

The Powder Suspension is difficult to rinse off the surface leading to high background staining that may obscure or obliterate developed marks. Attempts to remove the staining with aggressive rinsing may also cause damage to marks.

If possible, ensure prior to processing that the surface is suitable for processing by testing a small area.

Re-apply Powder Suspension then rinse to reduce background staining. Note: Success cannot be guaranteed.

Home Office January 2014

Prevention

Correction

5.PS.14

Fingermark Visualisation Manual

Powder Suspension

Glossary

5.PS.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Distortion of Cellulose-Based Adhesive Tapes Recognition

The cellulose-backed adhesive item has become distorted during processing of the adhesive side with Powder Suspension.

Powder Suspension on a cellulosebased adhesive tape showing varying amounts of distortion

following wetting of the backing layer during application and/or subsequent rinsing with water.

Cause The cellulose backing layer used for some types of adhesive tapes is semi-porous and absorbs water, making the tape swell and distort.

Home Office January 2014

Effect ●● The distortion of the tape also results

in distortion of any marks that are present and may also cause damage to them. ●● The resultant damage and distortion makes the subsequent imaging and identification of marks difficult or impossible.

Prevention Ensure that Powder Suspension and any rinse water do not come into contact with the non-adhesive side of the tape.

Correction There are no corrective measures.

5.PS.15

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.PS.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Heavy Background Staining of Adhesive Surfaces Recognition

An adhesive surface processed using Iron oxide-based Powder Suspension exhibits heavy background staining.

Two different types of tape processed with Iron oxide-based

Powder Suspension, left-hand side showing a tape with

rubber-based adhesive and right-hand side showing a tape

with acrylic-based adhesive and heavy background staining by

the Powder Suspension.

Cause

Effect

The Iron oxide-based Powder Suspension formulation can heavily deposit on components of acrylic-based adhesives in addition to fingermark constituents.

The background of the adhesive surface becomes heavily stained, with the result that marks are extremely difficult to detect and are likely to be missed entirely.

Home Office January 2014

Prevention Ensure that the Carbon-based Powder Suspension formulation is selected for treatment of all light-coloured adhesive surfaces.

Correction There is no corrective action.

5.PS.16

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.PS.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Supplementary Information

Theory

The size of the powder particles is important. Electron micrographs of strongly

medium. No detailed studies have been published on the structure of the Iron oxide-

dioxide-based Powder Suspension reveal particles ranging from hundreds of

A Powder Suspension consists of fine powder particles dispersed through an aqueous based formulation or commercial products given in the Powder Suspension process instructions. However, it is thought that when a Powder Suspension is mixed, the

dissolved surfactant species accumulates to form surface layers on the particles, which encapsulate them and thereby allow for their dispersion. The resulting system is stable and resistant to aggregation.

Index

contrasting fingermarks visualised with Iron oxide-based, Carbon-based and Titanium nanometers to approximately one micron in diameter adhering to fingermark ridges.

Powder Suspension produced with powders comprised predominantly of particles larger than this, or of finer nanoparticles, has been seen to visualise fingermarks with poor contrast relative to those described above n

Image of high-contrast

The mechanism of interaction with latent fingermarks is currently unknown, but it is

fingermark ridges

believed that some component or property of the fingermark destabilises the surfactant

developed with Iron

molecules encapsulating the powder particles, allowing those particles to interact with

oxide-based Powder

the mark. One theory suggests that eccrine deposits held within a matrix of water-

Suspension.

insoluble material are responsible for this disruption; however, there is little evidence to

support this theory. It is entirely possible that multiple components of latent fingermarks are responsible.

With thanks to Dr Ben Jones, Brunel University and John Wiley & Sons, Inc for these two photographs.

Marks of three types developed using Powder Suspension, eccrine (left), sebaceous

© See Photo Credits

(middle) and ‘natural’ (right) showing strongest development in the natural mark.

An electron micrograph

of a high-contrast ridge boundary developed

with Iron oxide-based

Powder Suspension.

The particles range in

size from hundreds of

nanometres to 1 micron in diameter.

Home Office January 2014

5.PS.17

Fingermark Visualisation Manual

Powder Suspension

Appendices

5.SPR.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative names SPR

Contents Laboratory or Scene?................ 5.SPR.2 Laboratory Use........................... 5.SPR.3 Health and Safety..................... 5.SPR.3 Equipment................................. 5.SPR.5 Chemicals................................. 5.SPR.5 Solutions and Mixtures............. 5.SPR.6 Processing................................ 5.SPR.8 Post-Processing........................ 5.SPR.9 Scene Use................................. 5.SPR.10 Additional Considerations....... 5.SPR.10 Troubleshooting........................ 5.SPR.11 Supplementary Information..... 5.SPR.12

Main Uses ✔ Latent ✘ Blood ✘ Grease

Safety and Effectiveness Summary ✔ Non-Porous ✘ Semi-Porous ✘ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Full process details are given for laboratory use and

additional considerations are given for scene use.

Process Overview

Small Particle Reagent is a suspension of molybdenum

disulphide particles in a detergent solution. The molybdenum disulphide particles adhere to the fatty constituents of sweat

The Process

●● Small Particle Reagent can be used safely and effectively in a

laboratory.

●● Although it can be used safely at scenes, the effectiveness is

likely to be reduced due to the application method.

The Item or Surface

●● Small Particle Reagent is effective at visualising latent marks

on non-porous surfaces.

●● It can be used on surfaces that are wet, or have been wetted

and subsequently dried.

●● Effectiveness generally reduces with the age of the

fingermark.

Integrated Use

Small Particle Reagent may be detrimental to subsequent fingermark or forensic processing.

and/or some contaminants to produce a grey fingermark.

●● See Chapter 4 for information on its sequential use with other

is especially effective on waxed surfaces and expanded

●● See Chapter 7 for information on integration of fingermark

The process can be used on non-porous surfaces, and polystyrene.

fingermark visualisation processes. and other forensic processes.

It is a chemical process that involves the application of a mixture to the item or surface followed by a water wash. More Details

Home Office January 2014

5.SPR.1

Fingermark Visualisation Manual

A Small Particle Reagent

5.SPR.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Health and Safety

Small Particle Reagent can be used safely in the laboratory and at the scene.

Effectiveness

The process is at its most effective when used in the laboratory environment, where

items can be immersed in Small Particle Reagent. For use at scenes, there is a spray

application method for Small Particle Reagent, but it is considerably less effective than the immersion method.

Practicality

Small Particle Reagent is a messy process when applied via spray and it is generally considered more practical to remove small items back to a laboratory for treatment.

Processing large items at scenes may require additional considerations to avoid run-off of Small Particle Reagent and rinse water into areas not requiring treatment.

Home Office January 2014

5.SPR.2

Fingermark Visualisation Manual

Small Particle Reagent

5.SPR.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Small Particle Reagent may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g.

Glossary

Index

Laboratory Use Hazards associated with Small Particle Reagent ●● Small Particle Reagent is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions or mixtures.

●● Wear Standard PPE as a minimum.

●● There are no additional hazards associated with the process.

‘work within a fume cupboard’).These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.SPR.3

Fingermark Visualisation Manual

Small Particle Reagent

Appendices

5.SPR.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Health and Safety: Labelling Solutions and Mixtures While the hazards associated with

the chemicals used can be found on the SDS, those associated with the solutions and mixtures need to be

calculated from their percentages in

Hazards* typically associated with prepared Small Particle Reagent (CLP) Solution/Mixture

Symbols

DOSS Stock Detergent Solution

Signal Word and Hazard Statements ‘WARNING’ H319 ‘Causes serious eye irritation’

the final solution/mixture. To assist

Small Particle Reagent Concentrate

None required

None required

work to calculate the risks associated

Small Particle Reagent

None required

None required

Small Particle Reagent (spray formulation)

None required

None required

in this, in 2011, CAST commissioned

with the solutions and mixtures it was

using at the time. The results of those

calculations are given here for guidance only to those responsible for risk

assessments of solutions and mixtures used locally.

Hazards* typically associated with prepared Small Particle Reagent (CHIP) Solution/Mixture

Symbols

Hazard Statements

DOSS Stock Detergent Solution

None required

None required

Small Particle Reagent Concentrate

None required

None required

Small Particle Reagent

None required

None required

Small Particle Reagent (spray formulation)

None required

None required

* Solution/mixture hazards based on CAST’s solutions/mixtures and calculated by ChemLaw UK.

Flammability classifications assessed either theoretically or by measurement by Hazard Evaluation Laboratory (HEL).

Home Office January 2014

5.SPR.4

Fingermark Visualisation Manual

Small Particle Reagent

Appendices

5.SPR.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Equipment

Small Particle Reagent requires very little process-specific equipment. General laboratory equipment that may be required is outlined in Chapter 3. Equipment Treatment vessel

Requirements The treatment vessel unit should: ●● be large enough to submerge the item in Small Particle Reagent so that there is at least 50 mm of mixture above it. A dish, tray or tank is suitable.

Index

Laboratory Use Chemicals

The table below lists chemicals that are required for Small Particle Reagent. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

Unless specified, water used within the solutions or for rinsing is purified. See Chapter 3 safe handling of chemicals for general information. Common Name DOSS

Alternative Name(s) Dioctyl sulfosuccinate, sodium salt; DSS; Aerosol OT™, AOT™

Molybdenum MoS2 disulphide

CAS Number

Grade

577-11-7

≥96%*

1317-33-5

Superfine powder, average particle size approx. 1.5µm

*It may be possible to purchase aqueous DOSS solutions, which may be suitable for use instead of making DOSS Stock Detergent Solution from the solid.

Home Office January 2014

5.SPR.5

Fingermark Visualisation Manual

Small Particle Reagent

Glossary

5.SPR.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Consult Chapter 3 for general information on solution preparation, safe storage of chemicals, solutions and mixtures (which includes information on packaging and

Small Particle Reagent

500 mL Small Particle Reagent Concentrate 4.5 L tap water

(1) Prepare DOSS Stock Detergent Solution

(2) Prepare Small Particle Reagent Concentrate DOSS Stock Detergent Solution

Small Particle Reagent Concentrate

75 mL DOSS Stock Detergent Solution 425 mL tap water 50 g Molybdenum disulphide

DOSS Stock Detergent Solution

1 g Dioctyl sulfosuccinate, sodium salt 100 mL water

The working mixture is identified by a red border. For other quantities see Ready Reckoner.

Home Office January 2014

Continued on next column

Index

Laboratory Use

Solutions and Mixtures

Solutions and Mixtures

Glossary

labelling), management of waste for disposal of solutions and guideline expiry periods. This page gives additional information relevant to this process.

a) DOSS Stock Detergent Solution can take many hours to dissolve when preparing DOSS Stock Detergent Solution. b) DOSS Stock Detergent Solution is colourless. a) Small Particle Reagent Concentrate should be prepared in a wellventilated area. b) Mix the DOSS Stock Detergent Solution with the water first in a suitable vessel. The resultant solution is likely to turn cloudy. c) Add a small amount of the diluted DOSS Stock Detergent Solution to the required quantity of molybdenum disulphide powder in a beaker or similar vessel. Stir with a spatula until thoroughly mixed. Add further amounts of diluted DOSS Stock Detergent Solution whilst mixing until a smooth paste has formed (ensure there are no lumps). d) Add the remaining diluted DOSS Stock Detergent Solution to the paste whilst stirring to produce the Small Particle Reagent Concentrate. If transferring into a storage vessel, keep a small amount of dilute DOSS Detergent Solution back to rinse any molybdenum disulphide left deposited on the equipment into the storage vessel. e) Small Particle Reagent Concentrate mixture is dark grey. If left undisturbed for a few minutes the powder will settle, giving a grey layer of sediment below a transparent, pale yellow liquid.

(3) Prepare Small Particle Reagent

a) Ensure the Small Particle Reagent Concentrate is well mixed (the molybdenum disulphide must be fully dispersed). Decant Small Particle Reagent Concentrate into an appropriately sized vessel and add the required volume of tap water. b) Small Particle Reagent is grey when mixed. If left undisturbed for a few minutes the powder will settle, giving a grey layer of sediment below a colourless solution.

(4) Label appropriately

a) All Small Particle Reagent solutions and mixtures should be labelled according to the information provided in Small Particle Reagent Health and Safety.

(5) Store appropriately

a) All Small Particle Reagent solutions and mixtures have a guideline expiry date of 12 months after preparation if stored at room temperature.

(6) Dispose of appropriately

5.SPR.6

Fingermark Visualisation Manual

Small Particle Reagent

Appendices

5.SPR.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Solutions and Mixtures continued Ready Reckoner Quantity of DOSS Stock Detergent Solution Chemical

200 mL

500 mL

1000 mL

Dioctyl sulfo-succinate, sodium salt

2g

5g

10 g

Water

200 mL

500 mL

1000 mL

Quantity of Small Particle Reagent Concentrate Chemical

500 mL

1L

2L

Molybdenum disulphide

50 g

100 g

200 g

Small Particle Reagent Stock Detergent Solution

75 mL

150 mL

300 mL

Water

425 mL

850 mL

1700 mL

Quantity of Small Particle Reagent Chemical

1L

5L

20 L

Small Particle Reagent Concentrate

100 mL

500 mL

2L

Water

900 mL

4.5 L

18 L

Home Office January 2014

5.SPR.7

Fingermark Visualisation Manual

Small Particle Reagent

Appendices

5.SPR.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Processing Preparation (1) Items

(2) Equipment and Small Particle Reagent

a) When treating items with Small Particle Reagent, only one surface/side of the item can be treated at a time (the surface facing up when immersing). a) Ensure the Small Particle Reagent in the storage container is fully mixed prior to transferring to the treatment vessel. There must be enough mixture so that the item can be submerged and still have at least 50 mm of mixture above it.

(4) Expose item to Small Particle Reagent

(5) Remove item

continued on next column

Home Office January 2014

(7) Dry item

(8) Examination

Processing (3) Stir the Small Particle Reagent

(6) Rinse item

a) The Small Particle Reagent must be fully mixed ensuring that all of the molybdenum disulphide powder is suspended in the liquid. a) Immediately immerse the item with the surface to be treated facing up. Push the item down until there is at least 50 mm of mixture above the surface. Avoid contact between the item and the bottom of the vessel where possible as this may damage fingermarks on the item’s underside. b) Keep the item stationary for approximately 30 seconds.

Primary: Visual Examination

a) Invert and draw the treated side of the item across the surface of tap water in a second vessel of similar size. Gently agitate the item to wash off the excess molybdenum disulphide. a) See Drying of items.

a) Items treated with Small Particle Reagent should be examined in a well-ventilated area preferably on a down-draught bench. b) Visual marks are coloured grey. c) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination, particularly for lowcontrast marks or marks on dark or patterned surfaces. d) Mark up viable fingermarks appropriately and capture image. e) After examination, items can be re-treated if necessary.

a) Carefully raise the item. A grey film of molybdenum disulphide will be seen coating the surface. The bulk of the film should be removed from the surface (via gentle agitation and pulling out at a slight angle) before the item is removed from the Small Particle Reagent. If at this point fingermark visualisation is weak or not evident, the Small Particle Reagent can be re-agitated and the sample can be immersed once more (i.e. return to step (3)).

5.SPR.8

Fingermark Visualisation Manual

Small Particle Reagent

Glossary

5.SPR.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Cleaning processed items

a) It may not be possible to return items to their original state. If possible, items may be thoroughly wiped or washed with soap and water.

(2) Disposal or return of processed items

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (3) Re-use of solutions

Home Office January 2014

a) Small Particle Reagent can be re-used provided it is not contaminated with debris. Consideration must be given to the impact of re-use on other forensic evidence types. The quantity of molybdenum disulphide in Small Particle Reagent will gradually deplete with use. This may be observed by the need to repeatedly immerse items to achieve optimal results.

5.SPR.9

Fingermark Visualisation Manual

Small Particle Reagent

Appendices

5.SPR.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Scene Use

Additional Considerations If a decision has been made to apply Small Particle Reagent at a scene, a

number of additional considerations need to be taken into account, over and above those given for laboratory use. The recommendations below

cannot be prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make the process as effective as possible

within the constraints of the scene;

●● present a range of practical issues that need to be overcome.

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

3, Section 3.1 - Scene use of the processes and treatment of large areas for other general information.

For health and safety, consider:

●● what additional packaging and labelling will be needed for transporting the mixtures

(made in the laboratory) to the scene.

For effectiveness consider:

●● that for scene application, it may only be practical to apply Small Particle Reagent

as a spray (see below). Spray application is considerably less effective than the

immersion method described for laboratory use. A more concentrated mixture is required (500 ml Small Particle Reagent Concentrate; 3 L tap water) in order to attempt to get the surface exposed to molybdenum disulphide.

For practicality, consider:

●● access to the areas to be treated;

●● the additional time and costs of applying the process at the scene, including: ■■ ■■

transport costs;

additional equipment to apply (e.g. a garden sprayer), rinse and contain Small Particle Reagent so that mess is minimised. This includes preventing wash

water/Small Particle Reagent run-off from contaminating areas not requiring

treatment. It should not come in contact with porous surfaces (such as grouting between tiles) as it cannot be removed;

●● scene clean-up, which may involve dismantling badly stained surfaces for disposal.

Home Office January 2014

5.SPR.10

Fingermark Visualisation Manual

Small Particle Reagent

Glossary

5.SPR.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Separation of Small Particle Reagent Recognition

The mixture has separated into layers.

Particles of molybdenum

Beaker containing SPR

disulphide fully settled as a

suspension starting to

layer at the bottom of the

settle out.

beaker.

Cause

Effect

Molybdenum disulphide powder particles have a higher density than water and do not form a stable suspension in it, causing a layer of powder to progressively settle at the bottom of the container over time.

A reduced quantity of powder particles are present in suspension to settle on the substrate during processing, reducing the effectiveness of the process. This results in low-contrast marks which are difficult to see or may be missed.

Home Office January 2014

Prevention Ensure that: ●● the Small Particle Reagent is thoroughly mixed immediately prior to treating the substrate; ●● the substrate is submerged in the Small Particle Reagent as quickly as possible to maximise the number of particles capable of settling on it.

Correction ●● Capture images of any marks already

developed in case of subsequent over-development. ●● Re-treat the substrate.

5.SPR.11

Fingermark Visualisation Manual

Small Particle Reagent

Appendices

5.SPR.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

Small Particle Reagent is comprised of molybdenum disulphide particles temporarily suspended in water via the action of detergent. It is thought that the dissolved

surfactant species accumulates to form surface layers on the particles, or structures

that encapsulate them and thereby allow for their temporary suspension. The particles

then settle gravitationally onto the item/surface being treated. Where fingermark ridges are encountered by these particles, the detergent surface structures are disrupted,

allowing the molybdenum disulphide to interact with the fatty and oily components. This mechanism is shown schematically below.

The formulation relies on the DOSS detergent concentration being between one-third and one times the critical micelle concentration (CMC). If the DOSS concentration

is below this limit, deposition of molybdenum disulphide on the background surface can increase, while at higher concentrations the clarity of developed fingermarks

Detergent layers destabilised by fingerprint constituents, MoS₂ particles settle on ridges

diminishes n

Suspended MoS₂ particles surrounded by detergent molecules

MoS₂ particles deposited on fingerprint ridges

Schematic illustration of the Small Particle Reagent process showing (left) detergent layers or micelles formed around particles of molybdenum disulphide, (top)

destabilisation of those layers by fingerprint constituents leading to particles settling on ridges and (above) dried mark, leaving particles adhering to ridges.

Fingerprint deposit

Home Office January 2014

Substrate

5.SPR.12

Fingermark Visualisation Manual

Small Particle Reagent

Appendices

5.SB3.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names SB3; Sudan Black

Contents Laboratory or Scene?.................5.SB3.2 Laboratory Use............................5.SB3.3 Health and Safety....................5.SB3.3 Equipment...............................5.SB3.5 Chemicals................................5.SB3.5 Solutions..................................5.SB3.6 Processing...............................5.SB3.7 Post-Processing......................5.SB3.8 Scene Use....................................5.SB3.9 Additional Considerations.......5.SB3.9 Troubleshooting.........................5.SB3.10 Supplementary Information......5.SB3.14

Main Uses ✔ Latent ✘ Blood ✔ Grease

Safety and Effectiveness Summary ✔ Non-Porous ✘ Semi-Porous ✘ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for one

The Process

●● Solvent Black 3 can be used safely and effectively in the

laboratory and at scenes.

●● Solvent Black 3 is most effective on grease contamination.

The Item or Surface

●● Solvent Black 3 is most appropriate for use on non-porous

surfaces. This process may produce background staining, particularly if the surface has some porosity.

●● Marks on dark and patterned surfaces may be very difficult

to visualise.

Category A Solvent Black 3 formulation based on PGME.

Integrated Use

previous editions of this Manual.

forensic processing.

This replaces the ethanol-based formulation given in ●● Full process details are given for laboratory use and

additional considerations given for scene use.

Process Overview

Solvent Black 3 is a dye which stains grease- and oil-

contaminated fingermarks, and the fatty constituents of

Solvent Black 3 may be detrimental to subsequent fingermark or ●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

with other forensic processes.

sebaceous sweat in latent fingermarks. It is effective on non-

porous substrates, and the resultant marks are visible and blueblack in colour.

It is a chemical process that involves exposing the item or surface to a staining solution followed by a water wash. More Details

Home Office January 2014

5.SB3.1

Fingermark Visualisation Manual

A Solvent Black 3

2nd proof

5.SB3.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety,

Solvent Black 3 can be used safely in the laboratory

Practicality

the use of this process. Those responsible for deciding

avoid the creation of a flammable atmosphere.

and it is generally considered more practical to remove

effectiveness and practical issues associated with whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

and at scenes, as long as measures are taken to

Health and Safety

Solvent Black 3 Working Solution is flammable and if the

temperature exceeds 48ºC, there is a risk of developing a flammable atmosphere when using it.

●● In a laboratory, the risks of creating a flammable

atmosphere will be minimal as long as processing

is carried out in a fume cupboard or well-ventilated area.

●● At scenes, the risk of fire may increase significantly

at scenes where it may not be possible to provide sufficient ventilation and to remove heating and

ignition sources. The use of personal gas flammability monitors may be required.

Solvent Black 3 is a very messy process if not contained items back to a laboratory for treatment. Processing large items may require additional considerations

to avoid run-off of solutions into areas not requiring treatment.

●● In a laboratory it should be possible to contain the

Working Solution and rinse water.

●● At scenes, clean-up is particularly problematic due

to the insolubility of Solvent Black 3 in water; this must be considered before the process is used.

Consideration must also be given to the need for

suitable equipment for the containment of Solvent

Black 3 staining solutions and rinse water to minimise the mess.

Effectiveness

Solvent Black 3 is equally effective if used in the

laboratory or at the scene, provided the details as written in the process instruction can be followed.

Home Office January 2014

5.SB3.2

Fingermark Visualisation Manual

Solvent Black 3

5.SB3.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Solvent Black 3 may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’).These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and

Laboratory Use Hazards associated with Solvent Black 3 ●● Solvent Black 3 is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions or mixtures.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional Hazard

Risk Fire

●● Prepare and apply the

Exposure to quantities of dye solution.

Staining hands, clothes and body with dye.

●● Wear appropriate

instructions must be provided locally.

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

Suggested control measures

Creation of a flammable atmosphere when preparing and using the Working Solution.

●● In providing the Category A process instructions it is assumed that: ■■

Index

Working Solution in a fume cupboard or well-ventilated area. See working with flammable liquids for further information.

gloves when preparing or using solutions to protect the hands, especially if they are to be immersed in the solutions. ●● Wear a disposable apron to protect the clothes and body.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.SB3.3

Fingermark Visualisation Manual

Solvent Black 3

Glossary

5.SB3.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Health and Safety: Labelling Solutions While the hazards associated with the chemicals used can be found on the SDS, those associated with the solutions need to be calculated from their percentages in the final solution. To assist in this, in 2011, CAST commissioned work to calculate the risks

associated with the solutions it was using at the time. The results of those calculations are given here for guidance only to those responsible for risk assessments of solutions used locally.

Hazards* typically associated with prepared Solvent Black 3 Solutions (CLP) Solution Working

Symbols

Hazards* typically associated with prepared Solvent Black 3 Solutions (CHIP)

Signal Word and Hazard Statements ‘DANGER’ H226 ‘Flammable liquid and vapour’ H336 ‘May cause drowsiness or dizziness’

Solution Working

Symbols

Hazard Statements R10 ‘Flammable’ R67 ‘Vapours may cause drowsiness and dizziness’

* Solution hazards based on CAST’s solutions and calculated by ChemLaw UK.

Flammability classifications assessed either theoretically or by measurement by Hazard Evaluation Laboratory (HEL).

Home Office January 2014

5.SB3.4

Fingermark Visualisation Manual

Solvent Black 3

Appendices

5.SB3.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Equipment

Solvent Black 3 only requires general laboratory equipment as described in Chapter 3.

Chemicals

This table lists chemicals that are required for Solvent Black 3. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

Unless specified, water used for making solutions or for rinsing items is purified.

Common Name

Alternative Name(s)

CAS Number

Grade

Solvent Black 3

CI26150; Sudan Black; Sudan

4197-25-5

≥ 90%

PGME

Propylene Glycol Monomethyl

107-98-2

≥ 99.5%

(SB3)

Black B; Fat Black HB

Ether; 1-Methoxy-2-propanol

See Chapter 3 safe handling of chemicals for general information or effective use of chemicals for details on dye purity.

Home Office January 2014

5.SB3.5

Fingermark Visualisation Manual

Solvent Black 3

Glossary

5.SB3.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Solutions

a) Solvent Black 3 Working Solution must be prepared in a fume cupboard or well-ventilated area. b) Solvent Black 3 Working Solution should be stirred for at least one hour. A saturated solution will form. Some particulate matter will remain in suspension or as a sediment (this may be difficult to observe due to the blueblack solution colour) and should be transferred with the solution for storage. c) Solvent Black 3 Solution is dark blue.

Consult Chapter 3 for general information on solution

preparation, safe storage of chemicals, solutions and mixtures (which includes information on packaging

(1) Prepare solution

and labelling), management of waste for disposal of

solutions and guideline expiry periods. This page gives additional information relevant to this process.

Solution Solvent Black 3 (SB3) Working Solution

10 g Solvent Black 3 500 mL 1-Methoxy-2- propanol (PGME) 500 mL water

a) Solvent Black 3 Working Solution should be labelled in line with the guidance in Solvent Black 3 Health and Safety.

(2) Label appropriately

a) Solvent Black 3 Working Solution has a guideline expiry date of one month after preparation if stored at room temperature, after which the intensity of staining reduces.

(3) Store appropriately

(4) Dispose of appropriately

For other quantities see Ready Reckoner.

Ready Reckoner Quantity of SB3 Solution Chemical

Home Office January 2014

1L

2L

5L

SB3

10 g

20 g

50 g

PGME

500 mL

1L

2.5 L

Water

500 mL

1L

2.5 L

5.SB3.6

Fingermark Visualisation Manual

Solvent Black 3

Glossary

5.SB3.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Work area (2) Item (3) Equipment and solutions

Processing

a) SB3 Working Solution should be used in a fume cupboard or well-ventilated area. a) If necessary, prepare item so that processing is practical to carry out (e.g. some items may need to be cut), whilst considering effective handling of items. a) Pour a sufficient amount of SB3 Working Solution into a suitable dish or vessel. If using a wash-bottle, ensure that no undissolved solid is transferred as this will block the nozzle. b) For dipping items: remove any metallic-looking film that appears on the surface of the SB3 Working Solution before use with blotting or tissue paper.

(4) Expose item to SB3 Working Solution

a) Apply SB3 Working Solution to the item by suitable means such as immersion or pouring. Do not spray. Exposure times are normally between ten seconds and one minute depending upon the susceptibility of the surface to background stain. b) If immersing the item, the SB3 Working Solution should be replenished as necessary.

(5) Rinse item

a) Rinse item until excess dye has been removed from the background using suitable means, such as cold running tap water, or garden spray unit for larger items. Do not allow rinse water to run onto adjacent sections that are yet to be treated.

(6) Dry item

(7) Examination Primary: Visual Examination

Home Office January 2014

a) See Drying of items. a) Visible marks are coloured blue-black. b) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination, particularly for low contrast marks or marks on dark or patterned surfaces. c) Mark up viable fingermarks appropriately and capture image immediately. Fingermarks developed with this process will fade, sometimes within minutes. d) After examination, items can be re-treated if necessary, but effectiveness will be dependent upon the level of background staining.

5.SB3.7

Fingermark Visualisation Manual

Solvent Black 3

Appendices

5.SB3.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Cleaning processed items

(2) Disposal or return of processed items

Equipment and Chemicals (3) Re-use of solutions

Home Office January 2014

a) It is not normally possible to return items or surfaces to their original state. Solvent Black 3 is insoluble in water making cleaning by conventional methods (wiping or washing with soap and water) ineffective. Scrubbing items or surfaces with 1:1 (v:v) solution of PGME and water will remove some staining. This solution will have the same flammability hazard as Solvent Black 3 Working Solution. Other solvents may be effective at removing residual chemicals, although they may cause further damage to the item. a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

a) Solvent Black 3 Working Solution can be reused provided it is not contaminated with debris. Consideration must also be given to the impact of reuse on other forensic evidence types.

5.SB3.8

Fingermark Visualisation Manual

Solvent Black 3

Appendices

5.SB3.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Scene Use

Additional Considerations If a decision has been made to apply Solvent Black 3 at a scene, a number of additional considerations need to be taken into account, over and

above those given for laboratory use. The recommendations below cannot

For health and safety, consider:

●● minimising the risk of fire by reducing the flammability hazard by: ■■

be prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and will require different control

windows; ■■

measures to mitigate any risks identified before work can be carried out safely and

■■

●● different approaches may be needed to make the process as effective as possible

■■

in compliance with the requirements of the Health and Safety at Work Act 1974; within the constraints of the scene;

●● present a range of practical issues that need to be overcome.

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

3, Section 3.1 - Scene Use of the processes and treatment of large areas for other general information.

ensuring adequate ventilation of the processing area, e.g. by opening doors and removing all sources of ignition;

limiting the area treated and restricting the amount of flammable material used by targeted application of the processing solutions;

keeping surfaces for treatment and processing area below 48˚C;

●● what additional packaging and labelling will be needed for transporting the

solutions (made in the laboratory) to the scene;

●● providing additional PPE to protect practitioners, and if required specialist

equipment such as personal gas monitors and thermometers.

For effectiveness consider:

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, after consideration of the constraints posed by the scene.

For practicality, consider:

●● access to the areas to be treated;

●● the additional time and costs of applying the process at the scene, including: ■■ ■■

transport costs;

additional equipment to make the process safe and effective and to minimise

mess, e.g. tissue or plasticine™ to contain the solutions during application and to avoid run-off onto areas not requiring treatment;

■■

scene clean-up, which may involve dismantling badly stained surfaces for disposal.

Home Office January 2014

5.SB3.9

Fingermark Visualisation Manual

Solvent Black 3

Glossary

5.SB3.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Metallic-Looking Film on the Surface of the Solution Recognition

An ‘oily’ metallic-looking film has formed on the surface of the Solvent Black 3 Working Solution.

Dish containing Solvent Black 3 with a metallic film beginning to form on the surface.

Cause Solvent Black 3 has not fully dissolved or has precipitated from solution, with the excess appearing as a concentrated layer on the surface.

Home Office January 2014

Effect

Prevention

This film can transfer to the item’s surface during processing and is not readily washed off. Thus any items processed with this solution will exhibit increased levels of background staining that may obscure or obliterate developed marks.

Ensure that: ●● solutions are prepared as described in the process instruction; ●● thorough mixing of solution occurs; ●● solvent evaporation is minimised.

Correction The film can be removed from the surface of the solution using absorbent paper. There are no corrective measures once the film has been picked up on the surface of the item and has caused background staining.

5.SB3.10

Fingermark Visualisation Manual

Solvent Black 3

Appendices

5.SB3.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Changes to the Intensity or Colour of the Mark Recognition

Developed marks are either not the expected colour (blue-black) or

have lower contrast with the background than expected. This effect also occurs if marks are stored for a period of time prior to imaging.

Ceramic tiles processed

with a Solvent Black 3

solution aged for several

months (the fingermark on

the left was a sebaceous

mark, and the one on the

right was a latent mark).

Cause ●● The Working Solution or developed

marks have become oxidised or degraded over time.

Home Office January 2014

Effect ●● The colour of the marks is different

from that expected of Solvent Black 3.

●● Contrast reduces significantly with

increased age of the solution or the time from development to imaging. ●● Marks are more difficult to see and image and may be missed.

Prevention Ensure that: ●● chemical and solutions are in-date; ●● marks are imaged immediately.

Correction ●● Low contrast marks may be improved

using other Optical Processes.

5.SB3.11

Fingermark Visualisation Manual

Solvent Black 3

Appendices

5.SB3.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

High Background Staining Recognition

Heavy background staining has occurred on a surface treated with Solvent Black 3.

White melamine processed

with Solvent Black 3 washed off after a few seconds

(right) and washed off after a

minute (left).

Cause

Effect

Heavy background staining can be caused The heavy staining may by: obscure developed marks. ●● the substrate being more porous than expected and the dye absorbing into it; ●● high levels of contamination on the surface that are targeted by the dye; ●● excessive staining time for the surface type.

Home Office January 2014

Prevention

Correction

If unsure of how the substrate will respond, There are no corrective measures. test a small area with Solvent Black 3 before carrying out the full process. Testing in this way may give an indication of how to adjust the exposure time. On heavily contaminated surfaces, consider using other processes, as outlined in the Charts, that do not target greasy contaminants before using Solvent Black 3.

5.SB3.12

Fingermark Visualisation Manual

Solvent Black 3

Appendices

5.SB3.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Water Marks Recognition

‘Water marks’ are visible on treated areas.

Ceramic tile processed

with Solvent Black 3.

Cause Whilst treating an area, rinse water has run onto adjacent sections causing uneven development when processed. Home Office January 2014

Effect Patchy and uneven staining may obscure ridge detail within developed marks.

Prevention

Correction

Ensure that Solvent Black 3 or rinse water There are no corrective measures. is not allowed to run off into areas adjacent to those being treated.

5.SB3.13

Fingermark Visualisation Manual

Solvent Black 3

Appendices

5.SB3.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

Solvent Black 3 is a lysochrome, more commonly known as a fat stain. Dyes of this type colour fats by dissolving

into them, the fat effectively acting as the solvent for the dye. Lysochromes are mostly insoluble in strongly polar solvents such as water, and more soluble in less polar solvents such as PGME. The triglycerides present in

fingermarks, being non-polar compounds, dissolve them quite well. Other lipids containing fatty components may also dissolve them.

Lysochromes such as Solvent Black 3 are applied from solvents in which they are sparingly soluble. As they come into contact with materials in which they are

strongly soluble, significant transfer of the dye occurs

into the material in which they are more soluble, often colouring the material more strongly than the original

Optical micrographs of two different fingermarks developed using Solvent Black 3, showing different levels of staining and selective staining of certain constituents within the fingermark ridges.

solvent. This process is known as preferential solubility. The dyeing process of Solvent Black 3 is illustrated schematically on the next page.

Home Office January 2014

5.SB3.14

Fingermark Visualisation Manual

Solvent Black 3

Appendices

5.SB3.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Solvent (limited solubility for Solvent Black 3)

Glossary

Index

Supplementary Information Solvent Black 3 molecule

a

Solutions

Solvent Black 3 formulations

Two Solvent Black 3 solutions have previously been

recommended for operational use by CAST, one based on ethanol and the other on PGME. The ethanol-based formulation was only suitable for use in a laboratory

because of its flammability, whereas the PGME-based Substrate Fingermark deposit (lipids with high solubility for Solvent Black 3)

formulation can be used both in a laboratory and at

scenes provided that appropriate precautions are taken. Tests indicated that the performance of the PGME-

based formulation is closely equivalent to if not better than the ethanol-based formulation in a laboratory

b

environment, and therefore the ethanol-based formulation was withdrawn because it was felt that it offered no operational benefits n

Solvent Black 3 molecules dissolving into fingermark deposit Dyed fingermark ridges

c

Schematic illustration of the Solvent Black 3 process (a) Solvent Black 3

molecules in solvent with limited solubility (b) lipophilic component of Solvent

Black 3 molecule preferentially dissolving into lipids in fingermark ridges and (c) fingermark after drying, leaving dyed ridges. Home Office January 2014

5.SB3.15

Fingermark Visualisation Manual

Solvent Black 3

Appendices

5.SFDS.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Fluorescent stains; Superglue dyes; Superglue stains

Contents Options ..................................... 5.SFDS.2 Laboratory or Scene? ............. 5.SFDS.3 Laboratory Use......................... 5.SFDS.4 Health and Safety .................. 5.SFDS.4 Equipment .............................. 5.SFDS.6 Chemicals .............................. 5.SFDS.7 Solutions ................................ 5.SFDS.8 Processing ........................... 5.SFDS.10 Post-Processing ................... 5.SFDS.11 Scene Use............................... 5.SFDS.12 Additional Considerations..... 5.SFDS.12 Troubleshooting...................... 5.SFDS.13 Supplementary Information .. 5.SFDS.16

Main Uses ✘ Latent ✘ Blood ✘ Grease ✔ Other*

is highly fluorescent and must be viewed using Fluorescence

✔ Non-Porous ✘ Semi-Porous ✘ Porous

* Enhancement of marks treated with Superglue Fuming.

Key information

●● Competent personnel specialising in fingermark

enhancement must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for four Category

A Superglue Fluorescent Dye Staining formulations: ■■ ■■

ethanol-based Basic Yellow 40 and Basic Red 14; water-based Basic Yellow 40 and Basic Red 14.

●● Full process details are given for selection, laboratory use

and additional considerations given for scene use.

Process Overview

It is a chemical process that involves the application of a

solution to the item or surface followed by washing with water. More Details

Safety and Effectiveness Summary The Process

●● Superglue Fluorescent Dye Staining can be used safely and

effectively in a laboratory.

●● Ethanol-based formulations are generally more effective than

water-based ones. However, for safety reasons, water-based formulations are normally used at scenes.

●● It is only effective at enhancing marks previously treated with

Superglue Fuming.

●● The process requires subsequent fluorescence examination

to be effective.

The Item and Surface

●● The process is only effective at enhancing superglue-

developed marks on non-porous surfaces.

Fingermarks developed using Superglue Fuming can be

●● Fluorescent dyes can adversely stain the background of

maximise the contrast between the developed mark and the

Integrated Use

enhanced in a variety of ways to make them more visible i.e. background. One method is to use dyes which cause the superglue marks to fluoresce.

These stain the superglue marks in the same way as dyes stain

textiles. The noodle-like structure of the superglue mark consists of fibres of poly-cyanoacrylate, which are similar to acrylic textile fibres as they contain several anionic groups. These anionic groups interact with the basic dye during the dyeing stage,

increasing retention of the dye by the fibres. The resultant mark Home Office January 2014

Examination.

semi-porous items, hence obscuring the mark.

Superglue Fluorescent Dye Staining is only used after the Superglue Fuming process but may be detrimental to subsequent fingermark or forensic processing.

●● See Chapter 4 for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7 for information on integration of fingermark

and other forensic processes.

5.SFDS.1

Fingermark Visualisation Manual

A Superglue Fluorescent Dye Staining

5.SFDS.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options Ethanol-based Basic Yellow 40 and Basic Red 14

●● The ethanol-based superglue fluorescent dye formulations are generally the most

effective for the visualisation of fingermarks developed with Superglue Fuming.

●● The ethanol-based formulations are highly flammable. ●● Where ethanol is causing some printed inks to run

and there is no issue with using highly flammable solvents, consider using the Category B process

Superglue Fluorescent Dye Staining (propanol-

based) rather than the water-based formulation as the former is more effective.

●● The performance of Basic Yellow 40 and Basic Red

14 are similar.

●● The choice of whether to choose Basic Yellow 40 or

Basic Red 14 is dependent on the availability of the

high-intensity light source used during Fluorescence Examination.

●● Basic Yellow 40 is best visualised by illuminating

in the violet/blue region resulting in green/yellow fluorescence.

●● Basic Red 14 is be best visualised by

illuminating in the green region giving

Water-based Basic Yellow 40 and Basic Red 14

●● Water-based formulations are significantly less effective in dyeing the superglue-

developed fingermarks and the resultant fluorescence is much less intense.

●● However, where flammable ethanol-based dye formulations cannot be used the

water-based dyes may be used as an alternative.

●● Situations where it may be considered (although there may be more effective

alternative processes) are: ■■ ■■ ■■

at a scene;

where there is excessive dye take-up by the substrate; in a laboratory with insufficient extraction.

Sequential Use of Fluorescent Dyes

●● It is possible to use either of these fluorescent dyes in sequence with one another if

the background fluorescence interfered with the fluorescence of the dye. This may be achieved on targeted areas by carefully washing out the first dye with ethanol and then applying the alternative dye as normal.

●● See Chapter 4: Process Selection for information on its sequential use with other

fingermark visualisation processes.

●● See Chapter 7: Other Forensics for information on its sequential use with other

forensic methods.

orange/red fluorescence.

●● It should also be considered that

Basic Yellow 40 fluoresces where the eye is most sensitive.

Basic Red 14 dyed superglue on a plastic bag (top).

Basic Yellow 40 dyed superglue on an adhesive tape (bottom).

Home Office January 2014

5.SFDS.2

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

5.SFDS.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of health and safety, effectiveness and practical issues associated with the use of this process. Those responsible for deciding

whether to process items in the laboratory or at the scene, e.g. crime scene managers or investigators, must consider in addition to the information below: ●● the detailed process instructions; and

●● other factors dictated by the investigation.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’.

Superglue Fluorescent Dye Staining can be used safely and effectively in a laboratory, and, providing the water-based formulation is used, at scenes.

Health and Safety

The ethanol-based formulations are highly flammable (flash point approximately13˚C)

and should not generally be used at scenes without extremely stringent conditions to operating procedures.

●● In a laboratory, the risks of creating a flammable atmosphere will be minimal

as long as processing is carried out in purpose-built tanks positioned in an wellventilated area or a fume cupboard.

●● At scenes, the water-based fluorescent dye formulations must be used in situations

where flammable atmospheres would be produced by ethanol-based formulations.

Effectiveness

The ethanol-based formulations are significantly more effective than the water-based formulations and should be used where possible.

Practicality

Superglue Fluorescent Dye Staining is a messy process if not contained and it is

generally considered more practical to remove items back to a laboratory for treatment. Processing large items may require additional considerations to avoid run-off of

solution and wash into areas not requiring treatment. Removal of residual dye from processed items may be difficult.

●● In a laboratory it should be possible to contain the Staining Solution and wash

waste.

●● At scenes consideration must also be given to the need for suitable equipment for

the containment of the Staining Solution and wash waste.

Home Office January 2014

5.SFDS.3

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

5.SFDS.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Superglue Fluorescent Dye Staining may be carried out with no known hazards

to health provided practitioners are trained and competent, if appropriate control

measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’).These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

Laboratory Use Hazards associated with Superglue Fluorescent Dye Staining ●● Superglue Fluorescent Dye Staining is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions or mixtures.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional hazard

Risk

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

Suggested control measures

Creation of a flammable atmosphere when preparing and using the ethanol-based Working Solution.

Fire.

●● Prepare and apply the

Exposure to quantities of dye solution.

Staining hands, clothes and body with dye.

●● Wear appropriate

●● In providing the Category A process instructions it is assumed that: ■■

Index

Working Solution in a fume cupboard or well-ventilated area. See working with flammable liquids for further information.

gloves when preparing or using solutions to protect the hands, especially if they are to be immersed in the solutions. ●● Wear a disposable apron to protect the clothes and body.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.SFDS.4

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Glossary

5.SFDS.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Health and Safety: Labelling Solutions While the hazards associated with the chemicals used can be found on the SDS, those associated with the solutions need to be calculated from their percentages in the final solution. To assist in this, in 2011, CAST commissioned work to calculate the risks

associated with the solutions it was using at the time. The results of those calculations

are given here for guidance only to those responsible for risk assessments of solutions used locally.

Hazards* typically associated with prepared Superglue Fluorescent Dye Solutions (CLP) Solution

Symbols

Signal Word and Hazard Statements

Ethanol-based Basic Yellow 40

‘DANGER’ H225 ‘Highly Flammable liquid and vapour’

Ethanol-based Basic Red 14

‘DANGER’ H225 ‘Highly Flammable liquid and vapour’

Water-based Basic Yellow 40

None required

None required

Water-based Basic Red 14 None Required

None required

Powder Suspension Stock Detergent

‘DANGER’ H302 ‘Harmful if swallowed’ H318 ‘Causes serious eye damage’

Home Office January 2014

Hazards* typically associated with prepared Superglue Fluorescent Dye Solutions (CHIP) Solution

Symbols

Hazard Statements

Ethanol-based Basic Yellow 40

R11 ‘Highly flammable’

Ethanol-based Basic Red 14

R11 ‘Highly flammable’

Water-based Basic Yellow 40

None required

None required

Water-based Basic Red 14

None required

None required

Powder Suspension Stock Detergent

R22 ’Harmful if swallowed’ R41 ‘Risk of serious damage to eyes’ *Solution hazards based on CAST’s solutions and calculated by ChemLaw UK. Flammability classifications assessed either theoretically or by measurement by Hazard Evaluation Laboratory (HEL).

5.SFDS.5

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Appendices

5.SFDS.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Equipment

Superglue Fluorescent Dye Staining should be used in areas where the solutions can be easily contained. The equipment listed below is often used if the process is used

regularly, although it can also be applied using simple equipment (dishes, wash bottles etc.) within a fume cupboard.

Laboratory Use Equipment

Requirements

Wet bench with integral dye tanks

A wet bench with integral dyeing facility should: ●● be made from a chemical-resistant material of suitable thickness and suitably sealed to prevent leaks; ●● contain a dye tank fitted with a drain to facilitate disposal of contaminated dye and for cleaning purposes; ●● have a catch tank large enough to collect all the dye from a ruptured dye tank; ●● contain a dye tank designed so that wide and tall items can be easily treated – an upside-down L-shaped dye tank may be preferable as larger items can be treated, whilst minimising the quantity of stored ethanol (if using an ethanol-based dye solution); ●● contain a dye tank covered by a lid when not in use to reduce evaporation of ethanol and build up of highly flammable vapours in the laboratory – evaporation of ethanol can be further reduced by use of a floating bath lid or floating spheres; ●● incorporate a similar wash tank with water inlet and outlet valves so that the flow of water is sufficient to remove excess dye – alternatively a hose or shower head can be used to rinse items.

Extraction for wet bench and dye tanks

Extraction must: ●● be provided if other local exhaust ventilation is not sufficient to reduce ethanol vapours to below flammable limits – this should allow enough space to dye and wash typical items without restriction.

Drying facility

A drying facility should: ●● have hanging rails/lines to enable the adequate drying of items such as plastic bags; ●● have a drip tray capable of collecting any residual dye/water from the treated items; ●● be well ventilated; ●● have the capacity to allow a day’s typical throughput to dry.

If equipment is to meet the requirements as outlined here, it must be well maintained

and, if appropriate, serviced regularly in accordance with the manufacturer’s instructions. General laboratory equipment that may be required is outlined in Chapter 3.

Home Office January 2014

Index

5.SFDS.6

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Glossary

5.SFDS.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists process-specific chemicals that are required for Superglue Fluorescent Dye Staining.

Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

Unless specified, water used within the solutions or for rinsing is purified. See Chapter 3 safe handling of chemicals for general information and effective use of chemicals for details on dye purity. Common Name

Alternative Name(s)

CAS Number

Grade

Basic Yellow 40 There are many (BY40) alternative names.

29556-33-0

Basic Red 14 (BR14)

Yoracryl Red 4G

12217-48-0

> 50 %

Ethanol

Ethyl alcohol

64-17-5

≥96 %

Ethylene glycol

Ethane-1,2-diol

107-21-1

> 99 %

Triton® X-100

There are many alternative names.

9002-93-1

Laboratory

Home Office January 2014

> 80 %

Basic Yellow 40 refers to several dyes with different CAS numbers. Alternatives are structurally similar and may be indistinguishable, in terms of mark enhancement, from the one given.

5.SFDS.7

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Appendices

5.SFDS.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Solutions

Consult Chapter 3 for general information on solution preparation, safe storage of chemicals, solutions and mixtures

(which includes information on packaging and labelling), management of waste

for disposal of solutions and guideline

expiry periods. This page gives additional information relevant to this process.

Glossary

Index

Laboratory Use

Solutions Ethanol-based Staining Solution

2 g dye 1 L ethanol Dye options: Basic Yellow 40 (BY40) or Basic Red 14 (BR14)

(1) Prepare selected solution

Water-based Staining Solution

1 g dye 2 mL Powder Suspension Stock Detergent* 1 L water Dye options: Basic Yellow 40 (BY40) or Basic Red 14 (BR14)

Powder Suspension Stock Detergent Solution

(2) Label appropriately

(3) Store appropriately

a) Triton® X-100 should either be mixed with ethylene glycol before addition of water, or with the ethylene glycol and water already mixed. Then stir for approximately ten minutes to insure thorough mixing. b) BY40 Solutions are yellow. BR14 Solutions are red. Powder Suspension Stock Detergent Solution is colourless. a) All solutions should be labelled in line with the guidance in Superglue Fluorescent Dye Staining Health and Safety.

a) Staining Solutions and Powder Suspension Stock Detergent Solution have guideline expiry dates of 12 months after preparation if stored at room temperature.

(4) Dispose of appropriately

350 mL ethylene glycol 250 mL Triton® X-100 400 mL water

* Stock Detergent Solution can be replaced with Kodak Photo-Flo on a one-for-one basis. Final solutions are identified by a red border. See Ready Reckoner for other quantities of solution. Home Office January 2014

5.SFDS.8

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Appendices

5.SFDS.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Solutions continued Ready Reckoner Quantity Solution

Chemical

1L

2L

5L

Ethanol-based Staining Solutions

Dye

2g

4g

10 g

Ethanol

1L

2L

5L

Dye

1g

2g

5g

Water

1L

2L

5L

PS Stock Detergent Solutions

2 mL

4 mL

10 mL

Water-based Staining Solutions

Ready Reckoner Quantity of Powder Suspension Stock Detergent Solution Chemical

500 mL

1L

2L

Ethylene glycol

175 mL

350 mL

700 mL

Triton® X-100

125 mL

250 mL

500 mL

Water

200 mL

400 mL

800 mL

Home Office January 2014

5.SFDS.9

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Appendices

5.SFDS.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Processing Preparation (1) Work area

(2) Chemicals

a) The application method is not a critical factor to the success of the process. Small items can be dipped into a tray or a specially designed tank. Alternatively, or for larger items, they can be stained in a fume cupboard by pouring, squirting or brushing fluorescent dye solution over the surface. a) The absolute concentration of dye solutions is not critical to the success of the process.

(3) Items

(5) Rinse thoroughly

If using and storing the dye solution within a tank the concentration of the solution may change as the solvent evaporates and/or the solution is used up. When topping up try to ensure the concentration of the Staining Solution is very roughly that of the Starting Solution.

a) Minimise handling of items during processing.

(6) Dry item

(7) Examination Primary: Fluorescence Examination

Processing (4) Apply solution

Continued on next column Home Office January 2014

a) Apply the Staining Solution to the item by suitable means such as immersion, floating or pouring for an appropriate amount of time. The time required for the ethanol-based staining is about 15–20 seconds, but longer times of approximately one minute are required when waterbased solutions are used. b) Ethanol-based formulations are highly flammable and must not be sprayed. c) Immediately proceed to the next step if inks are seen to run or dissolve in ethanol-based staining solutions.

Secondary: Visual Examination

a) Rinse the item until excess dye has been removed from the background. This can be done using suitable means, such as cold, slow running tap water or by applying tap water with a suitable applicator such as a wash bottle, small garden spray unit or shower head. b) Strong background fluorescence may be reduced by targeted washing with ethanol.

a) See Drying of items.

a) Fluorescent BY40 marks are green/yellow. Fluorescent BR14 marks are orange. Visible BY40 marks are pale yellow. Visible BR14 marks are red. b) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination and Fluorescence Examination, particularly for low-contrast marks or marks on dark or patterned surfaces. c) Mark up viable fingermarks appropriately and capture image. d) After examination, items can be re-treated if necessary.

5.SFDS.10

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Glossary

5.SFDS.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Residual processing chemicals

a) Items may emit an odour of superglue vapour from undyed areas when items are only partially dyed. See Superglue Fuming for further details.

(2) Cleaning

a) Items can be cleaned in several ways, but it may not be possible to return items to their original state. b) Option 1 (preferred): Items may be scrubbed with detergent and water to physically remove solid superglue deposits and dye. Abrasive cloths will aid in this, although damage may be caused to the surface. c) Option 2: Polar solvents such as butanone can be used to dissolve and remove solid superglue deposits and dye. However, it may dissolve some surfaces such as plastics and there are additional health and safety precautions to take into consideration (not given).

(3) Disposal or return

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (4) Re-use of solutions

Home Office January 2014

a) Staining Solutions may be re-used provided this will not interfere with subsequent forensic processes such as DNA.

5.SFDS.11

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Appendices

5.SFDS.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Scene Use

Additional Considerations If a decision has been made to apply Superglue Fluorescent Dye Staining at a scene, a number of additional

considerations need to be taken into account,

over and above those given for laboratory use. The

recommendations below cannot be prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and

will require different control measures to mitigate

any risks identified before work can be carried out

safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make

the process as effective as possible within the constraints of the scene;

●● present a range of practical issues that need to be

overcome.

This page must be read in conjunction with the laboratory process instruction.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter 3, Section 3.1 –

Scene use of processes and treatment of large

For health and safety, consider:

●● using water-based fluorescent dye formulations in

situations where flammable atmospheres would be produced by ethanol-based formulations;

●● that the ethanol-based fluorescent dye formulations

are highly flammable (flash point approximately13˚C)

For practicality, consider:

●● access to the areas to be treated;

●● the additional time and costs of applying the process

at the scene, including: ■■ ■■

and should not generally be used at scenes

to contain the solutions during application, and

procedures;

needed for transporting the solutions (made in the laboratory) to the scene;

additional equipment to make the process safe and effective and to minimise mess, e.g. tissue

without extremely stringent conditions to operating ●● what additional packaging and labelling will be

transport costs;

avoid run-off onto areas not requiring treatment; ■■

scene clean-up, which may involve dismantling badly stained surfaces for disposal.

●● providing additional PPE to protect practitioners, and

if required specialist equipment such as personal gas flammability monitors and thermometers.

For effectiveness consider:

●● whether the process instructions as given for carrying

out the process in the laboratory can be followed,

after consideration of the constraints posed by the scene;

●● that the water formulations are considerably less

effective than the ethanol-based formulations.

areas for other general information.

Home Office January 2014

5.SFDS.12

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Glossary

5.SFDS.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Damage to Superglue-Developed Fingermarks Recognition

Damage to the superglue-developed mark.

A superglue-developed fingermark on a plastic bag before and after handling.

Cause Rough handling of items.

Home Office January 2014

Effect

Prevention

Rubbing of developed marks can damage Handling of items before, during and after the superglue deposit resulting in loss of processing should be kept to a minimum detail and less fluorescence intensity. and carried out with care.

Correction There are no corrective measures.

5.SFDS.13

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Appendices

5.SFDS.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Dissolving of Surface Inks Recognition

A bag with printed text has been placed into ethanol-based Basic Yellow 40 solution and the ink is beginning to dissolve from certain areas of the surface.

Inks on a plastic bag dissolving in a bath of ethanol-based Basic Yellow 40. Cause Some inks used for printing on surfaces of items are soluble in certain solvents including ethanol.

Home Office January 2014

Effect Once the ink has started to dissolve it may run across regions of the surface and obscure developed marks.

Prevention If possible, before treating unknown surfaces, carry out a spot test with the dye solution on the surface away from the area of interest to assess whether running of inks may occur. If the spot test indicates ink running may be a problem, either: ●● use a water-based formulation (less effective); or ●● use Category B Superglue Fluorescent Dye Staining (propanol-based).

Correction Remove the item from the dye solution immediately to limit the damage. There are no corrective measures.

5.SFDS.14

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Appendices

5.SFDS.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

High Background Staining Recognition

It has proved difficult to wash Basic Yellow 40 from the

surface, resulting in large areas of background staining.

PVC processed with Superglue Fuming

and enhanced with ethanol-based Basic Yellow 40.

Cause The surface has a high affinity for the dye or can absorb it, which may be because: ●● the surface has a degree of porosity; ●● the chemical nature of the surface means it can be stained by the dye used; ●● contamination is present on the surface.

Home Office January 2014

Effect The background retains the dye after processing and washing, resulting in the background also fluorescing strongly during Fluorescence Examination. This may obscure developed marks.

Prevention If possible, before treating unknown surfaces, carry out a spot test with the dye solution on the surface away from the area of interest to assess whether background staining may occur. Use an alternative, non-dye-based superglue enhancement method if high background staining is likely or indicated by the spot test.

Correction Use an additional, non-dye-based superglue enhancement method on the surface that is capable of discriminating between the mark and background e.g. Powders or VMD. Then use Fluorescence Examination to further improve the contrast during image capture. Success is not guaranteed.

5.SFDS.15

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Appendices

5.SFDS.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

The theory for the application of fluorescent dye stains is essentially the same

enhanced:

polycyanoacrylate, which are similar in nature to acrylic textile fibres in that they contain

There are several means by which marks developed using Superglue Fuming can be ●● optical methods, such as oblique lighting;

●● physical methods, such as Powders and Vacuum Metal Deposition; ●● chemical methods, such as visible or fluorescent dye staining.

Superglue Fluorescent Dye Staining is among the most effective processes for the

visualisation of Superglue Fuming marks. A range of such dyes have been proposed

as for textile dyeing. The noodle-like structure of the mark consists of fibres of

several anionic groups. These anionic groups interact with the basic (cationic) dye

during the dyeing stage, ensuring retention of the dye by the fibres whilst excess dye is washed from the background. Electron micrographs appear to show that the noodle-

like structure may be flattened by the dyeing stage, but this does not interfere with the visualisation as the resultant mark is highly fluorescent n

but almost all are basic in character. The two dyes recommended in this Manual (Basic

A close-up of a mark enhanced with

and safety issues.

Basic Yellow 40.

Yellow 40 and Basic Red 14) are very effective and currently believed to have no health

Superglue Fuming then stained with

Scanning electron micrographs of part of a mark developed using Superglue Fuming (left) before and (right) after application of a fluorescent dye.

Home Office January 2014

5.SFDS.16

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining

Appendices

5.SF.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

CNA Fuming; Cyanoacrylate Fuming

Contents Laboratory or Scene?................... 5.SF.2 Laboratory Use.............................. 5.SF.3 Health and Safety.........................5.SF.3 Equipment.....................................5.SF.4 Chemicals.....................................5.SF.4 Processing....................................5.SF.5 Post-Processing............................5.SF.6 Scene Use...................................... 5.SF.7 Additional Considerations.............5.SF.7 Troubleshooting............................. 5.SF.8 Supplementary Information........ 5.SF.11

Main Uses ✔ Latent ✘ Blood ✘ Grease

Safety and Effectiveness Summary ✔ Non-Porous ✔ Semi-Porous ✘ Porous

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Superglue Fuming refers to fuming only and does not include

subsequent enhancement.

●● This section contains process instructions for Superglue

The Process

●● Superglue Fuming can be used safely and effectively in a

laboratory using specialist equipment.

●● Although it can be used at scenes there will be additional

health and safety issues and the effectiveness is likely to be variable.

●● The effectiveness is linked to the ability to control

temperature and relative humidity.

The Item or Surface

●● Superglue Fuming can be effective at visualising latent marks

on non-porous, semi-porous and adhesive surfaces, although the number of marks developed falls as the surface porosity increases.

Fuming using high humidity only.

●● Process effectiveness reduces considerably on surfaces that

additional considerations given for scene use.

●● It is particularly useful on rough surfaces where other

●● Full process details are given for laboratory use and

Process Overview

Superglue vapour polymerises on some latent fingermarks to produce a white deposit. This polymerisation can be initiated

by water and some other latent fingermark constituents. Salts

within fingermarks are important as they absorb moisture at high humidity.

It is a chemical process that involves exposing items or

surfaces to superglue vapour at high humidity within a specialist superglue fuming cabinet (if possible). More Details

have been previously wetted.

processes become ineffective.

●● Some weakly developed fingermarks can be difficult to see,

even on dark surfaces; use of subsequent enhancement

is essential to reveal the maximum number of fingermarks although options may be limited at scenes.

Integrated Use

Superglue Fuming may be detrimental to subsequent fingermark or forensic processing.

●● See Chapter 4: Process Selection for information on its

sequential use with other fingermark visualisation processes.

●● See Chapter 7: Other Forensics for information on integration

of fingermark and other forensic processes.

Home Office January 2014

5.SF.1

Fingermark Visualisation Manual

A Superglue Fuming

1st proof

5.SF.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of

Superglue Fuming can be used both in the laboratory and at

practical issues associated with the

treat removable items with Superglue Fuming in a laboratory

health and safety, effectiveness and use of this process. Those responsible for deciding whether to process items in the laboratory or at the scene, e.g.

crime scene managers or investigators, must consider in addition to the information below:

●● the detailed process instructions;

and

●● other factors dictated by the

investigation.

See Chapter 2, Section 2.4,

‘Fingermark Evidence Recovery Planning’.

scenes, although it is safer, and generally more effective, to taking care to reduce additional handling and packaging which may damage any fingermarks present.

Health and Safety

Exposure to superglue fumes in excess of the Workplace

Exposure Limit by anyone (staff, members of the public, home owners etc.) must be avoided.

●● In a laboratory, this is easy to achieve as fumes are

contained within specially designed superglue fuming cabinets.

●● At scenes, Superglue Fuming can be used in temporary

enclosures such as tents or rooms. It can be difficult to

contain fumes during processing; a practitioner may have to

enter the area to ventilate directly after fuming and there may be longer-term out-gassing of fumes from all surfaces within the enclosure.

Effectiveness

●● In a laboratory, specialist superglue fuming cabinets are

used to control environmental parameters and allow the

practitioner to observe development. Optimal glue quantities

are generally known. Consistently good results are achieved. There are more options for subsequent enhancement of marks.

●● At scenes, optimal environmental parameters may be

difficult to achieve. It may be difficult to predict how much superglue is required and it is not normally possible to

observe fingermark development. Results are variable. There are limited options for subsequent enhancement of marks.

Practicality

This will depend on the size of the item or surface to be treated and whether or not it can be readily removed to a laboratory. ●● In a laboratory, the process has few practicality issues

provided the item fits into the cabinet.

●● At scenes, equipment set-up and enclosure preparation can

be time-consuming. It may not be practical to used at some scenes due to scene clean-up difficulties.

The number of marks found with Superglue Fuming is dependent upon the set-up, use, level of control and familiarity with the required specialist fuming equipment by the practitioner.

Home Office January 2014

5.SF.2

Fingermark Visualisation Manual

Superglue Fuming

5.SF.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Superglue Fuming may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards

(e.g. ‘residual processing chemicals on items are hazardous’) and/or control

measures, (e.g. ‘work within a fume cupboard’).These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General health and safety information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

Index

Laboratory Use Hazards associated with Superglue Fuming ●● Superglue Fuming is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS). The SDS for superglue only covers the handling of superglue for its intended purpose as a glue. It does not include safety information for the

hazards associated with heating superglue, nor does it include hazards associated with outgassing of superglue fumes from processed items (see below).

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional Hazard

Risk

Exposure to superglue fumes generated: ●● during processing; ●● from outgassing from surfaces previously exposed to fumes such as items or the inside of the superglue fuming cabinet.

Adverse respiratory health effects associated with breathing in fumes whilst: ●● (un)loading the cabinet; ●● evaporating superglue during processing; ●● cleaning the cabinet; ●● examining items. Concentrations of superglue fumes during processing will considerably exceed the WEL. There is a possibility of prolonged exposure to superglue fumes above the WEL causing chronic effects in some individuals.

Suggested control measures ●● The process must be

carried out in a sealed enclosure such as a superglue fuming cabinet to contain the fumes generated during processing. ●● The superglue fuming cabinet must have adequate LEV so that operators are not exposed to levels above the WEL at any stage. ●● Examine items which have been treated with Superglue Fuming in a well-ventilated area or preferably on a downdraught bench.

5.SF.3

Fingermark Visualisation Manual

Superglue Fuming

Glossary

5.SF.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Index

Laboratory Use

Equipment

Superglue Fuming must be carried out in an superglue fuming cabinet where possible. Modern cabinets can accommodate most items recovered from scenes, including

items such as doors or bikes. If items cannot be fitted into a cabinet then additional considerations for scene use must be considered prior to using an alternative enclosure.

If equipment is to meet the requirements as outlined below, it must be well-maintained

and, if appropriate, serviced regularly in accordance with the manufacturer’s instructions. General laboratory equipment that may be required for Superglue Fuming is outlined in Chapter 3.

Equipment

Requirements

Superglue fuming cabinet

A superglue fuming cabinet must: ●● maintain the relative humidity within the cabinet between 75-90% at the start of, and for the duration of, Superglue Fuming; ●● operate at ambient temperature and pressure; ●● have a circulation fan capable of evenly distributing superglue vapour and humidity within the cabinet; ●● have transparent windows so that fingermark development can be observed; ●● be airtight during operation and be fitted with an appropriate system for extraction or filtration. In addition, a superglue fuming cabinet should: ●● be located in such a position to minimise temperature variations across the cabinet; ●● have shelving and/or hangers to support items; ●● heat superglue to about 120°C for an acceptable evaporation rate (if producing superglue fumes via heating).

Superglue dish

If using a commercially available superglue cabinet, use dishes recommended by the manufacturer. These are normally disposable aluminium foil dishes.

Home Office January 2014

Glossary

Chemicals

This table lists chemicals that are required for Superglue Fuming. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3 safe handling of chemicals for general information. Common Name Superglue

Alternative Name(s)

CAS Number

Ethyl cyanoacrylate, 7085-85-0 ECA, CNA

Grade Standard commercial

superglue with no, or minimal, thickening additives

5.SF.4

Fingermark Visualisation Manual

Superglue Fuming

Appendices

5.SF.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Equipment and chemicals

(2) Items

a) Follow manufacturer’s instructions for use of equipment. b) Remove build-up of superglue fumes from within the cabinet prior to opening the cabinet door. There may still be a detectable odour of superglue fumes. c) Pour an appropriate quantity of superglue into a suitable, clean vessel such as a disposable aluminium foil dish. Place the dish on a heater block at ambient temperature. a) If possible, load the fuming cabinet with similar items. b) Support or suspend the items in the cabinet, allowing sufficient room for air to circulate between them. c) Items must be at ambient temperature prior to treatment. See underdeveloped fingermarks and overdevelopment.

a) Optimal contrast is normally achieved within10-30 minutes.

(7) Remove items from the cabinet

a) There may still be a detectable odour of superglue fumes. b) Care must be taken when handling the items as the white polymer deposit is fragile.

(8) Examination

Processing (3) Humidify cabinet

(6) Halt further development once optimal contrast is achieved by removing superglue fumes from within the cabinet

a) The relative humidity in the cabinet must be maintained within the range 75-90% whilst the items are exposed to superglue fumes.

(4) Evaporate superglue

a) The heater block should allow the superglue to reach about 120°C.

(5) Observe fingermark development

a) White deposits will gradually build up on the items. b) If it is not possible or practical to observe development then the operator must follow manufacturer’s instructions for recommended process conditions OR pre-determine the optimum process conditions.

Primary: Visual Examination

a) Items should be examined in a well-ventilated area preferably on a down-draught bench. b) Visible fingermarks are white. c) There are many non-destructive optical processes that can be considered when examining and imaging fingermarks in addition to Visual Examination. Ultraviolet (UVC) Reflection may prove particularly useful on some items. d) Mark up viable fingermarks appropriately and capture image. e) After examination, items can be re-treated if necessary.

Continued on next column

Home Office January 2014

5.SF.5

Fingermark Visualisation Manual

Superglue Fuming

Appendices

5.SF.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Residual processing of chemicals

(2) Cleaning processed items

(3) Disposal or return of processed items

Home Office January 2014

a) Items will emit low levels of superglue fumes for a period of time, the quantity of which depends on the size and nature of the treated item, and often these fumes are associated with an odour. b) The use of Superglue Fluorescent Dye Staining will quickly reduce or eliminate the emission of fumes from most items. c) Storage of items will slowly reduce the emission of fumes. d) Cleaning items will quickly reduce or eliminate the emission of fumes from most surfaces. a) Items can be cleaned in several ways, but it may not be possible to return items to their original state. b) Option 1 (preferred): Items may be scrubbed with detergent and water to physically remove solid superglue deposits. Abrasive cloths will aid in this, although damage may be caused to the surface. c) Option 2: Polar solvents such as butanone can be used to dissolve and remove solid superglue deposits. However, it may dissolve some surfaces such as plastics and there are additional health and safety precautions to take into consideration (not given).

Equipment and Chemicals (4) Disposal of residual superglue in dish

(5) Cleaning the cabinet

a) Add water to the dish and allow the liquid superglue to solidify before putting the dish into normal laboratory waste. Do not pour liquid superglue down the drain.

a) Superglue fuming cabinets should be regularly cleaned so that the practitioner can observe mark development when required. Follow manufacturer’s instructions or use Option 1 (described above), but do not use abrasive cloths as this may cause scratches and encourage accelerated polymer growth on the inside of the cabinet.

a) Provided items have been cleaned they may be returned to owner or discarded with ordinary waste.

5.SF.6

Fingermark Visualisation Manual

Superglue Fuming

Appendices

5.SF.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Scene Use

Additional Considerations If a decision has been made to apply Superglue Fuming at a scene, a

number of additional considerations need to be taken into account, over and above those given for laboratory use. The recommendations below

■■

■■

period of time, steam cleaning etc.). Note: cleaning-up protocols need to be

cannot be prescriptive since every scene will be different and:

studied in more detail to ensure that there is no risk to subsequent users or

●● each must be subject to a local risk assessment and will require different control

measures to mitigate any risks identified before work can be carried out safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make the process as effective as possible

within the constraints of the scene.

This page must be read in conjunction with the laboratory process instruction. See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter

3, Section 3.1 - Scene use of the processes and treatment of large areas for other general information.

For health and safety, consider:

●● whether it is possible to adequately contain superglue fumes in a temporary

enclosure (such as a fuming tent, vehicle or room) during processing and whether fumes can be safely vented/extracted afterwards;

●● whether it will be possible to remove all residual hazardous chemicals from the

scene as: ■■ ■■

superglue fumes may persist within the scene for long periods of time; all surfaces within the enclosure will be exposed to fumes leading to

considerable outgassing particularly for high surface areas (or porous) items/

surfaces; if not, serious consideration should be given to reversing the decision to carry out the process at the scene. ●● minimising the risk of exposing practitioners and the public to the hazards by:

Home Office January 2014

removing items from the enclosure that do not need to be exposed to superglue fumes (e.g. soft furnishings etc.); establishing an effective cleaning protocol (e.g. continuous ventilation for a

occupiers or items or premises treated and that the superglue levels will stay below the WEL subsequently;

●● providing additional PPE to protect practitioners from fumes.

For effectiveness consider:

●● whether the process instructions as given for carrying out the process in the

laboratory can be followed, with any constraints posed by the scene;

●● that it may be difficult to gauge the correct quantity of superglue to vaporise, create

the vapour, and distribute it evenly within the treatment space;

●● that it is not normally possible to observe mark development;

●● whether the temperature variations can be reduced to acceptable levels within the

enclosure;

●● whether the optimum humidity conditions are achievable;

●● how developed marks on light-coloured surfaces will be visualised as options may

be limited.

For practicality, consider:

●● access to the areas to be treated;

●● size of the area(s) requiring treatment;

●● the additional time and costs of applying the process at the scene, including: ■■ ■■

transport costs;

additional equipment to run and make the process safe and effective and to

minimise mess, e.g. heaters, humidifiers, sealing tape and warning signs etc.; ■■

longer set-up times (including removing all portable items/surfaces that do not need to be treated from the enclosure);

■■

scene clean-up, which may involve dismantling surfaces for safe disposal.

5.SF.7

Fingermark Visualisation Manual

Superglue Fuming

Glossary

5.SF.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Patchy Development Recognition

There is normal development on some areas of the item but no development on others.

(left) A crowded superglue fuming

cabinet with items overlapping and even

sticking together and (right) a fingermark developed on the black bin bag located within the centre of the cabinet.

Cause The item was not uniformly exposed to the superglue vapour and some areas may have had no exposure.

Home Office January 2014

Effect Limited or no polymer growth on some areas resulting in patchy fingermarks.

Prevention

Correction

Ensure that: ●● the superglue fuming cabinet is not overloaded and items are not touching; ●● items are not folded over on themselves; ●● movable items are secured so that they cannot move and touch other items or fold over on themselves.

It may be possible to reprocess areas that have not been exposed to superglue fumes already. The already developed areas may be further developed and should be imaged before reprocessing.

5.SF.8

Fingermark Visualisation Manual

Superglue Fuming

Appendices

5.SF.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Troubleshooting

Underdeveloped Fingermark Recognition

The fingermark is faint and appears underdeveloped.

Fingermark visualised with Superglue Fuming on a black plastic bin bag.

Home Office January 2014

Cause

Effect

Prevention

Correction

The relative humidity at the surface of the item was too low during processing.

Poor polymer growth resulting in fingermarks that are difficult to see and thus may be missed.

Ensure that: ●● the superglue fuming cabinet meets the requirements as outlined in equipment; ●● there is sufficient room for air to circulate between items; ●● items are at ambient temperature prior to processing.

It may be possible to re-treat the item. Faint fingermarks will often be enhanced with subsequent processes such as Superglue Fluorescent Dye Staining.

An insufficient quantity of superglue reached the surface.

Limited polymer growth resulting in fingermarks that are difficult to see and may be missed.

Ensure that: ●● the superglue fuming cabinet meets the requirements as outlined in equipment; ●● there is sufficient room for fumes to circulate between items; ●● enough superglue is used and processing times are adequate. Note: if the cabinet is functioning correctly and an appropriate quantity of glue is used, there should not be any liquid superglue remaining at the end of processing. If there is, this suggests that the heater is not hot enough or the fuming time is not long enough.

It may be possible to re-treat the item. Faint fingermarks will often be enhanced with subsequent processes such as fluorescent dye stains.

The fingermark contains limited constituents suitable for visualisation with Superglue Fuming.

Limited polymer growth resulting in fingermarks that are difficult to see and may be missed.

There are no preventive measures.

It may be possible to re-treat the item. Faint fingermarks will often be enhanced with subsequent processes such as fluorescent dye stains. Use alternative processes as outlined in Chapter 4.

5.SF.9

Fingermark Visualisation Manual

Superglue Fuming

Glossary

5.SF.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Overdevelopment Recognition

There is high superglue development across the mark and surface. The development appears granulated.

Surfaces treated with Superglue

Fuming showing

overdevelopment. Cause The relative humidity at the surface of the item was too high during processing.

Home Office January 2014

Effect

Prevention

Condensation droplets form on the item. Ensure that: The superglue fumes polymerise on these ●● the superglue fuming cabinet droplets in addition to the fingermark is operating within the correct resulting in high background development parameters; and obscured fingermarks. ●● items are at ambient temperature prior to processing.

Correction There are no corrective measures.

5.SF.10

Fingermark Visualisation Manual

Superglue Fuming

Appendices

5.SF.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

Ethylcyanoacrylate (superglue), under the right conditions, will polymerise to

poly[ethylcyanoacrylate]. This is observed as a gradual growth of a white deposit on the surface of items.

Superglue polymerisation is nucleophile (or Lewis base) initiated. Many compounds,

including water, can act as a nucleophile and initiate polymer growth. Fresh fingermarks, formed from predominantly eccrine sweat, contain a high percentage of water and so

will initiate polymerisation with relative ease. Once a superglue molecule has undergone

nucleophillic attack, it will readily react with another superglue molecule to form the start

of a polymer chain. Continued reaction occurs many times over (propagation), creating a long polymer chain that is eventually terminated by another reactive molecule, or as the supply of superglue is depleted. The macro-scale fibrils that form the white ridges of a developed fingermark are the result of many such chains.

High magnification image of a fingermark developed using Superglue Fuming.

The ability to initiate polymerisation reduces as water is lost from the fingermark as a

result of ageing. Fingermarks can be rehydrated to some extent by exposing the item to high humidity. It is known that salt crystals, found in dehydrated eccrine sweat, absorb

moisture at high relative humidity; in particular sodium chloride crystals absorb moisture if exposed to an environment where the relative humidity is > 75%. For this reason, this Manual recommends that the relative humidity is maintained between 75% and 90% during polymerisation.

This description explains one possible mechanism for polymer growth. Other

components within fingermark residues may also initiate polymerisation. Most

fingermarks, however, have an initially significant water and chloride content; this is therefore likely to be a significant initiation mechanism.

Home Office January 2014

5.SF.11

Fingermark Visualisation Manual

Superglue Fuming

Appendices

5.SF.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

The structure of the polymer growth is important as this affects the visibility of the

fingermark. Between 75% and 90% relative humidity (RH) superglue polymerises to

form fibrous ‘noodle-like’ structures on eccrine-based fingermark ridges, which appear as a white deposit. At lower values, or for fingermarks with a different composition

(such as sebaceous sweat), different, less visible, structures can form. At higher values, development of the polymer on the background of the item increases and the contrast between the fingermark and the surface is reduced.

Scanning electron micrographs showing polymer structures formed at (left) 60% relative humidity and (right) 80% relative humidity. Image (a) is at x580 magnification and image (b) at x2000 magnification and both show the boundary between a ridge (bottom-right)

Close-up image of fingermark ridges developed with Superglue Fuming (and enhanced with BY40) at (a) 80% relative humidity and (b) 100% relative humidity.

and a furrow (top-left).

Home Office January 2014

5.SF.12

Fingermark Visualisation Manual

Superglue Fuming

Appendices

5.SF.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory

Superglue fuming wands that operate at considerably higher fuming temperatures are

The relative humidity must be maintained within the range 75-90% (easily achieved

into hazardous gases at higher temperatures, and therefore they must not be used.

Controlling temperature and relative humidity

within a superglue fuming cabinet): if the humidity is too low, fingermarks may appear

underdeveloped; if too high, there is a risk of condensation forming on the item which will lead to high background development. Examples of these problems are shown in troubleshooting.

Temperature and relative humidity are closely linked: if the temperature varies across the area then the relative humidity will also vary. Thus temperature variations must be minimised so that the relative humidity is within range across the area. At 20°C a temperature variation of ± 1°C corresponds to a variation in relative humidity of

approximately ± 5%RH. For the relative humidity range 75-90% this translates to a maximum temperature variation across the area of 3°C. Practically this means:

●● the positioning of superglue fuming cabinet within a laboratory is very important and

it should be sited away from windows, radiators or other sources of heat/cold to

minimise temperature difference across the cabinet. Most cabinets are small enough that temperature variations can be controlled to within acceptable limits;

●● items must be at ambient temperature prior to treatment. If cold items are placed into

a processing enclosure set within the range 75-90% relative humidity, it is likely that condensation will form on the item as the relative humidity at the surfaces reaches 100%;

●● scene application, or application in larger enclosures such as tents, is likely to be

variable due the difficulties in controlling temperature variation across the area.

Producing superglue fumes

There are several ways to create superglue fumes. The most common is via a heating

block that evaporates the superglue at elevated temperatures. This method of fuming is

not particularly effective. They can also be unsafe because superglue can break down An alternative method includes the generation of fumes via a chemical reaction. There are several ways in which this can be achieved, such as applying superglue to pads

impregnated with chemicals such as sodium hydroxide, or commercial products that

can be split open to generate fumes on contact with air. Details of these methods are not given in this Manual.

Quantity of superglue

In a superglue fuming cabinet, the quantity of superglue required for optimal fuming

depends on the capacity of the cabinet: 3 g of superglue per cubic metre may provide an adequate concentration, although this can vary depending upon the type and quantity of items to be treated, the cleanliness of the cabinet and the size of the cabinet. If the

practitioner continually observes mark development during fuming, then the quantity of

superglue is less important as the practitioner can stop further evaporation and remove fumes once optimal development is achieved.

It may be more difficult to determine the required quantity of superglue for larger areas

such as tents or at scenes. In this case, manufacturer’s instructions should be followed along with knowledge gained from previous uses of Superglue Fuming in temporary enclosures.

Polymerisation of superglue on different items

Treatment times can vary depending on the nature and condition of the surface and

the age of and constituents within the fingermark. For this reason, cabinets should be loaded with similar items so that fingermark development occurs at a similar rate n

incorporated in most commercially available superglue fuming cabinets. An acceptable

evaporation rate occurs when the superglue reaches 120°C. A range of ± 20°C will have no effect of the process outcome although treatment times will vary considerably.

Home Office January 2014

5.SF.13

Fingermark Visualisation Manual

Superglue Fuming

Appendices

5.VMD.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

VMD; Metal evaporation; Metal deposition

Contents Options....................................... 5.VMD.2 Laboratory Use.......................... 5.VMD.3 Health and Safety.....................5.VMD.3 Equipment.................................5.VMD.4 Chemicals.................................5.VMD.6 Processing................................5.VMD.7 Post-Processing......................5.VMD.10 Troubleshooting....................... 5.VMD.11 Supplementary Information.... 5.VMD.17

Main Uses ✔ Latent ✔ Blood ✔ Grease ✔ Other*

items in a high vacuum chamber. More Details

✔ Non-Porous ✔ Semi-Porous ✘ Porous

*Enhancement of marks developed by Superglue Fuming

Key Information

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for two Category A

The Process

●● Vacuum Metal Deposition can be used safety and effectively

in a laboratory.

●● The effectiveness of the process is highly dependent on the

care and expertise of the operator.

The Item or Surface

●● Sealed containers must not be treated using Vacuum Metal

Deposition as they may explode under vacuum.

●● Vacuum Metal Deposition will develop fingermarks on a wide

range of substrates and: ■■

■■

Vacuum Metal Deposition cannot be used at scenes.

■■

●● Vacuum Metal Deposition uses commercial equipment and

specialist training will be required on its use in addition to the detail given in this process instruction.

Process Overview

Vacuum Metal Deposition (VMD) utilises vacuum coating

technology for the thermal evaporation of metals and deposition of thin metal films. It is a sensitive process capable of detecting monolayers of fats in fingermark deposits on smooth surfaces, although it is also capable of detecting most other types of

fingermark. Disturbances in the physical and chemical nature of

can be used on items that have been wetted and subsequently dried;

Vacuum Metal Deposition processes: Gold/Zinc; Silver.

●● Full process details are given for laboratory use only.

can be used on items that have been subjected to heating to high temperatures;

is mostly unaffected by the age of the mark.

●● The effectiveness of the process may vary significantly

between different substrates, even those that are visually similar.

●● All regions of the item need to be in direct line of sight from

the metal evaporation vessels, therefore items that are highly curved or uneven may be difficult to process.

Integrated Use

Vacuum Metal Deposition may be detrimental to subsequent fingermark or forensic processing.

the surface, including those associated with the presence of the

●● See Chapter 4 for information on its sequential use with other

films.

●● See Chapter 7 for information on integration of fingermark

fingermark, are revealed by different rates of growth of the metal It is a physical process that involves evaporating metals onto Home Office January 2014

Safety and Effectiveness Summary

fingermark visualisation processes. with other forensic processes.

5.VMD.1

Fingermark Visualisation Manual

A Vacuum Metal Deposition

5.VMD.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options Gold/Zinc Vacuum Metal Deposition

●● Gold/Zinc Vacuum Metal Deposition (VMD) is

generally the most effective VMD option.

●● It is effective at enhancing latent and contaminated

marks on most non-porous and some semi-porous substrates.

●● It is capable of enhancing marks on both natural and

synthetic fabrics.

●● It is capable of enhancing marks on substrates

which have been exposed to temperatures of up to

900ºC providing the surface has remained clean and free from soot contamination.

●● It produces visible, metallic grey fingermarks.

Silver Vacuum Metal Deposition

●● Silver VMD is generally the most effective VMD

option on plasticised PVC (vinyl) or plastic packaging (clingfilm).

●● It is highly effective in developing fingermarks

contaminated with grease or oil which have been deposited on clean surfaces.

●● It is capable of enhancing marks on substrates

which have been exposed to temperatures of up to

●● Unless specified in the processing charts within

Chapter 4, Gold/Zinc VMD is the first VMD option that should be considered for treating an item or surface.

●● Silver VMD can be used after Gold/Zinc VMD to

enhance ‘empty’ marks or to fill in detail in areas where the surface coating is patchy.

900ºC providing the surface has remained clean and

●● There is unlikely to be any benefit in using the Gold/

VMD option above 500ºC.

●● See Chapter 4: Process Selection for information on

free from soot contamination. It is the most effective

●● Although it is extremely sensitive, marks can be faint

and difficult to see, especially on dark surfaces. They are also particularly fragile (see Chapter 3, Effective handling of processed items).

●● It produces visible fingermarks than can vary in

colour (typically purple, pink, or brown).

Home Office January 2014

Sequential use of Vacuum Metal Deposition

Zinc process after the Silver process.

its sequential use with other fingermark visualisation processes.

●● See Chapter 7: Other Forensics for information

on integration of fingermark and other forensic processes.

5.VMD.2

Fingermark Visualisation Manual

Vacuum Metal Deposition

5.VMD.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes.

●● Vacuum Metal Deposition may be carried out with no known hazards to health

provided practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and

■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

Index

Laboratory Use Hazards associated with Vacuum Metal Deposition ●● Vacuum Metal Deposition is a physical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and must be aware of the hazards associated with the VMD equipment.

●● Wear Standard PPE as a minimum.

●● Hazards associated with the use of the process are identified below but those cited

must not be regarded as exhaustive, nor the control measures prescriptive. Hazard

Risk

Suggested control measure

Loading the VMD chamber with closed or pressured containers

Explosion within the chamber

●● Never put closed containers (e.g.

Exposure to zinc dust during cleaning of the VMD chamber.

Adverse health effect due to ingestion or inhalation

●● In addition to standard PPE,

instructions must be provided locally.

●● In providing the Category A process instructions it is assumed that:

Glossary

aerosol cans, batteries, bottles with caps, tins etc.) into the vacuum metal deposition chamber as they may explode under vacuum. ●● Remove all residual liquids and solids when treating containers. consider using a respirator when cleaning the VMD equipment. ●● Remove loose zinc dust and flakes from the chamber with a vacuum cleaner. ●● Seal contaminated aluminium foil in polythene bags for safe disposal after removal from the chamber.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

5.VMD.3

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Equipment

Vacuum Metal Deposition requires specialist vacuum equipment and some ancillary equipment required for its operation. If equipment is to meet the requirements as

outlined below, it must be well maintained and, if appropriate, serviced regularly in

accordance with the manufacturer’s instructions. General laboratory equipment that may be required is outlined in Chapter 3. Equipment Vacuum metal deposition chamber

Requirements A vacuum metal deposition chamber must: ●● be capable of being pumped down to vacuum levels of 1.5 x 10 -4 mbar or lower; ●● have a viewing window and internal lights to enable the progress of metal coating to be observed; ●● have at least two sets of evaporation vessels that can be heated up to yellow/white heat for gold and/or silver deposition by means of controlling a current passed through them; ●● be well maintained and serviced regularly in accordance with the manufacturer’s instructions. In addition, a vacuum metal deposition chamber should: ●● have a magnetic sample holder to enable suitable items to be mounted using magnets; ●● have features (such as holes drilled into the sample holder) enabling more complex-shaped items to be secured in place over the filaments/boats; ●● have a cold finger or trap to condense contaminants and accelerate pump down of chamber; ●● be of a size that can accommodate most items recovered from scenes that are typically processed with Vacuum Metal Deposition. Most vacuum metal deposition chambers used for this process will consist of a 600 to 900 mm diameter, horizontal, cylindrical, steel vacuum chamber with a door on one end. This chamber is usually connected through a system of valves to two vacuum pumping systems.

Home Office January 2014

Equipment

Requirements

Vacuum pumping system

A vacuum pumping system must: ●● be capable of pumping down the vacuum metal deposition chamber to vacuum levels of at least 1.5 x 10 -4 mbar. The equipment generally used for this purpose includes two pump systems: ●● a conventional rotary pump and mechanical booster combination for initial pumping, where a piston or rotary vane displaces a fixed volume on each revolution of the pump drive shaft; ●● an oil vapour diffusion pump for high vacuum pumping, using a stream of vapour to draw in and carry gas from the chamber and along to the rotary pump.

Chiller unit (optional

If used, a chiller unit will reduce the time taken to reach the required low pressures. It reduces the temperature of a ‘cold finger’ situated within the vacuum chamber so that moisture and contaminants condense and freeze on it during evacuation of the chamber. The cold finger needs to reach a temperature of -100ºC or lower to be effective in this capacity. A cold finger will be particularly useful if highly contaminated, or porous items (e.g. wood, fabrics) are being treated.

5.VMD.4

Fingermark Visualisation Manual

Vacuum Metal Deposition

Glossary

5.VMD.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Equipment continued Equipment

Requirements

Equipment

Water recirculating unit (optional)

If used, a water recirculating unit assists in the cooling of the diffusion pump element of the vacuum pumping system. It may be required if mains water pressure is insufficient to provide the required level of cooling, and/or to reduce the amount of water running to waste.

Zinc evaporation vessels (also known as sources, filaments, or boats)

Use evaporation vessels recommended by the equipment manufacturer. The vessels should be molybdenum foil, 0.05–0.1 mm thick, to the general design below.

16 mm

Rotary sample holder (optional)

Requirements If used, the rotary sample holder must: ●● be capable of being firmly attached to the rotating spindle at the back of the vacuum chamber; ●● have a diameter small enough to accommodate the mounting of bottles and other similar cylindrical items; ●● rotate whilst the gold, zinc or silver are evaporated. It is important to ensure that the item gets an even coating of evaporated metal.

PLAN 25 mm approx. FOLDED TROUGH

Gold and silver evaporation vessels (also known as sources, filaments, or boats)

ELEVATION

Use evaporation vessels recommended by the equipment manufacturer. The vessels should be molybdenum foil, 0.05–0.1 mm thick, to the general design below. 12 mm

ELEVATION 25 mm approx.

An alternative design for use with gold only is given below. 5 mm

PLAN ELEVATION 25 mm approx.

Home Office January 2014

Example of a rotary sample holder showing the fitting for attaching it to the rotating spindle in the vacuum metal deposition chamber, and a cylindrical item fitted onto it.

PLAN

Fine wire

The fine wire should: ●● have high tensile strength (e.g. steel, nylon); ●● be as thin as possible. Fine wire can be passed over the item and through the holes drilled into the work holder to fix solid items in place. The wire used should have sufficient strength to hold the item in place, but be as fine as possible so that the surface area masked by the wire is minimised.

5.VMD.5

Fingermark Visualisation Manual

Vacuum Metal Deposition

Glossary

5.VMD.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists chemicals that are required for Vacuum Metal Deposition. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3 Good Laboratory Practice: Chemicals for general information. Common Name

Alternative Name(s)

CAS Number

Grade

Gold

Gold wire

7440-57-5

99.9%

Zinc

Zinc foil; Zinc pellets

7440-66-6

≥99%

Silver

Silver wire

7440-22-4

99.9%

Home Office January 2014

5.VMD.6

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Equipment and Chemicals

a) Follow manufacturer’s instructions for use of equipment. b) Bring the chamber to atmospheric pressure and open the chamber door. c) If used, check that the chamber’s protective coating is intact. d) Zinc foil should be cut into small pieces (~ 30 mm2) ready for use in Gold/Zinc VMD. e) If using Gold/Zinc VMD, divide an appropriate amount of zinc equally between the zinc evaporation vessels (normally two). If the vessels are empty, use ~1 g of zinc for chambers of 600–900 mm in diameter. Thereafter small amounts should be added so that evaporation vessels are kept between a quarter and half full. f) If using Gold/Zinc VMD, place an appropriate amount of gold in the gold evaporation vessel (normally one). Use ~2 mg of gold (equating to ~2–3 mm of 0.25 mm diameter wire) for chambers of 600–900 mm in diameter. g) If using Silver VMD place an appropriate amount of silver in the silver evaporation vessel (normally one). Use ~60 mg of silver (equating to ~15 mm of 0.5 mm diameter wire) for chambers of 600–900 mm in diameter. h) Ensure that the observation window and the internal light bulbs are clean to allow the deposition process to be clearly observed.

(2) Item

Processing

a) If using Gold/Zinc VMD, different types of substrate should not be treated together in a single processing cycle. However, multiple items may be treated together regardless of substrate type and condition when using Silver VMD. b) Carefully attach items such as plastic packaging to the work holder using strong magnets, with minimum possible contact with the surface. Minimise large creases in the item. Larger bags or sheets should be cut into sections rather than folded. c) For clear plastic items, a white sheet of paper should be placed behind the item to aid observation of development. If white paper is not present, the operator is trying to distinguish growth of a metallic film on the item against a metal background and may not be able to determine when to stop evaporation. d) Attach solid items to the work holder using fine wire. e) If treating cylindrical objects, consider attaching them to the rotary holder (if present). f) Only surfaces facing the evaporation vessels will receive an adequate metallic coating.

Proceed to the appropriate processing page (Gold/Zinc or Silver). See Modifying processing conditions according to substrate type.

Continued on next column

Home Office January 2014

5.VMD.7

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Gold/Zinc) Processing (3) Close chamber door

(4) Evacuate chamber

(5) Evaporate gold

a) If applicable, turn off the interior light.

a) The pressure within the chamber should reach < 3.0 x 10-4 mbar before gold evaporation is initiated. a) If a rotary holder is being used, start it rotating. b) Switch on the power to the gold evaporation vessel and slowly increase the current until it glows yellow/ white. Maintain this current level for approximately 20 seconds. Reduce the current slightly and look for residual gold (this may be visible as a dark spot or greenish pool in the evaporation vessel). Repeat this step until all the gold has evaporated then turn the source off. Note: care should be taken because overheating the vessel to an intense white colour may destroy it.

(6) Adjust chamber pressure

a) The pressure within the chamber should be raised to 4 x 10-4 ± 1 x10-4 mbar by admitting a small amount of air. Most modern machines will do this automatically. It may take a few seconds for the pressure to stabilise.

(7) Evaporate zinc

a) Switch on the power to the zinc evaporation vessels and gradually increase the current until they glow the desired colour, typically dull red to dull orange (there may be a few seconds lag between increments in vessel temperature and perceivable effect). Practice is needed in judging the appropriate processing conditions for substrates. b) As soon as vessels are glowing the desired colour, turn on the interior light (and/or use an additional light source to illuminate the item through the viewing window) and immediately proceed to the next step.

Continued on next column Home Office January 2014

(8) Observe mark development on the item

(9) Halt development once optimal contrast is achieved

(10) Decontaminate gold evaporation vessel

(11) Bring chamber to atmospheric pressure and open door

(12) Examination Primary: Visual Examination

a) Continue zinc deposition until a metallic grey deposit is seen to form on the surface or on any marks present. Some items will coat rapidly (seconds) whilst others will coat more slowly (minutes). The coating may appear patchy due to varying levels of surface contamination.

a) Switch off the power to the zinc evaporation vessels before over-development occurs, and switch off the rotary holder (if used). It is a matter of experience when the evaporation should be stopped; this is usually a compromise as there are likely to be areas of good and weak development. a) Switch on the power to the gold evaporation vessel and increase the current until it glows yellow/orange. Maintain it at temperature for approximately ten seconds to burn off any zinc contamination, then switch off.

a) Visible marks are metallic grey. b) Most thin plastic materials should be examined using transmitted light on a light box. There are many nondestructive optical processes that can be considered when examining and imaging marks in addition to the primary process. Marks on dark plastic packaging may also be enhanced by Lifting. c) Mark up viable fingermarks appropriately and capture image. Marks may fade and should be photographed as soon as possible. Consider that on thin sheets marks may very occasionally develop on the opposite side to the surface originally touched by the finger. d) After examination, items can be retreated with gold/zinc if necessary (an extra quantity of gold will improve the zinc deposition rate, but is not always required). This is most appropriate where marks are under-developed or there is no coating. The Silver VMD process may also be used, particularly if empty marks are observed.

5.VMD.8

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Silver) Processing (3) Close chamber door

(4) Evacuate chamber

(5) Evaporate silver

(6) Bring chamber to atmospheric pressure and open door

a) If applicable, turn off the interior light.

a) The pressure within the chamber should reach < 3.0 x 10-4 mbar before silver evaporation is initiated.

a) If a rotary holder is being used, start it rotating. b) Switch on the power to the silver evaporation vessel and increase the current until it glows yellow/white. c) Observe the silver in the vessel and maintain the current level until the silver has visibly melted to a dark pool and then evaporated. d) Switch off the power to the silver evaporation source and the rotary holder (if used).

(7) Examination Primary: Visual Examination

Home Office January 2014

a) Visible marks can be many colours, typically purple, pink, or brown. b) Most thin plastic materials should be examined using transmitted light on a light box. There are many nondestructive optical processes that can be considered when examining and imaging marks in addition to the primary process. c) Mark up viable fingermarks appropriately and capture image. Marks may fade and should be photographed as soon as possible. Consider that on thin sheets marks may very occasionally develop on the opposite side to the surface originally touched by the finger. After examination, items can be re-treated if necessary. This may be required if marks are under-developed.

5.VMD.9

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3: Good Laboratory Practice for general advice on packaging, storage, cleaning and disposal of items, equipment and chemicals. This page gives additional information relevant to this process.

Processed item (1) Cleaning processed items (2) Disposal or return of processed items

a) It may not be possible to return items to their original state. However, zinc can be removed from some surfaces by washing with a 10% acetic acid solution (details not given). Although this will slowly dissolve zinc it will have no effect on the thin gold film (or silver) but in most circumstances the gold film is transparent.

(4) Cleaning the chamber (Regular tasks)

a) Residual processing chemicals that are present are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and chemicals For the following activities (points 3-5, below), avoid inhalation of zinc dust

(3) Chamber protection

Continued on next column Home Office January 2014

(5) Cleaning the chamber (Occasional tasks)

a) Where possible cover exposed surfaces within the chamber with aluminium foil to simplify routine cleaning. The foil should be carefully shaped to the inside walls and liners of the chamber and held securely with adhesive tape. b) Ensure that the foil does not come into contact with the filament bars or the lead-through electrodes and cables as this could cause a hazardous short circuit.

a) Remove any dusty or flaky oxidised zinc from the zinc evaporation vessels. b) Keep the windows and the glass of the interior chamber lamps free of metal deposits. This can be achieved by wiping these surfaces with a paper tissue after every run and then lightly applying furniture polish and again, wiping over with clean paper tissue. If metal films have built up on these surfaces, they may be removed with a tissue moistened with 10% acetic acid solution before treating with polish as above. c) Any loose metal particles or dust in the chamber should be removed using a vacuum cleaner. d) If used, the cold finger must be kept clean and free from loose flaking deposits of zinc. The easiest way to achieve this is to allow the frost on the surface to thaw out every two or three cycles and to wipe the surface with a damp tissue. a) The clamping surfaces used to attach the evaporation vessels to the filament bar should be cleaned occasionally. The clamps must be fully tightened after cleaning. b) The aluminium foil must be removed periodically before thick, flaky zinc coatings build up, and disposed of in sealed bags. c) Mechanical components inside the chamber such as the filament bar assembly cannot be protected by foil and should be removed occasionally and cleaned appropriately with consideration for its fragility. Options include using: ●● acids (acetic or dilute hydrochloric) (details not given); ●● abrasives (emery paper; or a detergent solution and a wire brush; or sandblasting). d) Major cleaning of the baffle valve area is best left to the equipment suppliers. Depending on usage this may prove necessary about every 12 months.

5.VMD.10

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Under-Developed Marks Recognition

The marks appear under-developed.

A clear polythene bag processed with VMD (Silver) showing (left) under-

developed marks and (right) clearly visible marks after re-treatment.

Cause

Effect

Prevention

Correction

The item has been exposed to an insufficient amount of metal.

There is insufficient contrast between the ridges in the mark and the background. This results in marks which are difficult to see or are missed.

Ensure that: ●● there is a sufficient amount of silver or zinc in the evaporation vessel; ●● silver or zinc deposition is closely observed and not stopped too early.

Capture images of any marks of value and re-treat item. Fingermarks adequately developed during the first evaporation may be protected by covering with small pieces of paper or plastic during subsequent evaporations.

Contamination or additives on the surface inhibiting metal deposition.

There is insufficient contrast between the ridges in the mark and the background. This results in marks which are difficult to see or are missed.

There are no preventative measures.

Capture images of any marks of value and re-treat item. Fingermarks adequately developed during the first evaporation may be protected by covering with small pieces of paper or plastic during subsequent evaporations. If several repeat treatments do not deposit sufficient metal, consider use of an alternative process.

The gold wire has been expelled from the evaporation vessel and so the item has not been exposed to gold.

No development.

Ensure that the gold does not jump out of the vessel by: ●● increasing the current slowly; ●● reducing any vibrations across the vessel.

Re-treat item.

Home Office January 2014

5.VMD.11

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Over-Developed Marks Recognition

The mark appears over-developed.

Marks developed on a greetings card

using Vacuum Metal Deposition (Gold/

Zinc) imaged using (left) diffuse white light

showing excessive metal deposition filling

in ridges and (right) specular light showing some restoration of ridge detail.

Cause The item has been exposed to too much metal (silver or zinc).

Home Office January 2014

Effect The excess amount of metal deposited means that ridge detail in the mark that had been visible at lower levels of metal deposition subsequently becomes filled in, resulting in insufficient contrast between the ridges in the mark and the background. This results in marks which are difficult to see or are missed.

Prevention

Correction

Ensure that: ●● the item is closely observed during the zinc deposition stage of the Gold/Zinc process and deposition is stopped as soon as mark development is considered sufficient; ●● the amount of silver outlined in the process instructions is not exceeded when using the Silver process.

It may be possible to remove excess zinc using a 10% acetic acid solution and then to re-treat the item, but this is not guaranteed to be effective in restoring the ridge detail that may have originally been present. Using alternative lighting angles as outlined in Visual Examination may reveal some obscured ridge detail, but this is not guaranteed to be effective.

5.VMD.12

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

No Development on Obscured Areas Recognition

The item looks like it has coated evenly whilst observing deposition through the chamber window, but reveals no

developments on obscured areas once it is removed from the chamber and flattened out.

A plastic bag poorly processed with VMD

where (top left) shows the bag loaded

inappropriately with creases in the chamber,

(top right) shows the patchy development post-processing, and (bottom) shows a

close-up of an area of the bag that clearly

shows the lack of metal deposition in creased area.

Cause The item was not uniformly exposed to metal vapour because of the creases present in the item.

Home Office January 2014

Effect

Prevention

Limited or no metal deposition occurs on areas obscured from direct line of sight of the metal evaporation vessels. This may result in uneven metal deposition across the surface and marks not being developed in obscured regions.

Ensure that: ●● the VMD chamber is loaded correctly and items are not touching or overlapping; ●● items are not folded over on themselves; ●● all areas requiring treatment are mounted so that they are fully in line of sight of the metal evaporation vessels.

Correction The item can be correctly mounted to open out creases and re-treated to expose areas that have not already received a metal coating. The previously enhanced areas may become overdeveloped and therefore any marks present should be imaged before retreatment.

5.VMD.13

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Variations in Development Rate between Substrates Recognition

Observed metal deposits at different rates and in different ways on surfaces of different types.

A fully loaded sample holder showing (top

left) dissimilar items, (top right) similar items but different sources, (bottom)

shows a fingermark developed with VMD

(Gold/Zinc) across the boundary between

two types of plastic (HDPE and LDPE),

clearly showing different deposition rates

and modes of development.

Cause

Effect

Prevention

Correction

There is great variability in the speed at which zinc coatings form on different substrates, and different modes of development (‘normal’ and ‘reverse’) can occur.

If dissimilar items are treated together, the rate of zinc deposition may be so different that marks on one item may be over-developed whilst those on the other may be under-developed. Potentially identifiable marks may therefore be missed or destroyed during re-treatment.

Ensure that: ●● VMD (Gold/Zinc) is only used to treat multiple items when they are known to be of the same type and in the same condition. VMD (Silver) can be used to treat multiple items regardless of substrate type and condition.

See corrective action for over-developed marks. Remove any items with an adequate coating. Separate remaining items into batches of the same type and condition and re-treat together in batches with the VMD (Gold/Zinc).

Home Office January 2014

Alternatively, re-treat all remaining items together using VMD (Silver) (if appropriate).

5.VMD.14

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Empty Marks after Gold/Zinc Deposition Recognition

The VMD (Gold/Zinc) has developed ‘empty’ marks with no ridge detail, even after several deposition runs.

(left) Empty marks developed with VMD (Gold/Zinc) on a clear polystyrene film

and (right) additional development after

subsequent treatment with VMD (Silver). Cause

The marks present on the substrate have a high content of either sebaceous sweat or greasy contamination. The gold nuclei deposited in the initial stage of the Gold/Zinc process sink into the layer of grease and are not available on the surface to initiate growth of the zinc layer.

Home Office January 2014

Effect Because there are no gold clusters present on the surface of the ridges, subsequent zinc growth cannot be initiated and no discrimination between ridges and furrows is possible in these regions. Processed marks therefore appear ‘empty’ or ridge detail is very faint, making imaging more difficult.

Prevention There are no preventative measures.

Correction After imaging of any ridge detail revealed using VMD (Gold/Zinc), re-treating the item using VMD (Silver) may fill in ridge detail in the ‘empty’ regions.

5.VMD.15

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Troubleshooting

Fading of Marks Developed by Vacuum Metal Deposition Recognition

For VMD (Gold/Zinc) the

processed marks and the

background fade with time. For VMD (Silver) the

processed marks and

the background fade and change colour with time (therefore the optimum

contrast for marks may

not be immediately after treatment).

Cellophane processed with Vacuum Metal Deposition (Silver)

photographed (left) one minute, (centre left) ten minutes, (centre right)

Cause The deposited metal film has oxidised after removal from the vacuum chamber. This may occur for both zinc and silver coatings, and can be accelerated by: ●● exposure to elevated temperature; ●● exposure to elevated humidity; ●● the type of surface present.

Home Office January 2014

Effect ●● For zinc coatings, oxidation results in

formation of transparent zinc oxide and marks may fade and disappear over time. ●● For silver coatings, the colour of both mark and background may change over a short period of time, changing the contrast of the mark and ultimately resulting in marks disappearing.

half an hour and (right) two hours after removal from the development chamber.

Prevention ●● Fading cannot be prevented. All

marks of value should be imaged as soon as possible. For VMD (Silver), if fading or colour changes begin to occur marks should also be imaged repeatedly over time to ensure that the optimum image is captured.

Correction ●● It may be possible to re-treat and re-

develop the mark but this cannot be guaranteed.

5.VMD.16

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Theory

Gold/Zinc Vacuum Metal Deposition – Normal Development

There is general agreement on the theory associated with what is described as ‘normal

Glossary

Index

Supplementary Information Small, densely packedgold nuclei

Large, dispersed gold nuclei

Zinc deposit

Fingermark residue

development’ of marks with some sebaceous content by the VMD (Gold/Zinc) method. The deposition characteristics of zinc are key, as zinc will not condense on greases,

including those in the sebaceous component of fingermark residues, even when these

substances are only present as a monolayer. However, zinc will deposit on small nuclei of metal, and this is the reason that gold deposition is carried out first.

Gold can be deposited over the entire surface, and will begin to form nuclei, the size, distribution and morphology of which depends on the nature of the surface (surface

energy, chemical species present). The amount of gold is selected so that the resultant gold coating is very thin (several nanometres only) and discontinuous. The actual

Substrate Substrate Schematic diagram of normal development for Vacuum Metal Deposition, showing zinc selectively depositing where gold nuclei are available on the surface.

deposition pressure for gold is not critical provided that the pressure is below 3 x 10-4

It should, however, be noted that there is no conclusive evidence of nuclei diffusion and

number of molecules in the air, thus providing sufficient gold to form the nuclei required

of zinc on regions where gold nuclei of different sizes have been formed.

mbar. This enables gold atoms to reach the surface without colliding with a significant to visualise the marks.

In the regions coated with the fatty residues of the latent fingermark, the gold may

diffuse into the fats with the result that there are no gold nuclei available close to the

surface. As a consequence, when zinc is subsequently deposited, it will condense on the regions where gold nuclei are present on the surface (i.e. the background substrate), but not on the regions where the gold has diffused into the fatty deposit (i.e. the fingermark ridges). This is shown schematically top right.

Home Office January 2014

it is possible that the effect observed may be solely attributable to different growth rates The deposition pressure for zinc needs to be in the region of 4 x 10-4 ± 1 x10-4 mbar. If the pressure is too low, zinc vapour may be too energetic when it hits the surface and

will re-evaporate without forming a coating. Another problem that may be encountered if deposition pressure is too low is that the zinc coating may develop too quickly to be

controlled, resulting in over-development of the mark. If the zinc deposition pressure is

too high, the zinc will not evaporate or may oxidise during deposition resulting in a paler coating that may make marks more difficult to visualise.

5.VMD.17

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory continued

Gold/Zinc Vacuum Metal Deposition – Reverse Development

In practice, many marks developed using Vacuum Metal Deposition may be ‘reverse developed’, i.e. zinc preferentially deposits on the fingermark ridges rather than the

background. There are differences in opinion as to why this arises. One theory proposes absorption of mobile organic species of the fingermark residue into the substrate,

leaving a solid, primarily inorganic residue on the surface which acts as a preferential

nucleation site for the gold. More gold diffuses into the polymer substrate than into the solid residue, hence zinc deposits on the ridges first.

Another recent theory is that the reverse development is due to the fingermark deposits becoming dried out or contaminated, thus inhibiting the diffusion of the gold nuclei into

the fingermark residue. Because the gold nuclei on the ridges are larger, zinc deposition occurs at a faster rate in these regions, as illustrated schematically below. A further

theory closely relates the type of mark developed (reverse or normal) to the amount of gold deposited initially and the polymer type of the substrate.

Small, densely packed gold nuclei

Large, dispersed gold nuclei

Dried fingermark residue

Examples of different modes of development with Vacuum Metal Deposition: (left) shows Thick zinc deposit on large nuclei

Thinner zinc deposit on small nuclei

‘normal’ development on a high-density polyethylene bag, with ridges lighter than the

background, and (right) shows ‘reverse’ development on a low-density polyethylene bag with ridges darker than the background. The example on the left also shows significant

differences between zinc deposition rate on the printed green areas and on the unprinted white background.

Substrate

Schematic diagram of reverse development for Vacuum Metal Deposition, showing

different rates of zinc deposition according to size of gold nuclei available on the surface. The appearance of both ‘normal’ and ‘reverse’ types of developed marks is shown in the images on the right.

Home Office January 2014

5.VMD.18

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory continued

Gold/Zinc Vacuum Metal Deposition – No Development

There are also situations where VMD (Gold/Zinc) may not produce a zinc coating on

some, or all of the surface area being treated. The most common reasons for this are

that the surface is either heavily contaminated with grease or oils, or that the substrate contains plasticisers or other additives that have migrated to the surface. If gold nuclei can diffuse downwards into the substances on or close to the surface, there will be

no gold nuclei available on the surface to initiate deposition of the zinc coating and therefore no fingermarks will be visualised (see below). Zinc unable to nucleate on gold

Surface layer of plasticiser

Substrate

Schematic diagram of a situation where no development occurs during Gold/Zinc

Vacuum Metal Deposition because all gold clusters formed have sunk into the fingermark and surface layer of plasticiser.

Home Office January 2014

5.VMD.19

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory continued

Silver Vacuum Metal Deposition

In cases where development cannot be achieved using VMD (Gold/Zinc), it may still be possible to visualise marks using VMD (Silver). The silver process is thought to work

because silver, like gold, deposits uniformly across the surface. The nuclei formed vary in size and distribution between the fingermark ridges and the background, giving a

difference in reflected and/or transmitted colour between the two regions. The amounts of silver used are significantly greater than those in the gold stage of the Gold/Zinc

process, making the deposited silver film and the associated colour differences easier to visualise.

Small, densely packed silver nuclei

Large, dispersed silver nuclei

Surface layer of plasticiser

Fingermark residue

Atomic force microscopy images showing (left) small, tightly packed silver clusters formed on a clean polyethylene substrate and (right) larger, more widely dispersed

clusters formed on the ridges of a fingermark placed on the same polyethylene substrate.

Substrate

Schematic diagram of VMD (Silver) on a fingermark on a substrate with a surface layer of plasticiser present. Although all silver clusters have diffused below the surface, the

mark can still be discriminated because of the differences in size and distribution of the clusters between the ridges and background.

Home Office January 2014

5.VMD.20

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.21

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Supplementary Information

Theory continued

Other factors influencing Vacuum Metal Deposition

The presence of greases/fats in fingermarks is not the only means by which Vacuum

Metal Deposition can visualise marks and other surface features. Any factor that results in local variations in surface properties can potentially influence the nucleation and

growth of gold nuclei and therefore the subsequent growth of zinc. Factors that are

known to have resulted in differential growth rates of zinc film on different regions of the surface include the following.

●● The presence of eccrine fingermark constituents on the surface. ●● The presence of blood contamination on the surface.

●● Different surface oxidation states. Regions initially protected from oxidation by the

presence of fingermarks that are subsequently vaporised at high temperatures

will have different degrees of exposure to oxidising environments than adjacent unprotected regions where no fingermarks were present. This may result in

differences between the size of gold/silver nuclei formed. It is believed that Vacuum Metal Deposition continues to visualise fingermarks on clean surfaces exposed to temperatures up to 900ºC because of this mechanism, even though none of the

original constituents or their degradation products remain on the surface to influence gold or silver nucleation.

●● Physical abrasion of the surface resulting in local deformation and regions of higher

surface energy.

●● Different pigments being present in adjacent regions (e.g. different coloured inks

printed on the surface).

●● Surface treatments (e.g. corona discharge to prepare plastic surfaces for printing).

●● The presence of additives. The plastics industry is constantly developing production

methods, and the inclusion of additives in particular can have a strong influence on the surface properties of plastic packaging materials (some are specifically

incorporated to form surface layers). This may be a contributing factor as to why the effectiveness of Vacuum Metal Deposition on such substrates has been observed

to fall from the early 2000s onwards. The modern practice of recycling plastics may also be influencing the suitability of these items for treatment with Vacuum Metal Deposition.

Home Office January 2014

5.VMD.21

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.22

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Equipment

Metal evaporation vessels

The design of the metal evaporation vessels used is important to the successful

operation of the process. The vessels are typically formed from molybdenum foil

Glossary

Index

Supplementary Information Schematic diagram showing the approximate location of metal evaporation vessels along the bottom of a vacuum metal deposition chamber.

because this metal is capable of withstanding the high (>1000°C) temperatures that it is heated to in order to evaporate gold, zinc and silver.

Filament bars

Gold evaporation vessels have a shallow depression in the centre to locate the piece of gold wire. This is because the quantity of gold used is very small (~2 - 3 mg), and it is

important that all the gold is evaporated upwards and towards the substrate. If deeper

containers are used, ‘shadowing’ may occur where metal vapour is unable to leave the

evaporation vessel in certain directions and not all regions of the item may be coated as a consequence.

Silver evaporation vessels utilise a filament similar in construction to that used for gold, with the principal difference being that the filament is wider and the depression in the centre is deeper so that the larger quantities of silver can be contained.

Silver evaporation vessel Zinc evaporation vessels

Zinc evaporation vessels are larger so that large quantities of zinc can be contained,

enabling zinc deposition to continue for several minutes if required. It is essential that all the zinc boats used are of the same dimensions so that they may run at approximately

the same temperatures. It is therefore recommended that commercially produced boats are used.

The recommended geometry for positioning of evaporation vessels within the chamber is illustrated on the right.

Gold evaporation vessel

Very long chambers may benefit from the use of two gold evaporation vessels at

approximately one-quarter and three-quarters of the way along the chamber. Three zinc

evaporation vessels may be needed for the largest chambers with one in the centre and one close to each of the gold evaporation vessels.

Home Office January 2014

5.VMD.22

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

5.VMD.23

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Processing

Modifying processing conditions according to substrate type

Different substrate types will have different nucleation and growth characteristics and processing conditions should be adjusted to account for this where known. This will require practice by the operator to identify what type of material is present. This is

particularly important for polymer substrates which may be difficult to distinguish from each other without reference to recycling symbols.

Different substrate types will have different nucleation and growth characteristics and the amount of gold used may need to be adjusted to account for this where the substrate is known to require a different amount of gold. This will require practice by the operator to identify what type of material is present.

●● In general, low-density polyethylene items (e.g. soft, ‘waxy’ plastic bags) and high-

recycled-content plastic bags usually require slightly greater amounts of gold than other types of polymer.

Some guidance is given below relating to the deposition temperatures used for VMD (Gold/Zinc) of different types of polymers that may be encountered in operational

Glossary

Supplementary Information Items of this type generally take several minutes to coat and often produce ‘reverse developed’ marks.

●● High-density polyethylene items (e.g. thin, ‘crinkly’ plastic bags) require lower

temperatures with the zinc evaporation vessel a very dull red colour. Coatings are generally achieved more quickly than for low-density polyethylene.

●● Polypropylene items (e.g. cigarette packet wrappers, potato crisp wrappers) require a

dull red zinc evaporation vessel colour, but may coat very rapidly, sometimes within a few seconds.

●● Polyethylene terephthalate (PET) or polystyrene items (e.g. drinks bottles, ‘blister

pack’ packaging) also require a dull red zinc evaporation vessel colour and coat rapidly. ‘Empty’ marks are more likely to occur on this type of material.

●● Some plastics such as black waste sacks may take several minutes to coat. Dark-

coloured surfaces can prove difficult to coat due to heat absorption effects. This

raises the surface temperature which in turn inhibits the condensation of zinc on the

surface. The temperature of the zinc evaporation vessel must therefore be kept down when processing items of this type.

work. This guidance may be significantly modified by the presence of contaminants,

Certain types of polymer such as cling film and plasticised vinyl will not be coated

the substrate. It is important that the operator continues to observe deposition on the

conditions used, and alternative processes should be considered instead n

the application of surface treatments, printing on the surface or pigments/additives in

surface, especially during the Gold/Zinc process, and stops development before the zinc

Index

by VMD (Gold/Zinc) regardless of the number of processing cycles and processing

coating obscures any marks that are present due to over-development. It is easier to

stop a deposition run before a mark is at optimum development and replace it for further zinc coating than it is to recover a mark that has become over-developed.

●● Low-density polyethylene items (e.g. soft, ‘waxy’ plastic bags) usually require the

zinc evaporation vessel temperature to be raised to a dull to medium orange/red.

Home Office January 2014

5.VMD.23

Fingermark Visualisation Manual

Vacuum Metal Deposition

Appendices

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

6 Category B-F Processes Contents Category B Processes............................................ 6.1.1 Category C Processes............................................ 6.2.1 Category D Processes............................................ 6.3.1 Category E Processes............................................. 6.4.1 Category F Processes............................................. 6.5.1

Introduction

Category B–F processes have been proposed at some time for the visualisation of

fingermarks. They are not regarded by CAST as meeting the criteria for Category A

processes (see Chapter 2, Section 2.3 for full classification details) and are therefore not used routinely for operational work.

The level of information provided for the Category B–F processes is in line with the possible usage of individual processes, as indicated below:

B

Optional processes for occasional operational use. Possible reasons for use: no other options available; all Category A options have been exhausted; niche application; or lack of equipment for other processes. These have varying levels of detail, from single-page summaries to more comprehensive information, as appropriate. The information is presented in a template similar to that used for the Category A processes.

C

Optional processes for occasional operational use. Possible reasons for use: no other options available; all Category A options have been exhausted; niche application. Only a summary page for each is provided to give an indication of where the process may be beneficial.

D

Corrective action processes. Not generally for routine use but may be used to recover marks in situations where initial selection of processes has resulted in undesirable consequences. The two Category D processes may be used for corrective action and have more detail to explain how they may be used most effectively.

Home Office January 2014

E

Processes with no known operational benefits.

F

Processes should not be used for health and safety reasons.

Listed with short explanations of why they are not considered suitable for use.

Listed with short explanations of why they are not considered suitable for use.

6.0.1

Fingermark Visualisation Manual

Chapter 6: Category B-F Processes

6.0.1

CH6

6.1.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Acid Dyes (water-based)......................................... 6.1.2 Adhesive Tape Removal (solvent-based)............ 6.1.12 Body Decomposition Residue Removal.............. 6.1.13 DMAC..................................................................... 6.1.14 Earth and Mud Removal....................................... 6.1.22 Europium Chelate.................................................. 6.1.23 Gun Blueing............................................................ 6.1.24 Indandione............................................................. 6.1.25 Iodine Fuming........................................................ 6.1.32 Iodine Solution....................................................... 6.1.41 Leuco Crystal Violet.............................................. 6.1.42 Natural Yellow 3..................................................... 6.1.43 Oil Red O................................................................ 6.1.44 Palladium Deposition............................................ 6.1.45 Radioactive Sulphur Dioxide................................ 6.1.46 Scanning Electron Microscopy............................ 6.1.47 Scanning Kelvin Probe.......................................... 6.1.48 Silver Nitrate.......................................................... 6.1.49 Superglue Fluorescent Dye Staining (propanolbased)..................................................................... 6.1.56

Home Office January 2014

Fingermark Visualisation Manual

Category B Processes Introduction Description

Established processes known to be generally less

effective than alternative options or processes that are

likely to offer benefit but have not been fully evaluated by the Home Office.

Use

Optional processes for occasional operational use.

Possible reasons for use: no other options available; all Category A options have been exhausted; niche

application; or lack of equipment for other processes.

Level of detail

These have varying levels of detail, from single-page summaries to more comprehensive information, as

appropriate. The information is presented in a template similar to that used for the Category A processes n

6.1.1

6.1.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Protein Stains; Blood Dyes

Contents Options............................................. 6.1.3 Laboratory or Scene?..................... 6.1.4 Laboratory Use................................ 6.1.5 Health and Safety........................ 6.1.5 Equipment................................... 6.1.6 Chemicals.................................... 6.1.7 Solutions...................................... 6.1.8 Processing................................... 6.1.9 Post-Processing........................ 6.1.10 Scene Use...................................... 6.1.11 Additional Considerations......... 6.1.11

Key Information Where this process could be used

It is a chemical process that involves exposing the item or surface to three solutions in sequence.

The process may be of use at scenes that cannot be adequately ventilated as the formulation is non-flammable. See Category B-C process options.

Much of the detail contained within the Category A Acid Dyes

Why the process is not in Category A

Safety and Effectiveness Summary

It is less effective than the Category A Acid Dyes process. It may also give higher background staining and more diffuse ridges on porous surfaces than the Category A process. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options, especially Acid Dyes,

have been explored before using this process.

process instructions will be of relevance when using Acid Dyes (water-based).

The Process

●● Acid Dyes (water-based) can be used safely and effectively at

scenes.

●● Blood that is not suitably fixed by the first solution will

dissolve when exposed to the second solution and process effectiveness will be reduced.

●● Acid Yellow 7 requires subsequent Fluorescence

Examination to be effective.

●● It is recommended that all sections are read prior to using

The Item or Surface

●● This section contains process instructions for three water-

●● This formulation will develop fingermarks in blood on most

this process for the first time. based acid dye formulations: ■■ ■■ ■■

Acid Black 1

Acid Violet 17 Acid Yellow 7

●● Process details are given for laboratory use and additional

considerations given for scene use, although the process

instruction contains less detail than for a Category A process.

Process Overview

Acid Dyes stain protein present in blood and other protein-rich

contaminants to give a coloured or fluorescent product. They will

not detect the constituents normally present in latent fingermarks and therefore must be used in sequence with other processes

●● Be aware of the possible hazards from body fluids.

surfaces.

●● The three water-based dye formulations will vary in

effectiveness depending on the colour of the item or surface and the surface porosity.

●● Acid Dyes (water-based) can adversely stain the background

of some porous items, obscuring the fingermark.

Integrated Use

Acid Dyes (water-based) may be detrimental to subsequent fingermark or forensic processing.

Further Reading

CAST Fingerprint Source Book, Chapter 3, Section 1.

when blood-contaminated items or surfaces are examined.

Home Office January 2014

6.1.2

Fingermark Visualisation Manual

B Acid Dyes (water-based)

6.1.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options Acid Yellow 7

●● Acid Yellow 7 is generally the most sensitive water-

based acid dye.

●● It is only effective at enhancing blood on non-porous

surfaces.

●● It is most effective on very light or visually

imperceptible deposits of blood (heavy deposits of blood fluoresce weakly due to quenching effects).

●● It produces fluorescent fingermarks*.

* The number of fingermarks detected with

Fluorescence Examination is dependent on many

factors e.g. suitability of light source and viewing filters,

level of dark adaptation and the surrounding examination environment.

Acid Yellow 7 enhanced blood on the neck of a bottle.

Acid Black 1 and Acid Violet 17

●● Acid Black 1 and Acid Violet 17 are both effective at

enhancing blood on all types of surface.

●● When Acid Black 1 and Acid Violet 17 are used

on porous and semi-porous surfaces, there may be some background staining which will reduce

contrast with the stained blood. However, each dye responds differently and for porous surfaces one

may prove more suitable than the other. If possible,

a small part of the surface, away from the area of interest, should be tested for dye retention.

●● Both Acid Black 1 and Acid Violet 17 produce visible

fingermarks.

Acid Black 1 enhanced blood on a foreign bank note.

Sequential use of Acid Dyes

●● Acid Violet 17 may be used after Acid Yellow 7 to

develop and increase contrast of visible fingermarks, although coloration will not be as dark as achieved by use of Acid Violet 17 alone.

●● Acid Black 1 should not be used after Acid Yellow 7

as the density of the staining is significantly less than if Acid Violet 17 is used after Acid Yellow 7.

●● The use of Acid Yellow 7 after Acid Black 1 or Acid

Violet 17 is normally of little benefit. However, it may

be used as a counterstain on porous surfaces where it will produce a fluorescent background that boosts contrast with the developed, absorbing fingermark.

●● There is no benefit to be gained by using Acid Black

1 and Acid Violet 17 insequence with one another.

●● See Chapter 4 for general information on the

sequential use of fingermark visualisation processes.

●● See Chapter 7 for information on integration of

fingermark and other forensic processes.

Acid Violet 17 enhanced blood on paper wallpaper.

Home Office January 2014

6.1.3

Fingermark Visualisation Manual

Acid Dyes (water-based)

6.1.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Laboratory or Scene? This page only gives an overview of

health and safety, effectiveness and practical issues associated with the

use of this process. Those responsible

for deciding whether to process items in

Health and Safety

Practitioners must be aware of the possible biological

hazards from blood and other body fluids remaining on items or surfaces after processing.

the laboratory or at the scene, e.g. crime

Effectiveness

consider in addition to the information

A Acid Dyes process so items must be removed back to the

scene managers or investigators, must below:

Acid Dyes (water-based) are less effective than the Category laboratory where possible.

●● the detailed process instructions;

However, Acid Dyes (water-based) can be used at the scene,

●● other factors dictated by the

followed.

and

investigation.

See Chapter 2, Section 2.4,

‘Fingermark Evidence Recovery

provided the details as written in the process instruction can be

Practicality

Acid Dyes (water-based) are messy processes if not contained and it is generally considered more practical to remove items back to a laboratory for treatment with the Category A Acid

Dyes process. Processing large items may require additional considerations to avoid run-off of solutions into areas not

requiring treatment. Removal of residual dye from processed items may be difficult.

●● In a laboratory it should be possible to contain the Fixing,

Staining and Washing Solutions.

●● At scenes, residual biological hazards may make clean-up

problematic and this must be considered before the process is used. Consideration must also be given to the need for

suitable equipment for the containment of the Fixing, Staining and Washing Solutions.

Planning’.

Home Office January 2014

6.1.4

Fingermark Visualisation Manual

Acid Dyes (water-based)

6.1.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes. This information can also be consulted for working with Category B processes, although it may not cover all situations.

●● Acid Dyes (water-based) may be carried out with no known hazards to health

provided practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category B process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working

Index

Laboratory Use Hazards associated with Acid Dyes (water-based) ●● Acid Dyes (water-based) are chemical processes.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive.

Additional hazard

Risk

Suggested control measures

Nuisance odour from processed items.

Some individuals may experience watery eyes and sneezing.

●● Examine treated items in a well-

Exposure to quantities of dye solution.

Staining hands, clothes and body with dye.

●● Wear appropriate gloves when

ventilated area or preferably on a down-draught bench.

preparing or using solutions to protect the hands, especially if they are to be immersed in the solutions. ●● Wear a disposable apron to protect the clothes and body.

environment; ■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

6.1.5

Fingermark Visualisation Manual

Acid Dyes (water-based)

Glossary

6.1.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

Acid Dyes (water-based) only require general laboratory equipment as described in Chapter 3 but using unbreakable equipment to minimise the risk from possible biohazards.

Equipment Processing dishes

Requirements Processing dishes must:

●● be unbreakable and easy to clean and sterilise

due to the biohazard risk. A suitable material would be stainless steel.

Home Office January 2014

6.1.6

Fingermark Visualisation Manual

Acid Dyes (water-based)

Appendices

6.1.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists chemicals that are required for Acid Dyes (water-based). Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

Unless specified, water used for making solutions or for rinsing items is purified. See Chapter 3 safe handling of chemicals for general information or effective use of chemicals for details on dye purity. Common Name

Alternative Name(s)

CAS Number

Grade

5-Sulphosalicylic acid, dehydrate

5-SSA dehydrate

5965-83-3

Laboratory

Acid Yellow 7 (AY7)

CI 56205; Brilliant Sulphoflavin

2391-30-2

≥50 %

Acid Violet 17 (AV17)

CI 42650; Coomassie Brilliant Violet R150

4129-84-4

≥50 %

Acid Black 1 (AB1)

CI 20470; Amido Black 10B; Naphthol Blue Black; Naphthalene Black 12B

1064-48-8

≥80 %

Acetic acid

Ethanoic acid

64-19-7

Laboratory

Home Office January 2014

6.1.7

Fingermark Visualisation Manual

Acid Dyes (water-based)

Appendices

6.1.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Solutions

Consult Chapter 3 for general information on solution

preparation, safe storage of chemicals, solutions and

(1) Prepare solutions

mixtures (which includes information on packaging

and labelling), management of waste for disposal of

solutions and guideline expiry periods. This page gives additional information relevant to this process.

Solutions

(2) Label appropriately

(3) Store appropriately

Fixing Solution

23 g 5-Sulphosalicylic acid dihydrate 1 L water AND

a) The Staining Solutions should be stirred for at least 30 minutes. b) Fixing and Washing Solutions are colourless. Staining Solutions are dark blue (AB1), purple (AV17) and yellow (AY7). a) The Fixing, Staining and Washing Solutions should be labelled as determined by a local hazard assessment.

a) Fixing, Staining and Washing Solutions have guideline expiry dates of 12 months after preparation if stored at room temperature.

(4) Dispose of appropriately

Staining Solution

2 g dye 1 L Washing Solution Dye options: Acid Black 1 (AB1) or Acid Violet 17 (AV17) or Acid Yellow 7 (AY7) AND

Washing Solution 50 mL acetic acid 950 mL water

For other quantities see Ready Reckoner.

Home Office January 2014

Ready Reckoner Quantity Solution

Chemical

1L

2L

5L

Fixing Solution

5-SSA dehydrate

23 g

46 g

115 g

Water

1L

2L

5L

Staining Solution

Dye

2g

4g

10g

Washing Solution

1L

2L

5L

Washing Solution

Acetic Acid

50 mL

100 mL

250 mL

Water

950 mL

1.90 L

4.75 L

6.1.8

Fingermark Visualisation Manual

Acid Dyes (water-based)

Glossary

6.1.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Processing Preparation (1) Equipment and Solutions

a) Pour sufficient amounts of Fixing, Staining and Washing Solutions into separate dishes or vessels to treat the item. At least two Washing Solution dishes should be considered.

(4) Expose item to Washing Solution

Processing (2) Expose item to Fixing Solution

a) Apply the Fixing Solution to the item, ensuring that the surface is kept wetted for five minutes using suitable means, such as immersion or pouring. Longer times may be needed to fix heavy deposits of blood. b) If immersing the item, the Fixing Solution should be changed if it becomes contaminated with debris or changes colour.

(3) Expose item to Staining Solution

a) If using Acid Black 1 or Acid Violet 17, apply the Staining Solution to the item, ensuring that the surface is kept wetted for 3–4 minutes using suitable means, such as immersion or pouring. Weak staining of marks will indicate that longer exposure times are required or dye concentration is insufficient. b) If using Acid Yellow 7, apply the Staining Solution to the item, ensuring that the surface is kept wetted for 5–10 minutes using suitable means, such as immersion or pouring. Weak staining of marks will indicate that longer exposure times are required or dye concentration is insufficient. c) If immersing the item, the Staining Solution should be changed or replenished as required.

Continued on next column

Home Office January 2014

(5) Dry item

a) Apply the Washing Solution to the item, ensuring that the surface is kept wetted, until excess dye has been removed from the background and greatest contrast is achieved between the enhanced fingermarks and the background. This should be done using suitable means, such as immersion with gentle agitation, or pouring. b) If immersing the item, the Washing Solution should be changed when it becomes heavily contaminated with dye. The final Washing Solution should remove final traces of excess dye from the item. a) See drying of items.

(6) Examination (AY7) Primary: Fluorescence Examination

(6) Examination (AB1/AV17) Primary: Visual Examination Secondary: Fluorescence Examination

a) Items treated with Acid Dyes should be examined in a well-ventilated area preferably on a down-draught bench. b) Visible marks are coloured dark blue (AB1), purple (AV17) and yellow/brown (AY7). Fluorescent marks are coloured yellow (AY7). c) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination and Fluorescence Examination, particularly for low-contrast marks or marks on dark or patterned surfaces. d) Mark up viable fingermarks appropriately and capture image. e) After examination, items can be re-treated if necessary. In this case, application of Fixing Solution is not required.

6.1.9

Fingermark Visualisation Manual

Acid Dyes (water-based)

Glossary

6.1.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Residual processing chemicals

a) Items treated with Acid Dyes may emit a nuisance odour comprising of acetic acid vapour. Its concentration is likely to be below the workplace exposure limit (WEL).

(2) Cleaning processed items

a) It may not be possible to return items to their original state. If possible, items may be thoroughly wiped or washed with an anti-viral disinfectant (if body fluids are present) followed by soap and water. Some solvents may be effective at removing residual chemicals, although they may cause further damage to the item.

(3) Disposal or return of processed items

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner provided anti-viral disinfectants have been used.

Equipment and Chemicals (4) Re-use of solutions

Home Office January 2014

a) Fixing, Staining and Washing Solutions should not be re-used.

6.1.10

Fingermark Visualisation Manual

Acid Dyes (water-based)

Appendices

6.1.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Scene Use

Additional Considerations If a decision has been made to apply Acid Dyes at a scene, a number of additional considerations need to be taken into

account, over and above those given for laboratory use. The recommendations below cannot be prescriptive since every scene will be different and:

●● each must be subject to a local risk assessment and

will require different control measures to mitigate

any risks identified before work can be carried out

safely and in compliance with the requirements of the Health and Safety at Work Act 1974;

●● different approaches may be needed to make

the process as effective as possible within the constraints of the scene;

For health and safety, consider:

●● the risk of contagion due to biohazard and,

depending on the quantity of potentially hazardous

material, whether additional safety measures or PPE are required;

●● what additional packaging and labelling will be

For practicality, consider:

●● access to the areas to be treated;

●● the additional time and costs of applying the process

at the scene, including: ■■ ■■

needed for transporting the solutions (made in the

or plasticine™ to contain the solutions during application and avoid run-off onto areas not

For effectiveness consider:

out the process in the laboratory can be followed,

after consideration of the constraints posed by the scene.

additional equipment to make the process safe and effective and to minimise mess, e.g. tissue

laboratory) to the scene.

●● whether the process instructions as given for carrying

transport costs;

requiring treatment; ■■

scene clean-up, which may involve dismantling surfaces contaminated with residual biological hazards or stained surfaces for disposal n

●● present a range of practical issues that need to be

overcome.

This page must be read in conjunction with the laboratory process instruction.

See Chapter 2, Section 2.4, ‘Fingermark Evidence Recovery Planning’ and Chapter 3, Section 3.1 –

Scene use of the processes and treatment of large areas for other general information.

Home Office January 2014

6.1.11

Fingermark Visualisation Manual

Acid Dyes (water-based)

Glossary

6.1.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names ‘UnDo’; Heptane

Key Information Where this process could be used

Adhesive Tape Removal (solvent-based) may be of use where adhesive surfaces cannot be easily separated from the surface that they are adhering to using Category A methods. Solvents are generally most suited for use on porous or semi-porous surfaces. See Preparation processes overview.

Why the process is not in Category A

The process dissolves the adhesive, fundamentally changing its integrity, which may be detrimental to fingermarks deposited in this layer. Solvent

Porous surface

●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the

Adhesive surface

use of this process.

●● Ensure that Adhesive Tape Removal (Category A) has been

explored before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to

Safety and Effectiveness Summary The Process

●● Adhesive Tape Removal (solvent-based) uses flammable

solvents. It can be used safely in a laboratory and at scenes provided appropriate precautions are taken to control the

flammability hazard (such as using it sparingly and/or using suitable LEV).

●● The effectiveness is dependent on the ability of the solvent

to soften the adhesive.

The Item or Surface

●● Adhesive Tape Removal (solvent-based) is effective at

separating commonly found pressure sensitive adhesives from all surfaces.

●● It may be destructive to the adhesive layers and the

fingermarks present on them.

Integrated Use

Adhesive Tape Removal (solvent-based) may be detrimental to subsequent fingermark or forensic processing n

considering the use of this process.

Process Overview

The process involves careful application of a solvent to locally soften and dissolve the adhesive layer so that it loses its

ability to adhere to the item or surface. The tape can then be physically lifted from the item or surface and the solvent will

then evaporate. This leaves the adhesive layer intact, although fundamentally changed.

It is a preparation process that involves the localised

application of a solution to the adhesive bond between two surfaces followed immediately by physical separation.

Home Office January 2014

6.1.12

Fingermark Visualisation Manual

B Adhesive Tape Removal (solvent-based)

6.1.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Key Information Where this process could be used

This process may be used on surfaces that are heavily contaminated with body decomposition residue where it is suspected latent fingermarks may be present under the contaminant layer. See Preparation processes overview.

Why the process is not in Category A

It has not been researched in sufficient detail to identify an optimised method. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Safety and Effectiveness Summary The Process

●● This method can be used safely in a laboratory provided

appropriate biohazard precautions are taken.

●● The effectiveness will depend on the amount of

contamination and the solubility of the contamination in the detergent solution.

●● Detergents used should be of neutral pH, which will minimise

interference with subsequent processes.

●● Temperatures of the detergent solution, wash water and that

used for drying should be kept where possible to below 30˚C.

The Item or Surface

●● Although the process can be used on all types of item or

surface, care must be taken to ensure the continued integrity of porous and semi-porous items and surfaces.

●● Physical rubbing of items or surfaces must be kept to a

minimum so as not to damage fingermarks.

The process is used to remove body decomposition residue by

Integrated Use

tepid detergent solution to loosen and ultimately remove heavy

subsequent fingermark or forensic processing n

gently washing or soaking and agitating items or surfaces in a contamination. Multiple wash baths may be required to fully

Body Decomposition Residue Removal may be detrimental to

remove contamination. Tepid water is then used to wash the item or surface which is subsequently dried. This process will also remove marks in blood.

It is a preparation process that involves exposing the item or © See Photo Credits

surface to a detergent solution followed by a water wash.

Home Office January 2014

6.1.13

Fingermark Visualisation Manual

B Body Decomposition Residue Removal

6.1.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

4-dimethylaminocinnamaldehyde

Contents Laboratory Use.............................. 6.1.15 Health and Safety...................... 6.1.15 Equipment................................. 6.1.16 Chemicals.................................. 6.1.17 Solutions.................................... 6.1.18 Impregnated sheets................... 6.1.19 Processing................................. 6.1.20 Post-Processing........................ 6.1.21

Key Information

Where this process could be used

DMAC may be of use for the development of marks on thermal papers where retention of printed information is important. See Category B-C process options.

Why the process is not in Category A

DMAC is less effective than both DFO and Ninhydrin on porous surfaces. Physical Developer and Category C process ThermaNin may be more effective than DMAC for thermal papers where it is necessary to retain the printed information. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Process details are given for laboratory use, although the

process instruction contains less detail than for a Category A process.

Safety and Effectiveness Summary The Process

●● DMAC can be used safely and effectively in a laboratory. It is

not practical to use at scenes.

●● The effectiveness is linked to the close proximity and the

length of time the impregnated sheets are in contact with the item.

●● The process requires subsequent Fluorescence Examination

to be effective.

The Item or Surface

●● The process is most effective at developing latent

fingermarks on porous and semi-porous surfaces.

●● DMAC is not effective on items or surfaces that have been

wetted, even if they have been subsequently dried.

Integrated Use

●● DMAC may be detrimental to subsequent fingermark or

forensic processing.

Further Reading

CAST Fingerprint Source Book, Chapter 5, Section 2.

Process Overview

DMAC reacts with amino acids, urea and possibly other

components in latent marks to form a fluorescent product which must be subsequently viewed using Fluorescence Examination.

It is a chemical process that involves impregnating paper

sheets with a solution and pressing these impregnated sheets into close contact with the item to be processed.

Home Office January 2014

6.1.14

Fingermark Visualisation Manual

B DMAC

6.1.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes. This information can also be consulted for working with Category B processes, although it may not cover all situations.

●● DMAC may be carried out with no known hazards to health provided practitioners are

trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and

Glossary

Index

Laboratory Use Hazards associated with DMAC ●● DMAC is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional hazard

Creation of a flammable atmosphere when preparing and using DMAC Impregnating Solution.

Risk Fire

Suggested control measures ●● Prepare and use DMAC

Impregnating Solution in a fume cupboard. See working with flammable liquids for further information.

instructions must be provided locally.

●● In providing the Category B process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

6.1.15

Fingermark Visualisation Manual

DMAC

Appendices

6.1.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

DMAC requires very little process-specific equipment. General laboratory equipment that may be required is outlined in Chapter 3. Equipment

Requirements

Suitable vessel

Processing troughs used in DFO and Ninhydrin are suitable and convenient for the application of DMAC Impregnating Solution to papers.

Press or other means of ensuring very close proximity of the item and the impregnated sheets

A means of simultaneously applying light pressure to the impregnated sheets and item being treated is required. The pressure needs to be sufficient to keep the impregnated paper sheets and the item in direct contact.

Paper sheets for impregnating

The paper used for making impregnated sheets must be porous. Those that are matt in appearance are generally suitable while those that appear highly smooth or glossy are not.

Aluminium foil

Thin aluminium foil that can be readily wrapped around items during processing to form an impervious barrier to DMAC vapours.

Sealable polythene bags

Polythene bags of an appropriate size to contain the impregnated paper sheets. The bag should have a means of being sealed, either via an integral sealing system or by sealing it shut with nonporous adhesive tape.

Home Office January 2014

6.1.16

Fingermark Visualisation Manual

DMAC

Appendices

6.1.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists chemicals that are required for DMAC. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3: Safe Handling of Chemicals for general information. Common Name

Alternative Name(s)

CAS Number

Grade

DMAC

4-dimethylaminocinnamaldehyde, p-DMAC

6203-18-5

98%

Ethanol

Ethyl alcohol

64-17-5

≥96 %

Home Office January 2014

6.1.17

Fingermark Visualisation Manual

DMAC

Appendices

6.1.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Solutions

Consult Chapter 3 for general information on solution

preparation, safe storage of chemicals, solutions and

(1) Prepare solutions

mixtures (which includes information on packaging

and labelling), management of waste for disposal of

solutions and guideline expiry periods. This page gives

(2) Label appropriately

a) The DMAC Impregnating Solution should be labelled as determined by a local hazard assessment.

(3) Store appropriately

a) The DMAC Impregnating Solution has a guideline expiry date of 12 months after preparation if stored at room temperature.

additional information relevant to this process.

Solutions DMAC Impregnating Solution

1.25 g DMAC 500 mL ethanol

a) DMAC Impregnating Solution must be prepared in a fume cupboard. b) The DMAC Impregnating Solution is yellow.

(4) Dispose of appropriately

For other quantities see Ready Reckoner.

Ready Reckoner Chemical

DMAC Impregnating Solution Home Office January 2014

Quantity of DMAC solution (approximate number of impregnated paper sheets produced) 100 mL (20)

200 mL (40)

500 mL (100)

DMAC

0.25 g

0.5 g

1.25 g

Ethanol

100 mL

200 mL

500 mL

6.1.18

Fingermark Visualisation Manual

DMAC

Glossary

6.1.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Impregnated sheets (1) Prepare paper sheets

a) Ensure a sufficient supply of paper sheets for impregnating.

(2) Prepare work area

a) The DMAC Impregnating Solution must be used in a fume cupboard.

(3) Prepare equipment

a) Pour the DMAC Impregnating Solution into a suitable clean, dry vessel such as a processing trough.

(4) Apply DMAC Impregnating Solution

(5) ‘Dry’ item

a) Draw a paper sheet through the DMAC Impregnating Solution allowing excess to drain back into the trough. b) Hang dipped paper sheet within the fume cupboard. c) The trough may be replenished with fresh DMAC Impregnating Solution as required. a) Allow the solvent to completely evaporate from DMAC Impregnated Sheets before removing them from the fume cupboard. b) Place DMAC Impregnated Sheets into a sealable polythene bag.

(6) Label appropriately

a) The DMAC Impregnated Sheets should be labelled as determined by a local hazard assessment.

(7) Store appropriately

a) The DMAC Impregnated Sheets have guideline expiry dates of three months after preparation if stored in a refrigerator at 4˚C until required.

Home Office January 2014

6.1.19

Fingermark Visualisation Manual

DMAC

Appendices

6.1.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (6) Examination

Preparation (1) Item

(2) Equipment

a) Remove the required number of DMAC impregnated sheets from the refrigerator and allow to reach room temperature. a) Cut aluminium foil to an appropriate size.

Primary: Fluorescence Examination

a) Fluorescent fingermarks are coloured yellow. b) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Fluorescence Examination, particularly for low-contrast marks or marks on dark or patterned surfaces. c) Mark up viable fingermarks appropriately and capture image. d) After examination, items can be re-treated if necessary.

Processing (3) Layer items and impregnated sheets

a) Form a ‘sandwich’ by placing the item to be treated between two DMAC impregnated sheets. Multiple items may be treated as long as each item layer is sandwiched between layers of DMAC impregnated sheets. Completely wrap the sandwich of items being treated with aluminium foil. Single sheet Aluminium foil

(4) Apply pressure to sandwich

(5) Remove treated items from the sandwich

Home Office January 2014

Multiple sheets Item being treated DMAC

a) Apply light pressure to the sandwich of items being

treated for 8-12 hours using a press or other suitable means.

a) Release the pressure, carefully unwrap the sandwich and remove the treated item.

6.1.20

Fingermark Visualisation Manual

DMAC

Appendices

6.1.21

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Residual processing chemicals

a) Items processed using DMAC may transfer their yellow colouration to other items that they are left in contact with or contained with. Processed items should be kept in sealed non-porous packaging.

(2) Cleaning processed items

a) It may not be possible to return items to their original state. If possible, items may be thoroughly washed with soap and water.

(3) Disposal or return of processed items

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (4) Re-use of DMAC impregnated sheets

(5) Cleaning of equipment

Home Office January 2014

a) DMAC impregnated sheets may be re-used up to three times before effectiveness noticeably deteriorates. Return to the refrigerator at 4˚C in a sealed polythene bag until required. a) Equipment used for pressing sandwiches including DMAC impregnated sheets (e.g. presses) must be thoroughly cleaned before being used for any other purpose otherwise transfer of yellow colouration to other items may occur. Aluminium foil can be disposed of with ordinary waste n

6.1.21

Fingermark Visualisation Manual

DMAC

Appendices

6.1.22

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Key Information Where this process could be used

This process may be used on surfaces that are heavily contaminated with earth/mud where it is suspected fingermarks may be present under the contaminant layer. See Preparation processes overview.

Why the process is not in Category A

It has not been researched in sufficient detail to identify an optimised method. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

The process is used to remove earth/mud by gently washing or soaking and agitating items or surfaces in tepid water to

Safety and Effectiveness Summary The Process

●● Earth and Mud Removal can be used safely in a laboratory

and at scenes.

●● The effectiveness will depend on the amount of

contamination and the solubility of the earth/mud in water. If the earth/mud contains oils or greases this process will not be as effective.

●● Water should be used without detergents in the first instance

as they may interfere with subsequent processes; however, if these are subsequently used they should be of neutral pH.

●● The temperature of the wash water and that used for drying

should be kept where possible to below 30˚C.

The Item or Surface

●● Although the process can be used on all types of item or

surface, care must be taken to ensure the continued integrity of porous and semi-porous items and surfaces.

●● Physical rubbing of items or surfaces must be kept to a

minimum so as not to damage fingermarks.

loosen and ultimately remove heavy contamination. This may be

Integrated Use

then dried.

fingermark or forensic processing n

repeated until the item or surface is clear of contamination and

Earth and Mud Removal may be detrimental to subsequent

It is a preparation process that involves the immersion of items

in, or application of, water to a surface.

Home Office January 2014

6.1.22

Fingermark Visualisation Manual

B Earth and Mud Removal

6.1.23

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Key Information Where this process could be used

The process may be of use for grease-contaminated marks on dark surfaces, where marks developed by Basic Violet 3 and Solvent Black 3 may be difficult to see. See Category B-C process options.

Why the process is not in Category A

The process is less effective than Basic Violet 3 or Solvent Black 3 and has not been extensively compared to the alternative Category B process Natural Yellow 3. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Safety and Effectiveness Summary The Process

●● Europium Chelate can be used safely and effectively in a

laboratory.

●● The process requires subsequent Fluorescence

Examination to be effective.

The Item or Surface

●● The process is most effective at developing grease-

contaminated fingermarks on non-porous surfaces.

●● The process is relatively ineffective on latent fingermarks

unless they are rich in sebaceous sweat.

●● The effectiveness of Europium Chelate is known to decrease

significantly for marks more than a few days old.

Integrated Use

●● Europium Chelate may be detrimental to subsequent

fingermark or forensic processing.

Further Reading

CAST Fingerprint Source Book, Chapter 5, Section 13.3 n

Process Overview

Europium Chelate preferentially migrates from solution into the fats and lipids in latent fingermarks and some grease contaminants to form a complex that is fluorescent.

It is a chemical process that involves the application of a

solution to the item or surface followed by washing with water.

Home Office January 2014

6.1.23

Fingermark Visualisation Manual

B Europium Chelate

6.1.24

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Perma Blue

Key Information Where this process could be used

Gun blueing may be of use on copper, brass and bronze items either previously treated with Superglue Fuming or that are grease-contaminated. See Category B-C process options.

Why the process is not in Category A

The process has not yet been fully evaluated and optimised. Gun Blueing may be marginally less effective than the Category B process Palladium Deposition. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Gun Blueing solution chemically reacts with the surface of copper and its alloys, including brass and bronze. Latent

fingermarks, greases and some development processes such as Superglue Fuming protect the copper, brass or bronze surface

so deposition only occurs on the background metal turning it

Safety and Effectiveness Summary The Process

●● Gun Blueing can be used safely and effectively in a

laboratory. However, commercially pre-mixed preparations

may be safer to use as the principal chemical component is highly toxic.

The Item or Surface

●● The process is specifically suited for use on copper and

copper-based alloys such brass and bronze.

●● The process is most effective when the metal surface is

protected from the Gun Blueing solution in the region of fingermark ridges, for example by grease-contaminated marks and those developed by Superglue Fuming. In comparison, it is less effective on latent fingermarks.

Integrated Use

Gun Blueing may be detrimental to subsequent fingermark or

forensic processing. The impact of Gun Blueing on subsequent

ballistic forensic analysis processes such as comparison of firing marks has not yet been established.

Further Reading

1. CAST Fingerprint Source Book, Chapter 5, Section 3.1.

2. Dominick, A. J., Laing, K. J. Forens Ident, vol 61(2), 2011, p144 n

dark blue.

It is a chemical process that involves the application of a © See Photo Credits

solution to the item followed by washing with water.

Home Office January 2014

6.1.24

Fingermark Visualisation Manual

B Gun Blueing

6.1.25

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names IND; 1,2 IND; 1,2-Indandione; 1,2-Indanedione

Contents Laboratory Use.............................. 6.1.26 Health and Safety...................... 6.1.26 Equipment................................. 6.1.27 Chemicals ................................. 6.1.28 Solutions.................................... 6.1.29 Processing................................. 6.1.30 Post-Processing........................ 6.1.31

Key Information Where this process could be used

Indandione is likely to be more effective than DFO as a single process on most paper types, particularly brown paper and cardboard. See Category B-C process options.

Why the process is not in Category A

Process optimisation and operational trials have not yet been completed under UK conditions. Sequences incorporating DFO and Ninhydrin are possibly more effective than those with Indandione. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Process details are given for laboratory use, although the

process instruction contains less detail than for a Category

A process. Note that information in the Category A DFO and

Ninhydrin process instructions (such as Troubleshooting) may

It is a chemical process that involves the application of a

solution to the item or surface followed by use of specialist

ovens (if possible) to increase the speed of the reaction. The

resultant mark is highly fluorescent and must be viewed using Fluorescence Examination.

Safety and Effectiveness Summary The Process

●● Indandione can be used safely and effectively in the

laboratory, but is normally considered impractical to use at scenes.

●● The effectiveness may be influenced by the method of

application.

●● The effectiveness is linked to the ability to control the

temperature of the item or surface using specialist equipment.

●● The process requires subsequent Fluorescence Examination

to be effective.

The Item or Surface

●● The process is most effective at developing both latent and

bloody fingermarks on porous surfaces although it can be used on semi-porous surfaces.

also be relevant to Indandione.

●● Indandione is not effective on items or surfaces that have

of these have yet been investigated by CAST or compared to

Integrated Use

●● Various formulations are in operational use worldwide. Not all

the formulation presented here.

Process Overview

Indandione reacts with amino acids in latent fingermarks to

give a fluorescent product. It also reacts with amine-containing compounds (mainly proteins) in blood.

been wetted, even if they have been subsequently dried.

Indandione may be detrimental to subsequent fingermark or forensic processing.

Further Reading

1. CAST Fingerprint Source Book, Chapter 5, Section 7.

2. Lam, R., Wilkinson, D. J. Forens Ident, vol 61(6), (2011), p607620.

Home Office January 2014

6.1.25

Fingermark Visualisation Manual

B Indandione

6.1.26

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes. This information can also be consulted for working with Category B processes, although it may not cover all situations.

●● Indandione may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

Hazards associated with Indandione ●● Indandione is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional hazards

Risk

Air depletion when preparing and using Indandione Working Solution

Asphyxiation

Nuisance odour from processed items

Some individuals may experience watery eyes and sneezing.

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category B process instructions it is assumed that:

the process will be carried out in a laboratory that can provide a safe working environment;

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

Suggested control measures ●● Prepare and apply Indandione

Working Solution in an extracted fume cupboard.

HFE7100 is not absorbed by the activated carbon filters found in recirculating fume cupboards. It passes through them unaffected and unless the HFE7100 vapour is extracted from the laboratory it will displace the air from the ground up as it is much heavier than air.

●● The health and safety information provided throughout the Manual must be

■■

Index

Laboratory Use

General Health and Safety Information

■■

Glossary

●● Examine treated items in a well-

ventilated area or preferably on a down-draught bench.

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

6.1.26

Fingermark Visualisation Manual

Indandione

Appendices

6.1.27

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Equipment

Indandione requires the use of some process-specific equipment for the application of

Indandione Working Solution and for creating the environmental conditions required for development.

Laboratory Use Equipment

A processing trough must: ●● be made of a material compatible with solvents used in the Indandione Working Solution. In addition, a processing trough should: ●● be of suitable length to accommodate the size of items being processed; ●● be shallow with a curved, corrugated bottom surface.

Indandione development oven

An Indandione development oven must: ●● maintain air temperature within the oven whilst at equilibrium at 100 ± 5˚C; ●● provide close control and rapid recovery of temperature so that at least 95˚C is reached across all shelves, when fully loaded, in less than five minutes after the oven door, that has been open for one minute, is closed; ●● not have air flow so strong as to blow normal paper casework items around within the oven; ●● have an over-temperature safety cut-out; ●● have an adjustable airflow inlet; ●● be able to be connected to a negative pressure exhaust system (see below). In addition, an Indandione development oven should: ●● have a working capacity of at least 150 L; ●● have interior and shelves resistant to acetic acid vapour; ●● incorporate a timer; ●● have a way of monitoring items whilst in the oven.

Extraction for Indandione development oven

Extraction for an Indandione development oven must: ●● be connected to the Indandione development oven via an extraction pipe with a continuous upward slope; ●● be a negative pressure exhaust system which provides a continuous extraction rate of between five and ten times the total volume of the oven per hour; ●● have an extraction pipe that is be able to resist the temperature being used and acetic acid vapour at that temperature.

maintained and, if appropriate, serviced regularly in accordance with the manufacturer’s instructions. General laboratory equipment that may be required is outlined in

Home Office January 2014

Requirements

Processing trough

If equipment is to meet the requirements as outlined on the right, it must be well

Chapter 3.

Index

6.1.27

Fingermark Visualisation Manual

Indandione

Glossary

6.1.28

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists chemicals that are required for Indandione. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3 safe handling of chemicals for general information. Common Name

Alternative Name(s)

CAS Number

Grade

1,2 Indandione

1,2 IND, 1,2 indanedione

16214-27-0

>99%

Acetic acid

Ethanoic acid

64-19-7

Analytical ≥99.7%

Ethyl acetate

Ethyl ethanoate

141-78-6

Analytical

HFE7100

Methyl nonafluorobutyl ether; 1 Methoxynonafluorobutane

HFE7100 is only available as a mixture of two isomers. The isomers are inseparable but have essentially identical properties. Each isomer has its own CAS number (163702-08-7 and 16370207-6). The isomeric mixture within HFE7100 does not have its own unique CAS number.

As supplied

Zinc chloride

-

7646-85-7

Reagent grade ≥98%

Home Office January 2014

6.1.28

Fingermark Visualisation Manual

Indandione

Appendices

6.1.29

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Solutions

Consult Chapter 3 for general information on solution

preparation, safe storage of chemicals, solutions and

(1) Prepare solution

mixtures (which includes information on packaging

and labelling), management of waste for disposal of

solutions and guideline expiry periods. This page gives additional information relevant to this process.

Solutions Indandione Working Solution

0.25 g 1,2 Indandione 90 mL ethyl acetate 10 mL acetic acid 1 L HFE 7100 1 mL Zinc Chloride Stock Solution

Zinc Chloride Stock Solution

(2) Label appropriately

a) The Indandione Working and Zinc Chloride Stock Solutions should be labelled as determined by a local hazard assessment.

(3) Store appropriately

a) Indandione Working and Zinc Chloride Stock Solutions have guideline expiry dates of 12 months after preparation if stored at room temperature.

(4) Dispose of appropriately

0.1 g zinc chloride 4 mL ethyl acetate 1 mL acebtic acid

Final solutions ready for use are identified by a red border. For other quantities see Ready Reckoner.

Home Office January 2014

a) Indandione Working Solution must be prepared in an extracted fume cupboard. b) Indandione Working Solution should be prepared by first dissolving Indandione in ethyl acetate and acetic acid, before adding HFE7100 and Zinc Chloride Stock Solution. c) Zinc Chloride Stock Solution is clear. Indandione Working Solution is pale yellow. d) Solutions with a separate ‘oily’ layer should not be used.

Ready Reckoner Quantity of Indandione Working Solution Chemical

1L

2L

5L

Indandione

0.25 g

0.50 g

1.25 g

Ethyl acetate

90 mL

180 mL

450 mL

Acetic acid

10 mL

20 mL

50 mL

HFE7100

1L

2L

5L

Zinc Chloride Stock Solution

1 mL

2 mL

5 mL

6.1.29

Fingermark Visualisation Manual

Indandione

Glossary

6.1.30

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Work area

(2) Equipment

Processing (3) Apply Indandione Working Solution

(4) ‘Dry’ item

Continued on next column Home Office January 2014

a) The Indandione Working Solution must be applied in an extracted fume cupboard. a) The Indandione development oven should be preconditioned to 100 ± 5˚C. b) Pour the Indandione Working Solution into an appropriate clean, dry trough. Small quantities should be used to minimise waste. a) Draw the item through the Indandione Working Solution allowing excess to drain back into the trough. Alternatively, quickly immerse and remove the item. It is necessary only to wet the surface with the solution. Prolonged immersion is undesirable. b) Place item onto a suitable surface to ‘dry’ flat and horizontally within the fume cupboard. A suitable surface could be thick, dry, single ply or bonded tissue. Corrugated cardboard is not suitable. c) If it is not possible to immerse the item carefully apply the solution with a soft brush. The surface must be ‘wetted’ evenly. d) If the item turns grey/black during processing see Thermal Coating Removal process instruction. e) Indandione Working Solution must be discarded if it changes in appearance (forms ‘oily’ droplets, or becomes contaminated). Provided there is no sign of contamination the trough may be replenished with fresh solution, but if changes in appearance occur, a clean dry trough must be used. There should be very little (if any) solution remaining in the trough at the end of the processing session, minimising wastage. a) Allow the solvents to evaporate from the items before removing them from the fume cupboard.

(5) Transfer item to a pre-conditioned Indandione development oven

(6) Heat item (7) Remove item from Indandione development oven

(8) Examination Primary: Fluorescence Examination Secondary: Visual Examination

a) Minimise the time the oven door is open during transfer. b) The item may be placed on cardboard for transferring directly into the oven. c) Some items such as envelopes with plastic windows may be damaged at 100˚C. Most plastics will tolerate a temperature of 50˚C but samples of items should be tested if possible to determine the maximum temperature to which they can be subjected without damage. Items heated at less than 100˚C may take many hours to develop marks. a) The item should be heated for at least ten minutes. a) Items should be examined in a well-ventilated area preferably on a down-draught bench. b) Extraneous fingermarks may develop if items are handled after processing. c) Fluorescent marks are coloured yellow/orange. Visible marks are coloured pink. d) The item may be examined as soon as cool enough to handle. e) Almost all marks that Indandione will target develop during treatment, although re-examination after a few days may identify some additional marks. The item should be kept in the dark if awaiting additional development. f) Indandione developed fingermarks can fade over time so it is important to image all fingermarks found immediately. g) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination and Fluorescence Examination, particularly for low-contrast marks or marks on dark or patterned surfaces. h) Mark up viable fingermarks appropriately and capture image. i) After examination, items can be re-treated if necessary, but this is only worthwhile if there is very little background development.

6.1.30

Fingermark Visualisation Manual

Indandione

Appendices

6.1.31

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

‘Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.’

Processed item (1) Residual processing chemicals

a) Items treated with Indandione may emit a nuisance odour comprising of acetic acid vapour. Its concentration is likely to be below the workplace exposure limit (WEL).

(2) Cleaning processed items

a) It may not be possible to return items to their original state. If possible, items may be thoroughly wiped or washed with soap and water.

(3) Disposal or return of processed items

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (4) Disposal of used Indandione Working Solution

Home Office January 2014

a) Used Indandione Working Solution must not be poured back into a container for re-use at a later date as the effectiveness and solution lifetime are significantly reduced n

6.1.31

Fingermark Visualisation Manual

Indandione

Appendices

6.1.32

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Contents Laboratory Use.............................. 6.1.33 Health and Safety...................... 6.1.33 Equipment................................. 6.1.35 Chemicals.................................. 6.1.36 Solutions.................................... 6.1.37 Processing (Fuming).................. 6.1.38 Post-Processing........................ 6.1.40

Key Information Where this process could be used

Iodine Fuming is a lower impact process than those involving solution dipping and may be used for particularly delicate items and where it is important to minimise potential damage to a document. See Category B-C process options.

Why the process is not in Category A

Iodine Fuming is significantly less effective than DFO and Ninhydrin on most types of paper. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Process details are given for laboratory use, although the

process instruction contains less detail than for a Category A process.

Process Overview

Iodine vapour interacts with some components of latent

fingermarks and some greases and fats to produce brown-

coloured fingermarks. These marks are not permanent as the

iodine will readily resublime. However, it is possible to react the iodine with α-naphthoflavone to form a dark blue compound

which produces a more durable mark, although they may still not be permanent.

It is a chemical process that involves exposing items or

cabinet (if possible). This may be followed by application of a fixing solution (optional).

Safety and Effectiveness Summary The Process

●● Iodine Fuming (and the optional fixing stage) can be used

safely and effectively in a laboratory using specialist equipment.

●● Iodine-fumed marks will immediately begin to fade unless

fixed and must be photographed immediately.

●● ‘Fixed’ iodine-fumed marks may not be permanent,

especially on non-porous surfaces and should be photographed immediately.

The Item or Surface

●● The process is most effective at developing latent marks

on porous and semi-porous surfaces although it will also develop marks on non-porous surfaces.

●● Iodine Fuming can develop fingermarks on surfaces highly

contaminated with greases and oils.

●● The effectiveness of Iodine Fuming begins to decrease for

marks more than a few days old.

●● The process is highly corrosive and should not be used on

untreated metals.

Integrated Use

Iodine Fuming alone has minimal impact on subsequent

fingermark or forensic processing. The fixing stage may be more detrimental.

Further Reading

CAST Fingerprint Source Book, Chapter 5, Section 10.

surfaces to iodine vapour within a specialist iodine exposure

Home Office January 2014

6.1.32

Fingermark Visualisation Manual

B Iodine Fuming

6.1.33

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes. This information can also be consulted for working with Category B processes, although it may not cover all situations.

●● Iodine Fuming may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category B process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

6.1.33

Fingermark Visualisation Manual

Iodine Fuming

Appendices

6.1.34

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Health and Safety continued Hazards associated with Iodine Fuming ●● Iodine Fuming is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional hazard

Risk

Exposure to iodine fumes generated: ●● during processing; ●● from out-gassing; ●● from surfaces previously exposed to fumes such as items or the inside of the iodine fuming cabinet.

Adverse respiratory health effects associated with breathing in fumes whilst: ●● (un)loading the cabinet; ●● subliming iodine during processing; ●● cleaning the cabinet; ●● examining items. Concentrations of iodine fumes during processing will considerably exceed the WEL.

Home Office January 2014

Suggested control measures ●● The process must be

carried out in a sealed enclosure such as an Iodine Exposure Cabinet to contain the fumes generated during the process. ●● The Iodine Exposure Cabinet must have adequate LEV so that operators are not exposed to levels above the WEL at any stage. ●● Examine items which have been treated with Iodine Fuming in a well-ventilated area or preferably on a downdraught bench.

Additional hazard

Risk

Suggested control measures

Air depletion when preparing and using Iodine Fixing Solution.

Asphyxiation

●● Prepare and apply

Nuisance odour from iodine-fixed items.

Some individuals may experience watery eyes and sneezing.

●● Examine iodine-fixed

Iodine Fixing Solution in an extracted fume cupboard. HFE7100 is not absorbed by the activated carbon filters found in recirculating fume cupboards. It passes through them unaffected and unless the HFE7100 vapour is extracted from the laboratory it will displace the air from the ground up as it is much heavier than air. items in a wellventilated area or preferably on a downdraught bench.

6.1.34

Fingermark Visualisation Manual

Iodine Fuming

Glossary

6.1.35

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

Iodine Fuming must be carried out in an Iodine Exposure Cabinet. If equipment is to meet the requirements as outlined below, it must be well maintained

and, if appropriate, serviced regularly in accordance with the manufacturer’s instructions. General laboratory equipment that may be required is outlined in Chapter 3. Equipment

Requirements

Iodine Exposure Cabinet

An Iodine Exposure Cabinet must: ●● be iodine resistant including shelving and/or hangers to support items; ●● have transparent windows so that fingermark development can be observed; ●● be airtight during operation and be fitted with an appropriate system for extraction or filtration; alternatively, be small enough to be used in a fume cupboard; ●● incorporate a means of subliming iodine crystals at an acceptable rate. Heating iodine crystals to ~50 ̊C will facilitate this; ●● operate at ambient temperature and pressure. An Iodine Exposure Cabinet should: ●● be capable of evenly distributing iodine vapour within the cabinet.

Spray gun

Home Office January 2014

The spray gun should be capable of delivering a fine, even mist.

6.1.35

Fingermark Visualisation Manual

Iodine Fuming

Appendices

6.1.36

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists chemicals that are required for Iodine Fuming and the optional Fixing stage.

Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3 safe handling of chemicals for general information. Common Name

Alternative Name(s)

CAS Number

Grade

Iodine

-

7553-56-2

≥99%

α-naphthoflavone

7,8 Benzoflavone

604-59-1

As supplied

Acetic acid

Ethanoic acid

64-19-7

Analytical ≥99.7%

HFE7100

Methyl nonafluorobutyl ether; 1 Methoxynonafluorobutane

HFE7100 is only available as a mixture of two isomers. The isomers are inseparable but have essentially identical properties. Each isomer has its own CAS number (163702-08-7 and 163702-07-6). The isomeric mixture within HFE7100 does not have its own unique CAS number.

As supplied

Home Office January 2014

6.1.36

Fingermark Visualisation Manual

Iodine Fuming

Appendices

6.1.37

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Solutions (for optional Fixing stage only) Consult Chapter 3 for general information on solution

preparation, safe storage of chemicals, solutions and

a) Iodine Fixing Solution is clear.

(1) Prepare solution

mixtures (which includes information on packaging

and labelling), management of waste for disposal of

solutions and guideline expiry periods. This page gives additional information relevant to this process.

(2) Label appropriately

a) Iodine Fixing Solution should be labelled as determined by a local hazard assessment.

(3) Store appropriately

a) Iodine Fixing Solution has a guideline expiry date of 12 months after preparation if stored at room temperature.

Solution Iodine Fixing Solution

1 g α-naphthoflavone 50 mL acetic acid 300 mL HFE 7100*

(4) Dispose of appropriately

Final solutions ready for use are identified by a red border. For other quantities see Ready Reckoner.

Ready Reckoner Quantity of Iodine Fixing Solution Chemical

175 mL

350 mL

700 mL

α-naphthoflavone

0.5 g

1g

2g

Acetic acid

25 mL

50 mL

100 mL

HFE7100*

150 mL

300 mL

600 mL

* HFE7100 has not been fully evaluated as the solvent for the fixing solution. It is

suggested as a direct replacement for 1,1,2-Trichlorotrifluoroethane (CFC113) which is

no longer available. Any unusual behaviour in the solution should be reported to CAST. Home Office January 2014

6.1.37

Fingermark Visualisation Manual

Iodine Fuming

Glossary

6.1.38

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Fuming) Preparation (1) Equipment and Chemicals

a) Follow manufacturer’s instructions for use of equipment. b) Extract any iodine vapours from within the exposure cabinet prior to opening the cabinet door. c) Pour an appropriate quantity of iodine crystals into a suitable, clean vessel such as a glass dish. Place the dish on a heater block at ambient temperature.

(2) Items

a) If possible, load the exposure cabinet with similar items. b) Support or suspend the items in the cabinet, allowing sufficient room for iodine fumes to circulate between them. c) Items must be at ambient temperature prior to treatment.

Processing (3) Produce iodine vapour

(4) Observe development

Home Office January 2014

(5) Halt further development once optimal contrast is achieved by removing iodine fumes from within the cabinet

(6) Remove items from the cabinet

a) Fingermarks may take minutes or hours to develop.

a) There may still be a detectable odour of iodine fumes.

(7) Examination a) Iodine will gradually sublime at room temperature producing a pink/purple vapour. Warming the crystals up to ~50˚C using a heater block will increase sublimation rate. a) Iodine is absorbed by the fingermarks, turning them brown. b) If it is not possible or practical to observe development then the operator must follow manufacturer’s instructions for recommended process conditions OR pre-determine the optimum process conditions.

Primary: Visual Examination

(8) Fixing (Optional)

a) Items should be examined in a well-ventilated area preferably on a down-draught bench. b) Visual fingermarks are brown. Iodine-fumed marks will immediately begin to fade. Consideration should be given to either immediate photography or fixing. c) There are many non-destructive optical processes that can be considered when examining and imaging fingermarks in addition to Visual Examination. d) Mark up viable fingermarks appropriately and capture image. e) After examination, items can be re-treated if necessary.

6.1.38

Fingermark Visualisation Manual

Iodine Fuming

Appendices

6.1.39

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing (Fixing) Preparation (1) Work area

a) Iodine Fixing Solution must be used in an extracted fume cupboard.

(2) Equipment

a) Pour a small quantity of Iodine Fixing Solution into the reservoir of a spray gun.

Processing (3) Apply Iodine Fixing Solution

a) Very carefully spray the Iodine Fixing Solution onto the iodine-developed marks. b) Any brown iodine staining will change to a dark blue colour. Wait 2–3 minutes to assess the extent of colour change and respray any faint areas.

(4) Examination Primary: Visual Examination

Home Office January 2014

a) Items should be examined in a well-ventilated area preferably on a down-draught bench. b) Visible fingermarks are dark blue. Iodine-fixed marks may still fade especially on non-porous items. Photograph immediately. c) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination and Fluorescence Examination, particularly for low-contrast marks or marks on dark or patterned surfaces. d) Mark up viable fingermarks appropriately and capture image. e) After examination, items can be re-treated if necessary.

6.1.39

Fingermark Visualisation Manual

Iodine Fuming

Appendices

6.1.40

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Residual processing chemicals

a) Items treated with Iodine Fuming and Iodine Fixing may emit a nuisance odour comprising either iodine, acetic acid vapour, or both. The concentration is likely to be below the workplace exposure limit.

(2) Cleaning processed items

a) It may not be possible to return items to their original state. If possible, items may be thoroughly wiped or washed with soap and water.

(3) Disposal of processed items

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (4) Disposal of used iodine crystals

a) Any iodine crystals remaining in the dish may be stored in a container for re-use at a later date.

(5) Disposal of used Iodine Fixing Solution

a) Unused Iodine Fixing Solution must not be poured back into a container for re-use at a later date n

Home Office January 2014

6.1.40

Fingermark Visualisation Manual

Iodine Fuming

Appendices

6.1.41

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Key Information Where this process could be used

Iodine Solution may be of use on paper and vinyl wallpapers and at scenes where an immediate result is required. See Category B-C process options.

Why the process is not in Category A

Iodine Solution is significantly less effective than DFO and Ninhydrin on porous surfaces or Powders, Superglue Fuming and Powder Suspension on non-porous surfaces. Iodine Solution reduces the effectiveness of the processes used subsequently such that a sequence of Iodine Solution then Ninhydrin gives fewer marks than Ninhydrin alone. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

Safety and Effectiveness Summary The Process

●● Some Iodine Solution formulations use highly flammable

solvents. These may be the most effective but can only be used safely and effectively in the laboratory.

●● A non-flammable formulation must be used at scenes.

The Item or Surface

●● The process is capable of developing latent marks on all

types of surface.

●● Iodine-Solution-developed marks may not be permanent,

especially on non-porous surfaces and must be photographed immediately.

●● The effectiveness of Iodine Solution begins to decrease for

marks more than a few days old.

●● The process is highly corrosive and should not be used on

untreated metals.

before using this process.

Integrated Use

information is gathered from appropriate sources prior to

forensic processing.

●● In the first instance, it is recommended that all relevant

considering the use of this process.

Process Overview

Iodine Solution interacts with some components of latent

Iodine Solution may be detrimental to subsequent fingermark or

Further Reading

CAST Fingerprint Source Book, Chapter 5, Section 10 n

fingermarks and greases to produce a brown-coloured mark. The colour then very quickly charges to dark blue as the

α-naphthoflavone in the solution quickly converts the iodine to a more durable product.

It is a chemical process that involves the application of a solution to an item or surface.

Home Office January 2014

6.1.41

Fingermark Visualisation Manual

B Iodine Solution

6.1.42

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names LCV; Leuco Basic Violet 3

Key Information Where this process could be used

The process may be of use where other protein-containing contaminants (such as semen) may be present in addition to blood. The process is more specific to blood than Acid Dyes and is less destructive to fingermarks than the Category E process Luminol. See Category B-C process options.

Why the process is not in Category A

This process is less effective than Acid Dyes for the visualisation of blood. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Leuco Crystal Violet (LCV) is a haem reagent. It uses the iron

ion present in haemoglobin to catalyse its oxidation from the

colourless leuco form to crystal violet giving purple-coloured marks.

It will not detect the constituents normally present in latent

fingermarks and therefore must be used in sequence with other processes when blood-contaminated items or surfaces are examined.

Safety and Effectiveness Summary The Process

●● Leuco Crystal Violet can be used safely and effectively in a

laboratory.

●● Although it can be used effectively at scenes, its use is

strongly discouraged due to the persistence of the hazardous coloured product.

●● There are no significant factors that will alter the effectiveness

of the process provided solutions are made up properly.

●● Process effectiveness will be increased by using

Fluorescence Examination in addition to Visual

Examination during examination of treated items or surfaces.

The Item or Surface

●● This formulation will develop fingermarks in blood on most

surfaces.

●● Once the process has been carried out there will be

unreacted LCV on the background that may be difficult

to see. This will slowly oxidise to become the hazardous chemical crystal violet. This reaction is accelerated by

exposure to light, and as the oxidation occurs the contrast between visualised mark and surface decreases.

Integrated Use

Leuco Crystal Violet may be detrimental to subsequent fingermark or forensic processing.

Further Reading

CAST Fingerprint Source Book, Chapter 5, Section 1 n

It is a chemical process that involves the application of a solution to an item or surface.

Home Office January 2014

6.1.42

Fingermark Visualisation Manual

B Leuco Crystal Violet

6.1.43

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names NY3; Curcumin

Key Information Where this process could be used

Natural Yellow 3 may be of use on dark non-porous surfaces where marks developed with Basic Violet 3 or Solvent Black 3 may be difficult to see and optimal excitation is not available for effective Basic Violet 3 fluorescence. See Category B-C process options.

Why the process is not in Category A

The Natural Yellow 3 formulation has not been optimised. This process has not been extensively compared to other lipidspecific processes. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Natural Yellow 3 is a dye which stains grease- and oil-

contaminated fingermarks, and the fatty constituents of

sebaceous sweat in latent fingermarks. It is effective on nonporous substrates and gives a fluorescent product.

Safety and Effectiveness Summary The Process

●● Natural Yellow 3 can be used safely and effectively in a

laboratory.

●● The process requires subsequent Fluorescence Examination

to be effective.

The Item or Surface

●● The process is most effective at developing sebaceous latent

and grease-contaminated marks on non-porous surfaces, especially those that are dark in colour.

Integrated Use

Natural Yellow 3 may be detrimental to subsequent fingermark or forensic processing.

Further Reading

1. Gaskell, C., Bleay, S. M., Ramadani, J., ‘The enhancement of

fingermarks on grease contaminated non-porous surfaces: Parts 1 – natural yellow 3, a novel, fluorescent reagent for use on dark surfaces’, J Forens Ident, vol 63 (3), 2013 p274-285.

2. Gaskell, C., Bleay, S. M., Willson, H., Park, S., ‘The

enhancement of fingermarks on grease contaminated, nonporous surfaces: Part 2 – a comparative assessment of

processes for light and dark coloured surfaces’, J Forens Ident, vol 63 (3), 2013 p286-319 n

It is a chemical process that involves applying a dye solution to the item followed by washing with water.

Home Office January 2014

6.1.43

Fingermark Visualisation Manual

B Natural Yellow 3

6.1.44

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

ORO; Solvent Red 27; Sudan Red 5B

Key Information Where this process could be used

Oil Red O may be of use on paper types that are otherwise severely degraded or exhibit high levels of background development during the Physical Developer process. It may find additional marks if used after Physical Developer. See Category B-C process options.

Why the process is not in Category A

The process is less effective than Physical Developer especially on marks more than four weeks old. This process has not been extensively tested to quantify the benefits. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

Safety and Effectiveness Summary The Process

●● Oil Red O can be used safely and effectively in a laboratory.

The Item or Surface

●● The process is most effective at developing grease-

contaminated and latent fingermarks on porous and semiporous surfaces.

●● The effectiveness of the process is known to decrease

noticeably for marks older than four weeks.

●● The process can be used on items that have been wetted.

Integrated Use

Oil Red O may be detrimental to subsequent fingermark or

forensic processing. It may develop additional marks when used after Physical Developer.

Further Reading

CAST Fingerprint Source Book, Chapter 5, Section 12 n

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Oil Red O interacts with the fats and lipids in latent fingermarks and some greases to give a red/brown-coloured product.

It is a chemical process that involves the application of a

solution to the item or surface followed by washing with water.

Home Office January 2014

6.1.44

Fingermark Visualisation Manual

B Oil Red O

6.1.45

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Key Information Where this process could be used

Palladium Deposition may be of use on copper, brass and bronze items either previously treated with Superglue Fuming or that are grease-contaminated. See Category B-C process options.

Why the process is not in Category A

The process has not yet been fully evaluated and optimised. Palladium Deposition may be marginally more effective than the Category B process Gun Blueing. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Palladium Deposition develops marks by electrochemical deposition of a palladium onto a copper, brass or bronze

Safety and Effectiveness Summary The Process

●● Palladium Deposition can be used safely and effectively in a

laboratory.

The Item or Surface

●● The process is specifically suited for use on copper, and

copper-based alloys such brass and bronze.

●● The process is most effective when the metal surface

is protected from the palladium solution in the region of

fingermark ridges, for example by grease-contaminated marks and those developed by Superglue Fuming. In comparison, it is less effective on latent fingermarks.

Integrated Use

Palladium Deposition may be detrimental to subsequent

fingermark or forensic processing. The impact of Palladium

Deposition on subsequent ballistic forensic analysis processes

such as comparison of firing marks has not yet been established.

Further Reading

1. CAST Fingerprint Source Book, Chapter 5, Section 3.1.

2. Dominick, A. J., Laing, K. J., Forens Ident, vol 61(2), 2011, p144 n

surface. Latent fingermarks, greases and some development

processes such as Superglue Fuming protect the copper, brass or bronze surface so deposition occurs only on the background, turning it dark grey. © See Photo Credits

It is a chemical process that involves the application of a

solution to the item followed by washing with water.

Home Office January 2014

6.1.45

Fingermark Visualisation Manual

B Palladium Deposition

6.1.46

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Radioactive SO2;

SO2

35

Key Information Where this process could be used

Radioactive Sulphur Dioxide may be of use on the development of marks on fabrics. The process is known to be more effective than all other currently available processes for this purpose. See Category B-C process options.

Why the process is not in Category A

Radioactive Sulphur Dioxide requires extremely specialist equipment and trained staff to carry out. Items treated with this process remain radioactive for two or more years and have to be stored securely during that time. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Radioactive Sulphur Dioxide gas is absorbed into the moisture

Safety and Effectiveness Summary The Process

●● Radioactive Sulphur Dioxide fuming can only be carried

out in a laboratory with extremely specialist equipment and trained staff.

●● The effectiveness is linked to the ability to control relative

humidity, the accurate measurement of the concentration

of sulphur dioxide gas and the radioactivity of the item after processing.

●● Developed fingermarks cannot be seen and require a

specialist visualisation process.

●● The visualisation process can only be carried out on items

that can be flattened.

The Item or Surface

●● The process is effective at developing latent marks on flat

porous, semi-porous and adhesive surfaces although it can also be used on non-porous surfaces.

●● Process effectiveness reduces considerably on surfaces that

have been previously wetted.

●● The effectiveness is linked to the ability of the surface to

retain ridge detail and is independent of surface texture.

contained within latent fingermarks to produce a radioactive

Integrated Use

moisture at high humidity. It is also believed that sulphur dioxide

makes the item radioactive and prevents further processing in

deposit. Salts within fingermarks are important as they absorb reacts with molecules with double bonds such as unsaturated fats.

It is a chemical process that involves exposing items or

surfaces to radioactive sulphur dioxide gas at high humidity

within a specialist Radioactive Sulphur Dioxide exposure cabinet.

Radioactive Sulphur Dioxide is a low-impact process, but

conventional laboratories until radioactivity has decayed below a certain level. This may take two or more years.

Further Reading

CAST Fingerprint Source Book, Chapter 5, Section 14 n

The item or surface then requires a specialist visualisation process such as autoradiography. Home Office January 2014

6.1.46

Fingermark Visualisation Manual

B Radioactive Sulphur Dioxide

6.1.47

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names SEM

Key Information Where this process could be used

detectors for all possible signals.

Scanning Electron Microscopy may be of use where fine detail and ridge continuity needs to be established to ensure identification of a mark. This is likely to be more valuable after a development process. See Category B-C process options.

It is a physical process but usually involves a preparation

Why the process is not in Category A

Safety and Effectiveness Summary

Scanning Electron Microscopy requires specialist equipment and trained staff to carry out and the process will only be applicable to a very small number of situations. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

The Scanning Electron Microscope (SEM) uses a focused

beam of high-energy electrons to visualise the fine detail of the fingermark on an item or surface.

The types of signals produced by an SEM include secondary

electrons (SE), back-scattered electrons (BSE), characteristic X-rays and light (cathodoluminescence, CL).

These different signals result from various interactions of the

electron beam with atoms at or near the surface of the sample. Generally, secondary electron detectors are standard on

Home Office January 2014

all SEMs but it is unlikely that a single machine would have

process in which a conducting coating is applied to the surface under examination before subjecting it to an electron beam in a high vacuum.

The Process

●● Scanning Electron Microscopy can only be carried out in a

laboratory with specialist equipment and operator, which may have to be sourced within academic institutions.

●● The effectiveness is linked to the ability of the mark and

surface to conduct electrons. Otherwise a conducting

coating will generally need to be applied before imaging can be carried out.

The Item or Surface

●● The process is effective on most types of surfaces. It may

be particularly effective at tracking ridge flow across areas

where interfering background text or patterns prevent normal visualisation.

●● The process is most likely to require the mark to be cut from

the item as the chamber within the equipment is of very limited size.

Integrated Use

Scanning Electron Microscopy may be detrimental to subsequent fingermark or forensic processing.

Further Reading

CAST Fingerprint Source Book, Chapter 6, Section 1 n

6.1.47

Fingermark Visualisation Manual

B Scanning Electron Microscopy

6.1.48

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names SKP

Key Information Where this process could be used

The process may be of use on cartridge casings before any other fingermark recovery process, DNA recovery or ballistic analysis process. It may also be of use where an attempt has been made to remove a mark from a small metallic item by rubbing or wiping. See Category B-C process options.

Why the process is not in Category A

Scanning Kelvin Probe requires specialist equipment and trained staff to carry out. Comparative data with other alternative processes are limited. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

Safety and Effectiveness Summary The Process

●● Scanning Kelvin Probe can only be carried out in a laboratory

with specialist equipment and operator, which may have to be sourced within academic institutions.

●● The effectiveness is linked to how the presence of the mark

changes the electrical potential of a metallic surface.

●● The process is very slow, taking many hours to scan the area

of a fingermark at an acceptable resolution.

The Item or Surface

●● The process is only effective at visualising marks on metallic

surfaces. It is most effective on those that can be corroded by fingermarks.

●● The nature of the equipment requires the size of the item to

be small and have simple topography.

before using this process.

Integrated Use

information is gathered from appropriate sources prior to

no detrimental impact on any subsequent fingermark or forensic

●● In the first instance, it is recommended that all relevant

considering the use of this process.

Process Overview

The Scanning Kelvin Probe process produces a map of electrical potential across the surface of a metal item. It does this by

Scanning Kelvin Probe is non-contact, non-destructive and has processing.

Further Reading

CAST Fingerprint Source Book, Chapter 6, Section 3.2 n

carrying out an initial scan to establish the topography of the

item and then a second scan is performed with a vibrating gold wire probe held at a constant (tiny) distance from the surface

which measures the surface Volta potential. Fingermarks may be © See Photo Credits

detected because they produce localised regions of corrosion or insulation that differ from the potential of the surface.

It is a physical process which is non-contact and may be nondestructive.

Home Office January 2014

6.1.48

Fingermark Visualisation Manual

B Scanning Kelvin Probe

6.1.49

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names AgNO3

Contents Laboratory Use.............................. 6.1.50 Health and Safety...................... 6.1.50 Equipment................................. 6.1.51 Chemicals.................................. 6.1.52 Solutions ................................... 6.1.53 Processing................................. 6.1.54 Post-Processing........................ 6.1.55

Key Information Where this process could be used

The process may be of use on large items made from untreated wood or cardboard where use of Physical Developer is not practical. See Category B-C process options.

Why the process is not in Category A

Silver Nitrate is generally less effective than Physical Developer. The process cannot be used effectively in sequence with Physical Developer. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains references that outline one formulation

of Silver Nitrate solution.

●● Process details are given for laboratory use, although the

process instruction contains less detail than for a Category A

Safety and Effectiveness Summary The Process

●● Sliver Nitrate is most effective when used in a laboratory

using specialist equipment.

●● The effectiveness may be influenced by the method of

application and the ability to control the intensity and wavelength of light falling on the item or surface.

The Item or Surface

●● The process is most effective at developing latent

fingermarks on porous surfaces although it can be used on semi-porous surfaces.

●● Silver Nitrate is not effective on items or surfaces that have

been exposed to high humidity or have been wetted, even if they have been subsequently dried.

Integrated Use

Silver Nitrate may be detrimental to subsequent fingermark or forensic processing.

Further Reading

CAST Fingerprint Source Book, Chapter 5 Section 15.

process.

Process Overview

Silver Nitrate reacts with chlorides present in fingermarks to

produce silver chloride, which on exposure to ultraviolet, violet and blue light turns gradually from brown to dark grey.

It is a chemical process that involves applying a solution to the item or surface followed by use of specialist lighting (if possible) to control the speed of the reaction.

Home Office January 2014

6.1.49

Fingermark Visualisation Manual

B Silver Nitrate

6.1.50

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes. This information can also be consulted for working with Category B processes, although it may not cover all situations.

●● Silver Nitrate may be carried out with no known hazards to health provided

practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category B process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working

Glossary

Index

Laboratory Use Hazards associated with Silver Nitrate ●● Silver Nitrate is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional hazard

Risk

Suggested control measures

Creation of a flammable atmosphere when preparing and using the Working Solution.

Fire

●● Prepare and apply the Working

Exposure to the Working Solution.

Staining hands, ●● Wear appropriate gloves when clothes and body. preparing or using solutions to protect the hands. ●● Wear a disposable apron to protect the clothes and body.

Solution in a fume cupboard or well-ventilated area. See working with flammable liquids for further information.

environment; ■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

6.1.50

Fingermark Visualisation Manual

Silver Nitrate

Appendices

6.1.51

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

Silver Nitrate requires the use of simple equipment for the application of Silver Nitrate

Working Solution and specialist light sources for creating the environmental conditions required for development.

If equipment is to meet the requirements as outlined below, it must be well maintained

and, if appropriate, serviced regularly in accordance with the manufacturer’s instructions. General laboratory equipment that may be required is outlined in Chapter 3. Equipment

Requirements

Brush

The brush must: ●● be soft; ●● be dedicated for use with Silver Nitrate Working Solution only.

Light source

A suitable light source for the development of Silver Nitrate marks should: ●● output violet and/or blue wavelengths of light*; ●● have an output power which is low enough not to pose an optical hazard but is sufficient to develop marks within an appropriate period of time (typical development times may need to be established for different light sources by prior testing).

*The reaction can be accelerated by the use of ultraviolet light sources (short and long wave), but there will be additional health and safety requirements if these are utilised.

Home Office January 2014

6.1.51

Fingermark Visualisation Manual

Silver Nitrate

Appendices

6.1.52

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists chemicals that are required for Silver Nitrate. Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3 safe handling of chemicals for general information. Common Name

Alternative Name(s)

CAS Number

Grade

Silver nitrate

Silver (I) nitrate

7761-88-8

Laboratory

Methanol

Methyl alcohol

67-56-1

Analytical ≥99.7%

Home Office January 2014

6.1.52

Fingermark Visualisation Manual

Silver Nitrate

Appendices

6.1.53

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Solutions

Consult Chapter 3 for general information on solution

preparation, safe storage of chemicals, solutions and

a) Silver Nitrate Working Solution must be prepared in a fume cupboard. b) Silver Nitrate Working Solution is clear.

(1) Prepare solution

mixtures (which includes information on packaging

and labelling), management of waste for disposal of

solutions and guideline expiry periods. This page gives additional information relevant to this process.

(2) Label appropriately

a) Silver Nitrate Working Solution should be labelled as determined by a local hazard assessment.

(3) Store appropriately

a) Silver Nitrate Working Solution has a guideline expiry date of 12 months after preparation if stored at room temperature and in the dark.

Solution Silver Nitrate Working Solution

10 g silver nitrate 500 mL methanol

For other quantities see Ready Reckoner.

(4) Dispose of appropriately

Ready Reckoner Quantity of Silver Nitrate Working Solution

Home Office January 2014

Chemical

1L

2L

5L

Silver nitrate

20 g

40 g

100 g

Methanol

1L

2L

5L

6.1.53

Fingermark Visualisation Manual

Silver Nitrate

Glossary

6.1.54

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Work area

(2) Solution

(7) Examination a) Silver Nitrate Working Solution must be applied in a fume cupboard. a) Pour Silver Nitrate Working Solution into an appropriate container.

Processing (3) Apply Silver Nitrate Working Solution

(4) Allow item to ‘dry’

(5) Expose item to light

(6) Observe mark development

Home Office January 2014

Primary: Visual Examination

a) Visible marks are coloured brown, which may darken to grey/black with increased exposure to light. b) It is important to image all fingermarks immediately as the background on items processed with Silver Nitrate will darken with exposure to light and over time. c) There are many non-destructive optical processes that can be considered when examining and imaging fingermarks in addition to the primary process. However, care must also be taken to keep light intensity to a minimum when using these processes to reduce the risk of background over-development. d) Mark up viable fingermarks appropriately and capture image.

a) In subdued lighting carefully apply the solution with a soft brush. The surface must be ‘wetted’ evenly.

a) Allow the solvents to evaporate from the item within the fume cupboard. If possible reduce light level to a minimum.

a) The light source used to develop the marks should have output in the violet/blue region of the spectrum.

a) Brown-coloured marks will be developed which darken with development. b) Development may occur in seconds or take several hours depending on the light source used and the type of surface being processed. c) The background will also progressively darken and the practitioner should decide when optimum contrast between mark and background has been obtained.

6.1.54

Fingermark Visualisation Manual

Silver Nitrate

Appendices

6.1.55

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Residual processing chemicals

a) Residual silver nitrate on the sample will gradually turn the background dark grey.

(2) Cleaning processed items

a) It may not be possible to return items to their original state. If possible, items may be thoroughly washed with soap and water.

(3) Disposal or return of processed items

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (4) Disposal of used Silver Nitrate Working Solution

Home Office January 2014

a) Used Silver Nitrate Working Solution must not be poured back into a container for re-use at a later date n

6.1.55

Fingermark Visualisation Manual

Silver Nitrate

Appendices

6.1.56

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Propanol-based superglue dyes,

Propanol-based superglue stains

Contents Laboratory Use.............................. 6.1.57 Options...................................... 6.1.57 Health and Safety...................... 6.1.58 Equipment ................................ 6.1.59 Chemicals.................................. 6.1.60 Solutions.................................... 6.1.61 Processing................................. 6.1.62 Post-Processing........................ 6.1.63

Key Information Where this process could be used

In place of ethanol-based superglue dyes where they cause destructive ink-running. See Category B-C process options.

Why the process is not in Category A

It is slightly less effective than ethanol-based dyes. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for two propanol-

based dye formulations: ■■ ■■

Basic Yellow 40 Basic Red 14

●● Process details are given for laboratory use, although the

process instruction contains less detail than for a Category A process.

Process Overview

Fingermarks developed using Superglue Fuming can be

fibres as they contain several anionic groups. These anionic groups interact with the basic dye during the dyeing stage,

increasing retention of the dye by the fibres. The resultant mark is highly fluorescent and must be viewed using Fluorescence

Examination.

It is a chemical process that involves the application of a

solution to the item or surface followed by washing with water.

Safety and Effectiveness Summary The Process

●● Superglue Fluorescent Dye Staining (propanol-based) can be

used safely and effectively in a laboratory.

●● The process requires subsequent Fluorescence

Examination to be effective.

The Item or Surface

●● The process is only effective at enhancing superglue-

developed marks on non-porous surfaces.

●● Fluorescent dyes can adversely stain the background of most

semi-porous and all porous items, hence obscuring the mark.

Integrated Use

Superglue Fluorescent Dye Staining (propanol-based) is used

after the Superglue Fuming process but may be detrimental to subsequent fingermark or forensic processing.

enhanced in a variety of ways to make them more visible i.e. maximise the contrast between the developed mark and the background. One method is to use dyes which cause the superglue marks to fluoresce.

These stain the superglue marks in the same way as dyes stain

textiles. The noodle-like structure of the superglue mark consists of fibres of polycyanoacrylate, which are similar to acrylic textile

Home Office January 2014

6.1.56

Fingermark Visualisation Manual

B Superglue Fluorescent Dye Staining (propanol-based)

6.1.57

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Options Basic Yellow 40 or Basic Red 14

●● The performance of the two dyes are similar and the choice of whether to choose

Basic Yellow 40 or Basic Red 14 is dependent on the power and wavelength output of excitation sources available, see Fluorescence Examination.

●● Basic Yellow 40 is best visualised

by illuminating in the violet/blue region resulting in green/yellow fluorescence.

●● Basic Red 14 is be best visualised by

Sequential use of fluorescent dyes

●● It is possible to use these fluorescent dyes in sequence with one another if the

background fluorescence interfered with the fluorescence of the dye initially used.

This may be achieved on targeted areas by carefully washing out the first dye with propanol and then applying the alternative dye as normal.

●● See Chapter 4 for information on its sequential use with other fingermark

visualisation processes.

●● See Chapter 7 for information on integration of fingermark and other forensic

processes.

illuminating in the green region giving orange/red fluorescence.

●● It should also be considered that

Basic Yellow 40 fluoresces where the eye is most sensitive.

(Top) Basic Yellow 40 dyed superglue on polythene.

(Bottom) Basic Red 14 dyed superglue on polythene.

Home Office January 2014

6.1.57

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining (propanol-based)

Glossary

6.1.58

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety ●● Consult Chapter 3 for general information on working safely with Category A

processes. This information can also be consulted for working with Category B processes, although it may not cover all situations.

●● Superglue Fluorescent Dye Staining (propanol-based) may be carried out with

no known hazards to health provided practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards

(e.g. ‘residual processing chemicals on items are hazardous’) and/or control

measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s

local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category B process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

Glossary

Index

Laboratory Use

Hazards associated with Superglue Fluorescent Dye Staining ●● Superglue Fluorescent Dye Staining (propanol-based) is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions or mixtures.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive. Additional hazard

Risk

Suggested control measures

Creation of a flammable atmosphere when preparing and using the Propanol-based Staining Solution.

Fire

●● Prepare and apply the Propanol-

Exposure to quantities of dye solution.

Staining hands, clothes and body with dye.

●● Wear appropriate gloves when

based Staining Solution in a fume cupboard or well-ventilated area. See working with flammable liquids for further information.

preparing or using solutions to protect the hands, especially if they are to be immersed in the solutions. ●● Wear a disposable apron to protect the clothes and body.

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations

are over and above those for laboratory applications of the processes.

Home Office January 2014

6.1.58

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining (propanol-based)

Appendices

6.1.59

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

Superglue Fluorescent Dye Staining (propanol-based) only requires general laboratory equipment as described in Chapter 3.

However, it is possible to use Superglue Fluorescent Dye Staining (propanol-based) in dye tanks such as those specified in the Category A process Superglue Fluorescent Dye Staining.

Home Office January 2014

6.1.59

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining (propanol-based)

Appendices

6.1.60

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists chemicals that are required for Superglue Fluorescent Dye Staining (propanol-based).

Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3 safe handling of chemicals for general information or effective use of chemicals for details on dye purity.

Alternative Name(s)

CAS Number

Grade

Basic Yellow 40 (BY40)

There are many alternative names.

29556-33-0

Basic Red 14 (BR14)

Yoracryl Red 4G

12217-48-0

> 50 %

2- Propanol

Isopropyl alcohol, Isopropanol

67-63-0

Laboratory ≥99.5%

Home Office January 2014

> 80 %

Basic Yellow 40 refers to several dyes with different CAS numbers. Alternatives are structurally similar and may be indistinguishable, in terms of mark enhancement, from the one given.

6.1.60

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining (propanol-based)

Appendices

6.1.61

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Solutions

Consult Chapter 3 for general information on solution preparation, safe storage of chemicals, solutions and

mixtures (which includes information on packaging and

(1) Prepare selected solution

a) Propanol-based Staining Solution must be prepared in a fume cupboard. b) BY40 Solution is yellow. BR14 Solution is deep pink/red.

(2) Label appropriately

a) Propanol-based Staining Solutions should be labelled as determined by a local hazard assessment.

(3) Store appropriately

a) Propanol-based Staining Solutions have guideline expiry dates of 12 months after preparation if stored at room temperature.

labelling), management of waste for disposal of solutions and guideline expiry periods. This page gives additional information relevant to this process

Solution Propanol-based Staining Solution

2 g dye 1 L propanol Dye options: Basic Yellow 40 (BY40) or Basic Red 14 (BR14)

(4) Dispose of appropriately

For other quantities see Ready Reckoner.

Ready Reckoner Quantity

Home Office January 2014

Solution

Chemical

1L

2L

5L

Propanol-based Staining Solutions

Dye

2g

4g

10 g

Propanol

1L

2L

5L

6.1.61

Fingermark Visualisation Manual

Laboratory Use

Superglue Fluorescent Dye Staining (propanol-based)

6.1.62

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Work area

(2) Chemicals

a) The application method is not a critical factor to the success of the process. Small items can be dipped into a tray or a specially designed tank. Alternatively, or for larger items, dye can be applied in a fume cupboard by pouring, squirting or brushing fluorescent dye solution over the surface. a) The absolute concentration of dye solutions is not critical to the success of the process. If using and storing dye solution within a tank, the concentration of the solution may change as the solvent evaporates and/or the solution is used up. When topping up try to ensure the concentration of the staining solution is very roughly that of the starting solution.

(6) Examination Primary: Fluorescence Examination Secondary: Visual Examination

a) Fluorescent BY40 marks are green/yellow. Fluorescent BR14 marks are orange. Visual BY40 marks are pale yellow. Visible BR14 marks are red. b) Mark up viable fingermarks appropriately and capture image. c) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination and Fluorescence Examination, particularly for low-contrast marks or marks on dark or patterned surfaces. d) After examination, items can be re-treated if necessary.

Processing (3) Apply solution

a) The item should be exposed to the dye solution for about 30 seconds. b) Propanol-based Staining Solutions are highly flammable and must not be sprayed. c) Immediately proceed to next step if inks are seen to run or dissolve.

(4) Rinse thoroughly

a) Rinse item until excess dye has been removed from the background. This can be done using suitable means, such as cold, slow running tap water or by applying tap water with a suitable applicator such as a wash bottle, small garden spray unit or shower head. b) Strong background fluorescence may be reduced by targeted washing with propanol.

(5) Dry item

Home Office January 2014

a) See Drying of items.

6.1.62

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining (propanol-based)

Appendices

6.1.63

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Residual processing chemicals

a) Items may emit an odour of superglue vapour from undyed areas when items are only partially dyed. The vapour concentration is likely to be below the WEL.

(2) Cleaning processed items

a) Items can be cleaned in several ways, but it may not be possible to return items to their original state. b) Option 1 (preferred): Items may be scrubbed with detergent and water to physically remove solid superglue deposits and dye. Abrasive cloths will aid in this, although damage may be caused to the surface. c) Option 2: Polar solvents such as butanone can be used to dissolve and remove solid superglue deposits and dye. However, it may dissolve some surfaces such as plastics and there are additional health and safety precautions to take into consideration (not given here).

(3) Disposal or return of processed items

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (4) Re-use of solutions

Home Office January 2014

a) Staining Solutions may be re-used provided this will not interfere with subsequent forensic processes such as DNA n

6.1.63

Fingermark Visualisation Manual

Superglue Fluorescent Dye Staining (propanol-based)

Appendices

6.2.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents ATR-FTIR.................................................................. 6.2.2 Basic Violet 2........................................................... 6.2.3 CERA........................................................................ 6.2.4 Drug Removal.......................................................... 6.2.5 Electrochromic Development................................. 6.2.6 Electroless Silver Deposition................................. 6.2.7 Fluorescent Superglue Fuming.............................. 6.2.8 Genipin..................................................................... 6.2.9 MALDI-MSI............................................................. 6.2.10 Nile Red.................................................................. 6.2.11 Powders (Fluorescent).......................................... 6.2.12 SIMS........................................................................ 6.2.13 Single Metal Deposition........................................ 6.2.14 S2N2......................................................................... 6.2.15 Tagged Nanoparticles........................................... 6.2.16 Thermal Development........................................... 6.2.17 ThermaNin.............................................................. 6.2.18 XRF......................................................................... 6.2.19

Home Office January 2014

Fingermark Visualisation Manual

Category C Processes Introduction Description

Processes at a development stage exhibiting potential as an effective fingermark recovery process.

Use

Optional processes for occasional operational use.

Possible reasons for use: no other options available; all Category A options have been exhausted; niche application.

Level of detail

Only a summary page for each is provided to give an indication of where the process may be beneficial n

6.2.1

6.2.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Attenuated total reflection-Fourier transform infrared spectroscopy

Key Information Where this process could be used

ATR-FTIR may be useful in detecting and mapping of unusual and/or significant contaminants contained within fingermarks. See Category B-C process options.

Why the process is not in Category A

The full range of applications for ATR-FTIR has not yet been explored, nor has its compatibility with conventional development processes. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Attenuated total reflection-Fourier transform infrared

spectroscopy (ATR-FTIR) is a process which enables samples

to be examined directly in the solid state without special sample

is placed onto a small crystal. The sample is then subjected to infrared light examination. The sample can be a lift of a fingermark.

Safety and Effectiveness Summary The Process

●● ATR-FTIR can only be carried out in a laboratory with

specialist equipment and operator, which may have to be sourced within academic institutions.

●● The effectiveness is linked to the ability of components of the

mark and surface to reflect infrared radiation.

The Item or Surface

●● The process is most effective at visualising latent marks on

non-porous surfaces, but can also be used on semi-porous surfaces.

●● The process is most likely to require the mark to be cut from

the item or lifted as the imaging crystal on the equipment is of limited size.

Integrated Use

ATR-FTIR may be detrimental to subsequent fingermark or forensic processing.

preparation. Infrared light is passed through a crystal of high-

Further Reading

that is in contact with the sample. This reflection isn’t clean

2. Ricci, C., Kazarian, S. G., Surface and Interface Analysis vol

refractive index in such a way that it reflects off the surface

and extends into the sample by a distance dependent on the wavelength of light, the angle of incidence and the indices of

© See Photo Credits

It is a physical process in which the surface being examined

1. CAST Fingerprint Source Book, Chapter 4, Section 2. 42(5), 2010, p386-392 n

refraction for the crystal and the medium being probed. The

reflected light is collected on a sensor array as it exits the crystal and is analysed. Images showing the distribution of compounds with different reflective properties can be generated.

Home Office January 2014

6.2.2

Fingermark Visualisation Manual

C ATR-FTIR

6.2.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

BV2, New Fuschin, New Magenta

Key Information Where this process could be used

Basic Violet 2 may be of use as an alternative for Basic Violet 3, although its colour density is not as great; however, its fluorescence is more visible to the eye and it may be safer to use. See Cagegory B-C process options.

Why the process is not in Category A

BV2 (left) and BV3 (right).

It is generally less effective than Basic Violet 3 and Solvent Black 3 in terms of visible mark development. It has not been compared to Basic Violet 3 in fluorescent mode, or to the Category B processes Europium Chelate and Natural Yellow 3. ●● Competent personnel specialising in fingermark

enhancement must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Basic Violet 2 is thought to stain the fatty constituents of sebaceous sweat, shed skin cells and some greasy

contaminants resulting in visible fingermarks which are red/pink

Fingermark Visualisation Manual

C Basic Violet 2 Safety and Effectiveness Summary The Process

●● Basic Violet 2 can be used safely and effectively in a

laboratory.

●● Process effectiveness will be increased by using

Fluorescence Examination in addition to Visual

Examination during examination of treated items or surfaces.

The Item or Surface

●● The process is most effective at developing both latent and

greasy fingermarks on non-porous surfaces provided the stain can be removed from the background.

●● It can also be used on adhesive surfaces with non-porous

backings.

Integrated Use

Basic Violet 2 may be detrimental to subsequent fingermark or forensic processing.

Further Reading

1. CAST Fingerprint Source Book, Chapter 3, Section 2.

2. Garrett, H. J., Bleay, S. M., ‘Evaluation of the solvent black 3 fingermark enhancement reagent: Part 1 Investigation of fundamental interactions and comparison with other lipid

specific reagents’, accepted for publication in Science and Justice, 2013 n

in colour. Some marks produced can be further enhanced by fluorescence.

It is a chemical process that involves applying a staining

solution to the item or surface followed by washing with water.

Home Office January 2014

6.2.3

6.2.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Cartridge Electrostatic Recovery and Analysis

Key Information Where this process could be used

Detection of fingermarks on fired cartridge casings. See Category B-C process options.

Why the process is not in Category A

Insufficient comparative test data have been obtained to establish the effectiveness of CERA relative to conventional Category A processes, or to alternative processes such as Gun Blueing and Palladium Deposition. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Safety and Effectiveness Summary The Process

●● CERA can be used safely and effectively in a laboratory using

specialist equipment.

●● The effectiveness is linked to how corrosion caused by the

mark differs in electrical charge from that of the untouched metallic surface.

The Item or Surface

●● The process is only effective at developing marks on metallic

surfaces.

●● The equipment requires the size of the item to be small.

Integrated Use

CERA may be detrimental to subsequent fingermark or forensic

processing. The impact of CERA on subsequent ballistic forensic analysis techniques such as comparison of firing marks has not yet been established.

Further Reading

1. CAST Fingerprint Source Book, Chapter 5, Section 3.2 n

The CERA process involves application of an electrical potential of several kV which gives preferential charging of areas of

corrosion. The differences in electrical charge are visualised by a developer powder (similar to that used in the ESDA process) which is cascaded over the charged surface. Any marks

visualised are imaged using a periphery camera integrated within the CERA equipment. © See Photo Credits

It is a physical process which involves applying an electrical potential. A developer powder is then applied to the charged surface.

Home Office January 2014

6.2.4

Fingermark Visualisation Manual

C CERA

6.2.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Key Information Where this process could be used

●● The temperature of the solvents and that used for drying

should be kept where possible to below 30˚C.

This process may be used on surfaces that are heavily contaminated with a drug where it is suspected fingermarks may be present under the contaminant layer. See Preparation processes overview.

The Item or Surface

Why the process is not in Category A

●● Physical rubbing of items or surfaces must be kept to a

It has not been researched in sufficient detail to identify an optimised method. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

●● The process can be used on all types of item or surface.

However, care must be taken to ensure the continued

integrity of porous and semi-porous items and surfaces. minimum so as not to damage fingermarks.

Integrated Use

Drug Removal may be detrimental to subsequent fingermark or forensic processing.

Further Reading

1. Ziv, Z., Springer, E., ‘Additional Methods for pre-treatment of Drug Contaminated Polythene Bags Prior to Vacuum

Metal Deposition of Latent Fingerprints’, Proceedings of

Process Overview

the International Symposium on Fingerprint Detection and

residues from surfaces, allowing them to be treated with

2. Magora, A., Azoury, M., Geller, B., ‘Treatment of Cocaine

A solvent or solvents are used to wash and/or dissolve drug fingermark visualisation processes.

It is a chemical process that involves the immersion of items in or application of a solvent or solvents to a surface.

Fingermark Visualisation Manual

C Drug Removal

Identification, June 26–30, 1995, Ne’urim, Israel, p179-196. Contaminated Polythene Bags Prior to Fingerprint development by Cyanoacrylate Fuming’, J Forens Ident, vol 52(2), (2002), p159-164 n

Safety and Effectiveness Summary The Process

●● Drug Removal can be carried out safely and effectively in a

laboratory.

●● If water is used as the solvent it should be used without

detergents wherever possible because they may interfere

with subsequent processes; however, if detergents are used they should be of neutral pH.

Home Office January 2014

6.2.5

6.2.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Electropolymeric deposition

Key Information Where this process could be used

Electrochromic Development may be of use on metal items. It is likely to be most effective where fingermark deposits mask the surface, for example grease-contaminated marks or marks developed using Superglue Fuming. See Category B-C process options.

Why the process is not in Category A

The process has not yet been included in extensive comparative trials with other processes. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Electrochromic Development visualises marks by

electrochemical deposition of a conducting polymer onto a metal

Safety and Effectiveness Summary The Process

●● Electrochromic Development can be used safely and

effectively in a laboratory.

The Item or Surface

●● The process is most effective at visualising latent and grease-

contaminated marks and those developed by superglue on stainless steel, platinum, gold, lead, brass, bronze, copper and nickel.

Integrated Use

Electrochromic Development may be detrimental to subsequent fingermark or forensic processing. The impact on subsequent ballistic forensic analysis techniques such as comparison of firing marks has not yet been established.

Further Reading

1. Hillman, A. R., Beresford, A. L., Anal. Chem., vol 82, 2010, p483-486.

2. Beresford, A. L., Brown, R. M., Hillman, A. R., Bond, J. W., J. Forens. Sci. vol 57(1), 2012, p93-102.

3. Brown, R. M., Hillman, A. R., Phys. Chem. Chem. Phys., vol 14, 2012, p8653-8661 n

surface. Latent fingermarks, greases and some development processes such as superglue protect the metal surface so

deposition occurs only on the background. The sample is then

transferred to a second solution where the colour of the polymer © See Photo Credits

can be varied by controlling the voltage.

It is a chemical process that involves the sequential submersion of items in two electrolytic solutions, the first to deposit the polymer and the second to enable its colour to be varied.

Home Office January 2014

6.2.6

Fingermark Visualisation Manual

C Electrochromic Development

6.2.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Galvanic silver deposition

Key Information Where this process could be used

Electroless Silver Deposition works on copper-containing surfaces (notably brass and bronze). It may be of use on items before or after their treatment with Powders or Superglue Fuming. See Category B-C process options.

Why the process is not in Category A

The process has not yet been included in extensive comparative trials with other processes. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Electroless Silver Deposition develops marks by a redox reaction in which silver ions in solution oxidise elemental copper. A small amount of copper dissolves into the solution and an equivalent amount of silver deposits on the surface. Latent fingermarks,

greases and some development processes such as Superglue

Fuming protect the metal surface so deposition occurs only on

the exposed metal background. Silver has strong visual contrast against the copper beneath the fingermark. With time, the silver © See Photo Credits

may blacken due to atmospheric exposure (e.g. silver sulfide

formation). This may result in improved contrast between the mark and surface.

Home Office January 2014

It is a chemical process that involves immersion of items in a

solution of a silver salt in an ionic liquid (e.g. Reline., a mixture

of choline chloride and urea). After deposition, excess reagent is removed by rinsing with water.

Safety and Effectiveness Summary The Process

●● Electroless Silver Deposition can be used safely and

effectively in a laboratory.

●● The reagents require no special handling provisions; their

effectiveness is not vulnerable to oxygen or trace water.

The Item or Surface

●● The process works on surfaces containing a metal that can

be oxidised by silver ions, notably copper.

●● The item may be pure copper or an alloy (brass or bronze).

Integrated Use

Electroless Silver Deposition may be used prior to or after certain processes; wider applicability with other fingermark or forensic processing techniques is yet to be established, including the

impact on subsequent ballistic forensic analysis techniques such as comparison of firing marks.

Further Reading

1. Abbott, A.P., Nandhra, S., Postlethwaite, S., Smith, E.L. and Ryder, K.S., Phys. Chem. Chem. Phys., 2007, 28, 3735.

2. Gu, C.D., Xu, X.J. and Tu, J.P., J. Phys. Chem. C, 2010, 114, 13614.

3. Abbott, A.P., Davies, D.L., Capper, G., Rasheed, R.K. and

Tambvraiah, V. Ionic liquids and their use as solvents. Patent WO 2002026701 (2002) n

6.2.7

Fingermark Visualisation Manual

C Electroless Silver Deposition

6.2.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Single step superglue, PolyCyano UV™, LumiCyano™, Fuming Orange™

Key Information Where this process could be used

Fluorescent Superglue Fuming may be of use on substrates such as expanded polystyrene, masking tapes and semiporous surfaces where Superglue Fuming is effective but it may not be possible to use dye stains. See Category B-C process options.

Why the process is not in Category A

Fluorescent Superglue Fuming is less effective than conventional Superglue Fuming used in sequence with the Superglue Fluorescent Dye Staining process. Trials against other methods of visualising superglue-developed marks such as Powders or Vacuum Metal Deposition have yet to be carried out. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Fluorescent superglue vapour polymerises on some latent fingermarks to produce a pale-coloured deposit. This

polymerisation can be catalysed by water and some other

constituents of latent fingermarks. Salts within fingermarks are

important as they absorb moisture at high humidity. Developed

marks are fluorescent and must be viewed using Fluorescence Examination.

Home Office January 2014

It is a chemical process that involves exposing items or

surfaces to fluorescent superglue vapour at high humidity within a specialist superglue fuming cabinet (if possible).

Safety and Effectiveness Summary The Process

●● Fluorescent Superglue Fuming is most effective if carried out

in a laboratory with specialist equipment. Although it can be used at scenes the effectiveness is likely to vary.

●● The effectiveness is linked to the ability to control

temperature and relative humidity.

●● PolyCyano UV requires modification of the hotplate

temperature used to evaporate superglue from 120 to 230°C.

●● LumiCyano can be carried out without modification of the

hotplate temperature.

●● Developed fingermarks can be difficult to see, even on dark

surfaces; use of subsequent Fluorescence Examination is essential to reveal the maximum number of fingermarks.

The Item or Surface

●● The process is most effective at developing latent marks on

non-porous, semi-porous and adhesive surfaces.

●● Process effectiveness reduces considerably on surfaces that

have been previously wetted.

●● The ability to enhance sweat deposits is independent

of surface texture making it particularly useful on rough

surfaces. Instead the effectiveness is linked to the ability of the surface to retain ridge detail.

Integrated Use

Fluorescent Superglue Fuming may be detrimental to subsequent fingermark or forensic processing n

6.2.8

Fingermark Visualisation Manual

C Fluorescent Superglue Fuming

6.2.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Key Information Where this process could be used

Genipin may be of use on certain red-coloured porous surfaces, where marks developed using Ninhydrin are not visible and fluorescence from DFO and Indandione is quenched or swamped by the background. The blue marks developed by Genipin may give better contrast. See Category B-C process options.

Why the process is not in Category A

Genipin was found to be less effective than both Ninhydrin and DFO in a small-scale trial on light-coloured paper types conducted by CAST. Trials on darker paper types have not yet been conducted. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Safety and Effectiveness Summary The Process

●● Genipin can be used safely and effectively in a laboratory. ●● The effectiveness may be influenced by the method of

application of the solution.

●● The effectiveness is linked to the ability to control the

temperature and relative humidity of the item or surface postapplication. This requires the use of specialist equipment to carry it out successfully.

The Item or Surface

●● Genipin is most likely to be effective on porous surfaces of a

contrasting colour to the blue reaction product.

●● Genipin is not effective on items or surfaces that have been

wetted, even if they have been subsequently dried.

Integrated Use

Genipin may be detrimental to subsequent fingermark or forensic processing.

Further Reading

1. CAST Fingerprint Source Book, Chapter 5, Section 9 n

Process Overview

●● Genipin reacts with amino acids and possibly other

components in latent fingermarks to give a blue product. Developed marks may also be fluorescent (red in colour)

and an additional examination should be conducted using Fluorescence Examination.

●● It is a chemical process that involves applying a solution

to the item or surface followed by use of a specialist oven

(if possible) to increase the speed and effectiveness of the reaction.

Home Office January 2014

6.2.9

Fingermark Visualisation Manual

C Genipin

6.2.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Matrix assisted laser desorption/

ionisation-mass spectral imaging

Key Information Where this process could be used

MALDI-MSI may be of use in identifying and mapping the distribution of unusual and/or significant contaminants present in fingermarks (e.g. drugs, explosives, condom lubricants etc.). The process may also be of use for ‘filling in’ ridge detail in marks that are only partially developed by conventional processes. See Category B-C process options.

Why the process is not in Category A

The full range of applications for MALDI-MSI has not yet been explored, nor has its compatibility with conventional development processes been explored in full. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

fingermark, either by spraying or powdering. Usually the matrix covered mark is lifted and the lift is placed into the MALDI instrument for analysis.

Safety and Effectiveness Summary The Process

●● MALDI-MSI can only be carried out in a laboratory with

specialist equipment and operator, which may have to be sourced within academic institutions.

●● The effectiveness is linked to the compatibility of the

fingermark components and the matrix composition.

The Item or Surface

●● The process is most effective at visualising latent marks on

porous, semi-porous and adhesive surfaces although it can be used on non-porous surfaces.

●● The process is most likely to require the mark to be lifted

from the item as the chamber within the equipment is of very limited size. The lift is then processed.

Integrated Use

MALDI-MSI may be detrimental to subsequent fingermark or

Process Overview

forensic processing.

imaging (MALDI-MSI) requires a homogeneous coating, known

1. Bradshaw, R., Wolstenholme, R., Blackledge, R., Clench, M.

Matrix assisted laser desorption/ionisation-mass spectral

Further Reading

as a ‘matrix’, to first be applied to the fingermark. Ions of a

R., Ferguson, L., Francese, S., Rapid Commun. Mass Spectrom.

component present in latent and/or developed fingermarks are then desorbed from the surface by irradiation with a laser. The

© See Photo Credits

It is a physical process involving a matrix being applied to a

laser is moved between each firing so that the distribution of the ions can be mapped, giving an image of the fingermark and/or

2011, 3: 415-422.

2. Ferguson, L., Bradshaw, R., Wolstenholme, R., Clench, M. R., Francese, S., Anal Chem. 2011, 83(14):5585-91 n

chemical composition information.

Home Office January 2014

6.2.10

Fingermark Visualisation Manual

C MALDI-MSI

6.2.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Key Information Where this process could be used

Nile Red may be an alternative to Oil Red O on porous and semi-porous surfaces. Nile Red may also be of use on dark non-porous surfaces where marks developed with Basic Violet 3 or Solvent Black 3 would not be visible and optimal excitation is not available for effective Basic Violet 3 fluorescence. See Category B-C process options.

Why the process is not in Category A

This process has not been compared to other lipid dyes. The Nile Red formulation has not been fully optimised. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to

Safety and Effectiveness Summary The Process

●● Nile Red can be used safely and effectively in a laboratory. ●● It may develop additional marks when used after Physical

Developer on porous or semi-porous surfaces.

The Item or Surface

●● The process is most effective at developing grease-

contaminated and latent fingermarks on porous and semiporous surfaces.

●● The process may also be effective on non-porous surfaces.

●● The process can be used on surfaces that have been wetted.

Integrated Use

Nile Red may be detrimental to subsequent fingermark or forensic processing.

Further Reading

1. Greenspan, P., Mayer , E. P., Fowler, S. D., ‘Nile Red: A

selective fluorescent stain for intracellular lipid droplets’, J Cell Biol., vol 100(3), 1985, 965-973 n

considering the use of this process.

Process Overview

Nile Red interacts with the fats and lipids in latent fingermarks and some greases to give a highly fluorescent product.

It is a chemical process that involves immersion of the item in water then a dyeing solution followed by washing with water.

Home Office January 2014

6.2.11

Fingermark Visualisation Manual

C Nile Red

6.2.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Several commercial trade names exist.

Key Information Where this process could be used

In place of conventional Powders on surfaces where developed marks are difficult to visualise or lift. The process may also be used on marks developed with Superglue Fuming on surfaces that would be damaged by Superglue Fluorescent Dye Staining. See Category B-C process options.

Why the process is not in Category A

Fluorescent Powders are generally less effective than the types outlined in the Category A process. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

It is a physical process that involves applying a dry powder to the item or surface using an appropriate applicator and observing how the deposition of powder progresses.

Safety and Effectiveness Summary The Process

●● Fluorescent Powders can be used effectively in a laboratory

and at scenes. The safety will be dependent on the constituents of the powder.

●● The effectiveness of powdering is variable depending on

the chemical and physical properties of the powder, the

type of applicator, the competence of the operator and the effectiveness of the excitation source.

●● The process requires simultaneous powdering and

Fluorescence Examination to be most effective.

The Item or Surface

●● Fluorescent Powders are most effective at developing latent

fingermarks on smooth non-porous surfaces which have less

affinity for the particles. However, some powders can be used on semi-porous and porous surfaces.

●● The effectiveness of Fluorescent Powders is likely to

decrease on older fingermarks.

Fluorescent Powders develop fingermarks by preferential

●● Fluorescent Powders are not effective on surfaces which are

particles adhesion is influenced by the presence of aqueous and/

●● Items or surfaces that are wet may be dried before using

mark. Fluorescent Powders are most effective on clean, smooth

Integrated Use

adhesion of fine particles to the deposited ridge detail. The

or fatty components in sweat, or by ‘sticky’ contaminants in the non-porous surfaces which have less affinity for the particles

and no surface features to trap them. However, some types of Fluorescent Powders can be used effectively on semi-porous

wet, highly textured or heavily contaminated. Fluorescent Powders.

Fluorescent Powders may be detrimental to subsequent fingermark or forensic processing n

surfaces. Developed marks are fluorescent and must be viewed using Fluorescence Examination.

Home Office January 2014

6.2.12

Fingermark Visualisation Manual

C Powders (Fluorescent)

6.2.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Secondary ion mass spectrometry

Key Information Where this process could be used

SIMS may be of use in ‘filling in’ ridge detail in marks that are only partially developed by conventional processes. It may also provide depth information to establish contextual information about developed marks, for example whether the mark was deposited before writing or vice versa. See Category B-C process options.

Why the process is not in Category A

The full range of applications for SIMS has not yet been explored, nor has its compatibility with conventional development processes. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Secondary ion mass spectrometry (SIMS) is a process used

to analyse the composition of solid surfaces and thin films by

bombarding the surface of the specimen with a focused primary ion beam and collecting and analysing ejected secondary ions. The mass/charge ratios of these secondary ions are measured © See Photo Credits

with a mass spectrometer to determine the elemental, isotopic,

or molecular composition of the surface to a depth of 1 to 2 nm and map the results.

Home Office January 2014

It is a physical process that normally takes place in a high

vacuum where the sample is subjected to an ion beam. MeV systems allowing analysis at ambient pressure are being developed.

Safety and Effectiveness Summary The Process

●● SIMS can only be carried out in a laboratory with specialist

equipment and operator, which may have to be sourced within academic institutions.

●● The effectiveness is linked to the differences in chemical

composition between the mark and the background.

The Item or Surface

●● The process is most effective at visualising latent marks on

porous, semi-porous and adhesive surfaces although it can be used on non-porous surfaces.

●● The process is most likely to require the mark to be cut from

the item as the chamber within the equipment is of very limited size.

Integrated Use

SIMS may be detrimental to subsequent fingermark or forensic processing.

Further Reading

1. CAST Fingerprint Source Book, Chapter 6, Section 3.1.

2. Bailey, M. J., Jones, B. N., Hinder, S., Watts, J., Bleay, S.,

Webb, R. P., Nucl. Instrum. & Meth. In Phys. Res. B vol 268(1112), 2010, p1929-32.

3. Bright, N. J., Webb, R. P., Bleay, S., Hinder, S., Ward, N. I.,

Watts, J. F., Kirby, K. J., and Bailey, M. J., (2012) Anal Chem vol 84(4) p4083-4087 n

6.2.13

Fingermark Visualisation Manual

C SIMS

6.2.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names SMD

Key Information Where this process could be used

Single Metal Deposition may be an alternative to Multi-Metal Deposition (MMD) on non-porous surfaces. The potential advantages over MMD are that less chemicals are used to produce the solutions and the developer solution is more stable. See Category B-C process options.

Why the process is not in Category A

This process has not been compared to Multi-Metal Deposition and currently produces marks of lower contrast with the surface. The Single Metal Deposition formulation has not been fully optimised. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

It is a chemical process that involves exposing the item or surface to a sequence of two metal depositing solutions, interspersed with water washes.

Safety and Effectiveness Summary The Process

●● Single Metal Deposition can be used safely and effectively in

a laboratory.

The Item or Surface

●● Single Metal Deposition can be used on surfaces that are

heavily plasticised, such as cling film and plasticised vinyl.

●● It can be used on surfaces that are wet, or have been wetted

and subsequently dried.

Integrated Use

Single Metal Deposition may be detrimental to subsequent fingermark or forensic processing.

Further Reading

1. CAST Fingerprint Source Book, Chapter 5, Section 11 n

information is gathered from appropriate sources prior to considering the use of this process.

Process Overview

Single Metal Deposition visualises fingermarks because certain amino acids, fatty acids and proteins in fingermarks become charged under acidic conditions, which promotes selective

deposition of gold from solution onto the ridges. The gold bound to the ridges is subsequently enhanced by further deposition of larger particles of gold, resulting in blue-grey coloured marks, which may also appear gold at certain viewing angles.

Home Office January 2014

6.2.14

Fingermark Visualisation Manual

C Single Metal Deposition

6.2.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Disulphur dinitride

Key Information Where this process could be used

This process may be of use for the development of marks on most metal surfaces. It may also be applicable to other surfaces such as fabrics, cling film and wetted paper where preliminary results show promise. See Category B-C process options.

Why the process is not in Category A

The process is not very mature and the method and processing conditions are not yet fully established. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

Safety and Effectiveness Summary The Process

S2N2 can only be carried out in a laboratory with specialist

equipment and operator, which may have to be sourced within academic institutions.

The Item or Surface

●● The process is effective at developing latent marks on non-

porous, semi-porous and porous surfaces.

●● The process is restricted to items that fit within the chamber,

which is of limited size.

Integrated Use

S2N2 may be detrimental to subsequent fingermark or forensic processing.

●● Ensure all Category A process options have been explored

Further Reading

●● In the first instance, it is recommended that all relevant

inkjet trace imaging using disulfur dinitride’, Chem Commun,

before using this process.

information is gathered from appropriate sources prior to considering the use of this process.

1. Kelly, P. F., King, R. S. P., Mortimer, R. J., ‘Fingerprint and (2008), p6111-6113 n

Process Overview

S2N2 vapour polymerises onto some latent fingermarks within a low vacuum chamber to produce dark grey/blue marks of (SN)x. The difference in growth rate of (SN)x polymer on the

fingermark constituents and the surface enables both latent and

contaminated marks to be visualised across a range of surfaces. It is a chemical process which involves placing the item in a low © See Photo Credits

vacuum chamber where it is exposed to S2N2 vapours.

Home Office January 2014

6.2.15

Fingermark Visualisation Manual

C S2 N 2

6.2.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Several commercial product names may be available.

Key Information Where this process could be used

Tagged Nanoparticles could be used where high specificity to a particular substance (e.g. body fluid or drug metabolite) is required, or where visualised marks may be subjected to subsequent chemical analysis. See Category B-C process options.

Why the process is not in Category A

The full range of particle types and taggants is still being explored and until mature products become available it is not possible to fully define their areas of application. ●● Competent personnel specialising in fingermark

enhancement must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

Safety and Effectiveness Summary The Process

●● Tagged Nanoparticles can be used effectively in a laboratory

and at scenes. Their safety depends on the constituents of the powder.

●● The effectiveness of Tagged Nanoparticles depends on the

presence of the specific chemicals with which the tag will react.

The Item or Surface

●● Tagged Nanoparticles could be used for developing latent

fingermarks on non-porous, semi-porous and porous surfaces.

Integrated Use

Tagged Nanoparticles may be detrimental to subsequent fingermark or forensic processing.

before using this process.

Further Reading

information is gathered from appropriate sources prior to

2009, p93-96.

●● In the first instance, it is recommended that all relevant

considering the use of this process.

Process Overview

Tagged Nanoparticles can be used either as a powder or in

suspension in a liquid. The tags are specifically engineered to

react with certain components of a fingermark such as blood,

saliva, semen, drug metabolites, nicotine etc. Alternatively, the

1. Hazarika, P., Jickells, S. M., Russell, D. A., Analyst, vol 134, 2. Spindler, X., Hofstetter, O., McDonagh, A. M., Roux, C., Lennard, C., Chem. Comm. Vol 47, 2011, p560-562.

3. Frascione, N., Thorogate, R., Daniel, B., Jickells, S., Analyst vol 137(2), 2012, p508-512.

4. Theaker, B. J., Hudson, K. E. and Rowell, F J. Forens Sci Int 174(1), 2008, p26-34 n

particles can be used to visualise marks and then act as a matrix © See Photo Credits

enhancer during subsequent chemical analysis.

It is a physical or chemical process which involves application of a powder in dry or wet form. The powder will react with specific components within the fingermark.

Home Office January 2014

6.2.16

Fingermark Visualisation Manual

C Tagged Nanoparticles

6.2.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names TFD, HPS

Key Information Where this process could be used

The process could be used in situations where it is not possible or undesirable to apply wet development processes. See Category B-C process options.

Why the process is not in Category A

If excessive temperatures and/or exposure times are used, background fluorescence increases and ultimately causes paper to darken and char. Also the subsequent effectiveness of DFO and Ninhydrin will be reduced. Physical Developer appears to be unaffected by the process. The impact of Thermal Development on ink analysis and document examination is currently unknown. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

It is a physical process which involves application of heat to an item.

Safety and Effectiveness Summary The Process

●● Thermal Development can be used safely and effectively in a

laboratory using specialist equipment.

●● The effectiveness of Thermal Development depends on

control of temperature and exposure time.

●● The process requires subsequent Fluorescence

Examination to be effective.

The Item or Surface

●● Thermal Development is most effective at developing latent

fingermarks on semi-porous and porous surfaces.

Integrated Use

Thermal Development may be detrimental to subsequent fingermark or forensic processing.

before using this process.

Further Reading

information is gathered from appropriate sources prior to

R. G., Tahtouh, M., ‘Revisiting the Thermal Development of

●● In the first instance, it is recommended that all relevant

considering the use of this process.

Process Overview

Thermal Development involves paper being passed at

a controlled rate under a heat source that exposes it to

temperatures in a range where fluorescent degradation products of fingermark components begin to be formed. An alternative

1. Brown, A .G., Sommerville, D., Reedy, B . J., Shimmon,

Latent Fingerprints on Porous Surfaces. New Aspects and Refinements’, J. Forens. Sci. vol 54(1), 2009, p114-121.

2. Dominick, A. J., Nic Daeid, N., Bleay, S. M., Sears, V.‘The

Recoverability of Fingerprints on Paper Exposed to Elevated

Temperatures – Part 2 Natural Fluorescence’, J. Forens. Ident. Vol 59(3), 2009, p340-355 n

application involves thermal paper being exposed to lower, controlled temperatures which cause the thermal paper to preferentially darken where fingermarks are present.

Home Office January 2014

6.2.17

Fingermark Visualisation Manual

C Thermal Development

6.2.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names None

Key Information Where this process could be used

ThermaNin may be of use for the development of marks on thermal papers where retention of printed information is important. See Category B-C process options.

Why the process is not in Category A

ThermaNin may be less effective than both DFO and Ninhydrin on porous surfaces. Physical Developer may be as effective as ThermaNin for thermal papers where it is necessary to retain the printed information. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● In the first instance, it is recommended that all relevant

information is gathered from appropriate sources prior to considering the use of this process.

It is a chemical process which involves dipping the item in a solution and allowing marks to develop over time at

room temperature, in darkened conditions and at elevated temperature.

Safety and Effectiveness Summary The Process

●● ThermaNin can be used safely and effectively in a laboratory. ●● The effectiveness of ThermaNin depends on control of

temperature, lighting conditions and relative humidity.

The Item or Surface

●● The process is most effective at developing latent

fingermarks on porous surfaces, in particular thermal papers.

Integrated Use

ThermaNin may be detrimental to subsequent fingermark or forensic processing.

Further Reading

1. CAST Fingerprint Source Book, Chapter 3, Section 4 n

Process Overview

ThermaNin is a hemiketal of ninhydrin that can be dissolved in non-polar solvents, eliminating the need to use polar solvents that can darken the active layer of thermal paper. On dipping

thermal paper in the non-polar solution, the hemiketal converts to ninhydrin and alcohol on contact with the water in the

paper or the surrounding atmosphere. Once the hemiketal has © See Photo Credits

converted to ninhydrin, marks are developed by keeping the item in the dark at room temperature and at high relative humidity (~80%).

Home Office January 2014

6.2.18

Fingermark Visualisation Manual

C ThermaNin

6.2.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names X-ray fluorescence

Key Information Where this process could be used

XRF may be of use in the enhancement of marks developed with processes that utilise heavy elements such as Physical Developer or Iodine Fuming, especially if the mark is on an interfering patterned or coloured surface. See Category B-C process options.

Why the process is not in Category A

The full range of applications for XRF has not yet been explored, nor has its compatibility with conventional development processes. ●● Competent personnel specialising in fingermark

enhancement must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

Safety and Effectiveness Summary The Process

●● XRF can only be carried out in a laboratory with specialist

equipment and operator, which may have to be sourced within academic institutions.

●● The effectiveness is linked to the ability of components of the

mark to absorb and fluoresce in the appropriate part of the electromagnetic spectrum.

The Item or Surface

●● The process is most effective at visualising enhancing marks

developed by Physical Developer or Iodine Fuming on

porous, semi-porous and adhesive surfaces although it can be used on non-porous surfaces.

●● The process can be conducted on items such as sheets of

paper that can be laid flat on the imaging area.

before using this process.

Integrated Use

information is gathered from appropriate sources prior to

processing.

●● In the first instance, it is recommended that all relevant

considering the use of this process.

Process Overview

X-ray fluorescence (XRF) is the emission of lower energy (or fluorescent) x-rays from a material that has been excited by

bombarding it with high-energy x-rays or gamma rays. It is also possible to record the x-ray transmission, and this may also

provide sufficient contrast for the mark to be seen. The process

utilises differences in the x-ray absorbent/fluorescent properties

XRF may be detrimental to subsequent fingermark or forensic

Further Reading

1. Bleay et al., CAST Fingerprint Source Book, Chapter 6, Section 2.

2. Worley, C. G., Wiltshire, S. S., Miller, T. C., Havrilla, G. J. and Majidi, V. (2006) ‘Detection of Visible and Latent Fingerprints

Using Micro-X-ray Fluorescence Elemental Imaging’, J. Forens. Sci, vol. 51 (1), pp 57–63 n

© See Photo Credits

between the developed fingermark and the background to produce an image of the fingermark.

It is a physical process that uses specialist excitation sources (x-ray or gamma rays) to excite x-ray fluorescence.

Home Office January 2014

6.2.19

Fingermark Visualisation Manual

C XRF

6.3.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Acid Dyes (Methanol-based).................................. 6.3.2 Ninhydrin Enhancement (Zinc Toning)................ 6.3.10

Fingermark Visualisation Manual

Category D Processes Introduction Description

Processes extensively evaluated by the Home Office and considered unsuitable for incorporating into processing charts in Chapter 4.

Use

Corrective action processes. Not generally for routine use but may be used to recover marks in situations where

initial selection of processes has resulted in undesirable consequences.

Level of detail

The two Category D processes may be used for

corrective action and have more detail to explain how they may be used most effectively n

Home Office January 2014

6.3.1

6.3.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names

Methanol-based protein stains; Methanolbased blood dyes

Contents Options............................................. 6.3.3 Laboratory Use................................ 6.3.4 Health and Safety........................ 6.3.4 Equipment................................... 6.3.5 Chemicals.................................... 6.3.6 Solutions...................................... 6.3.7 Processing................................... 6.3.8 Post-Processing.......................... 6.3.9

Key Information Where this process could be used

This formulation may be more effective at enhancing blood as a corrective action if items have previously been processed with Superglue Fuming.

Why the process is not in Category A

It is less effective and more hazardous than the Category A process. It may degrade or destroy some surfaces. ●● Competent personnel specialising in fingermark

visualisation must be consulted if considering the use of this process.

●● Ensure Acid Dyes Category A process options have been

explored before using this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● This section contains process instructions for three Acid Dye

(methanol-based) formulations: Acid Black 1; Acid Violet 17; Acid Yellow 7.

●● Process details are given for laboratory use only although

the process instruction contains less detail than for a Category A process.

Process Overview

will be of relevance when using Acid Dyes (methanol-based).

Safety and Effectiveness Summary The Process

●● This formulation can be used safely and effectively in a

laboratory.

●● The highly flammable and toxic nature of the formulation

makes it difficult to use safely at scenes.

●● Blood that is not suitably fixed by the first solution will leach

when exposed to the second and third solutions and process effectiveness will be reduced.

●● Acid Yellow 7 requires subsequent Fluorescence

Examination to be effective.

The Item or Surface

●● Be aware of the possible hazards from body fluids.

●● Acid Dyes (methanol-based) will develop fingermarks in

blood on most surfaces. However, this formulation may

degrade or destroy some surfaces, especially varnishes,

paints and some plastics, damaging or obliterating ridge detail.

●● The three dye formulations will vary in effectiveness

depending on the colour of the item or surface and the surface porosity.

Acid Dyes stain protein present in blood and other protein-rich

●● Acid Dyes (methanol-based) can adversely stain the

not detect the constituents normally present in latent fingermarks

Integrated Use

contaminants to give a coloured or fluorescent product. They will and therefore must be used in sequence with other processes when blood-contaminated items or surfaces are examined.

It is a chemical process that involves exposing the item or surface to three solutions in sequence. Much of the detail

Home Office January 2014

contained within the Category A Acid Dyes process instructions

background of some porous items, obscuring the fingermark.

Acid Dyes (methanol-based) may be detrimental to subsequent fingermark or forensic processing.

Further Reading

CAST Fingerprint Source Book, Chapter 3, Section 1.

6.3.2

Fingermark Visualisation Manual

D Acid Dyes (Methanol-based)

6.3.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Options Acid Yellow 7

●● Acid Yellow 7 is generally the most sensitive

methanol-based acid dye.

●● It is only effective at enhancing blood on non-porous

surfaces.

●● It is most effective on very light or visually

imperceptible deposits of blood (heavy deposits of blood fluoresce weakly due to quenching effects).

●● It produces fluorescent fingermarks*.

Acid Black 1 and Acid Violet 17

●● Acid Black 1 and Acid Violet 17 are both effective at

enhancing blood on all types of surface.

●● When Acid Black 1 and Acid Violet 17 are used

on semi-porous surfaces, there may be some

background staining which will reduce contrast with the stained blood. However, each dye responds

differently and for porous surfaces one may prove

more suitable than the other. If possible a small part of the surface, away from the area of interest, should be tested for dye retention.

●● Both Acid Black 1 and Acid Violet 17 produce visible

fingermarks.

Acid Black 1

enhanced blood on a dagger.

Sequential use of Acid Dyes

●● Acid Violet 17 may be used after Acid Yellow 7 to

develop and increase contrast of visible fingermarks, although coloration will not be as dark as achieved by use of Acid Violet 17 alone.

●● Acid Black 1 should not be used after Acid Yellow 7

as the density of the staining is significantly less than if Acid Violet 17 is used after Acid Yellow 7.

●● The use of Acid Yellow 7 after Acid Black 1 or Acid

Violet 17 is normally of little benefit. However, it may

be used as a counterstain on porous surfaces where it will produce a fluorescent background that boosts contrast with the developed, absorbing fingermark.

●● There is no benefit to be gained by using Acid Black

1 and Acid Violet 17 in sequence with one another.

●● See Chapter 4 for general information on the

sequential use of fingermark visualisation processes.

●● See Chapter 7 for information on integration of

Acid Yellow 7 enhanced blood on a chisel handle.

fingermark and other forensic processes.

*The number of fingermarks detected with

Fluorescence Examination depends on many factors e.g. suitability of light source and viewing filters, level of dark adaptation and the surrounding examination environment.

Acid Violet

17 enhanced blood on a carton.

Home Office January 2014

6.3.3

Fingermark Visualisation Manual

Acid Dyes (Methanol-based)

6.3.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category

A processes. This information can also be consulted for working with Category D processes, although it may not cover all situations.

●● Acid Dyes (methanol-based) may be carried out with no known hazards to health

provided practitioners are trained and competent, if appropriate control measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards (e.g.

‘residual processing chemicals on items are hazardous’) and/or control measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

●● The health and safety information provided throughout the Manual must be

considered as guidance only: definitive health and safety policies, procedures and instructions must be provided locally.

●● In providing the Category D process instructions it is assumed that: ■■

the process will be carried out in a laboratory that can provide a safe working environment;

■■

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

Index

Laboratory Use Hazards associated with Acid Dyes (methanol-based) ●● Acid Dyes (methanol-based) are chemical processes.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive.

Additional hazard

Risk

Suggested control measures

Creation of a flammable atmosphere when preparing and using Fixing, Staining and Washing Solutions.

Fire

●● Prepare and apply Fixing, Staining

Methanol is toxic and may be absorbed through the skin.

Poisoning

●● Wear appropriate PPE to prevent

and Washing Solutions in a fume cupboard. See working with flammable liquids for further information.

methanol coming into contact with routes of ingress into the body, including the skin.

Nuisance odour from Some individuals processed items. may experience watery eyes and sneezing.

●● Examine treated items in a well-

Exposure to quantities of dye solution.

●● Wear appropriate gloves when

Staining hands, clothes and body with dye.

ventilated area or preferably on a down-draught bench.

preparing or using solutions to protect the hands, especially if they are to be immersed in the solutions. ●● Wear a disposable apron to protect the clothes and body.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

6.3.4

Fingermark Visualisation Manual

Acid Dyes (Methanol-based)

Glossary

6.3.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Equipment

Acid Dyes (methanol-based) only require general laboratory equipment as described in Chapter 3 but using unbreakable equipment to minimise the risk from possible biohazards.

Equipment Processing dishes

Home Office January 2014

Requirements Processing dishes must: ●● be unbreakable and easy to clean and sterilise due to the biohazard risk. A suitable material would be stainless steel.

6.3.5

Fingermark Visualisation Manual

Acid Dyes (Methanol-based)

Appendices

6.3.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists chemicals that are required for Acid Dyes (methanol-based). Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

Unless specified, water used for making solutions or for rinsing items is purified. See Chapter 3 safe handling of chemicals for general information or effective use of chemicals for details on dye purity. Common Name

Alternative Name(s)

CAS Number

Grade

Acid Yellow 7 (AY7)

CI 56205; Brilliant Sulphoflavin

2391-30-2

≥50 %

Acid Violet 17 (AV17)

CI 42650; Coomassie Brilliant Violet R150

4129-84-4

≥50 %

Acid Black 1 (AB1)

CI 20470; Amido Black 10B; Naphthol Blue Black; Naphthalene Black 12B

1064-48-8

≥80 %

Acetic acid

Ethanoic acid

64-19-7

Laboratory

Methanol

Methyl alcohol

67-56-1

Analytical ≥99.7%

Home Office January 2014

6.3.6

Fingermark Visualisation Manual

Acid Dyes (Methanol-based)

Appendices

6.3.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Solutions

Consult Chapter 3 for general information on solution

preparation, safe storage of chemicals, solutions and

(1) Prepare solutions

mixtures (which includes information on packaging

and labelling), management of waste for disposal of

solutions and guideline expiry periods. This page gives additional information relevant to this process.

(2) Label appropriately

a) The Staining Solution and Washing Solutions should be labelled as determined by a local hazard assessment.

(3) Store appropriately

a) Staining and Washing Solutions have guideline expiry dates of 12 months after preparation if stored at room temperature.

Solutions Fixing Solution

1 L methanol

Staining Solution

2 g dye 1 L Wash Solution Dye options: Acid Black 1 (AB1) or Acid Violet 17 (AV17) or Acid Yellow 7 (AY7)

(4) Dispose of appropriately

Ready Reckoner

Wash Solution 1

100 mL acetic acid 900 mL methanol

Wash Solution 2

50 mL acetic acid 950 mL methanol

For other quantities see Ready Reckoner.

Home Office January 2014

a) Staining and Washing Solutions must be prepared in a fume cupboard. b) The Staining Solution should be stirred for at least 30 minutes. c) Washing Solutions are colourless. Staining Solutions are dark blue (AB1), purple (AV17) and yellow (AY7).

Quantity Solution

Chemical

1L

2L

5L

Fixing Solution Methanol

1L

2L

5L

Staining Solution

Dye

2g

4g

10 g

Wash Solution 1

1L

2L

5L

Wash Solution 1

Acetic Acid

100 mL

200 mL

500 mL

Methanol

900 mL

1.80 L

4.5 L

Wash Solution 2

Acetic Acid

50 mL

100 mL

250 mL

Water

950 mL

1.90 L

4.75 L

6.3.7

Fingermark Visualisation Manual

Acid Dyes (Methanol-based)

Glossary

6.3.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Processing Preparation (1) Prepare work area (2) Equipment and Solutions

Processing (3) Expose item to Fixing Solution

(4) Expose item to Staining Solution

(5) Expose item to Wash Solution 1

Home Office January 2014

a) Acid Dyes (methanol-based) must be carried out in a fume cupboard.

(6) Expose item to Wash Solution 2

a) Pour sufficient amounts of Fixing, Staining and Wash Solution 1 and Wash Solution 2 into separate dishes or vessels to treat the item. a) Apply the Fixing Solution to the item, ensuring that the surface is kept wetted for at least one hour using suitable means, such as immersion or pouring. Longer times may be needed to fix heavy deposits of blood. b) If immersing the item, the Fixing Solution should be changed if it becomes contaminated with debris or changes colour. a) If using Acid Black 1 or Acid Violet 17, apply the Staining Solution to the item, ensuring that the surface is kept wetted for 3–4 minutes using suitable means, such as immersion or pouring. Do not spray. Weak staining of marks will indicate that longer exposure times are required or dye concentration is insufficient. b) If using Acid Yellow 7, apply the Staining Solution to the item, ensuring that the surface is kept wetted for 5–10 minutes using suitable means, such as immersion or pouring. Do not spray. Weak staining of marks will indicate that longer exposure times are required or dye concentration is insufficient. c) If immersing the item, the Staining Solution should be replenished as required. a) Apply Wash Solution 1 to the item, ensuring that the surface is kept wetted, until excess dye has been removed from the background and greatest contrast is achieved between the enhanced fingermarks and the background. This should be done using suitable means, such as immersion with gentle agitation or pouring. b) If immersing the item, the Wash Solution 1 should be changed when it becomes heavily contaminated with dye.

(7) Dry item

a) Apply Wash Solution 2 to the item for approximately 30 seconds ensuring that the surface is kept wetted, using suitable means such as immersion with gentle agitation or pouring. b) If immersing the item, the Wash Solution 2 should be changed when it becomes heavily contaminated with dye. The final Wash Solution 2 should remove final traces of excess dye from the item. a) See drying of items.

(8) Examination (AY7) Primary: Fluorescence Examination

(8) Examination (AB1/AV17) Primary: Visual Examination Secondary: Fluorescence Examination

a) Items treated with Acid Dyes (methanol-based) should be examined in a well-ventilated area preferably on a down-draught bench. b) Visible marks are coloured dark blue (AB1), purple (AV17) and yellow/brown (AY7). Fluorescent marks are coloured yellow (AY7). c) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination and Fluorescence Examination, particularly for low-contrast marks or marks on dark or patterned surfaces. d) Mark up viable fingermarks appropriately and capture image. e) After examination, items can be re-treated if necessary. In this case application of Fixing Solution is not required.

6.3.8

Fingermark Visualisation Manual

Acid Dyes (Methanol-based)

Glossary

6.3.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Residual processing chemicals

a) Items treated with Acid Dyes (methanol-based) may emit a nuisance odour comprising of acetic acid vapour. Its concentration is likely to be below the WEL.

(2) Cleaning processed items

a) It may not be possible to return items to their original state. If possible, items may be thoroughly wiped or washed with an anti-viral disinfectant (if body fluids are present) followed by soap and water. Some solvents may be effective at removing residual chemicals, although they may cause further damage to the item.

(3) Disposal or return of processed items

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner provided anti-viral disinfectants have been used.

Equipment and Chemicals (4) Re-use of solutions

Home Office January 2014

a) Fixing, Staining and Wash Solutions should not be reused n

6.3.9

Fingermark Visualisation Manual

Acid Dyes (Methanol-based)

Appendices

6.3.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Alternative Names Zinc chloride toning

Contents Laboratory Use.............................. 6.3.11 Health and Safety...................... 6.3.11 Equipment................................. 6.3.12 Chemicals.................................. 6.3.13 Solutions.................................... 6.3.14 Processing................................. 6.3.15 Post-Processing........................ 6.3.16

Key Information Where this process could be used

The process may be used as a corrective action for the enhancement of marks developed by Ninhydrin on coloured or patterned surfaces where DFO has not been used as the initial process.

Why the process is not in Category A

Ninhydrin Enhancement by Zinc Toning is significantly less effective than the use of DFO. The formulation has not been optimised for use in HFE7100. Marks may be diffused or destroyed unless care is taken during application. ●● Competent personnel specialising in fingermark

enhancement must be consulted if considering the use of this process.

●● Ensure all Category A process options have been explored

before using this process.

●● It is recommended that all sections are read prior to using

this process for the first time.

●● Process details are given for laboratory use only although

the process instruction contains less detail than for a Category A process.

Process Overview

Zinc ions can react with Ruhemann’s purple (the product of the reaction between Ninhydrin and amino acids) to form orangeand magenta-coloured products. Generally the colours of the

complexes formed are weak and offer little or no advantage over the colour of Ruhemann’s purple. However, if the reaction is

It is a chemical process that involves applying a solution to the item or surface followed by use of a specialist oven (if possible) to increase the effectiveness of the reaction.

Some of the detail contained within the Category A Ninhydrin

process instructions will be of relevance when using Ninhydrin Enhancement (Zinc Toning).

Safety and Effectiveness Summary The Process

●● Ninhydrin Enhancement (Zinc Toning) can be used safely and

effectively in a laboratory.

●● The effectiveness may be influenced by the care taken during

application of the solution.

●● The effectiveness is linked to the ability to control the

temperature and relative humidity of the item or surface postapplication. This requires the use of specialist equipment to carry out successfully.

●● Ninhydrin Enhancement (Zinc Toning) requires subsequent

Fluorescence Examination to be effective.

The Item or Surface

●● Ninhydrin Enhancement (Zinc Toning) is only effective at

enhancing Ninhydrin-developed marks.

Integrated Use

Ninhydrin Enhancement (Zinc Toning) may be detrimental to subsequent fingermark or forensic processing.

Further Reading

CAST Fingerprint Source Book, Chapter 3, Section 4.

carried out at high humidity the magenta-coloured compound is

favoured and this is fluorescent. The material of the surface may play a role in the effectiveness of the complexing reaction. Home Office January 2014

6.3.10

Fingermark Visualisation Manual

D Ninhydrin Enhancement (Zinc Toning)

6.3.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Health and Safety

●● Consult Chapter 3 for general information on working safely with Category A

processes. This information can also be consulted for working with Category D processes, although it may not cover all situations.

●● Ninhydrin Enhancement (Zinc Toning) may be carried out with no known hazards

to health provided practitioners are trained and competent, if appropriate control

measures are in place and the process is carried out as described in this Manual.

●● Throughout the process instruction there may be reference to chemical hazards

(e.g. ‘residual processing chemicals on items are hazardous’) and/or control

measures (e.g. ‘work within a fume cupboard’). These are based on CAST’s local risk assessment (and Safety Data Sheets) and must not be assumed to be appropriate in all situations, but are given as guidance only.

General Health and Safety Information

Hazards associated with Ninhydrin Enhancement (Zinc Toning) ●● Ninhydrin Enhancement (Zinc Toning) is a chemical process.

●● Practitioners will need to know the hazards associated with handling individual

chemicals (from SDS) and the hazards associated with the process solutions.

●● Wear Standard PPE as a minimum.

●● Some additional hazards associated with the process are identified below but those

cited must not be regarded as exhaustive, nor the control measures prescriptive.

Additional hazard Air depletion when preparing and using Zinc Toning Solution.

Risk Asphyxiation

instructions must be provided locally.

●● In providing the Category D process instructions it is assumed that:

the process will be carried out in a laboratory that can provide a safe working environment;

a responsible person will carry out a risk assessment before the process is carried out to include at least: ❍❍ ❍❍

an assessment of the practitioner’s competence to carry out the process;

a review of all the hazards associated with the use of the process, consulting relevant documents, such as Safety Data Sheets (SDSs), where necessary;

❍❍

Suggested control measures ●● Prepare and apply Zinc Toning

Solution in an extracted fume cupboard.

HFE7100 is not absorbed by the activated carbon filters found in recirculating fume cupboards. It passes through them unaffected and unless the HFE7100 vapour is extracted from the laboratory it will displace the air from the ground up as it is much heavier than air.

considered as guidance only: definitive health and safety policies, procedures and

■■

Index

Laboratory Use

●● The health and safety information provided throughout the Manual must be

■■

Glossary

Nuisance odour from processed items.

Some individuals may experience watery eyes and sneezing.

●● Examine treated items in a well-

ventilated area or preferably on a down-draught bench.

a review of all the hazards associated with the working environment, the item(s) and any contaminants.

●● All control measures identified will be put in place, including the wearing of

appropriate PPE, and reviewed for their effectiveness.

●● Where information is included for scene use of the processes, the considerations are

over and above those for laboratory applications of the processes.

Home Office January 2014

6.3.11

Fingermark Visualisation Manual

Ninhydrin Enhancement (Zinc Toning)

Appendices

6.3.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Equipment

Ninhydrin Enhancement (Zinc Toning)

requires the use of some process-specific equipment for the application of Zinc

Equipment

Index

Laboratory Use Requirements

Ninhydrin development oven

A Ninhydrin development oven must: ●● maintain air temperature within the oven whilst at equilibrium at 80 ± 2 °C; maintain relative humidity of 62 ± 5%RH within the oven whilst at equilibrium; ●● provide close control and rapid recovery of temperature and humidity across all shelves (see calculating the oven recovery time and treatment time); ●● not have air flow so strong as to blow normal paper casework items around within the oven; ●● have an over-temperature safety cut-out; ●● have a way of monitoring items and observing mark development whilst in the oven; solutions may include multi-glazed windows with a wiper or heated glass and with suitable lighting; ●● have an adjustable airflow inlet; ●● be able to be connected to a negative pressure exhaust system (see Extraction for Ninhydrin development oven); ●● have a drain-pipe to remove condensed water, which must be connected with a continuous downward slope to a suitable outlet, such as an open drain and be resistant to acetic acid; ●● not allow condensation to drip onto the item. In addition, a Ninhydrin development oven should: ●● not exceed 80% RH for more than a few seconds in the usable part of the oven; ●● have a working capacity of at least 150 L; ●● have interior and shelves, resistant to acetic acid vapour; ●● incorporate an automatic timer that begins the cycle when the oven door is closed.

Extraction for Ninhydrin development oven

Extraction for the Ninhydrin development oven must: ●● be connected to the oven via an extraction pipe with a continuous upward slope; ●● be a negative pressure exhaust system which provides a continuous extraction rate of between five and ten times the total volume of the oven per hour; ●● have an extraction pipe that is able to resist the temperature being used and acetic acid vapour mixed with steam at that temperature. In addition, there should: ●● be an extraction hood over the oven extending in front to beyond the door end when it is fully opened.

Spray gun

The spray gun should: ●● be capable of delivering a fine, even mist. Garden sprayers are not generally suitable for this purpose.

Toning Solution and for creating the

environmental conditions required for development.

If equipment is to meet the requirements as outlined below, it must be well

maintained and, if appropriate, serviced regularly in accordance with the

manufacturer’s instructions. General laboratory equipment that may be required is outlined in Chapter 3.

Home Office January 2014

Glossary

6.3.12

Fingermark Visualisation Manual

Ninhydrin Enhancement (Zinc Toning)

Appendices

6.3.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Chemicals

This table lists chemicals that are required for Ninhydrin Enhancement (Zinc Toning). Refer to supplier’s Safety Data Sheet (SDS) for further information on specified chemicals.

See Chapter 3 safe handling of chemicals for general information. Common Name

Alternative Name(s)

CAS Number

Grade

Zinc chloride

-

7646-85-7

Reagent grade ≥ 98%

Acetic acid

Ethanoic acid

64-19-7

Analytical ≥ 99.7%

Ethanol

Ethyl alcohol, Absolute ethanol

64-17-5

Analytical ≥ 99.7%

2- Propanol

Isopropyl alcohol, Isopropanol

67-63-0

Laboratory ≥ 99.5%

HFE7100

Methyl nonafluorobutyl ether, 1 Methoxy nonafluorobutane

HFE7100 is only As supplied available as a mixture of two isomers. The isomers are inseparable but have essentially identical properties. Each isomer has its own CAS number (163702-08-7 and 163702-07-6). The isomeric mixture within HFE7100 does not have its own unique CAS number.

Home Office January 2014

6.3.13

Fingermark Visualisation Manual

Ninhydrin Enhancement (Zinc Toning)

Appendices

6.3.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Index

Laboratory Use

Solutions

Consult Chapter 3 for general information on solution

preparation, safe storage of chemicals, solutions and

a) Ensure zinc chloride has dissolved before addition of the HFE7100. b) Zinc Toning Solution is clear.

(1) Prepare solutions

mixtures (which includes information on packaging

and labelling), management of waste for disposal of

solutions and guideline expiry periods. This page gives additional information relevant to this process.

Solution Zinc Toning Solution

50 mL ethanol 10 mL 2-propanol 10 mL acetic acid 6 g zinc chloride 200 mL HFE7100*

*HFE7100 has not been fully evaluated as the solvent for the Zinc Toning Solution. It is suggested as a direct replacement for 1,1,2-Trichlorotrifluoroethane (CFC113) which is no longer available. Report any unusual behaviour in the solution to CAST. For other quantities see Ready Reckoner.

Home Office January 2014

(2) Label appropriately

a) Zinc Toning Solution should be labelled as determined by a local hazard assessment.

(3) Store appropriately

a) Zinc Toning Solution has a guideline expiry date of 12 months after preparation if stored at room temperature. b) Discard solution if a deposit appears.

(4) Dispose of appropriately

Ready Reckoner Quantity of Zinc Toning Solution Chemical

135 mL

270 mL

540 mL

Ethanol

25 mL

50 mL

100 mL

2-propanol

5 mL

10 mL

20 mL

Acetic acid

5 mL

10 mL

20 mL

Zinc chloride

3g

6g

12 g

HFE 7100

100 mL

200 mL

400 mL

6.3.14

Fingermark Visualisation Manual

Ninhydrin Enhancement (Zinc Toning)

Glossary

6.3.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Work area

a) Zinc Toning Solution must be used in an extracted fume cupboard.

(2) Equipment

a) For most items, the Ninhydrin development oven should be pre-conditioned to 80 ± 2°C and 62 ± 5% relative humidity. This may take many minutes to achieve. For solid items (i.e. those with a greater thermal mass than paper such as wood, plasterboard etc.) or cellophane, the oven must be pre-conditioned to 80 ± 2°C at ambient humidity to avoid condensation. b) Pour a small quantity of Zinc Toning Solution into the reservoir of a spray gun.

Processing (3) Apply Zinc Toning Solution

a) Very carefully spray the Zinc Toning Solution onto Ninhydrin-developed marks. b) Do not visibly ‘wet’ the surface as this may cause catastrophic diffusion of both developed marks and some inks. c) A colour change from purple to orange/magenta may be observed in the Ninhydrin-developed mark at this point, although in some cases this change may not occur until after Step 4.

(4) Transfer item to a pre-conditioned Ninhydrin development oven

(5) Remove item from Ninhydrin development oven

(6) Examination Primary: Fluorescence Examination Secondary: Visual Examination

Home Office January 2014

a) Minimise the time the oven door is open during transfer. b) If the oven is loaded with solid items (i.e. those with a greater thermal mass than paper such as wood, plasterboard etc.) or cellophane, the oven should be held at 80 ± 2°C and ambient humidity for up to an hour (or the time for the temperature of the item and oven to equilibrate). Only then should the humidity be increased to 62 ± 5%. c) Some items such as envelopes with plastic windows or plastic bottles with paper labels may be damaged at 80°C. Most plastics will tolerate a temperature of 50°C but samples of items should be tested if possible to determine the maximum temperature to which they can be subjected without damage. d) The item is heated and humidified for the Ninhydrin treatment time.

a) Items should be examined in a well-ventilated area preferably on a down-draught bench. b) Visible marks are orange/magenta. Fluorescent marks are yellow. c) There are many non-destructive optical processes that can be considered when examining and imaging marks in addition to Visual Examination and Fluorescence Examination, particularly for low-contrast marks or marks on dark or patterned surfaces. d) Mark up viable fingermarks appropriately and capture image.

6.3.15

Fingermark Visualisation Manual

Ninhydrin Enhancement (Zinc Toning)

Appendices

6.3.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Post-Processing

Consult Chapter 3 for general advice on packaging, storage, disposal or return of

items, and management of waste for disposal of equipment, chemicals, solutions and mixtures. This page gives additional information relevant to this process.

Processed item (1) Residual processing chemicals

a) Items treated with Ninhydrin Enhancement (Zinc Toning) may emit a nuisance odour comprising of acetic acid vapour. Its concentration is likely to be below the workplace exposure limit.

(2) Cleaning processed items

a) It may not be possible to return items to their original state. If possible, items may be thoroughly wiped or washed with soap and water.

(3) Disposal or return of processed items

a) Residual processing chemicals that cannot be removed during cleaning are non-hazardous so items can be discarded with ordinary waste or returned to the owner.

Equipment and Chemicals (No additional information) n

Home Office January 2014

6.3.16

Fingermark Visualisation Manual

Ninhydrin Enhancement (Zinc Toning)

Appendices

6.4.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Acid Dyes................................................................. 6.4.2 Amino Acid Reagents.............................................. 6.4.3 Fat/Lipid Reagents.................................................. 6.4.4 Fuming/Evaporation Processes............................. 6.4.5 Haem Reagents....................................................... 6.4.6 Powders................................................................... 6.4.7 Powder Suspensions.............................................. 6.4.8

Fingermark Visualisation Manual

Category E Processes Introduction Description

Processes that are known to be less effective than

alternative processes with no obvious niche application,

or those with no reliable data on the success rate and no

reason to believe that they are as good as or significantly better than other processes.

Use

Processes with no known operational benefits.

Level of detail

Listed with short explanations of why they are not considered suitable for use n

Home Office January 2014

6.4.1

6.4.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

E Acid Dyes Overview

●● Includes a range of acid dyes that react with the protein components of blood to

produce visible or fluorescent products.

●● They have been evaluated for development of marks in blood on both non-porous

and porous surfaces.

Process

Acid Violet 19 (Hungarian Red): Produces red visible and fluorescent marks with blood proteins. Visible marks have less colour density and contrast than those produced by

equivalent formulations incorporating Acid Black 1 or Acid Violet 17. The fluorescence

is much less intense than that produced by equivalent formulations incorporating Acid Yellow 7.

Acid Blue 83 (Coomassie Blue): Produces blue visible marks with blood proteins.

Visible marks have considerably less colour density and contrast than those produced by equivalent formulations incorporating Acid Black 1 or Acid Violet 17.

Acid Yellow 23 (Tartrazine): Produces pale yellow fluorescent marks with blood

proteins. The fluorescence is much less intense than that produced by equivalent formulations incorporating Acid Yellow 7.

Crowles Double Stain (Acid Blue 83 and Acid Red 71): Produces blue visible marks with blood proteins. Visible marks have considerably less colour density and contrast

than those produced by equivalent formulations incorporating Acid Black 1 or Acid Violet 17 n

Examples of various acid dyes being compared.

Home Office January 2014

6.4.2

6.4.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

E Amino Acid Reagents Overview

●● Includes a range of reagents that have been shown to react with either the amine or

carboxylic acid groups of the amino acids and proteins present in latent fingermarks.

●● They have been primarily evaluated for development of marks on porous surfaces.

Process

Alloxan: Detects amino acids on porous surfaces. It develops visible, faint orange marks that may be difficult to detect and is significantly less effective than Ninhydrin.

Benzo[f]ninhydrin: Detects amino acids on porous surfaces. It develops visible, dark green/grey marks and is significantly less effective than Ninhydrin.

Fluorescamine: Detects primary amines on porous surfaces. It develops non-

visible, blue fluorescent marks that are excited by long-wave ultraviolet radiation. The fluorescence from the optical brighteners in paper can obscure fluorescence from developed marks. The process is less effective than Ninhydrin.

2,6-Dichlorophenol indophenol, sodium salt: Detects carboxylic acids on porous

surfaces. It develops visible, pink marks whilst staining the substrate background dark blue. The process is significantly less effective than Ninhydrin.

A Benzo[f]ninhydrin mark on a cheque.

Lawsone: Detects amino acids on porous surfaces. It develops red fluorescent marks

Fluorescamine marks on a cheque.

that may also be faintly visible (brown). It is less effective than DFO.

5-methylthioninhydrin (5-MTN): Detects amino acids on porous surfaces. A formulation incorporating zinc salts develops visible, faint purple marks that are also fluorescent (orange). The process is less effective than Ninhydrin for visible marks and DFO for fluorescent marks.

4-Chloro-7-nitrobenzofurazan (NBD chloride): Detects amino acids on porous

surfaces. It develops orange fluorescent marks that may also be faintly visible (yellow/ brown). The process is less effective than DFO.

Ortho-phthaladehyde: Detects amino acids on porous surfaces. It develops non-

visible blue fluorescent marks that are excited by long-wave ultraviolet radiation. The fluorescence from the optical brighteners in paper can obscure fluorescence from developed marks. The process is less effective than Ninhydrin n Home Office January 2014

6.4.3

6.4.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

E Fat/Lipid Reagents Overview

●● Includes a range of reagents that have been shown to react with the lipid groups

present in latent fingermarks.

●● They have been primarily evaluated for development of marks on porous surfaces.

Process

Cupric acetate/dithioxamide: Detects fats on porous surfaces. The process develops dark green, visible marks but its effectiveness relative to other processes has not yet been determined.

2,7-Dichlorofluorescein/aluminium chloride/ferric chloride: Detects fats on porous

surfaces. The process develops pink/red marks whilst staining the substrate background orange. Its effectiveness relative to other processes has not yet been determined.

Dodeca-molybdophosphoric acid: Detects fats and steroids. The process develops

dark green/blue visible marks whilst staining the substrate background pale green. Its effectiveness relative to other processes has not yet been determined.

Tungstomolybdic acid: Detects fats and steroids. It develops pale grey visible marks, but its effectiveness relative to other processes has not yet been determined n

Home Office January 2014

Mark developed with Cupric acetate/ dithioxamide.

Mark developed with 2,7-Dichlorofluorescein/ aluminium chloride/ferric chloride.

6.4.4

6.4.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

E Fuming/Evaporation Processes Overview

●● Includes a range of reagents that have been found to visualise fingermarks by

selective deposition from the vapour phase.

●● They have been primarily evaluated for development of marks on non-porous

surfaces.

Process

Vacuum Metal Deposition (VMD) (aluminium): Develops visible marks that are metallic silver in appearance. The process is significantly less sensitive than either VMD (gold/ zinc) or VMD (silver).

Anthracene Evaporation: Develops blue-green fluorescent marks. The process is less effective than VMD.

Camphor Burning: Develops visible black marks by selective binding of sooty particles to marks. Its effectiveness relative to other processes has not yet been determined. Superglue Fuming (vacuum): An alternative to Superglue Fuming using humidity

at ambient pressure. It was found to be less effective than the humidified process in

comparative trials, marks being more difficult to see and to stain with fluorescent dyes n

Home Office January 2014

Mark developed using anthracene evaporation.

An electron micrograph of a ridge of a

fingerprint developed by superglue fuming (vacuum).

6.4.5

6.4.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

E Haem Reagents Overview

●● Includes a range of reagents that react with the haem component of blood to

produce visible or chemiluminescent products.

●● They have been evaluated for development of marks in blood on both non-porous

and porous surfaces.

Process

Diaminobenzidine (DAB, Tetraaminobiphenyl TAB): Reacts with the haem constituent

of blood to form a brown-coloured reaction product. The observed colour change is very subtle and Leuco crystal violet (LCV) has been found to be more effective.

Fluorescein: Reacts with the haem constituent of blood to produce a fluorescent

reaction product. The ormulation is complex and can be difficult to produce and keep. No performance benefits have been observed over other haem reagents.

Leuco Malachite Green: Reacts with the haem constituent of blood to form a green/ blue-coloured reaction product. The observed colour is much less intense than that obtained using LCV.

Luminol: Reacts with the haem constituent of blood to produce a blue

Detail within bloody marks has been diffused whilst using Luminol.

chemiluminescence. The process is highly sensitive to small traces of blood if fully dark environments can be obtained. It is not recommended for visualisation of fingermarks because the formulation does not contain fixative, and therefore diffusion and destruction of ridge detail occurs without extremely careful application.

Tetramethylbenzidine (TMB): Reacts with the haem constituent of blood to form a

blue/green-coloured reaction product. It has been found to be less effective than LCV in comparative tests n

Home Office January 2014

6.4.6

6.4.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

E Powders Overview

●● Includes Powders that adhere to water and sebaceous constituents of marks.

●● They have been evaluated for development of marks on non-porous surfaces.

Process

Bichromatic powders: No benefits have been observed over conventional powder types n

Mark developed using bichromatic powder under different lighting conditions.

Home Office January 2014

6.4.7

6.4.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

E Powder Suspensions Overview

●● Includes powders in suspension that adhere to sebaceous constituents of marks or

possibly eccrine components trapped in a sebaceous matrix.

●● They have been evaluated for development of marks on adhesive surfaces with non-

porous backings.

Process

‘Sticky-side Powder’: Less effective than carbon and iron-oxide Powder Suspensions on light-coloured adhesive surfaces n

Marks on adhesive tape developed with ‘Sticky-side’ powder.

Home Office January 2014

6.4.8

6.5.1

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Contents Overview .................................................................. 6.5.2

Fingermark Visualisation Manual

Category F Processes Introduction Description

Processes with known health and safety issues. The

process uses chemicals and/or conditions that expose operators to unacceptable health hazards.

Use

Processes should not be used for health and safety reasons.

Level of detail

Listed with short explanations of why they are not considered suitable for use n

Home Office January 2014

6.5.1

6.5.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Overview

●● Category F processes include a range of reagents that are not

recommended for use, primarily due to health and safety concerns.

●● Health and safety category information is taken from the Classification,

Labelling and Packaging of Substances and Mixtures (CLP) Regulations EC No 1272/2008 n

Process

Use and health and safety issues

Benzidine

Used for developing marks in blood, producing dark blue marks. Carcinogen 1A, acute toxicity 4.

Vacuum Metal Deposition (VMD) (gold/ cadmium)

Gold/cadmium was the first operationally implemented VMD process. Cadmium is Carcinogen 1A, Mutagen 2, Reproductive hazard 2, Acute toxicity 2, specific target organ toxicity (STOT) repeated exposure (RE) 1.

Hydrogen fluoride

Used for selectively etching marks on glass. Acute toxicity 1, Skin corrosion 1A.

Hydrogen sulphide fuming

Process

Use and health and safety issues

Ninhydrin enhancement – Cadmium toning

Used to convert purple Ninhydrin marks to an orange, fluorescent product. Cadmium salts are carcinogen 1B, Mutagen 1B, Reproductive hazard 1B, Acute toxicity 2, specific target organ toxicity (STOT) repeated exposure (RE) 1.

Nitric acid fuming

A selective etching process used to reveal marks on brass. Oxidising liquid 3, skin corrosion 1A.

O-tolidine

Used for developing marks in blood, producing dark blue marks. Carcinogen 1B, acute toxicity 4.

A selective etching process used to reveal marks on brass. Flammable gas 1, acute toxicity 2.

Osmium tetroxide

Used for detecting fats, producing a grey reaction product. Acute toxicity 1, skin corrosion 1B.

Hydrogen chloride fuming

Used to reveal marks on thermal papers. Developed marks are dark green. Acute toxicity 3, skin corrosion 1A.

Ruthenium tetroxide

Lead powder

A powdering process intended for use in conjunction with x-ray imaging. Reproductive hazard 1A, acute toxicity 4, specific target organ toxicity (STOT) repeated exposure (RE) 2.

Used for detecting fats, producing a dark grey reaction product. The toxicological properties have not been thoroughly investigated. However, it may be similar to osmium tetroxide (see above).

Selenic acid

Used for development of marks on metals. Acute toxicity 3, specific target organ toxicity (STOT) repeated exposure (RE) 2, skin corrosion.

Superglue wands

An uncontrolled method of generating superglue fumes. The high temperature of the heater may generate hydrogen cyanide which is acute toxicity 1 n

Mercury and chalk powder

Home Office January 2014

An early powdering technique producing grey marks that are visible on both light and dark surfaces. Mercury is acute toxicity 3, specific target organ toxicity (STOT) repeated exposure (RE) 2.

6.5.2

Fingermark Visualisation Manual

F Category F Processes

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

7 Integrating Forensic Processes Contents Ballistics...................................................................... 7.2 Body Fluids................................................................. 7.4 CCTV............................................................................ 7.6 Digital Forensics......................................................... 7.8 DNA............................................................................ 7.10 Documents................................................................ 7.12 Drugs......................................................................... 7.14 Fibres......................................................................... 7.16 Footwear Marks........................................................ 7.18 Glovemarks............................................................... 7.20 Hairs........................................................................... 7.22 Toolmarks.................................................................. 7.24 Trace Evidence......................................................... 7.26

Introduction

This chapter provides overviews of a number of evidence types to provide general information on the potential

synergies and incompatibilities between examination

and recovery processes for different types of forensic evidence. It is included in the Manual since it is

recognised that in addition to fingermarks, there may

be other types of forensic evidence (including some not included here) that need to be considered as part of an overall Forensic Evidence Recovery Strategy. Careful

planning may be needed to maximise evidence recovery, ideally in consultation with appropriate practitioners in their field. Consideration must be given to prioritising evidence recovery as part of the Forensic Evidence

Recovery Plan, as recovery processes for fingermarks or

other forensic evidence types are potentially disruptive to each other.

It is not possible to prescribe a definitive approach to

integrated forensic recovery because each situation is

important, e.g. swabbing first for DNA where an item is likely to have been handled.

Similarly, employment of fingermark visualisation

processes that are believed to be detrimental to other evidence types should be considered with caution,

especially if a number of processes are used in sequence where the effects may be magnified. Optical fingermark processes are usually non-destructive, but care needs

to be taken not to contaminate or damage other forensic evidence, e.g. molecular damage caused by high-

intensity light sources. Physical fingermark processes are generally non-destructive but deposits of trace

material such as powder and the physical nature of their

application may cause disruption to other evidence types. Chemical processes are generally more destructive and

may remove or disrupt other evidence types and as such

they will usually be used after all other evidence has been recovered n

unique. As seen in Chapter 2, strategic direction will be

governed by many factors including the requirements and priorities of the case, the need for preservation of certain forensic evidence types as well as local constraints.

However, practitioners should be aware that there may be published guidelines for some forensic disciplines, e.g. digital forensics, which may give firm advice.

The approach required for handling one type of evidence may be to the detriment or lead to conflict with another but may also be beneficial. Employment of forensic

recovery methods that may damage fingermarks should be avoided if evidence from fingermarks is considered

Home Office January 2014

7.1

Fingermark Visualisation Manual

Chapter 7: Integrating Forensic Processes

7.1

CH7

7.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of

ballistics evidence to personnel specialising in fingermark recovery. If considering ballistics evidence in addition to fingermarks, competent specialists must be consulted.

Overview

comparisons of cartridge cases and bullets may provide

to associate:

used at a number of incidents.

Ballistics covers a range of processes that may be used ●● a fired bullet or cartridge case with a particular

Transfer, recovery and analysis of gunshot residue

●● use of a particular firearm at a number of scenes;

Material that is characteristic of the ammunition used

firearm;

●● an individual with discharge of a firearm.

Analysis of firearms and fired bullets or cartridge cases The process of discharging a firearm results in the

production of markings on the cartridge casing and

striations on the bullet. These markings are produced as a result of features introduced during the processes of

skin and clothing of the individual firing the weapon, or the immediate surroundings of the firing. This material

is referred to as gunshot residue (GSR) and is primarily composed of the combustion products from the

propellant and primer compounds, which may be burnt or un-burnt.

GSR may be recovered from skin by swabbing or from

removed or added as a result of wear and damage

vacuum filters are then processed in order to extract and

acquired during use, thus also influencing the markings produced. Consequently, these markings have the

potential to be characteristic of a particular firearm. It may be possible to eliminate or associate involvement of a firearm by comparing the markings present on

cartridge cases and bullets produced during test firing with those recovered from scenes using high-power comparison microscopy. Similarly, scene-to-scene

Home Office January 2014

is ejected during firing and may be deposited upon the

firearms component manufacture and assembly which in themselves are variable. Features may also be changed, An array of fired bullet casings.

intelligence to indicate whether the same firearm was

clothing by taping or vacuuming. Swabs, tapes or

present GSR material in a suitable form for analysis.

Reference material obtained from fired cartridge cases, or in some cases the muzzle area of firearms, is also

analysed. Samples will need to be collected prior to any other evidence types.

Composition of recovered and reference GSR materials are then compared to establish if they could have a common origin.

7.2

Fingermark Visualisation Manual

Ballistics

7.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on Ballistics Evidence

●● Firearm must be made safe prior to examination. ●● Preservation of the fine detail in firing marks and

striations on bullets is essential for subsequent comparison.

●● Firearms must not be examined in the same laboratory

used to examine items which are required for GSR examination.

●● GSR can be fragile and is easily disturbed or removed

from the surface.

●● Recovery and analysis of GSR is highly susceptible to

contamination from other sources of GSR, in particular firearms and ammunition and other items, surfaces or

●● All fingermark visualisation processes are likely to be

detrimental to some degree to GSR recovery as it is

easily disturbed or removed. However, chemical and physical ones will be considerably more destructive to GSR than optical ones. See Trace Evidence for further details.

Effect of ballistics processes on fingermarks ●● Excessive handling of firearms or ammunition during

any examinations or test firings may damage or destroy fingermarks.

●● Swabbing the exterior of casings for GSR may

damage or destroy fingermarks.

personnel that may have been in contact with them.

Maximising fingermark and ballistic evidence

should be undertaken in a controlled environment

●● Prioritising evidence recovery as part of the Forensic

●● Examinations that may involve recovery of GSR

maintained and monitored to GSR standards with

appropriate precautions and control samples taken.

Ballistics and Fingermarks

Effect of fingermark processes on ballistics ●● Fingermark visualisation processes (optical) have

no impact on subsequent analysis of firearms or ammunition (excluding GSR recovery).

●● Some fingermark visualisation processes (chemical

and physical) can interfere with analysis of firearms or ammunition as they may lead to infilling of fine striation detail and affect the results of analysis.

Fingermark Visualisation Manual

Ballistics

Evidence Recovery Plan is important, as recovery

processes for both evidence types can negatively

impact on each other. The plan should be developed jointly by practitioners from both fields.

●● GSR is easily disturbed or removed; therefore, if it is

considered important, recovery should take place at

an early stage and prior to any fingermark visualisation processes.

●● It may be most possible for fingermark practitioners

to treat localised external areas only prior to firearms testing/dismantling n

They may also affect the condition, characteristics or mechanical function of firearms during subsequent test firing.

Home Office January 2014

7.3

7.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of body fluids evidence to

practitioners specialising in fingermark recovery. If considering body fluids evidence in addition to fingermarks, competent body fluid practitioners must be consulted. Body fluids are an important source of DNA. This page refers to other important information about body fluids, but not DNA as this is covered on its own page (see DNA).

Overview

The presence, location and distribution of

blood, semen, saliva or urine which

items are subjected to screening using an

Body fluids are varied in type and include are commonly encountered in forensic

casework. Their presence may be used to indicate support for the occurrence of an alleged activity or a particular pattern of events involving transfer of body fluids.

Recovery and analysis

The presence, distribution and location of body-fluid staining may in itself be significant, providing an initial step

towards recovery of DNA, and it is also a

medium for marks (fingermarks, footwear

and urine on a toilet seat (bottom) both viewed using Fluorescence Examination.

appropriate presumptive test for the body fluid in question. A presumptive test is a

chemical reaction between a reagent and certain components (chemical markers)

of the body fluid in question which results in a visible colour change. A positive

presumptive test is only an indication that the body fluid is present and will

need to be supported or confirmed by

other means, either visually or by further testing.

marks, glovemarks etc.). Information as to

Where fine detail is required (e.g. ridge

be derived from blood pattern analysis

within footwear marks) Acid Dyes are

how blood may have been deposited can Semen on a pair of pants (top)

staining may only become apparent when

(BPA) of the staining present.

The presence of body fluids may

be observed visually (using Visual Examination or Fluorescence

Examination), though this is dependent

upon the amount of material present and there being sufficient contrast between

the staining and the underlying substrate. Stains of non-body-fluid origin may

detail within fingermarks, or fine detail often used as they fix protein in body

fluids such as blood, and so retain the

level of detail required for comparison.

Other fingermark visualisation processes (such as Ninhydrin or DFO) also target amino acids in blood. As with the

presumptive tests describe above, these processes also do not identify the body fluid.

© See Photo Credits

also appear or act indistinguishably.

Because of this, body-fluid stains cannot be identified positively by visual means alone.

Home Office January 2014

7.4

Fingermark Visualisation Manual

Body Fluids

7.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on Body Fluids Evidence

●● Body fluids are a good source of DNA and measures

must be taken to ensure that it is preserved if considered important (see DNA).

●● Chemical markers within body fluids responsible for

giving a positive response to presumptive testing must be preserved.

●● Details of the location, size, shape and pattern of

distribution of body-fluid stains should be preserved and recorded as these factors may be of major importance to an investigation.

Body Fluids and Fingermarks

Effect of fingermark processes on body fluids (excluding DNA) ●● Fingermark visualisation processes (optical) have no

impact on presumptive tests or BPA and may have a role to play in visualising stains/marks/spatter.

Fingermark Visualisation Manual

Body Fluids ●● Searching for BPA using Visual or Fluorescence

Examination will not impact on fingermarks and these processes can also be used to visualise fingermarks.

Maximising fingermark and body-fluid evidence ●● Prioritising evidence recovery as part of the Forensic

Evidence Recovery Plan is important, as recovery

processes for both evidence types can negatively

impact on each other. The plan should be developed jointly by practitioners from both fields.

●● Optical processes can be used for both visualising

fingermarks and finding BPA or other staining and a joint examination could be considered.

●● Where there is possible ridge detail in blood,

consideration must be given to the interpretation

of how the mark was made by consultation with a specialist in blood marks interpretation n

●● Fingermark visualisation processes (chemical and

physical), may remove or damage body fluids and

potentially impact on presumptive testing results (such as Kastle Mayer) or BPA. For example, liquid-based processes may remove, dilute, diffuse or damage

body fluids, although Acid Dyes are designed to fix proteins within blood to the surface.

Effect of presumptive testing and BPA on fingermarks ●● Use of screening tests and sampling for the purposes

of presumptive testing of body fluids has the potential to damage or remove fingermarks.

Home Office January 2014

7.5

7.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of CCTV evidence to practitioners specialising in fingermark recovery. If considering CCTV evidence in addition to fingermarks, competent CCTV practitioners must be consulted.

Overview

Once extracted, CCTV evidence

CCTV systems may contain valuable

various ways, for example by applying

Images or recordings obtained from

information. CCTV evidence may be used to corroborate accounts or confirm the time and location of specific events.

Recovery and analysis

Data may be preserved on video tape or on an electronic recording medium

(e.g. internal computer hard drive) which may be overwritten after a set period of time. For this reason, relevant data will

caused by motion. Processes such as photogrammetry can provide details

including the dimensions of features or an estimation of the height of an individual. However, these processes may not be

usable if the original imagery is of poor quality.

video systems, this may be a case of

images that may be used for identification

digital recording systems will require

the relevant section of the recording to be downloaded to a portable medium

(bottom).

algorithms to remove the effect of blur

Subsequent analysis of footage can yield

recovering the appropriate tape. However,

and CCTV footage on-screen

image sharpening tools or use of

need to be extracted from the system within the appropriate timeframe. For

A CCTV camera in-situ (top)

can be processed and analysed in

such as CD/DVD or USB hard drive/

stick. Where, as is often the case, the system owner is not a suspect in the

investigation, it may be appropriate to

ask them (or their security maintenance

provider) in the first instance to download the footage themselves onto portable

significant information, such as facial

purposes, vehicle registration marks and characteristic features such as logos on clothing.

In the context of other forensic evidence, CCTV may enable searches to be targeted, for example fingermark

recovery by identifying those surfaces

touched by an individual, or recovery of

DNA by identifying the location where an individual has spat.

storage media, which will then become the Master evidence.

Home Office January 2014

7.6

Fingermark Visualisation Manual

CCTV

7.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on CCTV Evidence

●● If CCTV evidence is to be recovered from a scene, it

is important to also note the make and model of the recorder, as this may be needed in order to identify the appropriate replay software.

●● The displayed time and date on the CCTV recorder

should also be checked and compared with the speaking clock, with any offset noted.

●● The data should be retrieved in their native file format.

This will ensure that image quality is maintained and

any information contained within the footage such as

Fingermark Visualisation Manual

CCTV CCTV and Fingermarks

Unless activity involving tampering with CCTV recording equipment has taken place, fingermark and CCTV processes are unlikely to impact on each other.

Maximising fingermark and CCTV evidence ●● Based on observation of footage indicating areas

likely to have been touched, CCTV evidence may be used to target surfaces for fingermark recovery.

●● CCTV evidence may also be used to indicate those

locations most appropriate for recovery of other types of forensic evidence n

internal clock, soundtrack, metadata, camera identifier or GPS location is retained.

●● The media containing the downloaded imagery should

be handled according to established procedures

to maintain the evidential integrity, and should be

packaged appropriately to minimise the likelihood of damage in transit.

Home Office January 2014

7.7

7.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of

digital forensics evidence to practitioners specialising in fingermark recovery. If considering digital forensics evidence in addition to fingermarks, competent digital forensics practitioners must be consulted.

Overview

information of dates and times of events such as file

captured, processed or retained in digital format.

an investigation.

Digital forensics covers a variety of evidential material Material may encompass documents, images, video

footage, emails, text messages, call logs and system

data. Storage media may include computer hard drives,

mobile phones, SIM cards, memory cards or sticks, CDs and DVDs.

Recovery and analysis

The extraction of data from digital devices requires the use of specialist equipment and software by trained practitioners in order that data are not subject to

alteration or corruption. Such equipment and software

may also be capable of recovering data that have been deleted.

The information contained within electronic files and/or

the metadata associated with those files detailing historic

creation, modification or saving may be of importance to The traditional approach to digital forensics was to

power-off devices upon seizure and rely solely upon

subsequent data extraction at the lab. However, there

is now a greater need to perform some live analysis at

the scene (to triage/filter for responsive devices and to gather highly volatile information such as encryption

keys, running processes and network connections). It is

important that fingermark practitioners are made aware if this has taken place.

The data extracted may be used to provide evidence including trails of communication, verification of the time and place an event may have taken place and

possession or distribution of offensive or prohibited material.

A range of mobile phones (top) and the inside of a mobile phone showing the SIM card (bottom). Home Office January 2014

7.8

Fingermark Visualisation Manual

Digital Forensics

7.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on Digital Forensics Evidence

●● Information contained within the files together

with any other data associated with them such as

metadata or times of access/modification must be preserved.

●● Storage media should be handled according to

established procedures to maintain the evidential

integrity, and should be packaged appropriately to minimise the likelihood of damage in transit.

●● Communications devices should be isolated from their

network and may require a Faraday environment to prevent modification of stored data.

Digital Forensics and Fingermarks Effect of fingermark processes on digital forensics ●● Fingermark visualisation processes (optical) are

generally not detrimental to digital forensics evidence. Magnetic storage media are probably not going to be

affected, but optical storage media (CD/DVD/Blu-Ray) could be susceptible to damage/alteration under high intensity or UV radiation.

●● Some fingermark visualisation processes (chemical

and physical) have the potential to affect electrical

contacts and circuitry. They may also affect readability of CDs and DVDs by deposition of material on to disc surfaces or separation of storage layers. Lifting is likely to be non-destructive.

Home Office January 2014

Fingermark Visualisation Manual

Digital Forensics Effect of digital forensics processes on fingermarks ●● Excessive handling of items for the purposes of

extracting data or removing components may damage or destroy fingermarks.

Maximising fingermark and digital forensics evidence ●● Prioritising evidence recovery as part of the Forensic

Evidence Recovery Plan is important, as recovery

processes for both evidence types can negatively

impact on each other. The plan should be developed jointly by practitioners from both fields.

●● Provided that all necessary handling precautions

are taken during the examination, it may be possible for data to be recovered from devices without compromising fingermarks.

●● If there is a requirement to obtain information

regarding the user of a device prior to data recovery, then the item may be examined for the presence of visible fingermarks using suitable fingermark

visualisation processes, typically optical processes or Lifting (note: Lifting may impact on the effectiveness of subsequent fingermark visualisation processes).

●● More destructive fingermark visualisation processes

(most chemical and physical ones) should only be attempted once the avenues afforded by the less

destructive processes have been exhausted and the digital evidence has been extracted successfully n

7.9

7.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of DNA evidence to practitioners

specialising in fingermark recovery. If considering DNA evidence in addition to fingermark evidence, competent DNA practitioners must be consulted.

Overview

Some background material will occur

and is found within cells of all people,

however, steps should be taken to

DNA contains genetic information

animals, plants, and other organic

matter. With the exception of identical twins, DNA is unique to an individual,

making it particularly useful in criminal investigations.

during the examination process. To this end, examinations that may involve

recovery of DNA should be undertaken in a DNA-controlled environment with appropriate precautions and control

the form of skin cells transferred as a

Swabs or tapes are processed in order

components of body fluids such as

material in a suitable form and quantity

result of handling or within the cellular blood, semen or saliva. The root of shed hair is also a source of DNA commonly encountered in forensic casework.

Recovery

Material containing DNA can be

recovered from surfaces upon which it

samples being taken.

to extract and present DNA-containing for analysis. The result of analysis is a

DNA profile. This is not a representation

of the entire genetic information available but rather a series of ‘snapshots’ of

specific areas of DNA known to exhibit variation between individuals.

has been deposited using processes

DNA profiles may be compared with

In some cases the area of interest on the

individuals known to have been involved

such as wet or dry swabbing and taping. item is cut out and recovered.

Analysis

Recovery and analysis of DNA is

highly susceptible to contamination by

introduction of DNA from other sources.

Home Office January 2014

prevent introduction of additional material

Transfer

DNA-containing material may be in

A practitioner swabbing a surface for DNA analysis.

naturally on items and cannot be avoided;

reference profiles obtained from

within a given scenario, or where there are no established links, compared

with profiles pertaining to individuals or unsolved crime stains held on the National DNA Database.

7.10

Fingermark Visualisation Manual

DNA

7.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on DNA Evidence ●● DNA material can be fragile and easily removed from

the surface.

●● Recovery and analysis of DNA is highly susceptible to

contamination. Appropriate DNA precautions, controls and anti-contamination measures must be in place to

Maximising fingermark and DNA evidence

●● Prioritising evidence recovery as part of the Forensic

Evidence Recovery Plan is important, as recovery

processes for both evidence types can negatively

impact on each other. The plan should be developed jointly by practitioners from both fields.

ensure the integrity of the DNA profile.

●● If possible DNA should be sampled from areas not

preserved in order that profiles can be obtained.

●● All fingermark visualisation processes can be used

●● Genetic information contained within DNA must be

DNA and Fingermarks

Effect of fingermark processes on DNA ●● Fingermark visualisation processes (optical) are

generally non-destructive to DNA though high

intensity or UV radiation may cause damage even for limited exposures.

●● Fingermark visualisation processes (chemical and

physical) may have an impact on the ability to obtain

a usable DNA profile. In most cases, it is unclear if this

Fingermark Visualisation Manual

DNA

suitable for fingermark recovery if done first.

to locate areas of contact for targeted DNA recovery.

Optical processes may be suitable for this purpose as they are typically non-destructive to DNA (see above) although they are normally not the most effective

at visualising contact areas. If chemical or physical

processes are used prior to DNA recovery, only one process should be used to minimise loss of DNA

evidence. In this case, the most effective process for the substrate should be used n

impact is a result of removal, dilution or damage to DNA.

●● Reagents and equipment used during fingermark

examinations are potential sources of DNA contamination.

Effect of DNA processes on fingermarks ●● Swabbing (both wet and dry) over a fingermark is

highly likely to damage or remove it completely.

●● Taping may lead to partial or complete removal

of fingermarks or result in deposition of residues on surfaces which may interfere with fingermark visualisation processes.

Home Office January 2014

7.11

7.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of document evidence to

practitioners specialising in fingermark recovery. If considering document evidence in addition to fingermarks, competent document practitioners must be consulted.

Overview

is genuine or a forgery. Inks may also

of processes that may be used to

analytical processes may be used to

Document examination covers a variety establish:

●● the original content of a document

where text has been altered or obscured;

●● whether documents are authentic or

forgeries;

●● the presence, extent and content of

indented writing;

●● if handwriting may be attributable to a

particular individual;

●● if printed or typed documents are

attributable to a particular machine.

Analysis

Examination of documents under sources of illumination of various wavelengths A cheque viewed using Visual Examination

(top) and IR Reflection

(bottom).

in the visible, ultraviolet and infrared

regions of the electromagnetic spectrum may visualise differences between

absorbance and reflectance properties of inks revealing altered or obscured

text. Differences in the behaviour of inks, paper and security features may also be

useful in determining whether a document

Home Office January 2014

be compared by chromatography. Other compare compositions of paper or other materials.

Physical pressure applied to writing

implements may transfer indentation

of the text written to underlying sheets of paper. Such text may be visualised by application of oblique lighting, gel

lifting or development using electrostatic document analysis (ESDA).

The potential for handwriting to be attributed to an individual may be

assessed by comparing features such as the style, formation and shape of

characters comprising handwriting in

a questioned document with reference samples of handwriting made by that individual.

Printed or typed documents may be attributed to a particular machine

by examination and comparison of

characteristic features, for example, typeface defects.

7.12

Fingermark Visualisation Manual

Documents

7.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on Document Evidence

●● Actual or indented text and the composition of inks

and papers must be preserved if considered important for document analysis.

Documents and Fingermarks

●● Gel lifting has the potential to remove, partially

remove or damage fingermarks and impact on more productive subsequent fingermark visualisation processes.

●● Sampling of ink and paper for analysis may lead to

damage or destruction of fingermarks.

Effect of fingermark processes on documents

Maximising fingermark and document evidence

●● Fingermark visualisation processes (optical) are

●● Prioritising evidence recovery as part of the Forensic

unlikely to have any adverse effect on document evidence and some may assist with document analysis.

●● Fingermark visualisation processes (chemical and

physical) have the potential to cause damage or loss of text, by obliteration or leaching or diffusion of inks

and may affect the result of analysis of inks and paper, through removal or addition of chemical components. They may also prevent the subsequent recovery of indented writing.

Effect of document processes on fingermarks

Fingermark Visualisation Manual

Documents

Evidence Recovery Plan is important, as recovery

processes for both evidence types can negatively

impact on each other. The plan should be developed jointly by practitioners from both fields.

●● It is unlikely that optical processes used for either

fingermark or document evidence will impact on each other and so these processes should be considered

early on or as part of a joint examination prior to more destructive processes.

●● If documents are to be examined prior to fingermark

examinations, handling must be kept to a minimum n

●● Inappropriate handling of documents may be

detrimental to fingermarks.

●● The wide range of optical processes used for

document analysis are unlikely to have any adverse effect on fingermarks and some may assist with fingermark visualisation.

●● ESDA is a process primarily used to examine

documents for indented writing, but it can also be

used to visualise fresh or heavy fingermarks. However, pre-humidification greater than 80% relative humidity will degrade fingermarks and should not be used. Home Office January 2014

7.13

7.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of drugs evidence to practitioners

specialising in fingermark recovery. If considering drugs evidence in addition to fingermarks, competent drugs practitioners must be consulted.

Overview

Recovery

substance which is controlled by the

packaging material. The item is recovered

An illicit drug is defined in the UK as any Misuse of Drugs Act 1971. Drugs can

be encountered as tablets, powders and liquids and often as mixtures which may contain other controlled drugs, cutting

agents and adulterants. Samples of illicit drugs can be encountered in a range of

different packaging materials which can be used to provide links between drug

seizures, people and places through the

packaging be used for further forensic investigations.

Trace drug contamination is usually

recovered from surfaces upon which it has been deposited using processes

such as wet or dry swabbing and taping.

with it.

forensic chemist will carry out to analyse

a sample contains a controlled drug

until it has been sent to a forensic drugs

laboratory for identification. If a sample is suspected to contain a controlled drug it should not be opened or tampered with

drugs wrap (bottom).

that the drug can be analysed and the

Analysis

It is not possible to determine whether

drugs wraps (top) and a cling film

to a suitable facility for decanting so

analysis of DNA, fingerprints and any

clothing fibres which may be associated

A selection of brown parcel tape

Drugs are normally recovered encased in

before it arrives at the forensic laboratory. Trace drug contamination, for example on bank notes, can also provide intelligence

There are a number of steps that a

a substance and these depend on what information is required. Most drugs

samples, however, can be analysed and quantified using GC-MS; more complex samples may require further analysis by

alternative techniques such as NMR and HR- LC-MS.

See DNA and Trace Evidence for more information on these evidence types.

information on the sample. Again, it is essential that any seizure expected to

contain drug contamination is not altered in any way.

Home Office January 2014

7.14

Fingermark Visualisation Manual

Drugs

7.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on Drugs Evidence

●● The composition of the suspect drug(s) must be

●● Any further contamination of the packaging with

the contents may inhibit subsequent fingermark visualisation processes.

preserved for analysis.

●● Swabbing (both wet and dry) over a fingermark is

packaging itself should be treated as a contaminated

●● Taping may lead to partial or complete removal

●● Once the drug is removed from the packaging, the

item as outlined in this Manual.

●● Trace drug evidence can be fragile and easily removed

from the surface.

●● Recovery and analysis of drug evidence (particularly

trace evidence) is highly susceptible to contamination. Ensure the integrity of drug evidence by taking appropriate precautions, controls and anticontamination measures.

Drugs and Fingermarks

Effect of fingermark processes on drugs

●● Fingermark visualisation processes (optical) are not

detrimental to subsequent drugs examination and analysis.

●● Fingermark visualisation (chemical and physical)

processes may permeate drugs packaging,

contaminate content and affect subsequent analysis and/or remove or damage trace drug evidence.

They may also change the properties of the drugs packaging (colour, appearance, size, distortion,

rigidity, loss of fine detail etc.) and affect subsequent comparisons of materials.

Fingermark Visualisation Manual

Drugs

highly likely to damage or remove it completely.

of fingermarks or result in deposition of residues on surfaces which may interfere with fingermark visualisation processes.

Maximising fingermark and drug evidence

●● Prioritising evidence recovery as part of the Forensic

Evidence Recovery Plan is important, as recovery

processes for both evidence types can negatively

impact on each other. The plan should be developed jointly by practitioners from both fields.

●● Fingermark visualisation processes (optical) may be

used to examine surfaces of unopened packages of drugs material prior to drug removal.

●● If possible, trace drug evidence should be sampled

from areas not suitable for fingermark recovery if done first.

●● It is important that forensic providers, if removing

packaging for subsequent fingermark processing,

inform the fingerprint laboratory which is the inside and which is the outside of the packaging and if in layers, what is the sequence n

Effect of drug recovery on fingermarks

●● Any contact with or damage made to the packaging

or surface whilst removing the drugs may lead to damage or removal of fingermarks.

Home Office January 2014

7.15

7.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of fibre evidence to practitioners

specialising in fingermark recovery. If considering fibre evidence in addition to fingermarks, competent fibres practitioners must be consulted.

Overview

microscopy in order to locate fibres of

Textile fibres may be transferred from

reference sample taken from the relevant

Transfer

fabrics to other surfaces. Transfer may

occur by direct contact or indirectly by

transfer to and then from an intermediate surface. The mechanism of transfer is complex and has many contributing factors including:

●● the ability of a donor fabric to shed its

component fibres;

●● the quantity of fibres involved;

●● the force and duration of contact;

A piece of fabric view using

Visual Examination (top) and Fluorescence Examination (bottom).

●● the ability of a recipient surface to

receive and retain transferred fibres;

●● the time elapsed since contact

occurred.

Recovery

Optical processes, including the use of

magnification or low power microscopy,

are valuable in searching for and locating fibres. Some fibres may be seen easily whilst others are invisible to the eye.

similar appearance to those present in a item.

Analysis

Target fibres are removed from the tape and mounted on microscope slides.

These fibres are subjected to a series of further tests that may include:

●● high power microscopy to assess

structural and comparative features including colour and appearance

under white light and fluorescence;

●● microspectrophotometry for analysis

and comparison of colour;

●● thin layer chromatography to compare

dye components;

●● infrared spectroscopy in order to

determine the precise composition of synthetic fibres.

See Trace Evidence and Hairs for more information on these evidence types.

As with Hairs, fibres can be recovered

individually by picking from surfaces with

forceps, or recovered by taping surfaces. Tapes are examined using low power

Home Office January 2014

7.16

Fingermark Visualisation Manual

Fibres

7.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on Fibre Evidence ●● Fibre evidence can be fragile and easily removed from

the surface.

●● Fibres must be retained on the surface in an unaltered

condition for recovery. The location of fibres may be of relevance for interpretation purposes.

●● Recovery and analysis of fibre evidence is highly

susceptible to contamination. Ensure the integrity

of fibre evidence by taking appropriate precautions, controls and anti-contamination measures.

Fibres and Fingermarks

Effect of fingermark processes on fibres

●● Providing that handling is minimised and adequate

anti-contamination measures are taken, fingermark visualisation processes (optical) are unlikely to be

detrimental to fibres and may have a role to play in visualising it.

Fingermark Visualisation Manual

Fibres Maximising fingermark and fibre evidence

●● Prioritising evidence recovery as part of the Forensic

Evidence Recovery Plan is important, as recovery

processes for both evidence types can negatively

impact on each other. The plan should be developed jointly by practitioners from both fields.

●● Fibres are easily displaced and therefore recovery is

of paramount importance. Undertake fibre evidence recovery prior to application of any potentially

destructive fingermark visualisation processes.

Fingermark visualisation processes (optical) may

assist provided anti-contamination measures are in place.

●● Taping to recover fibres should not be used on areas

suitable for fingermark recovery, unless agreed in the

Forensic Evidence Recovery Plan developed jointly by practitioners from both fields n

●● Fingermark visualisation processes (chemical and

physical) are potentially destructive to fibre evidence as they may: ■■ ■■

remove or disturb fibres;

change fibres irrecoverably by affecting

appearance, colour and/or colour fluorescent properties; ■■

affect the results of further analysis.

Effect of fibre recovery on fingermarks

●● Taping may lead to partial or complete removal of

material in which fingermarks have been formed or

result in deposition of residues on surfaces which may interfere with fingermark visualisation processes.

Home Office January 2014

7.17

7.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of footwear evidence to practitioners specialising in fingermark recovery. If considering footwear evidence in addition to fingermarks, competent footwear practitioners must be consulted.

Overview

are many other reported optical, chemical and

Contact between footwear soles and surfaces

mark recovery.

Transfer

may result in the formation of footwear marks.

These may be encountered as: positive marks,

where material adhering to the sole is deposited upon a surface; negative marks, where material present upon a surface is removed by contact

with the sole; or impressed marks, which result

from contact with soft, deformable surfaces such as mud, soil and snow.

Recovery

Many fingermark processes also have

applications in the visualisation of footwear marks. However, the majority of footwear

marks are either imaged directly on the surface (using lighting conditions as outlined in Visual

Examination), or recovered via Lifting (gelatin is normally the most effective lifting material).

physical processes that can be used for footwear

Analysis

Footwear marks may provide valuable

intelligence and be identified by searching and

comparing with footwear databases containing sole pattern types and other information such

as upper styles and colours. Information may be searched by manufacturer, footwear type or the shape and location of various pattern features present on the sole. Information derived from

databases may provide links between scenes

where similar patterns have been encountered. Bubbles or other moulding defects present on soles, though providing useful points of

comparison, are not unique as they may occur on any number of similar items of footwear.

Powders is also commonly used. Chemical

As footwear is worn, the soles will wear

unless the footwear marks are in blood in which

damage. The resulting degree and distribution

processes are not used extensively at present case Acid Dyes are effective. There are also

some processes that are specific to footwear mark recovery, the most common being:

electrostatic lifting for marks in dust; casting

for impressed marks; and haem reagents (e.g. luminol) for footwear marks in blood. There

progressively and in the process acquire random of wear along with the number and location of

damage features present have the potential to be characteristic and form the basis for comparison with footwear marks.

The footwear itself may be a useful source of DNA evidence.

A footwear impression in snow (top) and a footwear mark recovered using electrostatic lifting apparatus (ESLA) (bottom). Home Office January 2014

7.18

Fingermark Visualisation Manual

Footwear Marks

7.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on Footwear Mark Evidence

●● Non-destructive optical processes can be used to search for both fingermarks and

●● Some footwear marks are fragile and easily damaged. Recovery processes must

●● Fragile footwear marks (or less commonly fingermarks) in dust must be recovered at

●● Footwear patterning and any fine detail must be preserved.

minimise the risk of rubbing, abrasion, diffusion of transferred material or distortion of any features present.

Footwear Marks and Fingermarks

Effect of fingermark processes on footwear marks

●● Fingermark visualisation processes (optical) are unlikely to have any adverse effect

footwear marks prior to use of more destructive processes. an early stage and prior to more destructive processes.

●● Preservation of evidence by targeted application of appropriate chemical or physical

processes to specific areas should be considered. This is of particular importance where the effects of specific treatments on footwear marks or fingermarks are not known n

on footwear marks and some can be used to search for them.

●● Some fingermark visualisation processes (chemical and physical) may damage or

remove footwear marks whilst other may enhance them.

●● As for fingermarks, the degree of damage will be dependent upon the properties of

the footwear mark and the process mechanism and there are a lot of similarities with fingermarks as outlined in Chapter 2.

Effect of footwear mark processes on fingermarks

●● It is unlikely that electrostatic lifting will have any adverse effect on fingermarks,

although this will depend upon the nature of the fingermark and its ability to resist smudging or removal by the application of a charged sheet.

●● Lifting has the potential to remove, partially remove or damage fingermarks.

●● Other footwear mark visualisation processes (chemical or physical) may lead to

damage by leaching or diffusion or removal of the material in which fingermarks have been formed.

Maximising fingermark and footwear mark evidence

●● Prioritising evidence recovery as part of the Forensic Evidence Recovery Plan is

important, as recovery processes for both evidence types can negatively impact on each other. The plan should be developed jointly by practitioners from both fields.

●● Both evidence types have a lot in common in terms of recovery and the principles

outlined in Chapter 2 for fingermarks also apply to footwear marks. In order to

maximise potential for both evidence types, examination and recovery must be staged carefully.

Home Office January 2014

7.19

Fingermark Visualisation Manual

Footwear Marks

7.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of glovemarks evidence to

practitioners specialising in fingermark recovery. If considering glovemarks evidence in addition to fingermarks, competent glovemark practitioners must be consulted.

Overview

Analysis

Gloves are often worn to prevent

intelligence. Features such as patterning

Transfer

deposition of fingermarks. Glovemarks are closely related to fingermarks in

that they are deposited by contact with surfaces or handling of items. These

may be encountered as: positive marks, where material adhering to the glove

is deposited upon a surface; negative marks, where material present upon

a surface is removed by the glove; or impressed marks, which result from

contact with soft, deformable surfaces.

Recovery

Many fingermark processes also have applications in the visualisation of

glovemarks. In practice glovemarks

tend to be found whilst searching for fingermarks rather than a targeted

glovemark search and so Powders is one

of the most productive processes. There has been limited research in using other processes to visualise glovemarks.

Glovemarks may provide valuable

may be used to identify basic types of

glove such as knitted, rubber or industrial, enabling links to be established between

scenes where similar patterns have been encountered.

As gloves are worn, the contact surfaces of the fingers and palms will wear and

acquire random damage. The degree and

distribution of wear, creasing, the number and location of any damage features

present and patterning on natural leather has the potential to be characteristic

and forms the basis for comparison with glovemarks. Moulding defects in rubber glove patterning and surface patterning in synthetic leather materials, though

providing useful points of comparison,

are not unique as they may occur on any number of similar gloves.

The gloves themselves may be a useful

source of DNA evidence and fingermarks.

An example of a glove (top) and a glovemark enhanced with Powders (bottom). Home Office January 2014

7.20

Fingermark Visualisation Manual

Glovemarks

7.21

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Fingermark Visualisation Manual

Glovemarks Important Notes on Glovemark Evidence ●● Glovemark patterning and any fine detail must be preserved.

●● Glovemarks can be fragile and easily damaged. Recovery processes must minimise

the risk of rubbing, abrasion, diffusion of transferred material or distortion of any

features present. Some chemical and physical fingermark processes may damage or remove glovemarks whilst other may enhance glovemarks.

Glovemarks and Fingermarks

Effect of fingermark processes on glovemarks

●● Fingermark visualisation processes (optical) are unlikely to have any adverse effect

on glovemarks.

●● Some fingermark visualisation processes (chemical and physical) may damage or

remove glovemarks whilst others may enhance them.

●● As for fingermarks, the degree of damage will be dependent upon the properties of

the glovemark and the process mechanism and there are a lot of similarities with fingermarks as outlined in Chapter 2.

Effect of glovemark recovery on fingermarks

●● There are no processes that specifically target glovemarks and they are normally

found using fingermark visualisation processes.

Maximising fingermark and glovemark evidence

●● Glovemarks recovery is rarely targeted in preference to fingermark recovery. In any

case, fingermark processes would be used for both types of evidence n

Home Office January 2014

7.21

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

7.22

Contents

Appendices

Glossary

Index

Note: This page gives an awareness of hair evidence to practitioners

specialising in fingermark recovery. If considering hair evidence in addition to fingermarks, competent hair practitioners must be consulted.

Overview

Target hairs are mounted on microscope

Hairs are shed naturally over time; they

series of further tests that may include

Transfer

may also be shed as a result of breakage or application of force. Although in

general larger than textile fibres, the

mechanism for transfer to other surfaces is by similar means. See Fibres for more

detail.

Recovery

Optical processes at visible wavelengths, including the use of magnification or

low power microscopy, are valuable in searching for and locating hairs. Hairs

may be seen easily and are sufficiently large to be recovered individually by Hair trapped on fabric (top) and a

magnified image of a strand of hair (bottom).

picking from surfaces with forceps.

As for textile fibres, hairs may also be recovered by taping surfaces. Tapes are then examined under low power

microscopy in order to locate hairs of

similar appearance to those present in a reference sample.

Analysis

Hairs may be of human or animal origin. They may be differentiated by further

examination of structural characteristics

such as root and medulla profiles and the pattern of scales on the hair surface that may be indicative of particular species.

Home Office January 2014

slides. These hairs are subjected to a

measurement of length and high power microscopy to assess:

●● structural features such as root and

medulla profiles, scale patterning and measurement of hair and medulla diameters;

●● comparative features such as

appearance and colour.

Due to the range of natural variation

present within reference samples and limitations in the variety of hair types and colours across populations, hair

evidence provided by comparison alone cannot be unique. However, hairs are a

valuable source of DNA. Those that have been shed with roots and associated

cellular material may provide full DNA

profiles. Where there is no root material

present and it is of sufficient importance to an investigation, DNA evidence may

still be obtained from hair shaft material using the specialised technique of Mitochondrial DNA.

See Trace Evidence, Fibres and DNA

for more information on these evidence types.

7.22

Fingermark Visualisation Manual

Hairs

7.23

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on Hair Evidence

■■

●● Hair evidence can be fragile and easily removed from

container during powdering); ■■

condition for recovery. The location of hairs may be of relevance for interpretation purposes.

●● Hairs provide a valuable potential source of DNA.

Ensure the integrity of profiling results by taking

appropriate DNA precautions, controls and anticontamination measures.

●● Recovery and analysis of hair evidence is highly

susceptible to contamination. Ensure the integrity

of hair evidence by taking appropriate precautions, controls and anti-contamination measures.

Hairs and Fingermarks

Effect of fingermark processes on hairs

●● Providing that handling is minimised and adequate

anti-contamination measures are taken, fingermark visualisation processes (optical) are unlikely to be

detrimental to hair evidence (although some may be damaging to DNA within hair – see DNA for details) and may have a role to play in visualising it.

●● Fingermark visualisation processes (chemical and

physical) are potentially destructive to hair evidence as they may: ■■ ■■

remove or disturb hairs;

alter the appearance of hairs for the purposes of microscopy;

■■

contaminate the hair evidence with shed hair from natural animal hair brushes used during

add or transfer DNA material (for example, by repeated use of the same brush and powder

the surface.

●● Hair must be retained on the surface in an unaltered

Fingermark Visualisation Manual

Hairs

damage DNA-bearing material associated with hair roots;

■■

change hairs irrecoverably by affecting appearance and/or colour.

Effect of hair recovery on fingermarks

●● Taping may lead to partial or complete removal of

material in which fingermarks have been formed or

result in deposition of residues on surfaces which may interfere with fingermark visualisation processes.

Maximising fingermark and hair evidence

●● Prioritising evidence recovery as part of the Forensic

Evidence Recovery Plan is important, as recovery

processes for both evidence types can negatively

impact on each other. The plan should be developed jointly by practitioners from both fields.

●● Hairs are easily displaced and therefore recovery is

of paramount importance. Undertake hair evidence recovery prior to application of any potentially

destructive fingermark visualisation processes.

Fingermark visualisation processes (optical) may

assist provided anti-contamination measures are in place.

●● Taping to recover hairs should not be used on areas

suitable for fingermark recovery, unless agreed in the

Forensic Evidence Recovery Plan developed jointly by practitioners from both fields n

powdering;

Home Office January 2014

7.23

7.24

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of toolmark evidence to practitioners specialising in fingermark recovery. If considering toolmark evidence in addition to fingermarks, competent toolmark practitioners must be consulted.

Overview

Recovery

The result of contact between a tool and a

or cast with flexible materials such as silicone

Creation

surface is a toolmark. These may be presented

in several forms depending upon the tool and the action used.

Levers such as crowbars and screwdrivers may

leave an impression of the tip when used to force items open. The action used will result in two

toolmarks, one in the surface into which the tip of the tool is forced and the second in the surface against which another part of the tool is acting. The blades of cutting tools with a shearing

action such as snips, bolt or cable cutters may

leave fine striations in cut surfaces arising from imperfections or grinding detail on the blade

edges. In some cases where the cutting edges of blades have been chipped or scalloped with use,

these imperfections may appear as characteristic

Toolmarks are normally imaged directly and/ compounds.

Analysis

Toolmarks may provide intelligence regarding the type of tool used and where applicable,

dimensions such as tip width or drill bit diameter. This information may be used to establish if

similar tools have been used at a number of

scenes providing a link. As tools are used, cutting edges and tips will wear and acquire random

damage. The degree and distribution of damage present will produce a pattern of striations

that has the potential to be characteristic. This forms the basis of comparison with test marks produced from tools. Scene and test marks

are compared using high power comparison microscopy.

features in resulting toolmarks. Drill bits may

As tools are brought into forceful contact with

as a result of imperfections or grinding detail on

Evidence such as impacted paint and fragments

leave full or partial circular striation marks, again the cutting edges. The most detailed of this type of toolmark arises from the initial or attempted cuts into a smooth surface such as painted wood.

other items it should be borne in mind that Trace or smears of metals or other materials such

as plastic insulation from cables may also be present.

A selection of tools (top) and toolmarks on a lock (bottom). Home Office January 2014

7.24

Fingermark Visualisation Manual

Toolmarks

7.25

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on Toolmark Evidence

●● Fine detail within toolmarks must be preserved and

captured to enable comparison.

●● Damage to tools and any Trace Evidence that may be

present must be preserved.

Toolmarks and Fingermarks Effect of fingermark processes on toolmarks

●● Fingermark visualisation processes (optical) are

unlikely to have any adverse effect on toolmarks.

Fingermark Visualisation Manual

Toolmarks Maximising fingermark and toolmark evidence ●● Prioritising evidence recovery as part of the Forensic

Evidence Recovery Plan is important, as recovery

processes for both evidence types can negatively

impact on each other. The plan should be developed jointly by practitioners from both fields.

●● Use of non-destructive fingermark visualisation

processes may permit location of fingermarks prior to application of more destructive visualisation processes or production of test marks n

●● Some fingermark visualisation processes (chemical

and physical) may damage toolmarks by either infilling fine striation detail or causing swelling by absorption of liquid into porous surfaces such as wood.

●● Some fingermark visualisation processes (chemical

and physical) are also potentially destructive to Trace Evidence that may be present.

Effect of toolmark processes on fingermarks ●● Silicone-based casting materials used to produce

casts of toolmarks for recovery have a limited

use in lifting fingermarks. In most cases, use of

these materials may result in partial or total loss of fingermark detail.

●● Excessive handling during examination of tools and

production of test marks from them may result in damage or loss of fingermark detail.

Home Office January 2014

7.25

7.26

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Note: This page gives an awareness of trace evidence

to practitioners specialising in fingermark recovery. If considering trace evidence in addition to fingermarks, competent trace evidence practitioners must be consulted.

Overview

present as particles of varying size, some of

Trace evidence covers a variety of materials that

magnification.

Transfer

may be transferred from one surface to another by:

●● forceful contact such as paint in a vehicle/

vehicle collision;

●● contact with material such as glass breaking

or broken by impact;

●● contact with a specific environment such as

soil or pollen;

●● indirect contact by transfer to and then from

an intermediate surface.

The mechanism of transfer is complex and has many contributing factors including:

which may not be visible without the aid of

Recovery

Evidence may be recovered using a variety of

processes such as lifting with tape, or in the case of clothing, shaking or brushing to collect loose debris.

Analysis

Tapes and collected debris are examined under low power microscopy for the presence of any material of potential interest. This material is

recovered for further testing in comparison with

any reference material submitted using a range of processes that may include:

●● the nature and quantity of the material

●● specialised and high power microscopy;

●● the force and duration of contact;

●● infrared spectroscopy;

involved;

●● proximity of the recipient surface to the

source of material;

●● the ability of a recipient surface to receive and

retain transferred material;

●● the time elapsed since contact occurred.

Traces of soft materials may be seen on surfaces as smears. Brittle or flaky materials may be

●● measurement of refractive index (for glass); ●● elemental analysis;

●● chemical spot tests.

See Hairs and Fibres for more information on these evidence types and Ballistics for more information on gunshot residue (GSR). Some

trace evidence may be a useful source of DNA evidence.

Trace Evidence examples including sand particles (top) and vegetation (bottom). Home Office January 2014

7.26

Fingermark Visualisation Manual

Trace Evidence

7.27

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Important Notes on Trace Evidence

Effect of trace evidence recovery on fingermarks

●● Trace evidence can be fragile and easily removed from

●● Physical recovery of trace evidence such as brushing

●● Trace evidence must be retained on the surface in

●● Taping may lead to partial or complete removal of

the surface.

an unaltered state for recovery. The location of trace evidence may be of relevance for interpretation purposes.

●● Recovery and analysis of trace evidence is highly

susceptible to contamination. Ensure the integrity of trace evidence by taking appropriate precautions, controls and anti-contamination measures.

Trace Evidence and Fingermarks Effect of fingermark processes on trace evidence

●● Providing that handling is minimised and adequate

anti-contamination measures are taken, fingermark visualisation processes (optical) are unlikely to be

detrimental to trace evidence and may have a role to play in visualising deposits or smears of transferred

material though they are likely to be of limited value in detecting very small particles.

●● Fingermark visualisation processes (chemical and

physical) are potentially destructive to trace evidence as they may: ■■ ■■

remove or disturb trace evidence;

Fingermark Visualisation Manual

Trace Evidence

may result in damage or obliteration of fingermarks. material in which fingermarks have been formed or

result in deposition of residues on surfaces which may interfere with fingermark visualisation processes.

Maximising fingermark and trace evidence ●● Prioritising evidence recovery as part of the Forensic

Evidence Recovery Plan is important, as recovery

processes for both evidence types can negatively

impact on each other. The plan should be developed jointly by practitioners from both fields.

●● Unless impacted or smeared, trace evidence is easily

displaced and therefore recovery is of paramount

importance. Undertake trace evidence recovery prior

to application of any potentially destructive fingermark visualisation processes. Fingermark visualisation processes (optical) may assist provided anticontamination measures are in place.

●● Taping to recover trace evidence should not be used

on areas suitable for fingermark recovery, unless agreed in the Forensic Evidence Recovery Plan

developed jointly by practitioners from both fields n

alter the appearance of trace evidence for the purposes of microscopy;

■■

change it irrecoverably by altering appearance,

colour, behaviour under fluorescence or affect the results of chemical or analytical tests.

Home Office January 2014

7.27

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Index

Appendices Contents Appendix 1: Case Studies ......................................A.1.1 Appendix 2: Fingermark Research .......................A.2.1

Introduction

In Chapter 2 the planning of fingermark recovery was introduced. It was discussed in terms of the various considerations that need to be taken into account, from the perspective of the case, the policies and procedures of the organisation as well as

knowledge of the item and how its history can be used to guide the development of

the most suitable plan. Appendix 1 has a number of examples of operational situations

which demonstrate how plans have been generated after consideration of all the relevant facts, constraints and limitations.

Fingermark research is discussed in Appendix 2. The number of variables associated

with fingermarks and their visualisation makes the development of processes to visualise them particularly challenging, especially if the process is to be used on operational

material. The Home Office uses a methodology which has proven suitable for fingermark research for this purpose and those conducting studies of this nature are encouraged to use its principles to ensure robust advice can be given. The methodology is supported by additional information to illustrate how the Home Office assesses the maturity and

Technical Readiness Levels of processes proposed for fingermark visualisation for law enforcement applications n

Home Office January 2014

A.0.1

Fingermark Visualisation Manual

Appendices

A.0.1

AP

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Appendix 1: Case Studies Example 1*: The item was a rigid, lightly coloured, plastic charity collection box with paper labels around it. It had been recovered from a case involving theft.

Forensic Strategy

Only fingermark evidence was to be recovered.

Planning Considerations The Substrate

Index

Example 1 Fingermark Evidence Recovery Sequence General Points

●● The item was treated as a whole with one process targeting each substrate.

●● Powder Suspension was applied after Ninhydrin as it was considered too difficult to

apply/rinse without wetting the labels.

NINHYDRIN

Multiple: hard, light-coloured plastic; non-glossy paper labels. The presence of multiple surface types means that different processes are required for different areas. The

different areas can either be separated and treated as separate items, or selectively treated. The plastic may be affected by heat (i.e. possibly melt) and therefore oven treatment may not be possible.

Labels Only

Ninhydrin is an effective process for porous surfaces and was selectively applied to the porous paper areas of the item using a brush. Although DFO is more effective, Ninhydrin does not require Fluorescence Examination to view marks. For this type of crime that was considered acceptable. The development occurred at room temperature over a period of days.

Possible Fingermarks

Latent marks on the exposed surfaces only.

Item History

One week since the theft although environmental conditions during this time were unknown.

Local Police Force Policy

For this type of crime, force policy is to use only one process per surface type.

POWDER SUSPENSION

Plastic Only

Powder Suspension is an effective process for nonporous surfaces. The performance of the process was not detrimentally affected by the time taken for Ninhydrin to develop marks. As the final process in the sequence, it did not matter if the labels were wetted.

* This example is based on operational casework. Only limited detail is presented and

CAST may have modified parts of it to demonstrate certain points. There may be other processing sequences that are equally valid. Home Office January 2014

A.1.1

Fingermark Visualisation Manual

Appendix 1: Case Studies

A.1.1

Contents

A.1.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Index

Example 2

Example 2*: The item was a brown cardboard box which was largely covered in

clear adhesive tape. It had been sent through the postal system in a case related to terrorism.

Forensic Strategy

To get maximum forensic evidence without completely destroying the item.

Planning Considerations The Substrate

Multiple: cardboard and clear adhesive tape. The presence of multiple surface types

means that different processes are required for different areas. The different areas can either be separated and treated as separate items, or selectively treated.

Possible Fingermarks

Latent marks on exposed and protected surfaces.

Item History

The item was sent through the postal system. There was no reason to believe that it had been wetted.

Local Police Force Policy

Classed as serious crime. Any treatment would be done after consultation with the Senior Investigating Officer (SIO).

Multiple Evidence Types

●● The requirement for recovery of multiple evidence types means that joint

examinations should be conducted with specialists in other forensic evidence types. This may include DNA, fibre, other trace evidence etc.

●● The requirement for DNA recovery means that fingermark recovery should be carried

out in a DNA clean environment where possible and measures should be taken to avoid cross-contamination.

* This example is based on operational casework. Only limited detail is presented and

CAST may have modified parts of it to demonstrate certain points. There may be other processing sequences that are equally valid. Home Office January 2014

A.1.2

Fingermark Visualisation Manual

Appendix 1: Case Studies

Appendices Glossary

A.1.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Example 2 continued

Fingermark Evidence Recovery Sequence

Tape Only

General Points

●● The item was treated as a whole initially followed by attempts to

Powders was chosen instead of Superglue Fuming or Powder Suspension as it could be selectively applied to the tape and required no further enhancement.

POWDERS

remove some of the top layers of tape, bearing in mind that the item was to be returned primarily intact.

●● In order to not completely destroy the item, some processes were

omitted from the recovery sequence.

Cardboard Only

●● DNA was recovered following local procedures. In this case that

included swabbing areas of ridge detail deemed as insufficient for

DFO is the single most effective process on porous surfaces and could be selectively applied to the cardboard areas of the item using a brush. It was ensured that the tape could withstand the processing temperature before use.

DFO

identification.

●● Other trace evidence, such as hairs and fibres, located during visual

and fluorescence examinations, was carefully recovered following local procedures.

●● Visual and Fluorescence Examination were used at all relevant stages

of the sequence as they are non-contact processes.

Separation of Surfaces

An attempt was made to remove as much of the tape from around the box as possible although this was limited due to the requirements to keep the item intact. No further areas of cardboard were uncovered. The position and orientation of any tape removed was recorded.

ADHESIVE TAPE REMOVAL

Tape Only

Powder Suspension is effective on both sides of the tape.

Cardboard Only POWDER SUSPENSION

NINHYDRIN

Ninhydrin can detect additional marks when used after DFO.

Tape Only

Basic Violet 3 can find additional marks on both sides of the tape.

Home Office January 2014

BASIC VIOLET 3

A.1.3

Fingermark Visualisation Manual

Appendix 1: Case Studies

Index

A.1.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Example 3*: The item was a brown cardboard box, openings had been sealed using clear adhesive tape. The item had been recovered in a case involving theft.

Forensic Strategy

Only fingermark evidence was to be recovered.

Planning Considerations The Substrate

Example 3 Fingermark Evidence Recovery Sequence General Points

●● The item was treated as a whole. Although one process would normally be used, the

practitioner determined that all exposed surfaces could be treated with minimal extra effort by including Powders into a sequence with Ninhydrin.

POWDERS

Multiple: cardboard and clear adhesive tape (cellulose-backing). The

presence of multiple surface types means that different processes are

required for different areas. The different areas can either be separated

Tape Only

Used to treat the non-adhesive side of the tape as a ‘quick win’ as it is effective on non-porous surfaces, quick to apply on small items, can be selectively applied without impacting on the effectiveness of Ninhydrin, and will not destroy the cellulose backing.

and treated as separate items, or selectively treated.

Possible Fingermarks

Latent marks on the exposed surfaces only.

Item History

No reason to believe that it had been wetted.

Local Police Force Policy

For this type of crime, force policy is to normally use one process per

NINHYDRIN

Ninhydrin is an effective process for porous surfaces. Although DFO is more effective, it does not require Fluorescence Examination to view marks. For this type of crime that was considered acceptable. There is also the slim possibility of additional development on the non-adhesive side of the tape as it is cellulose-based so therefore the whole item was treated.

item.

* This example is based on operational casework. Only limited detail is

presented and CAST may have modified parts of it to demonstrate certain points. There may be other processing sequences that are equally valid. Home Office January 2014

A.1.4

Fingermark Visualisation Manual

Appendix 1: Case Studies

Index

A.1.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Index

Example 4

Example 4*: The item was a cardboard box taped shut with brown parcel tape. The victim had been buried in the box. The item had been used in a case of kidnap/ attempted murder.

Forensic Strategy

To get maximum forensic evidence.

Planning Considerations The Substrate

Multiple: cardboard and brown adhesive tape. The presence of multiple surface types

means that different processes are required for different areas. The different areas can either be separated and treated as separate items, or selectively treated.

Possible Fingermarks

Latent marks on exposed and protected surfaces.

Item History

The item was partially buried but probably hadn’t been wetted.

Multiple Evidence Types

●● The requirement for recovery of multiple evidence types means that joint

examinations should be conducted with specialists in other forensic evidence types. This may include physical fit, footwear marks, DNA, fibres, other trace evidence etc. In this case, physical fit was a strong possibility due to the recovery of rolls of tape from a suspect’s house.

●● The requirement for DNA recovery means that fingermark recovery should be carried

out in a DNA clean environment where possible and measures should be taken to avoid cross-contamination.

* This example is based on operational casework. Only limited detail is presented and

CAST may have modified parts of it to demonstrate certain points. There may be other processing sequences that are equally valid. Home Office January 2014

A.1.5

Fingermark Visualisation Manual

Appendix 1: Case Studies

Appendices Glossary

A.1.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Example 4 continued

Fingermark Evidence Recovery Sequence General Points

●● The item was first treated as a whole before surface separation. ●● DNA was recovered following local procedures.

REMOVAL OF TAPE ENDS

A number of debris-covered tape ends that were not stuck to the box were identified. They were recovered for later DNA recovery/physical fit/fingermark recovery.

●● Other trace evidence, such as hairs and fibres, located during visual

and fluorescence examinations, was carefully recovered following local procedures.

●● Visual and Fluorescence Examination were used at all relevant stages

of the sequence as they are non-contact processes. In this case,

footwear marks were found and recorded prior Superglue Fuming.

SUPERGLUE FUMING

The whole item was treated with Superglue Fuming as it is an effective process for the adhesive side of brown parcel tape and has little impact on subsequent porous processes.

Separation of Surfaces

Each layer was carefully separated for subsequent treatment. They were removed in a systematic manner and the location and orientation of individual layers were recorded.

ADHESIVE TAPE REMOVAL

Cardboard Only Tape Only

Powder Suspension is effective on both sides of the tape.

POWDER SUSPENSION

Tape Only

Basic Violet 3 can find additional marks on both sides of the tape.

Home Office January 2014

BASIC VIOLET 3

NINHYDRIN

Ninhydrin was used to treat the cardboard box in preference to DFO. This was because the item would have had to be cut to fit within the DFO oven, whilst the Ninhydrin oven was large enough to accommodate the box without any cutting. The drop in effectiveness between the processes was balanced with the potential destruction of marks caused by additional handling/cutting.

A.1.6

Fingermark Visualisation Manual

Appendix 1: Case Studies

Index

A.1.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Example 5

Example 5*: The item was a mass of multiple layers of clear adhesive tape used in a

Fingermark Evidence Recovery Sequence

with one vertical cut so that the tape remained as one item.

●● Visual and Fluorescence Examination were used at all relevant stages of the

case of murder. The tape had been wrapped around the victim’s head and removed

Forensic Strategy

To get maximum forensic evidence.

Planning Considerations The Substrate

Multiple layers of clear adhesive tape (cellulose-backing).

General Points

sequence as they are non-contact processes.

●● DNA was recovered following local procedures.

●● Other trace evidence, such as hairs and fibres, located during visual and

fluorescence examinations, was carefully recovered following local procedures.

●● Since the outside surfaces of the item had been wetted, Superglue Fuming was

omitted from the sequence.

●● Tape ends were to be targeted first.

Possible Fingermarks

Latent marks on exposed and protected surfaces.

Item History

Intelligence and the observation of white, opaque areas on some of the

ADHESIVE TAPE REMOVAL

Separation of Surfaces

The tape ends were gently peeled back ready for treatment.

tape suggested it had been wetted.

Multiple Evidence Types

●● The requirement for recovery of multiple evidence types means that

joint examinations should be conducted with specialists in other

Adhesive Side Only

forensic evidence types. This may include physical fit, DNA, fibres, other trace evidence etc.

●● The requirement for DNA recovery means that fingermark recovery

should be carried out in a DNA clean environment where possible and

POWDER SUSPENSION

The tape ends were carefully treated with Powder Suspension ensuring that water did not make contact with the cellulose-backing. Marks were found and identified and, given their significance, further work on this item was not needed.

measures should be taken to avoid cross-contamination.

* This example is based on operational casework. Only limited detail is

presented and CAST may have modified parts of it to demonstrate certain points. There may be other processing sequences that are equally valid. Home Office January 2014

A.1.7

Fingermark Visualisation Manual

Appendix 1: Case Studies

Index

A.1.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Example 6

Example 6*: A scene linked to a murder was a heavily grease-contaminated confined

Fingermark Evidence Recovery Sequence

the low ceiling.

●● Visual and Fluorescence Examination were used first. For this example they are

store room. Marks were thought to be present in the layer of grease contamination on

Forensic Strategy

Target the ceiling for fingermark evidence.

General Points

included in the flow diagram below.

●● The nature of the surface (horizontal, above head height) makes it impractical to use

liquid-based chemical visualisation processes (such as Solvent Black 3 or Basic Violet 3) to stain the grease layer.

Planning Considerations The Substrate

A horizontal, fixed, non-porous surface with a pre-existing layer of grease across it.

VISUAL EXAMINATION

Possible Fingermarks

Impressions within the grease layer.

Various lighting techniques used in Visual Examination were used to illuminate the mark for image capture. Oblique lighting was the most effective due to the 3D-impression in the grease layer, but the detail within the mark was still difficult to capture due to the confined conditions.

Surface History

Indoor environmental conditions.

Local Police Force Policy

High priority crime: every means of fingermark recovery should be

FLUORESCENCE EXAMINATION

Some greases fluoresce and attempts were made to capture marks using Fluorescence Examination. However, due to the confined conditions this was difficult to achieve.

considered.

Processing Practicality

The surface is fixed so processing must take place at the scene. As it is a ceiling there are likely to be practical difficulties in using some processes.

LIFTING

* This example is based on operational casework. Only limited detail

Due to the difficulties in imaging marks in situ, a gelatin lift was used to lift the grease layer from the surface, allowing the disturbances in the grease layer to be examined away from the confines of the store room. Further Visual Examination of the lift using both specular and oblique lighting conditions was used. As the greasy contaminants were fluorescent, further fluorescence examination of the lift was conducted. The fingermarks could be successfully captured as the imaging angles and conditions were controlled and optimised.

is presented and CAST may have modified parts of it to demonstrate

certain points. There may be other processing sequences that are equally valid.

Home Office January 2014

A.1.8

Fingermark Visualisation Manual

Appendix 1: Case Studies

Index

A.1.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Example 7*: The item was a booklet with a plastic cover which had been partially burnt, but not soot covered. The item was related to a case of arson.

Forensic Strategy

Only fingermark evidence was to be recovered.

Planning Considerations The Substrate

Multiple: plastic non-porous cover with porous paper pages. The presence of multiple surface types means that different processes are required for different areas. The

Example 7 Fingermark Evidence Recovery Sequence General Points

●● The item was fragile and particularly careful handling was required.

●● The item was dried at ambient temperature as it was to be stored prior to treatment. ●● The cover and inside pages had become separated so were be treated as individual

items.

●● Since the item had been wetted, Superglue Fuming, Ninhydrin and DFO were omitted

from the sequence.

●● Visual and Fluorescence Examination were used at all relevant stages of the

sequence as they are non-contact processes.

different areas can either be separated and treated as separate items, or selectively treated.

Possible Fingermarks Latent marks.

POWDER SUSPENSION

Plastic Cover Only

Powder Suspension is effective on wetted items and is one of the best options on items exposed to excessive heat.

Surface History

The booklet had been thrown from the blaze into a nearby bush which was wet. The fire had damaged the booklet to the extent that it was in pieces and the pieces were fragile and damp in areas. This knowledge limits the number of processes that can be used effectively.

Inside Pages Only PHYSICAL DEVELOPER

Physical Developer is the only chemical process effective on wetted, porous surfaces. It also may be effective on heat-exposed items.

* This example is based on operational casework. Only limited detail is presented and

CAST may have modified parts of it to demonstrate certain points. There may be other processing sequences that are equally valid. Home Office January 2014

A.1.9

Fingermark Visualisation Manual

Appendix 1: Case Studies

Index

A.1.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Example 8

Example 8*: The item was a plastic cash machine fascia with adhesive pads at the

Fingermark Evidence Recovery Sequence

cash point fraud.

●● Visual Examination was restricted to a quick examination for obvious marks during

rear and a mobile telephone taped to its interior. The item had been used in a case of

Forensic Strategy

Fingermark evidence and the data from the SIM card were to be recovered.

General Points

booking-in of the item.

●● The decision to use Superglue Fuming on the ‘as-received’ item maximised the

potential to recover any areas of ridge detail which could have been damaged or lost during subsequent dismantling.

Planning Considerations The Substrate

Multiple: rigid plastic, adhesive tape and metal. The presence of multiple surface types

MASKING

means that different processes are required for different areas. The different areas can either be separated and treated as separate items, or selectively treated.

Possible Fingermarks

Latent marks on the internal surfaces were to be targeted in order to avoid visualising

SUPERGLUE FUMING

marks from legitimate cash machine users.

Item History

The item was found attached to a cash machine and was submitted the same day it

DISMANTLING

was retrieved. Due to the busy location of the cash machine it was unlikely to have been there for more than an hour or two at most. The weather was dry.

Local Police Force Policy

For this type of crime the number of processes would be limited.

Multiple Evidence Types

SUPERGLUE FLUORESCENT DYE STAINING

The requirement for recovery of multiple evidence types means that joint examinations should be conducted with specialists in other forensic evidence types. In this case,

the SIM card needs to be protected from any processes that may inhibit the ability to retrieve data from it.

POWDER SUSPENSION

Silicone release paper was placed over the exposed adhesive surfaces. This was done to ensure subsequent processing of the adhesive surface with Powder Suspension would not be inhibited. Effective on both rigid plastic and metal. The item was treated soon after recovery; therefore this process is likely to be more effective than Powder Suspension on these substrates. The SIM card was carefully removed for analysis using Digital Forensics processes. Superglue Fuming was repeated on areas that had not been previously exposed e.g. parts of the phone and non-adhesive parts of the tape. Basic Yellow 40 was applied selectively to both the rigid plastic and metal areas ensuring that the adhesive surfaces were avoided.

Adhesive Areas Only

The silicone release paper was removed and the area treated with Powder Suspension.

* This example is based on operational casework. Only limited detail is presented and

CAST may have modified parts of it to demonstrate certain points. There may be other processing sequences that are equally valid. Home Office January 2014

A.1.10

Fingermark Visualisation Manual

Appendix 1: Case Studies

Index

A.1.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Index

Example 9

Example 9*: The item was a glass whisky bottle with paper labels. The item was from a cold case review of a murder that occurred in 1974.

Forensic Strategy

Fingermark evidence was to be recovered by using any available means, no matter how remote the chances of success.

Planning Considerations The Substrate

Multiple: glass and paper. The presence of multiple surface types means that different processes are required for different areas. The different areas can either be separated and treated as separate items, or selectively treated.

Possible Fingermarks Latent marks.

Item History

At the time of the original investigation the item had been powdered. Any marks will now be approximately 40 years old.

Cold Case Review

Fingermark visualisation processes that have been developed after the initial investigation should be reviewed and assessed for their suitability.

* This example is based on operational casework. Only limited detail is presented and

CAST may have modified parts of it to demonstrate certain points. There may be other processing sequences that are equally valid. Home Office January 2014

A.1.11

Fingermark Visualisation Manual

Appendix 1: Case Studies

Appendices Glossary

A.1.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Fingermark Evidence Recovery Sequence General Points

Index

Example 9 continued MASKING

●● There are many processes that have been developed since 1974.

The paper labels were protected with ‘post-it’ notes to prevent the porous surface being coated during subsequent treatment with Vacuum Metal Deposition, as a metal coating may be detrimental to other processes.

●● The paper label and bottle were treated separately, but not separated; instead

masking was used.

●● Visual and Fluorescence Examination were used at all relevant stages of the

sequence as they are non-contact processes. Although the item had been previously

VACUUM METAL DEPOSITION

Vacuum Metal Deposition was used as it is effective on glass and is known to have developed marks that are greater than ten years old.

SUPERGLUE FUMING

Superglue Fuming was used as it is effective on glass.

powdered, it was still worthwhile conducting these searches as there was nothing to lose.

Labels Only DFO

DFO is the most effective process on paper. It was selectively applied with a brush and the whole bottle processed in a DFO oven.

Labels Only NINHYDRIN

Ninhydrin was applied selectively to the label. The marks were left to develop at room temperature and humidity to avoid moisture damaging any superglue deposits. Physical Developer was not used for practical reasons.

SUPERGLUE FLUORESCENT DYE STAINING

As all porous processing had been completed, for practical reasons the whole item (rather than just the glass) was stained with Basic Yellow 40 to enhance Superglue Fuming marks.

POWDER SUSPENSION

Although it may be impeded by Superglue Fuming, it is generally more effective on older marks than Superglue Fuming. The success would be dependent on the amount of superglue deposit on the surface.

BASIC VIOLET 3

Home Office January 2014

May find additional marks, particularly if they are greasy in nature.

A.1.12

Fingermark Visualisation Manual

Appendix 1: Case Studies

Appendices Glossary

A.1.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Example 10*: The item was an Australian banknote from an organised crime investigation.

Forensic Strategy

Only fingermark evidence was to be recovered.

Planning Considerations The Substrate

Example 10 Fingermark Evidence Recovery Sequence General Points

●● This sequence focuses on the processes used to attempt to reduce background

pattern issues. It does not include all previously used processes.

●● All specialist imaging processes were considered to increase contrast between

the developed marks and the highly coloured and patterned surface. There was

no access to UVC Reflection systems, although it was possible to use document examination equipment present within the laboratory to carry out IR Reflection.

Polymeric currency.

Possible Fingermarks

Marks previously developed with Superglue Fuming and/or Vacuum

VISUAL EXAMINATION

Metal Deposition. They are difficult to see and image because of the highly coloured background pattern of the note.

Item History

The item had been previously treated in accordance with the guidance for this type of surface. Prior to this its history is unknown.

Local Force Policy

For this type of crime, all processing options were to be considered.

IR REFLECTION

LIFTING

The note was examined under a range of lighting conditions. Marks developed using Superglue Fuming were expected to improve when viewed with oblique lighting due to the 3D nature of the mark and the flat surface. Similarly, it may be possible to find lighting angles where the metallic zinc coating from the Vacuum Metal Deposition process reflects and the uncoated ridges do not, providing contrast.

This process was chosen as the metallic zinc coating from Vacuum Metal Deposition would be expected to remain visible in the infrared area of the spectrum whereas the patterned background may not.

A lifting medium (in this case, a gelatin lift) was used to lift traces of zinc coating and superglue from the surface and away from the interfering background patterns to see if any additional detail could be obtained. Specialist Visual Examination lighting techniques, such as hard specular lighting, were required to obtain optimum results from the lift.

* This example is based on operational casework. Only limited detail is

presented and CAST may have modified parts of it to demonstrate certain points. There may be other processing sequences that are equally valid. Home Office January 2014

A.1.13

Fingermark Visualisation Manual

Appendix 1: Case Studies

Index

A.1.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Example 11*: The item was a white paper document found at the scene and suspected of bearing traces of blood from a violent assault.

Forensic Strategy

Fingermark and DNA evidence was to be recovered.

Planning Considerations

Example 11 Fingermark Evidence Recovery Sequence General Points

●● This sequence focuses on the processes used to attempt to reduce contrast issues

between the mark and background. It does not include all previously used processes.

●● Blood (and DNA) was recovered following local procedures.

●● Normally processes would be constrained to those available locally, but in this case

it had been decided that specialist imaging equipment would be sought at other

The Substrate

locations.

Possible Fingermarks

FLUORESCENCE EXAMINATION (UVA)

This was considered a suitable process as Acid Black 1 and blood both absorb UVA radiation strongly, whilst most white paper contains optical brighteners which fluoresce strongly under UVA. A combination of these two effects may produce sufficiently improved contrast in the mark.

MULTI-SPECTRAL IMAGING

Multi-Spectral Imaging was used as it is very effective at separating differences in colour that are imperceptible to the eye. Acid Black 1 has a characteristic colour spectrum that differs significantly from that of white paper. The analysis software associated with Multi-Spectral Imaging may be able to boost this difference sufficiently to resolve the mark n

White, matt paper.

Marks previously developed using Acid Dyes (Acid Black 1). They are faint and currently insufficient for identification.

Item History

The item had been previously processed with DFO, Ninhydrin and Acid Dyes (Acid Black 1).

Local Force Policy

For this type of crime, all processing options were to be considered.

Multiple Evidence Types

●● The requirement for recovery of multiple evidence types means that

joint examinations should be conducted with specialists in other forensic evidence types.

●● The requirement for DNA recovery means that fingermark recovery

should be carried out in a DNA clean environment where possible and measures should be taken to avoid cross-contamination.

* This example is based on operational casework. Only limited detail is presented and

CAST may have modified parts of it to demonstrate certain points. There may be other processing sequences that are equally valid. Home Office January 2014

A.1.14

Fingermark Visualisation Manual

Appendix 1: Case Studies

Index

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Index

Appendix 2: Fingermark Research Introduction

●● the concept of Technology Readiness Levels (TRLs) and their use in determining

B, C and D cover those that may be considered for operational use, and for processes

●● a methodology that can be applied to research into fingermark visualisation

The processes outlined in this Manual are grouped in terms of categories. Categories A, in these categories an indication of process maturity is assigned. Underpinning both these means of describing processes is a significant body of research that has been

conducted to determine both whether a process is fit for the purposes of fingermark

visualisation and where it may be most effectively applied. A summary of the fingermark

research that has been conducted and/or supervised by CAST has been published in the Home Office Fingerprint Source Book (Home Office, 6 June 2012). [https://www.gov. uk/government/publications/fingerprint-source-book].

where a process has reached in terms of process maturity;

processes and the types of experiment involved in each stage, linked to TRLs. The

methodology provides a guide for those conducting fingermark research or process

validation and gives an indication of what level of evidence is required to progress a process through each TRL.

It is also shown how both these concepts can be linked to the way in which processes are grouped and described in Chapters 5 and 6 in the main body of the Manual n

There is also an increasing requirement to demonstrate that the processes used for forensic evidence recovery are fit for purpose, have been validated, and that the

laboratories conducting these processes are accredited to internationally recognised

standards. In the UK, laboratories carrying out fingermark recovery require accreditation to ISO 17025.

Independently of the ISO 17025 standard, it is good scientific practice that research into any novel visualisation processes is conducted using a recognised methodology and that published work is based on sufficient evidence to draw meaningful conclusions.

The purpose of this Appendix is to provide both practitioners and scientific researchers with an understanding of the work that may be required to progress a novel process

from a paper concept through to operational implementation. It also illustrates how the evidence required to validate a process can be obtained. This Appendix provides information on two concepts:

Home Office January 2014

A.2.1

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

A.2.1

Contents

A.2.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Technology Readiness Levels (TRLs)

The concept of a Technology Readiness Level (TRL) is used in many

Index

Process Maturity Technology Readiness Level

Fingermark context

government departments, agencies and commercial companies

1.

Published papers reporting synthesis of new chemicals, or reporting principles of a novel optical technique etc.

as they evolve from research and development toward operational

2.

Published papers or other references reporting reactions of chemicals that are relevant to the environment of a fingermark, or physical interactions of optical techniques with surfaces.

3.

Chemical spot tests using the process on individual fingermark constituents or on single marks to demonstrate feasibility, or trials to establish that the optical technique is applicable to the constituents within a fingermark.

4.

Chemical formulation and/or process optimisation using real fingermarks, or trials to establish optimum optical environment for fingermark visualisation.

5.

Extensive laboratory trials using the process on samples covering a range of donors, substrates, ages of mark. Testing in this phase may be conducted for several reasons and therefore experiments may vary according to end purpose. Information required at this TRL may include:

worldwide as a means of assessing the maturity of technologies

implementation. There is much synergy between this approach and the steps taken in evaluating and implementing a new fingermark

visualisation process, and therefore a TRL is used throughout this section to provide the practitioner and researcher with an understanding of the maturity of individual processes. The scale used is shown (right).

Tests to cover maturation of a process from TRL3 to TRL6 can generally be conducted within a research environment. Operational trials (TRL7) must be carried out by an organisation processing live casework,

but this could be in conjunction with the research organisation. Final

implementation of processes and incorporation into Manuals is generally carried out by the authority responsible for producing and maintaining

●● whether the process detects fingermarks not found by other processes;

such publications.

●● whether the process is the single most effective process for a particular

set of circumstances;

●● whether the process can be used in a sequence and if so, how it impacts

on other fingermark and forensic recovery processes.

Home Office January 2014

6.

Pseudo-operational trials using marks on realistically handled, operationally representative items and surfaces.

7.

Operational trials on items and surfaces encountered in live casework.

8.

Publication of results obtained from tests covering TRL3-7 and issue of processing instructions. Inclusion in processing Manuals.

9.

Provision of supporting data for process in operational use obtained by monitoring performance over several years.

A.2.2

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Appendices Glossary

A.2.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Relationship of TRLs to process categories

The categories of the processes proposed for operational use in the Manual can also be

Index

Process Maturity Process category

Technology Readiness Level of processes within category

related to their TRL, and this relationship is summarised in the table.

A

TRL8-9. Processes in this category have all been suitably tested and implemented for routine operational work, and are believed to represent the most effective processes for their proposed applications.

It can be seen that in general processes under research will move up from category C

B

TRL5-9. Processes in this category have all been subjected to suitable comparative testing and their potential applications have been identified. Some may have previously been in routine use but are no longer considered as effective as other processes for their originally proposed applications; others require further work before they can be considered for routine operational use.

C

TRL3-4. Processes in this category have demonstrated possible operational benefits in small-scale studies, and some limited comparative testing may have been conducted to identify potential applications.

D

TRL8-9. Processes in this category have been extensively tested for routine operational use but have since been replaced by other processes. However, they may be useful in certain remedial applications.

E

TRL3-7. Processes in this category may cover a wide range of TRLs, from those where a process has been reported but no further research carried out, to those where testing has proceeded to operational trials but no operational benefits have been found.

F

TRL3-8. Processes in this category may cover a wide range of TRLs, and have been tested to varying degrees. However, in all cases the process has not been implemented or has been discontinued in the UK because of concerns over health and safety.

to B and ultimately to category A as further testing is conducted and they continue to

demonstrate operational benefits. Processes may also move downwards from category A to category B (or possibly to category D or E) as they are superseded by other more effective processes.

Home Office January 2014

A.2.3

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Appendices Glossary

A.2.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Relationship of TRLs to the CAST Maturity Rating TRLs are useful in the research and validation environments but less

useful to those requiring a simple indication of the level of maturity of a process. As a consequence TRLs are not used in the main body of the

Manual. Instead, a CAST Maturity Rating is used to indicate the maturity

of the process in terms of the levels of validation, impact and confidence levels. For simplicity a ‘bar chart’ is used and there is direct correlation between the CAST Maturity Rating and the TRL.

Chart maturity in Chapter 4 is also described by a CAST Maturity Rating. In this case, chart maturity does not relate to the maturity of the processes within it, because all processes used in the charts are Category A processes and therefore have reached TRL8 or 9. Chart maturity relates more to the amount of testing that has been carried out on that particular substrate or scenario, and takes into account the level of knowledge about the effectiveness of the process on the particular substrate and the optimum order in which processes can be used. Where little testing has been done or level of certainty is low, chart maturity will be correspondingly low.

Home Office January 2014

Index

Process Maturity Process CAST Maturity Rating

Relationship to Technology Readiness Level Equivalent to TRL9. The process has been suitably evaluated in a research and operational environment and has been in operational use for many years. A significant amount of supporting operational data exists. Equivalent to TRL7-8. The process has been suitably evaluated in a research and operational environment, but has yet to be or has only recently been operationally implemented and little operational data has been gathered. Equivalent to TRL5-6. The process has been suitably tested on planted fingermarks in a research environment and may also have been tested on pseudo-operational material, but further testing is required before it can be progressed to operational trials. Equivalent to TRL4. The process has been shown to be effective in visualising fingermarks. Processing parameters and formulations have been optimised in preparation for comparative testing. Equivalent to TRL1-3. The process has been identified as being capable of visualising fingermarks and some proof of principle studies may have been conducted.

A.2.4

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Appendices Glossary

A.2.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Index

Methodology

Introduction

The means by which a process can be progressed from one TRL to another needs to be generally understood by practitioners and researchers to enable a common approach to fingermark research and validation. The stages of the validation process used by CAST have been described in detail in an external publication:

Sears, V. G., Bleay, S. M., Bandey, H. L., Bowman, V. J., ‘A methodology for finger mark research’, Science & Justice vol 52(3), 2012, p145-160.

A summarised version of the main points in this publication is given in the following pages. The four principal stages in the test methodology used are as follows: ●● tests using fingermark constituents/test strips/groomed fingermarks;

●● tests using planted fingermarks, including extensive laboratory trials; ●● pseudo-operational trials; ●● full operational trials.

These tests are equivalent to the TRL in the range 3 to 8. TRLs 1 and 2 are mainly

concerned with proposing novel concepts and conducting literature searches to identify technologies of potential interest and therefore do not generally involve experimental

work. The purpose of each of the experimental stages used to progress processes from TRL3 to TRL8, and some of the methods that can be used, are described in greater detail in the sections below. It should be noted that research into a process can be

halted at any TRL if results indicate there is no benefit in progressing further. In such

situations the data gathered should be retained because alternative applications for the process may subsequently arise.

During the writing of this Manual, a document titled ‘Guidelines for the Assessment of Fingermark Detection Techniques’ (due for publication in 2014) has been prepared in

consultation with members of the International Fingermark Research Group (IFRG) and has been endorsed by the IFRG Steering Committee. When published it will provide

further guidelines for the evaluation of new or modified fingermark detection processes from initial concept through to final casework implementation.

Home Office January 2014

A.2.5

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Appendices Glossary

A.2.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Index

Methodology

Cautionary notes

The amount of testing may also be modified according to whether work is being carried

for how evidence can be collected to support maturation and validation of processes;

testing to ensure that all of the evidence required is obtained and recorded. Fewer

The fingermark research methodology outlined over the next few pages gives guidance however, it should be regarded as a scaleable and adaptable framework that can be tailored to the particular scenario being investigated.

Alternative experimental methods may be substituted for those described in the

methodology provided that they can be shown to supply the evidence that is required.

out to validate or to verify a process. Validation requires a more significant body of

tests will be required to verify a previously validated process for use in a particular local

environment, but these should still include some essential elements of the methodology such as use of a range of donors, different types of substrate and fingermarks of different ages.

It may not be necessary for a process to be exposed to every stage in the methodology.

Forces considering taking part in an operational trial of a new process should satisfy

sensitive to small traces of it, there will be little benefit in artificially creating items for

it on operational material. At this stage supporting data from research trials must show

For example, once a process has been shown to visualise marks in blood and to be

pseudo-operational trials and this evaluation stage may be omitted in preference to full operational trials.

themselves that the process they are about to test has been fully evaluated before using that there is a likely operational benefit from using the process. The force should ensure that the testing is robust and preferably impartial.

The amount of testing that is conducted should take into account the position of the

process in a sequence and the likely impact of the process on fingermarks and other types of forensic evidence. Optical processes used at the beginning of sequences

may require less extensive testing than chemical or physical processes because they

are generally non-contact, non-destructive and have little or no impact on fingermarks or other forensic evidence. As a consequence, the risks associated with incorrect application of the process are minimal.

Similarly, the final process in a sequence may not require as comprehensive testing as processes used earlier in the sequence because all options for evidence recovery will

have already been exhausted and incorrect selection and application of the process will only impact on fingermarks that may have been recovered by that process.

On the other hand, a chemical or physical process that is used towards the beginning of a sequence or is recognised as the single most effective process for a particular substrate requires much more extensive testing because it potentially visualises a

significant number of marks and there are several processes that may be used after it. The potential impact of incorrect selection or application of such a process therefore includes a significant reduction in the number of marks visualised by it, and also

detrimental effects on subsequent fingermark recovery by other processes and the recovery of other types of forensic evidence. Home Office January 2014

A.2.6

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Appendices Glossary

A.2.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Index

Eccrine constituents processed with DFO.

A process at TRL3 will have been characterised in terms of what types of interactions can occur with fingermarks. The objective of tests to reach TRL3 is to establish what types of fingermark (eccrine, sebaceous, contaminated) the visualisation process is

most likely to interact with (if this is unknown), and how strong this interaction is likely

to be. More specific tests may also be carried out to determine which of the individual constituents within the fingermark the process is actually targeting (i.e. establishing specificity).

During validation of a process, it may also be necessary to extend these tests to look

at known dilutions of model constituents to demonstrate that the process is sufficiently sensitive to detect and react with the low concentrations of the target constituents present in real fingermarks (i.e. establishing sensitivity).

Some of the means by which specificity and sensitivity may be tested include:

Squalene dilution series processed with Oil Red O.

●● use of test spots of different fingermark constituents at a single concentration;

●● use of dilution series consisting of test spots of a single constituent or contaminant

at a range of concentrations;

●● use of test strips consisting of a mixture of constituents deposited at different

concentrations;

●● ‘groomed’ fingermarks obtained under conditions giving predominantly eccrine and/

or sebaceous sweat.

Natural (left), sebaceous

(centre) and eccrine marks (right) processed with

Powder Suspension (ironoxide-based). Home Office January 2014

A.2.7

Fingermark Visualisation Manual

Methodology

Appendix 2: Fingermark Research TRL3: Use of spot tests/test strips/groomed fingermarks

Appendices Glossary

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Index

Methodology

TRL4: Process optimisation using real fingermarks A process that has reached TRL4 will have matured to the point where it has been

optimised for fingermark visualisation. The objective of tests at this stage is to produce an optimised formulation and/or set of processing conditions that can be used in comparative trials with existing processes.

A test method most appropriate to the type of visualisation process being investigated

should be used, and at this stage testing should primarily focus on naturally deposited, as opposed to deliberately ‘groomed’ fingermarks.

One test that has been devised for this purpose is the ‘quartered fingermark’, where

a donor places a single natural fingermark in the centre of a surface which is divided

into four equal parts. Each of these quarters is then treated using different conditions

and then recombined for assessment. The quartered fingermark experiment should be repeated using several different donors.

Some of the parameters that may be varied in such a test include: ●● concentration of individual constituents of the formulation;

●● different options for individual constituents of the formulation;

Quartered fingermark with each segment

●● different application methods.

5MTN.

●● processing time and temperature;

For processes yielding fluorescent reaction products, excitation and emission spectra

may be determined at this stage so that illumination wavelengths and viewing filters can be optimised.

segment processed with different

processed with a different concentration of

fluorescamine formulations.

Emission and excitation spectra for natural yellow 3 120 100 80 Excitation Emission

60 40 20 0

Home Office January 2014

Quartered fingermark with each

400

450 500 550 Wavelength (nm)

600

650

Excitation and emission spectra for Natural Yellow 3.

A.2.8

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Normalised intensity

A.2.8

Contents

A.2.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

TRL5: Extensive laboratory trials

For a process to reach TRL5, it should have been subjected to a comprehensive test programme. This may include processing hundreds or thousands of planted, but

realistic, fingermarks in a research environment to establish its potential applications,

its effectiveness relative to other processes and its position in processing sequences.

Methodology may be applied to in operational work, the different ages of mark that may be

encountered, and the variation in fingermark composition within and between donors. Some of the ways in which these factors can be addressed in laboratory trials are described below.

The objective of this phase is to carry out as direct a comparison as possible between

Multiple donor study

process(es) for the proposed application.

population (which can be selected to represent the general population or those more

the effectiveness of the visualisation process under evaluation and that of the existing During such comparative studies, it is desirable to obtain information about the

sensitivity (i.e. how small a trace of residue can still give positive development) and

selectivity (i.e how many people in a typical population it will develop marks for) of the

process. To some extent the sensitivity aspect may have been explored at TRL3, but this part of the evaluation process extends this to real fingermarks.

Comparative testing

The comparison process should take into account the range of surfaces the process

Multiple donor study investigating silver nitrate on Kraft paper. Home Office January 2014

A multiple donor study is a means of establishing how many people in a sample

likely to commit crime, as appropriate) the process will typically develop fingermarks

for. For example, a single fingermark can be obtained from as many different people as possible (preferably > 40). The series of deposited marks is aged and then developed using the process under evaluation. An equivalent set may be deposited and treated using an existing process for comparative purposes. The number and quality of the

visualised marks are then recorded. The results obtained will be specific to the surface type and age of mark used, and multiple tests of this type may be required to build an overview of performance.

Multiple donor study investigating silver nitrate on brown envelope.

A.2.9

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Index

A.2.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Methodology

TRL5: Extensive laboratory trials continued Depletion series

The concept of a depletion series is used in the determination of the relative sensitivity of a process. A series of fingermarks is deposited by successive contacts of the same

finger with the substrate. Each contact will leave progressively less residue and therefore

the further down the depletion series that the process continues to visualise fingermarks, the more sensitive it is considered to be.

Where possible, split depletion series should be used to minimise the potential impact of variability in fingermark composition on the results. A depletion series of fingermarks is

deposited and physically divided in two along the centre line. Each half of the depletion series is then treated with a different visualisation process or formulation, and then recombined for an assessment of the number and quality of the visualised marks.

Range of donors

Depletion series from several different

donors visualised with superglue/BY40.

Fingermarks should be collected from a range of donors that are as representative of a cross-section of the population as possible, selecting donors that usually give a range of responses to the process under test. If the process being evaluated is for use in

developing fingermarks in contaminant, it is the contaminant that is important and it is not necessary to use a range of donors. A finger from a single donor is dipped in the contaminant and used to deposit a depletion series.

Age of mark

Fingermark composition changes with time after deposition. The experimental

programme should therefore include fingermarks across a range of ages that represent

Split depletion series on adhesive tapes treated with different Basic Violet 3 formulations.

operationally realistic timescales (e.g. one day, one week, one month).

Substrates

Comparative experiments should be carried out using a range of substrates that are

representative of those that the process may be applied to in operational work. Typically, five or six representative substrates may be selected, although the more that can be used the more robust the final conclusions will be.

A range of non-porous substrates. Home Office January 2014

A.2.10

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Index

A.2.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Index

Methodology

TRL5: Extensive laboratory trials continued

grading exercise repeated to establish the potential benefits of the second process. This

If the process under evaluation is intended for use in particular environments, it will be

recorded at each stage, and the total number of marks visualised by the sequence.

Environment

necessary to include an assessment of the effect of that environment in the trial. For

is repeated for each process in the sequence to establish the number of additional marks

example, if an evaluation is being carried out of a process intended for use on wetted substrates, the substrates should be subjected to conditions that replicate wetting.

Grading schemes

To enable comparisons of relative process effectiveness to be carried out, it is

necessary to have some means of converting the appearance of the visualised mark

to a numerical value. Such a method should not rely solely on the ability to detect and count minutiae. Because fingermarks from different donors contain different numbers of minutiae, identifications can be achieved from very small portions of a developed mark and therefore basing assessments solely on identification may skew results. It

is preferable that the method used should consider the extent and clarity of the ridge

detail that has been visualised across the entire region of contact by the process under

evaluation, regardless of whether the area visible would result in an identification. Simple numerical schemes utilise a scale with 0 = no mark and 4 = a fully visualised mark; other

comparative schemes assign a value according to which process has best visualised the mark.

Multiple marks on a paper substrate visualised with DFO.

Establishing fingermark visualisation sequences

To determine optimised processing sequences, tests for the overall effectiveness of the

sequence, the individual effectiveness of the processes within it and the impact of each process on subsequent processes is required. The methods that can be used for these purposes are simple adaptations of the methods used to compare the effectiveness of individual processes in laboratory trials, and these are outlined below.

The same set of marks after further treatment with Ninhydrin.

Sequential processing of multiple donor panels

A single fingermark is collected from as many different donors as possible on a single

substrate, which is then exposed to the desired environment for the selected period of

time. The surface is then exposed to the first visualisation process, and the number and quality of the fingermarks that are visualised by that process is recorded.

The substrate is then exposed to the next visualisation process in the sequence, and the Home Office January 2014

The same set of marks after further treatment with Physical Developer.

A.2.11

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Appendices Glossary

A.2.12

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

TRL5: Extensive laboratory trials continued Sequential processing of split fingermarks

The potential impact of one enhancement process on the subsequent application of another can be investigated by the ‘split fingermark’ method.

In this experiment, a depletion series of fingermarks are deposited down a centre line,

Methodology processes at the end of a sequence will probably require less evaluation than a process in the middle which generally develops most of the marks.

Split depletions on a semi-porous surface to investigate the effect of treating the substrate with Ninhydrin prior to Superglue Fuming.

either on a surface that is capable of being subsequently split (such as paper), or has

been pre-split. The surface is then divided and each half exposed to a different process or sequence of processes. The two treated halves of the fingermark can then be recombined and the effect of process A on process B determined.

By carrying out a series of these tests it is possible to determine which processes are incompatible and which can be used in sequence without detrimental effects.

Scale of a typical experiment

A typical experiment to carry out an initial comparative assessment of a process for a

porous surface would have at least five to six donors, five to six surface types, five to six depletions, and two ages of fingermark, which means 250–432 fingermarks which are

split in half and each treated with a different formulation. To conduct a comparison set of three variables or processes would require three experiments (A vs B, B vs C and C

vs A). However, to draw meaningful conclusions the set of three experiments should be carried out simultaneously using the same donors.

It would be expected to repeat each comparison set at least three times to give a fair

indication of performance by building up the quantity of data and increasing confidence

in the conclusion. In reality, it is extremely difficult to replicate exactly the experiment due to variations in donors marks (see Chapter 2). However, if a variation or process were

clearly underperforming it would be possible to drop that from the trial. Ideally, a rigorous statistical analysis would be applied to the results obtained. In practice, there are too many uncontrolled variables to make this a simple exercise. Results obtained from

separate experiments conducted at different times should be compared with caution as many of the variables (e.g. donor sets, temperature/time of year) may have changed.

The number of developed marks required to provide robustness in the results will vary

with the process or the process’s position in a sequence. Non-destructive processes or Home Office January 2014

A.2.12

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Index

A.2.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Methodology

TRL6: Pseudo-operational trials

Testing to TRL6 and beyond moves away from the comparison of processes using

known standards or planted marks towards the assessment of their relative performance across a range of items or surfaces that may have been handled in very different (and not necessarily known) ways.

Processes reaching TRL6 will have been evaluated in terms of their effectiveness on

items and surfaces representative of real casework, as opposed to marks generated

in a research environment. The reason that the testing to reach TRL5 is so extensive is because it is the last stage of testing that utilises marks deposited by known donors under controlled conditions. Many processes may reach TRL5 but in general they

will only be progressed to TRL6 and beyond if their implementation gives potential operational benefits over existing processes.

The purpose of carrying out the pseudo-operational trials to reach TRL6 is to investigate whether the results obtained in controlled laboratory trials are replicated on the types of items and surfaces that are typical of those that may be submitted to a fingermark

A range of materials collected for a pseudo-operational trial on plastic packaging material.

enhancement laboratory. This is achieved by collecting representative substrates from as many different sources as possible.

Once collected, these items should be divided into batches containing as even a mix of

similar items as possible, and each batch treated with a separate process. Alternatively, larger items can be split (e.g. plastic bags) and each section treated with a different

process. Some form of assessment will then be applied to the fingermarks developed,

such an assessment system being more representative of casework. Methods that have been used include:

●● use of fingerprint examiners;

●● use of a grading scheme based on developed area of ridge detail;

●● point counting by non-specialists, recording marks with over a certain number of

points.

A mark visualised on plastic packaging in a pseudo-operational trial using Basic Violet 3. Home Office January 2014

A.2.13

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Index

A.2.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Index

Methodology

TRL7: Operational trials

Processes at TRL7 will have been fully tested and their performance characterised in an

operational environment. In this phase of the work a trial is carried out on live casework, running the processes under comparison alongside each other with the objective of

establishing whether there is operational benefit in introducing the new process in place of those already in use.

In order to conduct operational trials, a protocol should initially be generated by the

organisation proposing implementation of the new process. This protocol will then need

to be agreed with the laboratories conducting the trial. Additional permissions may need to be obtained from other bodies that may include the Crown Prosecution Service and

the Forensic Science Regulator. All current guidance produced by these bodies relating to the running of operational trials should be consulted.

In the operational trial, cases should be randomly assigned between the different processes or process formulations being used. This may involve some intelligent

distribution so avoiding one process being used to treat excessive amounts of one type

of substrate. For instance, cases involving cheques, or brown envelopes or newspapers etc. would be evenly distributed between processes.

An operational trial should last as long as it takes to establish the effectiveness of the processes or formulations in the trial.

Casework awaiting treatment.

If possible this phase should be carried out blind so that the person carrying out the marking-up process is unaware of which process has been used on which item.

Fingermarks developed in this phase should be assessed by a fingerprint examiner using normal casework standards, counting fingermarks that can be identified and the number of cases and items marks are developed on.

Home Office January 2014

A.2.14

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

Appendices Glossary

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices Glossary

Index

Methodology

TRL8: Publication and implementation of process

TRL9: Collection of operational data

been published and implemented.

supported by a body of evidence that records their operational effectiveness.

Processes at TRL8 have been through extensive testing and the processing method has

Processes at TRL9 have been fully implemented and their continued operational use is

This typically occurs if the new process demonstrates operational benefits over a

Ongoing monitoring (including gathering data on, for example, number of marks

it into operational use. Work will then proceed to preparation of a finalised general

the item has experienced) of process effectiveness should continue post-implementation

prolonged period (typically several months) and there is a clear case for introducing

developed, type of substrate the process has been applied to, environmental conditions

processing instruction for the process and the results of the test programme published. Implementation of the process may require the provision of training, which may be

initiated by the organisation first validating the process. Local verification of the process

so that any changes in effectiveness can be recognised and addressed. In some cases

changes in effectiveness may arise as a result of changes to the types of materials found in substrates rather than any deficiency in the process itself n

and the writing of local operating procedures may be required by other organisations implementing the process in their own laboratories.

Contents

this Safe and Effective Process Category A B-F 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Category Processes 7 Integrating Forensic Recovery Processes Processes

Glossary

Index

Laboratory Use

Processing Preparation (1) Equipment and chemicals

(2) Items

a) Follow manufacturer’s instructions for use of equipment. b) Remove build-up of superglue fumes from within the cabinet prior to opening the cabinet door. There may still be a detectable odour of superglue fumes. c) Pour an appropriate quantity of superglue into a suitable, clean vessel such as a disposable aluminium foil dish. Place the dish on a heater block at ambient temperature. a) If possible, load the fuming cabinet with similar items. b) Support or suspend the items in the cabinet, allowing sufficient room for air to circulate between them. c) Items must be at ambient temperature prior to treatment. See underdeveloped fingermarks and overdevelopment.

a) Optimal contrast is normally achieved within10-30 minutes.

(7) Remove items from the cabinet

a) There may still be a detectable odour of superglue fumes. b) Care must be taken when handling the items as the white polymer deposit is fragile.

(8) Examination

Processing (3) Humidify cabinet

(6) Halt further development once optimal contrast is achieved by removing superglue fumes from within the cabinet

Fingermark Visualisation Manual

Superglue Fuming

Appendices

a) The relative humidity in the cabinet must be maintained within the range 75-90% whilst the items are exposed to superglue fumes.

(4) Evaporate superglue

a) The heater block should allow the superglue to reach about 120°C.

(5) Observe fingermark development

a) White deposits will gradually build up on the items. b) If it is not possible or practical to observe development then the operator must follow manufacturer’s instructions for recommended process conditions OR pre-determine the optimum process conditions.

Primary: Visual Examination

a) Items should be examined in a well-ventilated area preferably on a down-draught bench. b) Visible fingermarks are white. c) There are many non-destructive optical processes that can be considered when examining and imaging fingermarks in addition to Visual Examination. Ultraviolet (UVC) Reflection may prove particularly useful on some items. d) Mark up viable fingermarks appropriately and capture image. e) After examination, items can be re-treated if necessary.

Continued on next column

Home Office January 2014

Home Office January 2014

5.SF.5

A.2.15

Fingermark Visualisation Manual

Appendix 2: Fingermark Research

5.SF.5

A.2.15

Contents

GLO.1

GL

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

The descriptions of words or phrases in this glossary

evidence. A cold case review may include considering

at the time that the event relevant to the crime occurred

misinterpretation may occur. This glossary explains

original investigation and whether any processes that

picked up from one crime scene transferred to an item

are there to assist the reader where confusion or CAST’s use of the words or phrases.

Audit trail: a record of all events of significance to a

what forensic recovery processes were utilised in the

have been subsequently introduced could yield additional information.

particular piece of evidence that have taken place from

Contaminant: (1) a substance other than a naturally

refer to physical evidence, in which case the audit trail

skin that may be found in fingermarks or be the major

the time it was first recovered or captured. The term may may include the times, dates and names of personnel receiving and opening evidence packaging, and any processes that have been carried out. For physical

evidence, the audit trail should provide a complete, accountable timeline between time of recovery and

the time the evidence is presented in court. For digital evidence, such as fingermark images, the audit trail

represents a sequential record of digital enhancement

processes that have been applied to an original ‘master

copy’ image to convert it to the image format that is being presented to the court.

Background: the appearance of the surface where the

fingermark is present under the same conditions used to visualise the mark. The appearance of the background

is influenced by a range of surface properties including

colour, texture, reflectivity and any printed patterns that are present.

Chemical process: a process where the principal

interaction resulting in the visualisation of the fingermark

is chemical in nature, e.g. by means of a reaction between a chemical and the fingermark or by a staining action. Cold case review: a periodic review of an unsolved

case, which involves a reassessment of all leads and Home Office January 2014

occurring constituent of sweat secretions from the

constituent of them (e.g. grease, blood); (2) any substance not relevant to recovery and analysis of a particular

evidence type, but that is present on the item or surface and may interfere with the recovery and analysis

processes (e.g. dirt, drugs residue); (3) a substance

capable of being transferred from surface to surface and that may cause a nuisance or hazard to those coming

into unprotected contact with it (e.g. blood, processing chemicals).

Crime scene (also ‘scene’): a location where evidence

relevant to the investigation into the particular crime may be found. This includes, but may not necessarily be, the location where the crime was committed.

Crime scene practitioner: a person competent in the

examination of crime scenes for the location of multiple

by subsequent transfer from another source (e.g. DNA recovered from another).

Development: a subset of visualisation where a process applied to the fingermark results in it becoming visible

in a progressive way, producing a gradual change from invisible to clearly visible. Most chemical and physical

processes can be considered to ‘develop’ fingermarks. Enhancement: the improvement of a fingermark that is already visible to some extent by the application of an additional process that either reveals additional ridge

detail or makes that which is already visible more readily distinguishable from the background.

Evidence integrity: the maintenance of reliability of

evidence, achieved through effective handling to provide

a robust audit trail and to prevent compromising forensic material that may be required in evidence.

Evidence recovery: the process by which forensic

evidence of any class is first located and then translated into a form suitable for comparison and/or analysis by a person competent in that class of forensic evidence.

types of forensic evidence, and in the application of

Examination: a focused inspection of an item or surface

powdering, fluorescence examination. Numerous job

This differs from the more cursory inspection that may be

certain forensic recovery processes, e.g. DNA swabbing, titles may be used in UK police forces including Crime

Scene Investigator, Scene of Crime Officer, Crime Scene Examiner.

Cross-contamination: the introduction of a substance

not originally associated with a particular item or surface

with the objective of locating particular types of evidence. part of an initial assessment.

Fingermark (also ‘mark’): the mark left as a result of the

uncontrolled contact of a finger with a substrate. The term may also be used as a general description for the marks left by the contact of any region of friction ridge skin,

GLO.1

Fingermark Visualisation Manual

Glossary

GLO.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

which includes palms, toes and the soles of the feet.

evidence being targeted at each stage.

Fingermark Evidence Recovery Plan: a subset of the

Forensic Evidence Recovery Strategy: a strategy

specific objective of maximising fingermark recovery,

for an investigation, taking into account types and

Forensic Evidence Recovery Plan produced with the

taking into account any constraints associated with the

case. A Fingermark Evidence Recovery Plan consists of a sequence of fingermark preparation and visualisation processes to be applied to an item or surface.

Fingermark laboratory practitioner: a person

competent in the application of fingermark visualisation processes in a laboratory environment, possibly also having competence in applying these processes at

scenes of crime. Numerous job titles may be used in UK police forces including Fingerprint Laboratory Officer, Mark Enhancement Officer, Chemical Enhancement Laboratory Officer.

Fingerprint (also ‘print’): a reproduction of the friction ridge skin pattern on the fingertip obtained from a

known donor under controlled conditions, e.g. inked or ‘Livescan’ images obtained in a custody suite.

developed to maximise the recovery of forensic evidence priorities of different forensic evidence classes and any constraints associated with the case.

History: the sequence of events that an item or surface has experienced between the crime occurring and the

current moment in time. This may include knowledge of

environmental exposure conditions and timescales over

which these were experienced, handling and packaging, and the application of any preparation and visualisation processes.

Identification: one possible end result of a comparison

process between a fingermark and a fingerprint, between two sets of fingerprints, or between two fingermarks. The result is considered an ‘identification’ when the examiner

considers the level of agreement in the features occurring in the two marks/prints being compared is sufficiently

high that they must have originated from the same donor.

Fingerprint examiner: a person competent in the

Image: a permanent record that provides a visual

with sets of fingerprints, and qualified to give opinions

viewed under the relevant visualisation conditions. The

comparison of fingermarks recovered from crime scenes relating to identification (or exclusion) of fingermarks.

Forensic Evidence Recovery Plan: a plan developed

to meet the objectives outlined in the Forensic Evidence Recovery Strategy, integrating the recovery of different

reproduction of the original fingermark or object being image may either be a reproduction of what is directly observed by the eye, or what is displayed from an

imaging system. Images may exist in electronic form or as physical records, e.g. negatives or printed material.

forensic evidence classes. An evidence recovery plan

Image enhancement (also ‘image processing’):

processes to be applied and the classes of forensic

objective of producing an image that improves the

should include the sequences of evidence recovery

Home Office January 2014

processes applied to an image post-capture with the

ability of an examiner to distinguish ridge detail from the background or to more clearly define fine detail within fingermarks. The term now generally applies to digital adjustments performed on electronic images.

Image processing: see image enhancement. Impression: the outcome of a contact between a finger

and a substrate where the substrate has deformed during contact, leaving indentations that reproduce the ridge detail on the finger.

Initial assessment: a basic examination of an item or

surface using standard ambient lighting conditions or a

basic white light source with the objective of establishing the potential for the recovery of forensic evidence of any class from it and likely locations where such evidence may be found.

ISO 17025: An international standard concerned with general requirements for the competence of testing

and calibration laboratories. The UK Forensic Science

Regulator has determined that all laboratories conducting fingermark visualisation should be accredited to this standard.

Item: a general term used to describe all physical material that can potentially be removed from a crime scene

for treatment in a laboratory (e.g. plastic bags, knives,

documents), as opposed to non-removable parts of the scene (e.g. walls, ceilings).

Laboratory treatment: the application of processes within an environment where all relevant processing

parameters (e.g. temperature, humidity, extraction of

flammable vapours, lighting) can generally be controlled

GLO.2

Fingermark Visualisation Manual

Glossary

GLO.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

so that process effectiveness is optimised. Note that

to water, other liquids or air. Examples are glass, many

optimised conditions, for example where they will not fit

metals.

items may be processed in a laboratory under nonwithin a treatment chamber.

Latent fingermark: a fingermark that has been formed

on a substrate as a result of contact with a finger and is

not visible to a cursory visual examination. Marks of this

type will require the application of visualisation processes before they can be detected. Mark: see Fingermark. Marking up: the process by which visible or visualised

fingermarks are labelled with relevant information to aid subsequent identification.

Mirrored marks (also ‘reverse-oriented’ or ‘reverse-

direction’ marks): a mark that due to a range of factors may be visualised as a mirror image of the correct orientation.

Mixture: an intimate combination of a solid substance and a liquid material where the solid substance can

remain suspended in the liquid for a finite period of time before settling out. In mixtures the solid substance is

not soluble in the liquid. Powder Suspensions and Small Particle Reagent are examples of mixtures.

Negative mark: the outcome of a contact between a finger and a substrate where material has been

hard and soft plastics, metals, ceramics and painted Optical process: a process where the principal

interaction resulting in the visualisation of the fingermark is influenced by the optical properties of the mark

and surface. This description also includes processes

operating outside the visible region of the electromagnetic spectrum.

Physical process: a process where the principal

interaction resulting in the visualisation of the fingermark is physical in nature, e.g. the adhesive properties influencing powder adhesion during powdering,

nucleation and growth of metal films during Vacuum Metal Deposition.

Porous substrate: Surfaces that are composed of

materials that absorb water and other liquids. Examples are paper, card, cardboard, untreated wood and mattpainted surfaces.

Positive mark: the outcome of a contact between a finger and a substrate where material has been transferred from the finger to the surface.

Practitioner: a person competent in a particular forensic area involved in the practical application of processes relevant to that area.

transferred from the surface to the finger, i.e. material has

Preparation process: a process used to bring the item

contact.

subsequent visualisation processes will be maximised,

been selectively removed from the surface at the points of Non-porous substrate: Surfaces that are not permeable Home Office January 2014

or surface to a condition where the effectiveness of e.g. by removing potentially interfering layers of

contaminant or by separating surfaces to enable them to

interact with the visualisation process. Print: see Fingerprint. Process: a series of related actions that can be applied

to an item or surface towards the end goal of fingermark recovery, e.g. removal of contaminants, visualisation of fingermarks.

Process category: a means of defining the wide range

of processes available for fingermark visualisation, taking into account their maturity, effectiveness and any health and safety issues associated with them. The scale used runs from category A (mature, effective processes for

routine use) to category F (processes that should not be used for health and safety reasons).

Processing chart: the chart page (see Chapter 4) for

sequential processing of items depending upon substrate type or mark/contaminant type. This may be a primary

chart (e.g. Chart 1: Non-Porous) where generic process sequences are presented, or secondary charts where additional specific information is outlined.

Reverse-coloured marks: see Reverse-developed marks.

Reverse-developed marks (also ‘reverse-coloured

marks’): a mark developed using a visualisation process that normally produces marks of a certain appearance

(e.g. dark ridges against a light background), but in this

scenario has produced the opposite appearance to that expected (e.g. light ridges against a dark background). Reverse-direction marks: see Mirrored marks. Reverse-oriented marks: see Mirrored marks.

GLO.3

Fingermark Visualisation Manual

Glossary

GLO.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Ridge detail: the patterns and features formed by the

soluble (the solvent). Most chemical processes utilise

of the hands, toes and soles of the feet. Ridge detail

the solvent, and the solution therefore appears clear with

characteristic ridge structures found on the fingers, palms may be reproduced both within fingerprints taken under

controlled conditions and in fingermarks deposited under uncontrolled conditions.

Scene: see Crime scene. Scene treatment: the application of processes at a scene where it is not generally possible to control processing parameters to the extent required to optimise process effectiveness. Exceptions to this include Powders.

Semi-porous substrate: a material that exhibits neither truly porous nor non-porous properties in relation to its

absorption of liquids and gases. This is a broad category of surfaces which includes both materials of truly semiporous nature, such as leather, silk- and satin- painted

solutions where the solid substance is fully dissolved in

no residual solids. If the solute cannot be fully dissolved in the solvent, a ‘saturated solution’ is formed.

Substrate: the material with which the finger makes

contact during generation of the fingermark that includes

both the surface (which is important during initial contact) and the bulk of the material (which may subsequently

substrate, referring to the difference in height between Surfaces with minimal height difference are often

described as ‘smooth’ and those with a noticeable height difference described as ‘textured’ or ‘rough’.

readily visible during a cursory visual examination. Where

Solution: a liquid formed by the dissolving of a minor component (the solute, in this Manual usually a solid substance) into a liquid phase material in which it is Home Office January 2014

allocated to its investigation, e.g. theft from vehicles n

is important.

destructive processes and then utilising processes with substrate.

frequent basis and generally has fewer resources

properties or where a particular property of it (e.g. texture)

Visible fingermark: a fingermark that has been formed

a progressively increasing impact on the fingermark and

Volume crime: a crime type that occurs on a relatively

of a substrate, particularly where it differs from the bulk

Sequential processing involves the selection of the

processes in a logical sequence, beginning with non-

being used to examine the substrate.

(2) a term used to refer specifically to the surface layer

the peaks and troughs of any surface features present.

the objective of maximising fingermark recovery.

observer, or readily detectable by an imaging system

removable parts of the scene such as walls and ceilings;

printed paper or cardboard.

of visualisation processes to an item or surface with

on a substrate to make it either readily visible to a human

Surface: (1) a general term used to describe the non-

Texture: a description of the surface topography of a

Sequential processing: the application of a sequence

Visualisation process: a process applied to a fingermark

interact with the constituents of the mark).

surfaces, and those with regions of porous nature

interspersed with non-porous regions, such as heavily

this is achieved.

on a substrate as a result of contact with a finger and is

such marks have been deposited in visible contaminants

such as dirt, ink, blood or paint they may occasionally be described as ‘patent’ fingermarks.

Visualisation: the conversion of a latent fingermark into

a readily visible one, independent of the means by which

GLO.4

Fingermark Visualisation Manual

Glossary

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Index A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z. Illustrations and figures are in bold. Tables are in italics. 5-MTN (5-methylthioninhydrin) 6.4.3, A.2.8

Acid Black 1 see also Acid Dyes

alternative names 3.1.18, 5.AD.6, 6.1.7, 6.3.6

background staining 5.AD.12

A processes see category A processes Absorene® dough 5.SR.7, 5.SR.13

absorption of radiation 2.2.30, 5.VE.28, 5.VE.29

accreditation schemes 3.1.2, 3.3.2, 3.3.6, A.2.1 see also ISO 17025

acetate sheets for ESDA 5.ESDA.4 acetic acid

CAS number 3.1.18, 5.DFO.6, 5.Nin.7, 6.3.6, 6.3.13

DFO theory 5.DFO.13

methanol-based category D process overview 6.3.3 safety 6.3.4

sequential processing 6.3.3

overview 5.AD.2 theory 5.AD.14 water-based

overview 6.1.3

solution preparation 6.1.8

Acid Blue 83 6.4.2 Acid Dyes

age of mark effect 2.3.13

background staining 5.AD.12

category B process see Acid Dyes, water-based

category D process see Acid Dyes, methanol-based

colour enhancement 5.CF.6

CAS number 3.1.18

health and safety 5.TCR.3, 5.TCR.4 post-processing 5.TCR.6 Home Office January 2014

5.FE.28–9

laboratory organisation 3.1.7

solution preparation 5.DFO.7 acetone

visualisation 5.AD.8

fixing 5.AD.11

colour enhancement 5.CF.6

category E process 6.4.2

solution problems 5.DFO.12

Fluorescence Examination 5.FE.10,

faint marks 5.AD.11

footwear marks 4.51, 7.18

Ninhydrin theory 5.Nin.19 process uses 3.1.18

temperature effects 2.3.11, 2.3.18

CAS number 3.1.18

sequential processing 5.AD.2

A

equipment 5.AD.6

chemicals 3.1.18, 5.AD.6 contaminants 2.3.5

corrective action category D processes see Acid Dyes, methanol-based

date of introduction 2.3.4

effectiveness 5.AD.1, 5.AD.3, 5.AD.10

integrated use 5.AD.1 methanol-based

chemicals 6.3.6

effectiveness 6.3.2 equipment 6.3.5

integrated use 6.3.2 options 6.3.3

post-processing 6.3.9 process details 6.3.8

process overview 6.3.2 safety 6.3.2, 6.3.4

sequential processing 6.3.3 solution preparation 6.3.7 surface types 6.3.2

options 5.AD.2

theory 2.3.18, 5.AD.14 water-based

chemicals 6.1.7

compared to category A 5.AD.3, 6.1.2

effectiveness 6.1.2, 6.1.4, 6.1.11 equipment 6.1.6

integrated use 6.1.2 options 6.1.3

post-processing 6.1.10

practicality 6.1.4, 6.1.11 process details 6.1.9

process overview 6.1.2

safety 6.1.2, 6.1.4–5, 6.1.11

scene treatment 6.1.4, 6.1.11 sequential processing 6.1.3 solution preparation 6.1.8 surface types 6.1.2

water exposure 2.3.12

porous substrate problems 5.AD.13

Acid Red 71 6.4.2

practicality 5.AD.3, 5.AD.10

Acid Violet 17 see also Acid Dyes

post-processing 5.AD.9 process details 5.AD.8

process overview 5.AD.1, 5.AD.14

acid storage 3.1.15, 3.2.26

alternative names 3.1.18, 5.AD.6, 6.1.7, 6.3.6

safety 5.AD.1, 5.AD.3, 5.AD.4–5,

background staining 5.AD.12

scene treatment 5.AD.3, 5.AD.10

colour enhancement 5.CF.6

5.AD.10

sequential processing 2.3.8, 5.AD.2 solution preparation 5.AD.7

surface types 2.3.14, 5.AD.1 target properties 2.3.5

CAS number 3.1.18

methanol-based category D process overview 6.3.3 safety 6.3.4

sequential processing 6.3.3

IND.1

Fingermark Visualisation Manual

IND

IND.1

Contents

IND.2

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. Acid Violet 17 continued overview 5.AD.2

sequential processing 5.AD.2 theory 5.AD.14 water-based

overview 6.1.3

solution preparation 6.1.8

Acid Violet 19 6.4.2

acid wash solutions 5.SR.6, 5.SR.8, 5.SR.15

Acid Yellow 7 see also Acid Dyes

alternative names 3.1.18, 5.AD.6, 6.1.7, 6.3.6

CAS number 3.1.18

Fluorescence Examination 5.FE.10, 5.FE.28–9

methanol-based category D process overview 6.3.3 safety 6.3.4

sequential processing 6.3.3

overview 5.AD.2

porous substrate problems 5.AD.13 sequential processing 5.AD.2 theory 5.AD.14 water-based

overview 6.1.3

solution preparation 6.1.8

Acid Yellow 23 6.4.2

acrylonitrile butadiene styrene (ABS) 4.7 adhesive forces 5.Lif.16

Home Office January 2014

adhesive tape

Lifting 5.Lif.2, 5.Lif.6, 5.Lif.8–9

Powder Suspensions 4.39, 5.PS.15, 5.PS.16

storage post-processing 5.ATR.7 water 5.BV3.17, 5.FE.30

Adhesive Tape Removal

case studies A.1.3, A.1.6, A.1.7 category B process 6.1.12 condensation 5.ATR.2

effectiveness 5.ATR.1, 5.ATR.3, 5.ATR.8

equipment 5.ATR.5

integrated use 5.ATR.1

laboratory organisation 3.1.7 laboratory use 5.ATR.3

administrative controls, light source risk

category E reagents 6.4.3

Aerosol OT™ see DOSS

Ninhydrin 5.Nin.19

reduction 3.2.17

age of mark

estimation 2.2.17

laboratory trials A.2.10

analysis software, Multi-Spectral Imaging

visualisation effectiveness 2.3.9, 2.3.10, 2.3.13, 2.3.20

agglutinogens 5.AD.14 air depletion 3.2.18 airflow

Powders 3.1.13

wind effects 2.2.24

alloxan 6.4.3

safety 5.ATR.1, 5.ATR.4, 5.ATR.8

scene treatment 5.ATR.3, 5.ATR.8 sequential processing 5.ATR.2 solvents 5.ATR.2, 5.ATR.10 surface types 5.ATR.1 theory 5.ATR.9–10

adhesives with cellulose backings 4.40 adhesives with non-porous backings 4.19–21

adhesives with porous backings 4.32 adhesives with semi-porous backings 4.39

5.PDE.6

substrate effects 2.2.18–20

processing charts key 1.15

practicality 5.ATR.3, 5.ATR.8 process overview 5.ATR.1

5.MMD.6, 5.MMD.8, 5.MMD.9, 5.PD.6,

ammunition 4.18, 7.2 see also ballistics

aldimine 5.Nin.19

process details 5.ATR.6

ammonium iron (II) sulphate hexahydrate

persistence 2.2.17

options 5.ATR.2

post-processing 5.ATR.7

DFO 5.DFO.13

alkali wash solutions 5.SR.8, 5.SR.13 alloys 4.18

aluminium 4.18

aluminium powder

composition 5.Pow.9

effectiveness 5.Pow.2 glass 4.6

Lifting 5.Lif.13, 5.Lif.15, 5.Lif.16, 5.Pow.2

lighting techniques 5.VE.18, 5.VE.19, 5.VE.25

safety 5.Pow.2

theory 5.Pow.17

aluminium Vacuum Metal Deposition 6.4.5 amino acids

forensic analysis

5.MSI.9, 5.MSI.12–13

angle of illumination 2.2.31, 5.VE.9, 5.VE.24

angle of irradiation 5.UVCR.10, 5.UVCR.11

angled scales, image capture 3.3.17 animal hair brushes 5.Pow.7

anthracene evaporation 6.4.5

Anti-Stokes fluorescence 5.FE.23 AOT™ see DOSS

apocrine glands 2.2.8, 2.2.10 arc lamps 5.FE.37 arches 2.5.2

Artificial Optical Radiation (AOR) sources 3.2.14–17, 3.2.34–5

atmospheric pollution 2.2.25

ATR-FTIR (attenuated total reflection-

Fourier transform infrared spectroscopy) 6.2.2

audit trail see also record keeping contrast optimisation 2.5.8 definition 2.4.3, GLO.1

imaging 3.3.22–3, 3.3.24

auto-adhesion 5.Pow.18

IND.2

Fingermark Visualisation Manual

Index

IND.3

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. autoradiography 5.PDE.14, 6.1.46

overview 7.2–3

colour enhancement 5.CF.6

sequential processing 2.1.12, 7.3

date of introduction 2.3.4

Palladium Deposition 6.1.45 band-blocking filters 5.FE.40 band-pass filters

B

B processes see category B processes background

Acid Dye staining 5.AD.12

Basic Violet 3 staining 5.BV3.1, 5.BV3.2, 5.BV3.19

case studies A.1.13 definition GLO.1

fluorescence 5.FE.17–18, 5.FE.25, 5.FE.31, 5.FE.38

identification in images 3.3.16 Lifting 5.Lif.16

Ninhydrin development 5.Nin.15–17 Physical Developer development 5.PD.13–14

Powder Suspensions development 5.PS.14, 5.PS.16

Powders development 5.Pow.16, 5.Pow.18

Solvent Black 3 staining 5.SB3.11

Superglue Fluorescent Dye Staining 5.SFDS.15

backscattered light 5.VE.31 ballistics forensic analysis

Fluorescence Examination 5.FE.18, 5.FE.41

Infrared Reflection 5.IRR.4, 5.IRR.11

UVC Reflection 5.UVCR.5, 5.UVCR.14

bandwidth, visualisation options 2.2.31 bank notes see currency

process details 5.BV3.10

process overview 5.BV3.2

solution preparation 5.BV3.7, 5.BV3.9

solution problems 5.BV3.14

drying of items 5.FE.30

safety 5.BV3.1, 5.BV3.3, 5.BV3.4, 5.BV3.13

scene treatment 5.BV3.1, 5.BV3.3, 5.BV3.13

sequential processing 5.BV3.2

solution preparation 5.BV3.7–8

solution problems 5.BV3.14–15 surface types 2.3.14, 5.BV3.1

CAS number 3.1.18, 5.SFDS.7, 6.1.60

equipment 5.BV3.6

theory 5.BV3.20

Fluorescence Examination 5.FE.10,

faint marks 5.BV3.18

category B process 6.1.57, 6.1.61 5.FE.28–9

overview 5.SFDS.2

solution preparation 5.SFDS.8

Basic Violet 2 6.2.3 Basic Violet 3 (BV3)

adhesives with cellulose backings 4.40

adhesives with semi-porous backings 4.39

age of mark effect 2.3.13 alternative names 3.1.18

background staining 5.BV3.1, 5.BV3.2, 5.BV3.19

Electroless Silver Deposition 6.2.7

chemicals 5.BV3.6

Home Office January 2014

labelling systems 5.BV3.5

rubber 4.15

target properties 2.3.5

Fluorescent Dye Staining

CAS number 3.1.18

Gun Blueing 6.1.24

DOSS

PVC 4.13

effectiveness 5.BV3.1, 5.BV3.3,

Basic Red 14 see also Superglue

CERA 6.2.4

Electrochromic Development 6.2.6

contaminants 2.3.5

process overview 5.BV3.1

case studies A.1.3, A.1.6, A.1.12 cling film 4.14

5.BV3.13

expanded polystyrene 4.11 Fluorescence Examination 5.BV3.2, 5.BV3.18, 5.FE.10, 5.FE.28–9

integrated use 5.BV3.1

laboratory organisation 3.1.7

options on additional post-processing 4.2

Phenol

background staining 5.BV3.19 labelling systems 5.BV3.5 process details 5.BV3.11

process overview 5.BV3.2

solution preparation 5.BV3.8, 5.BV3.10

solution problems 5.BV3.15

post-processing 5.BV3.12

practicality 5.BV3.3, 5.BV3.13 process details 5.BV3.9–11

temperature effects 2.3.11 transfer process 5.BV3.11, 5.BV3.17– 18

uPVC 4.9

water exposure 2.3.12

Basic Yellow 40 see also Superglue Fluorescent Dye Staining

background staining 5.SFDS.15

CAS number 3.1.18, 5.SFDS.7, 6.1.60 category B process 6.1.56

faint fluorescent marks 5.FE.15

Fluorescence Examination 5.FE.10, 5.FE.28–9

overview 5.SFDS.2

solution preparation 5.SFDS.8 transparent items 5.FE.22

beam size 2.2.31 bedclothes 4.41 benzidine 6.5.2

7,8 benzoflavone 6.1.36

IND.3

Fingermark Visualisation Manual

Index

IND.4

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. benzo[f]ninhydrin 6.4.3

biaxially oriented polypropylene (BOPP) 4.12

blood

composition 5.AD.14

forensic evidence recovery 7.4–5

blood contamination

Acid Dyes 5.AD.1, 5.AD.2, 5.AD.11 see also category D processes

bichromatic powders 6.4.7

age of mark 2.3.10

biodegradable plastics 4.10, 4.43

category A processes 2.3.5

bifurcations 2.5.2

biological hazards 3.2.12–13

biological safety cabinets 3.2.13 bit depth 3.3.20, 3.3.21

black boxes 5.VE.6, 5.VE.18, 5.VE.20, 5.VE.31

case studies A.1.14

category B processes 4.61–2, 6.1.2 category C processes 4.61–2

category E processes 6.4.2, 6.4.6

combined with grease contamination 4.54

black granular powder 5.Lif.17, 5.Pow.3,

Fingermark Evidence Recovery Plan

black lights see low pressure mercury

fingermarks generation 2.2.12–13

black magnetic powder

hazard consideration 3.2.12

5.Pow.9 see also granular powders

vapour tubes

cling film 4.14

Lifting 5.Lif.17

process overview 5.Pow.4 PVC 4.13

specifications 5.Pow.9 uPVC 4.9

black powder lighting techniques 5.VE.19

2.4.10

Fluorescence Examination 5.FE.9 Infrared Reflection 5.IRR.7 interpretation 4.58–9 overview 4.57

process selection, non-porous substrates 4.22

process selection, porous substrates 4.33

black wet powder see carbon-based

process selection, semi-porous

blades, cutting tools 7.24

processing charts key 1.13

bleach 3.1.20, 5.PDE.6, 5.PDE.14 see

time of deposition 4.58

Powder Suspension

blanking plates 5.VE.6

also sodium hypochlorite

blocking artefacts 3.3.21

Home Office January 2014

substrates 4.47

temperature effects 2.3.10 water exposure 2.3.10

blood dyes see Acid Dyes

blood-mark interpretation 4.58–9

blood pattern analysis (BPA) 4.58, 7.4, 7.5 Blu-Ray discs 7.9

blue toning 5.PDE.2, 5.PDE.6, 5.PDE.11,

‘bronze’ powder 5.Pow.2, 5.Pow.9 brushes

Powder Suspensions 5.PS.5 Powders 5.Pow.7

5.PDE.14

brushes for Powders 5.Pow.15

6.1.13

bullets 7.2 see also ballistics forensic

Body Decomposition Residue Removal body decomposition residues 4.57 body fluids

DNA evidence 7.10

fingermarks generation 2.2.12–13

BT20 see blue toning analysis

BV2 6.2.3

BV3 see Basic Violet 3

fluorescence 5.FE.9

C

hazards 3.2.12

cadmium 6.5.2

forensic evidence integration 7.4–5 presumptive tests 7.4

body protection 3.2.9, 3.2.17

BOPP see biaxially oriented polypropylene borosilicate glass 3.1.13–14, 3.2.24 bottles

labelled 4.53 plastic 4.8

BPA (blood pattern analysis) 4.58, 7.4, 7.5 brass 4.18

brass alloy powder 5.Pow.2, 5.Pow.9

C processes see category C processes calibration 3.3.2, 3.3.6, 3.3.17 camera filters 5.FE.46

camera systems see imaging systems camphor burning 6.4.5 candles 4.16

capacity of mass balances 3.3.5 car dashboards 4.7 car exteriors 4.17

carbolic acid see Phenol-based Basic Violet 3

breathing apparatus 3.2.11

carbon-based Powder Suspension

bright field transmitted lighting

carbon black 4.15

brick 4.45

application examples 5.VE.9, 5.VE.11, 5.VE.19

equipment 5.VE.5, 5.VE.19 set-up 5.VE.19 theory 5.VE.32

bronze 4.18

5.PS.1, 5.PS.2, 5.PS.6, 5.PS.17

card 4.37

cardboard 4.27, 4.37 carpets 2.1.8

cartridge cases 7.2 see also ballistics forensic analysis

IND.4

Fingermark Visualisation Manual

Index

IND.5

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics.

Multi-Spectral Imaging A.1.14

Ninhydrin A.1.1, A.1.3, A.1.4, A.1.6, A.1.12

Cartridge Electrostatic Recovery and

overview 1.5, A.0.1

cascade developer powder 5.ESDA.4,

Physical Developer A.1.9

Analysis 6.2.4

5.ESDA.6, 5.ESDA.9

case studies

paper A.1.14

Powder Suspensions A.1.1, A.1.3,

A.1.6, A.1.7, A.1.9, A.1.10, A.1.12

Adhesive Tape Removal A.1.3, A.1.6,

Powders A.1.3, A.1.4

background A.1.13

SIM cards A.1.10

A.1.7

Basic Violet 3 (BV3) A.1.3, A.1.6, A.1.12

scene treatment A.1.8 Superglue Fluorescent Dye Staining A.1.10, A.1.12

blood contamination A.1.14

Superglue Fuming A.1.6, A.1.10,

complex items A.1.1, A.1.2–3, A.1.9

trace evidence A.1.5–6, A.1.7

DFO A.1.3, A.1.12

Visual Examination A.1.3, A.1.6, A.1.7,

cold case review A.1.11–12 currency A.1.13

digital forensics A.1.10

DNA evidence A.1.5–6, A.1.7, A.1.14 Fingermark Evidence Recovery Plan A.0.1, A.1.1–14

fire scenes A.1.9

Fluorescence Examination A.1.3,

A.1.12

Vacuum Metal Deposition A.1.12 A.1.8, A.1.9, A.1.13

CAST maturity ratings definition 1.8

processing charts 1.9, 1.13, 1.16

Technology Readiness Levels (TRLs) A.2.4

A.1.6, A.1.7, A.1.8, A.1.9, A.1.14

casting 5.VE.10, 7.18, 7.25

A.1.5–6, A.1.7, A.1.10, A.1.14

category A processes

forensic evidence integration A.1.2–3, glass A.1.11–12

grease contamination A.1.8 Infrared Reflection A.1.13

integration of forensic evidence A.1.2– 3, A.1.5–6, A.1.7, A.1.10, A.1.14

Lifting A.1.8, A.1.13

Home Office January 2014

catch tanks 3.1.11, 5.SFDS.6 date of introduction 2.3.3–4

process instruction usage overview 1.4, 1.16–17, 5.1

sequential processing 2.3.8 target properties 2.3.5

Technology Readiness Levels (TRLs)

chemicals 6.3.13

usage guidance 2.3.2

equipment 6.3.12

A.2.3

category B processes

complex items 4.50

overview list of methods 6.1.1

overview of surface types 4.61–2

Technology Readiness Levels (TRLs) A.2.3

usage guidance 1.5, 1.18, 2.3.2, 6.0.1, 6.1.1

category C processes

complex items 4.50

overview list of methods 6.2.1

overview of surface types 4.61–2

Technology Readiness Levels (TRLs)

Fingermark Visualisation Manual

Index effectiveness 6.3.10 integrated use 6.3.10

post-processing 6.3.16 process details 6.3.15

process overview 6.3.10 safety 6.3.10, 6.3.11

solution preparation 6.3.14 surface types 6.3.10

Technology Readiness Levels (TRLs) A.2.3

usage guidance 1.5, 1.18, 2.3.2, 6.0.1, 6.3.1

category E processes 1.5, 1.18, 2.3.2, 6.0.1, 6.4.1, A.2.3

A.2.3

category F processes 1.5, 1.18, 2.3.2,

6.2.1

caustic soda see sodium hydroxide

usage guidance 1.5, 1.18, 2.3.2, 6.0.1, category D processes

Acid Dyes (methanol-based)

6.0.1, 6.5.1–2, A.2.3

CCD (charge coupled device) sensors 5.IRR.10

chemicals 6.3.6

CCTV 7.6–7

equipment 6.3.5

cellophane packaging 4.43

effectiveness 6.3.2 integrated use 6.3.2 options 6.3.3

post-processing 6.3.9 process details 6.3.8 safety 6.3.2, 6.3.4

sequential processing 6.3.3 solution preparation 6.3.7 surface types 6.3.2

Ninhydrin Enhancement

CDs 7.9

CERA 6.2.4

ceramics, processing charts 4.6 chairs, plastic 4.7

chalk powder 6.5.2

charge coupled device (CCD) sensors 5.IRR.10

chemical processes

definition GLO.1

fingermark properties 2.2.28

IND.5

IND.6

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. chemical processes continued

forensic evidence integration 7.1

clothing 4.41

CLP Chemicals Classification 3.2.20,

colour images 3.3.20

CMOS (complementary metal-oxide-

colour wheel 5.CF.6, 5.CF.10

3.2.30–2

semiconductor) sensors 5.IRR.10

information maximisation 2.4.4

CNA fuming see Superglue Fuming

surface effects 2.2.32

cold case review 2.3.3, A.1.11–12, GLO.1

overview 5.1, 5.CPP.1

target properties 2.3.5

chemicals

theory 5.CF.9–13

co-axial illumination 5.VE.8

colloidal gold 5.MMD.4, 5.MMD.7, 5.MMD.9, 5.MMD.14

colour vision 5.FE.49

communications between practitioners

images 2.5.7–8, 2.5.9, 2.5.15, 2.5.20, 3.3.23, 3.3.25

lifts 2.5.6

marking up 2.5.5

overview 2.5.1, 2.5.4

contaminant prevention 3.3.4

colloidal silver 5.MMD.4, 5.MMD.8,

communications devices 7.8, 7.9

effective use 3.3.3–4

colour-blindness 5.FE.49

competence 3.1.2, 3.3.2, 3.3.22

disposal 3.2.28–9 handling 3.2.23

hazard management 3.2.20–7 inventory tables 3.1.18–20 shelf-life 3.3.4

specifications 3.3.3

storage 3.1.15, 3.2.24, 3.2.26–7, 3.3.4

CHIP (Chemicals (Hazard Information

and Packaging for Supply) Regulations) 3.2.20, 3.2.33

chipboard 4.30

4-chloro-7-nitrobenzofurazan (NBD chloride) 6.4.3

chromium 4.18

cis-butenedioic acid see maleic acid

citric acid 5.MMD.4, 5.MMD.6, 5.MMD.7, 5.MMD.9, 5.PD.6, 5.PDE.6

classification of processes 2.3.2

‘clean’ environments 4.51, A.1.5 see also cross-contamination

cling film 4.14

Home Office January 2014

5.MMD.9, 5.MMD.13, 5.MMD.14

colour cancellation 5.CF.6, 5.CF.13, 5.IRR.7, 5.IRR.8

colour enhancement 5.CF.6, 5.CF.11–12 Colour Filtration

application examples 4.60 colour selection 5.CF.6

compared to Multi-Spectral Imaging

comparative testing A.2.9–11, A.2.12 complementary metal-oxide-

semiconductor (CMOS) sensors 5.IRR.10

complex items

case studies A.1.1, A.1.2–3, A.1.9 category B-C processes 4.50

Adhesive Tape Removal 5.ATR.2

Fluorescence Examination 5.FE.30 Numberplate Splitting 5.NS.5

storage of forensic evidence 2.2.22

condoms 4.15

cones, eye structure 5.FE.48 constraints

effect on Forensic Evidence Recovery Strategy 2.1.11, 2.1.13–15

force policies 2.1.3, 2.1.13 health and safety 2.1.14

laboratory treatment 2.1.15

process selection 1.11, 2.1.13–15, 4.2 resources 2.1.15, 2.4.13 scene treatment 2.1.15

sequential processing 2.1.14 time 2.1.13, 2.4.13 types 2.1.1

volume crime 2.1.13

coordination with other forensic

contact angle 2.2.16

date of introduction 2.3.3

masking 2.4.10, 4.53, A.1.10, A.1.12

contact marks

equipment 5.CF.5

preparation processes 3.3.13, 4.50

5.MSI.10

effectiveness 5.CF.1, 5.CF.3, 5.CF.8 integrated use 5.CF.1 options 5.CF.2

practicality 5.CF.3, 5.CF.8

analysis 4.51

optical processes 4.50

process selection 4.49–54

sequential processing 4.52

targeted processing 4.53, 4.54

contact environment 2.2.16 DNA evidence 7.11 fabrics 4.41

Fluorescence Examination 4.51 initial assessment 2.1.8 leather 4.44

process details 5.CF.7

complex scenario planning 2.4.2, 2.4.9–

contact pressure 2.2.14–15, 2.5.16

safety 5.CF.1, 5.CF.3–4, 5.CF.8

complex solutions definition 3.3.7

contaminants see also blood

surface types 5.CF.1

concrete 4.45

process overview 5.CF.1

scene treatment 5.CF.1, 5.CF.3, 5.CF.8 targets 4.60

10, 2.4.13

compression of image files 3.3.21 condensation

contact time 2.2.16

contamination; cross-contamination;

grease contamination; Soot Removal; water

IND.6

Fingermark Visualisation Manual

Index

IND.7

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. contaminants continued age of mark 2.3.10

atmospheric pollution 2.2.25 category A processes 2.3.5 definition GLO.1

DNA evidence 7.10

drugs evidence recovery 7.15

Earth and Mud Removal 6.1.22

Fingermark Evidence Recovery Plan 2.4.10

fingermarks generation 2.2.8, 2.2.12– 13

Fluorescence Examination 4.2, 5.FE.21

glove usage 3.2.10, 3.3.10-11 Infrared Reflection 5.IRR.7

integrity of fingermark evidence 3.3.10 overview 4.56–9

Physical Developer 5.PD.18

Powders theory 5.Pow.17, 5.Pow.18 processing chemicals 3.3.4 release paper 5.ATR.5

removal processes 4.55, 4.57

reverse-developed marks 2.5.16

storage of forensic evidence 2.1.5 targeted processing 4.57

temperature effects 2.3.10 textiles 7.17

time of deposition 4.56

Vacuum Metal Deposition problems Home Office January 2014

5.VMD.21, 5.VMD.23

visualisation 2.2.26

water exposure 2.3.10

context 1.2, 1.4

contextual evidence 2.5.6, 2.5.7, 3.3.16, 4.41

contrast optimisation audit trail 2.5.8

initial planning 2.4.5

lighting techniques 4.2, 5.CF.6, 5.CF.10–13

Multi-Spectral Imaging 5.MSI.6, 5.MSI.7

optical processes 2.2.28, 4.2

ridge detail requirements 2.5.8 surface effects 2.2.32 wet surfaces 4.3

Control of Substances Hazardous to

Health (COSHH) regulations 3.2.7, 3.2.13

cooling for image enhancement 5.FE.30 Coomassie Blue 6.4.2 copper 4.18, 6.2.7

copper acetate 6.4.4

copy lighting 5.VE.29

options 6.3.3

post-processing 6.3.9

visual ability 5.FE:49

visual attention 5.FE:49

process details 6.3.8

critical micelle concentration (CMC)

safety 6.3.2, 6.3.4

cross-contamination

process overview 6.3.2 sequential processing 6.3.3 solution preparation 6.3.7 surface types 6.3.2

Ninhydrin Enhancement chemicals 6.3.13

effectiveness 6.3.10 equipment 6.3.12

integrated use 6.3.10

post-processing 6.3.16 process details 6.3.15

process overview 6.3.10

5.SPR.12

complex items 4.51 definition GLO.1 handling 3.1.3

integrity of fingermark evidence 3.3.10 segregation of forensic evidence 2.1.5

cross-polarised lighting

application examples 5.VE.10, 5.VE.16, 5.VE.21

equipment 5.VE.4, 5.VE.7–8, 5.VE.21

set-up 5.VE.21 theory 5.VE.34

safety 6.3.10, 6.3.11

Crowles Double Stain 6.4.2

surface types 6.3.10

cupric acetate/dithioxamide 6.4.4

solution preparation 6.3.14 usage guidance 1.5, 1.18, 2.3.2, 6.0.1, 6.3.1

corrosion of metals 2.2.20, 4.18 COSHH (Control of Substances

Hazardous to Health) regulations 3.2.7, 3.2.13

crystal violet see Basic Violet 3 curcumin 6.1.43 currency

case studies A.1.13 coins 4.18

fluorescence 4.12, 4.29

Infrared Reflection 5.IRR.7

corona wand, ESDA 5.ESDA.4, 5.ESDA.5,

cosmetics 2.2.13, 4.23, 4.34, 4.48

corrective action category D processes

crime scene definition GLO.1

curtains 4.41

crime scene practitioners

cyanoacrylate fuming see Superglue

5.ESDA.10

Acid Dyes (methanol-based) chemicals 6.3.6

effectiveness 6.3.2 equipment 6.3.5

integrated use 6.3.2

costs 2.1.15, 3.2.2

Crime Scene Investigators (CSI) 2.1.6 competence 3.1.2 definition GLO.1

paper 4.25, 4.29

polymeric 4.12, A.1.13

cutting tools 7.24 Fuming

fatigue 5.FE:49

IND.7

Fingermark Visualisation Manual

Index

IND.8

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics.

image transfer 2.5.9

storage of forensic evidence 2.1.5, 2.4.12

D

delamination during lifting 5.Lif.14

DAB 6.4.6

depletion series A.2.10, A.2.12

D processes see category D processes damage to forensic evidence 2.1.4, 2.1.15, 3.3.11, 4.3, 4.24

Dangerous Preparations Directive 3.2.20 Dangerous Substances Directive 3.2.20 dark adaptation

examination rooms 3.1.5

goggles 5.FE.7, 5.FE.12, 5.FE.48 theory 5.FE:48, 5.FE:49

density of liquids 3.3.5 dermis 2.2.8

detergent solutions 3.3.8

development definition GLO.1 development ovens

DFO 3.1.8, 3.1.10, 5.DFO.5 Indandione 6.1.27 Ninhydrin

humidity 5.Nin.19

time required 5.FE:49

process details 5.Nin.9, 5.Nin.10

dark field reflected lighting

requirements 5.Nin.5, 6.3.12 safety 3.1.8, 3.1.10

advantages 5.VE.31

application examples 5.VE.9, 5.VE.18 equipment 5.VE.4, 5.VE.6, 5.VE.18 set-up 5.VE.18 theory 5.VE.31

dark field transmitted lighting advantages 5.VE.33

application examples 5.VE.9, 5.VE.20 equipment 5.VE.5, 5.VE.6, 5.VE.20 set-up 5.VE.20 theory 5.VE.33

data recovery see digital forensics day-to-day communication 2.5.4 dead-man’s switch 5.FE.5

decontamination, emergency 3.2.8 deformation of skin 2.2.3, 2.2.14 degradation

Home Office January 2014

DFO

set-up 5.Nin.6

age of mark effect 2.3.13

background fluorescence 5.FE.17–18

illumination light transmission 5.FE.19

digital image resolution requirements

labelling solutions 5.DFO.4

digital image transfer 2.5.9, 3.3.21,

Multi-Spectral Imaging 5.MSI.7

digital printers 3.3.23

integrated use 5.DFO.1

laboratory organisation 3.1.7 post-processing 5.DFO.9 practicality 5.DFO.2

dilution series A.2.7

sequential processing 2.3.8

solution preparation 5.DFO.7

discharge lamps 5.FE.37

temperature effects 2.3.11, 2.3.17

disulphur dinitride 6.2.15

targeted processing 4.53 theory 2.3.17, 5.DFO.13 thermal paper 4.26

thermal paper blackening 5.DFO.12 water exposure 2.3.12

1,8-diazafluoren-9-one see DFO chloride/ferric chloride 6.4.4

date of introduction 2.3.4

diffuse reflection 2.2.30, 5.VE.27, 5.VE.28

equipment 3.1.8, 3.1.10, 5.DFO.5

digital forensics 2.1.12, 7.8–9, A.1.10

5.DFO.13, 5.FE.10, 5.FE.28–9

21

target properties 2.3.5

surface types 5.DFO.1

2,6-dichlorophenol indophenol, sodium

grease contamination 4.34

4-dimethylaminocinnamaldehyde 6.1.14– dioctyl sulfosuccinate, sodium salt see

contaminants 2.3.5

Fluorescence Examination 5.DFO.8,

Ninhydrin

solution problems 5.DFO.10–11

2,7-dichlorofluorescein/aluminium

effectiveness 5.DFO.1, 5.DFO.2

3.3.17

safety 3.2.18, 5.DFO.1, 5.DFO.2–3

chemicals 5.DFO.6

dark-coloured paper 4.28

Digital Single Lens Reflex (DSLR) cameras 2,2-dihydroxy-1,3-indandione see

process overview 5.DFO.1

diaminobenzidine 6.4.6

compared to Ninhydrin 5.Nin.20

3.3.23, 3.3.25

process details 5.DFO.8

CAS number 3.1.18

case studies A.1.3, A.1.12

3.3.19

salt 6.4.3

diffusing hemispheres 5.VE.7 digital image enhancement interpretation 2.5.20 options 3.3.22

DOSS-based Basic Violet 3

distortion interpretation 2.5.19 DMAC (4-dimethylaminocinnamaldehyde) 6.1.14–21

DNA evidence

body fluids preservation 7.5

case studies A.1.5–6, A.1.7, A.1.14 CCTV guidance 7.6

contaminants due to handling 2.1.5 fabrics 4.41

hairs 7.10, 7.22

method overview 7.10–11

National DNA Database 7.10

sequential processing 2.1.12, 2.1.14, 7.11

document evidence 7.12–13

document evidence recovery 2.1.9

IND.8

Fingermark Visualisation Manual

Index

IND.9

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. documentation see also record keeping quality documents 2.5.4

risk assessments 3.2.7, 3.2.15

Standard Operating Procedures 2.5.4

dodeca-molybdophosphoric acid 6.4.4

n-dodecylamine acetate 3.1.18, 5.PD.6

drench showers 3.2.8

dynamic risk assessments 3.1.16–17

environmental effects 2.0.1, 2.4.13

drug contamination 2.2.13, 4.57

E

equipment 3.3.2, 3.3.5–6

drugs evidence recovery 7.14–15

earth 4.50, 4.57, 6.1.22, 7.26

Europium Chelate 6.1.23

drill bits 7.24

Drug Removal 6.2.5 drying of items

Fluorescence Examination 5.FE.30 latent fingermark damage 4.3 standard options 3.3.12–13

door frames 4.9, 4.17

DSLR (Digital Single Lens Reflex) cameras

DOSS

DSS see DOSS

doors 4.17

alternative names 3.1.18, 5.BV3.6, 5.SPR.5

CAS number 3.1.18

cloudiness 5.BV3.14

solution preparation 5.BV3.7, 5.SPR.6, 5.SPR.7

theory 5.SPR.12

DOSS-based Basic Violet 3

3.3.17

Duran® glass 3.1.13–14

dust contamination 5.PD.18

solution preparation 5.BV3.7, 5.BV3.9

double-gloving 3.2.9, 3.2.10

down-draught benches 3.1.6, 3.1.8, 3.1.13, 3.2.12

dpi (dots per inch) 3.3.23 drain pipes 4.7, 4.9

drainage systems 3.2.4 Home Office January 2014

2.3.5, 2.3.6 see also sweat

effectiveness

Acid Dyes 5.AD.1, 5.AD.3, 5.AD.10 Acid Dyes (methanol-based) 6.3.2 Adhesive Tape Removal 5.ATR.1, 5.ATR.3, 5.ATR.8

age of mark effect 2.3.9, 2.3.10,

ventilation

Lifting 5.VE.9

lighting techniques 5.VE.9, 5.VE.13

dusting see Powders

dyes

dots per inch (dpi) 3.3.23

eccrine sweat category A processes

dust impressions

overview 5.BV3.2

process details 5.BV3.9

eccrine glands 2.2.9, 2.2.10, 2.5.11

Adhesive Tape Removal category B

DVDs 7.9

post-processing 5.BV3.12

Earth Removal 6.1.22

dust extraction see local exhaust

cloudy solution 5.BV3.14

labelling solutions 5.BV3.5

E processes see category E processes

dye tanks 3.1.11, 3.3.4, 5.SFDS.6 cling film 4.14

process 6.1.12 2.3.13, 2.3.20

ATR-FTIR 6.2.2

Basic Violet 2 6.2.3

Basic Violet 3 (BV3) 5.BV3.1, 5.BV3.3,

thermal paper 5.TCR.8 uPVC 4.9

dynamic range, file formats 3.3.20, 3.3.21

5.FE.3, 5.FE.11, 5.FE.14

Fluorescent powders 6.2.12

Fluorescent Superglue Fuming 6.2.8 Genipin 6.2.9

Good Laboratory Practice (GLP) 3.3.2 Gun Blueing 6.1.24

handling items 3.3.1

history effects 1.11, 1.13 imaging 3.3.1, 3.3.16–25 Indandione 6.1.25

Infrared Reflection 5.IRR.1, 5.IRR.2, 5.IRR.6

integrity of fingermark evidence 3.3.10–15

ISO 17025 3.3.2, 3.3.3

Colour Filtration 5.CF.1, 5.CF.3, 5.CF.8

specifications 3.3.3

Fluorescence Examination 5.FE.1,

6.1.13

re-use 3.3.4 safety equipment 3.2.9

examination rooms 3.1.5

Iodine Fuming 6.1.32

CERA 6.2.4

rubber 4.15

ESDA 5.ESDA.1, 5.ESDA.2, 5.ESDA.7

5.BV3.13

Body Decomposition Residue Removal

expanded polystyrene 4.11 PVC 4.13

see also temperature; water

chemicals 3.3.3–4

DFO 5.DFO.1, 5.DFO.2

Iodine Solution 6.1.41

laboratory treatment overview 3.3.1–2 Leuco Crystal Violet (LCV) 6.1.42

Lifting 5.Lif.1, 5.Lif.2, 5.Lif.3, 5.Lif.4, 5.Lif.12

DMAC 6.1.14

MALDI-MSI 6.2.10

Earth and Mud Removal 6.1.22

Monochromatic Illumination 5.MI.1,

Drug Removal 6.2.5

Electrochromic Development 6.2.6 Electroless Silver Deposition 6.2.7

measuring equipment 3.3.5–6, 3.3.26 5.MI.2, 5.MI.6

IND.9

Fingermark Visualisation Manual

Index

IND.10

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. effectiveness continued

Multi-Metal Deposition (MMD) 5.MMD.1

Multi-Spectral Imaging 5.MSI.1, 5.MSI.2, 5.MSI.8

Natural Yellow 3 6.1.43 Nile Red 6.2.11

Scanning Kelvin Probe 6.1.48

water-based Acid Dyes 6.1.2, 6.1.4,

cleaning 3.3.2–3

SIMS (secondary ion mass

water exposure 2.3.9, 2.3.10, 2.3.12,

effectiveness 3.3.2, 3.3.5–6

Single Metal Deposition 6.2.14

XRF (X-ray fluorescence) 6.2.19

Silver Nitrate 6.1.49

spectrometry) 6.2.13

elasticity of substrate 2.2.5

solutions 3.3.3, 3.3.7–9

electricity supply 3.2.4

5.SPR.2, 5.SPR.10

Solvent Black 3 5.SB3.1, 5.SB3.2, 5.SB3.9

Soot Removal 5.SR.1, 5.SR.5,

Numberplate Splitting 5.NS.1, 5.NS.2

storage of forensic evidence 3.3.12

Oil Red O 6.1.44

overview 3.0.1, 3.1.1

2.3.15–16

Small Particle Reagent 5.SPR.1,

Ninhydrin 5.Nin.1, 5.Nin.2, 5.Nin.12 Ninhydrin Enhancement 6.3.10

6.1.11

5.SR.16

Superglue Fluorescent Dye Staining

5.SFDS.1, 5.SFDS.3, 5.SFDS.12

electrical insulation tape 4.21 Electrochromic Development 6.2.6 Electroless Silver Deposition 6.2.7 electromagnetic radiation 5.FE.23 electron excitation 5.FE.23

electronic file transfer 2.5.9

electropolymeric deposition 6.2.6 electrostatic charge 5.Pow.18

packaging of forensic evidence

Superglue Fluorescent Dye Staining

Palladium Deposition 6.1.45

Superglue Fuming 5.SF.1, 5.SF.2,

electrostatic fringing fields 5.ESDA.11–12

Physical Developer Enhancement

Tagged Nanoparticles 6.2.16

ELV (exposure limit values) 3.2.14

3.3.11–12

Physical Developer 5.PD.1 5.PDE.1

planning 2.4.13

(propanol-based) 6.1.56 5.SF.7

temperature effects 2.3.9, 2.3.10, 2.3.11, 2.3.17–19

Powder Suspensions 5.PS.1, 5.PS.3,

test marking 2.4.9

Powders 5.Pow.1, 5.Pow.2, 5.Pow.3,

Thermal Coating Removal 5.TCR.1

5.PS.11

5.Pow.4, 5.Pow.5, 5.Pow.14, 5.Pow.18

preparation processes 3.3.13 processing charts key 1.15

texture effects 2.3.9, 2.3.14, 2.3.21 Thermal Development 6.2.17 ThermaNin 6.2.18

UVC Reflection 5.UVCR.1, 5.UVCR.2, 5.UVCR.8

electrostatic detection apparatus see ESDA

electrostatic lifting 7.18, 7.19

emergency decontamination 3.2.8 emission of radiation 2.2.30

engineering controls see also local exhaust ventilation

light source risk reduction 3.2.17

Visual Examination 5.VE.1, 5.VE.2,

equipment see also laboratory

Home Office January 2014

legislation 3.1.9

maintenance 3.3.2, 3.3.6

measuring 3.1.14, 3.3.5–6, 3.3.26

organisation 3.1.3, 3.1.8, 3.1.9–14 practicality 3.1.9

record keeping 3.3.2, 3.3.6 specifications 3.1.9 storage 3.1.14 training 3.3.2

erythrocytes 5.AD.14 ESDA

age of mark effect 2.3.13

application problems 5.ESDA.8–10 contaminants 2.3.5

date of introduction 2.3.4

document evidence recovery 7.12, 7.13

effectiveness 5.ESDA.1, 5.ESDA.2, 5.ESDA.7

laboratory organisation 3.1.7

2.1.4, 2.1.6, 2.2.17, 2.2.21, 2.4.2, A.2.11

S2N2 6.2.15

5.VE.22

imaging 3.3.17–18

environmental effects on forensic evidence epidermis 2.2.8, 2.2.11

Scanning Electron Microscopy 6.1.47

general laboratory 3.1.13–14

equipment 3.1.8, 5.ESDA.4

Environment Agency 3.2.29

Vacuum Metal Deposition (VMD) 5.VMD.1

fixed 3.1.9, 3.2.5

enhancement definition GLO.1

Radioactive Sulphur Dioxide 6.1.46 research A.2.11

disposal 3.3.2

epoxy resin Lifting 5.Lif.3, 5.Lif.7, 5.Lif.10 organisation

integrated use 5.ESDA.1

lighting techniques 5.VE.11 post-processing 5.ESDA.6

practicality 5.ESDA.2, 5.ESDA.7 process details 5.ESDA.5

process overview 5.ESDA.1

IND.10

Fingermark Visualisation Manual

Index

IND.11

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

audit trail GLO.1

Illustrations and figures are in bold.

definition GLO.1

Tables are in italics. ESDA continued

safety 5.ESDA.1, 5.ESDA.2–3

evidence recovery definition GLO.1

examination benches 3.1.4, 3.1.5, 3.1.6, 3.1.13

category B processes 6.1.23, 6.1.44

illumination light transmission

category E processes 6.4.4

labelling systems, light sources

category C processes 6.2.11 fatigue 5.FE:49 fencing

scene treatment 5.ESDA.2, 5.ESDA.7

examination definition GLO.1

target properties 2.3.5

excitation filter cut-off point 5.FE.11

ferric ammonium citrate 5.PDE.14

excitation of electrons 5.FE.23

ferric nitrate nonahydrate see iron (III)

surface types 2.3.14, 5.ESDA.1 temperature effects 2.3.11 theory 5.ESDA.11–12

water exposure 2.3.12

ethane-1,2-diol see ethylene glycol ethanoic acid see acetic acid ethanol

examination rooms 3.1.4–5

excitation filter cut-on point 5.FE.11 expanded polystyrene 4.11 expensive items

effect on process selection 4.2 storage 3.1.3

CAS number 5.AD.6, 5.BV3.6, 5.Nin.7,

exposure cabinets, Iodine Fuming 6.1.35

process uses 3.1.18

extraction systems for storage areas 3.1.3

5.SFDS.7, 6.3.13

specifications 3.3.3

ethanol-based Superglue Fluorescent Dye Staining

overview 5.SFDS.2

post-processing 5.SFDS.11

exposure limit values (ELV) 3.2.14 eye protection 3.2.8

eye structure 5.FE.48–9 eyesight 5.FE.49 eyewear

dark adaptation goggles 5.FE.7,

process details 5.SFDS.10

5.FE.12

solution preparation 5.SFDS.8, 5.SFDS.9

ethyl alcohol see ethanol

wood 4.30

ferric ferrocyanide 5.PDE.14 nitrate nonahydrate

file formats for images 3.3.20–2 file transfer 2.5.9

filtered arc lamps 5.FE.37 filters

band-blocking filters 5.FE.40 band-pass

Fluorescence Examination 5.FE.18, 5.FE.41

visual ability correction 5.FE:49

UVC Reflection 5.UVCR.5,

5.IRR.11

5.UVCR.14

cross-polarised lighting 5.VE.7–8,

ethylene glycol 3.1.18, 5.PS.6, 5.PS.7,

fabrics 4.41, 7.16–17

Fluorescence Examination

Europium Chelate 6.1.23 evidence integrity

Home Office January 2014

face masks 3.2.11

faint fluorescent marks 5.FE.15 fat reagents

practicality 5.FE.42

selection 5.FE.7, 5.FE.8, 5.FE.10, 5.FE.26, 5.FE.43–6

theory 5.FE.39–46

long-pass filters 5.FE.40

fibres evidence recovery 4.41, 7.16–17

F

5.PS.8, 5.SFDS.7

optical density (OD) 5.FE.39

fibreboard 4.30

Infrared Reflection 5.IRR.4,

F processes see category F processes

mercury vapour tubes 5.FE.38

Infrared Reflection 5.IRR.4, 5.IRR.11

ammonium iron (II) sulphate hexahydrate

ethyl ethanoate see ethyl acetate

ethylcyanoacrylate see Superglue Fuming

5.FE.11

low contrast 5.FE.20

ferrous ammonium sulphate see

Fluorescence Examination 5.FE.43–5 safety 3.2.8, 3.2.17

ethyl acetate 3.1.18, 5.Nin.7

metal 4.18

5.FE.19

5.VE.21, 5.VE.34

background fluorescence 5.FE.18 discharge lamps 5.FE.37

filtered arc lamps 5.FE.37

latent fingermarks 2.2.29 maintenance 5.FE.6

Monochromatic Illumination 5.MI.4, 5.MI.9

optical 3.3.18

process selection 2.2.31 short-pass 5.FE.41

UVC Reflection 5.UVCR.5, 5.UVCR.14

Fingermark Evidence Recovery Plan case studies A.0.1, A.1.1–14 chart use 2.4.4–8

complex scenarios 2.4.2, 2.4.9–10, 2.4.13

constraints 2.4.11–13

contaminant considerations 4.56 coordination approach 2.4.11,

2.5.1 see also forensic evidence integration

definition GLO.2

development of plan 2.4.14

IND.11

Fingermark Visualisation Manual

Index

IND.12

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Contents

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. Fingermark Evidence Recovery Plan continued

initial assessment 2.1.10, 2.4.2–3 initial planning 2.4.4–8

manual usage guide 1.3 optimisation 2.4.8

overview 2.1.11–12

process selection 1.12 record keeping 2.4.3

review 2.1.11, 2.1.13, 2.4.11 safety 2.4.11, 3.2.1

scene treatment 2.4.12

sequential processing constraints 2.1.14

sequential processing rules 2.3.7–8, 2.4.7–8, 4.52

compared to fingerprints 2.2.1

comparison process 2.5.1, 2.5.2–3, 2.5.10, 3.3.16

complexity 2.0.1

marking up 2.5.5

overview 2.5.1, 2.5.4

competence 3.1.2, 3.3.2

generation

contact angle 2.2.16

Fingerprint Source Book A.2.1

contaminants 2.2.8, 2.2.12–13 maximising information 2.2.4 overview 2.2.1, 2.2.2 skin properties 2.2.3

communications

fingerprints

compared to fingermarks 2.2.1

comparison process 2.5.1, 2.5.2–3, 2.5.10, 3.3.16

substrate properties 2.2.5, 2.2.15

definition GLO.2

types 2.2.6–8

reference prints 2.2.1, 2.2.2, 2.5.1

sweat 2.2.8–12, 2.2.12

5.VE.9, 5.VE.13

integrity of evidence 3.3.10–15 latent see latent fingermarks negative marks

forms 2.2.2

fire risks 3.1.15, 3.2.18–19, 3.2.27 fire scenes

fluorescamine 6.4.3, A.2.8 fluorescein 6.4.6 fluorescence

Anti-Stokes 5.FE.23 DFO 5.DFO.13

infrared 5.IRR.7

spectra for wavelength selection 5.FE.29

substrate 2.2.30

theory 5.FE.23, 5.FE.27–8, 5.FE.31 time resolved 5.FE.24

XRF (X-ray fluorescence) 6.2.19

Fluorescence Examination

application examples 4.60

background fluorescence 5.FE.17–18, 5.FE.25, 5.FE.31, 5.FE.38

cold case review A.1.11

5.SR.17

first generation copies 2.5.9

age of mark 2.2.17

flood lighting, UVC Reflection 5.UVCR.10

soot contamination 4.57, 5.SR.2,

visualisation 2.2.27

patent definition GLO.4

flatbed scanners 3.3.17, 3.3.19

case studies A.1.3, A.1.6, A.1.7, A.1.8,

forensic evidence recovery 2.2.21

firearms 2.1.12, 7.2–3 see also ballistics

generation 2.2.7

3.2.26, 3.2.27

case studies A.1.9

definition GLO.3

persistence

Home Office January 2014

visualisation see visualisation

contact time 2.2.16

safety responsibilities 3.2.2, 3.2.22 age of mark 2.2.17, 2.2.18–20

visible, definition GLO.4

fingerprint examiners 2.5.10 see also

contact pressure 2.2.14–15, 2.5.16

partial 2.2.4

fingermarks

positive marks 2.2.7–8

contact environment 2.2.16

definition GLO.2

manual usage guide 1.2

substrate 2.2.17, 2.2.18–20

smudged 2.2.4, 2.5.3

information maximisation 2.2.29

2.5.20, 3.3.23, 3.3.25

flash points 3.2.18

2.2.21–5, 2.4.2

‘dotty’ 2.5.11, 2.5.12

definition GLO.1–2

image transfer 2.5.9

lifts 2.5.6

overview 2.2.1

physical properties 2.2.26

impressions 2.2.6, 2.2.27, 4.16,

images 2.5.7–8, 2.5.9, 2.5.15,

flammable liquids 3.1.15, 3.2.18–19,

composition 2.2.26

fingermark laboratory practitioners communications

environmental effects 2.2.17,

forensic analysis

fixing solutions

Acid Dyes 5.AD.7, 5.AD.11, 5.AD.14 Iodine Fuming 6.1.37, 6.1.39

water-based Acid Dyes 6.1.8

flake powders, Lifting 5.Lif.2

A.1.9, A.1.14

combined with Basic Violet 3 5.BV3.2, 5.BV3.18, 5.FE.10, 5.FE.28–9

combined with DFO 5.DFO.8,

5.DFO.13, 5.FE.10, 5.FE.28–9

combined with Lifting 5.FE.22

combined with Multi-Spectral Imaging 5.MSI.7

combined with UVC Reflection 5.FE.22

IND.12

Fingermark Visualisation Manual

Index

IND.13

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. Fluorescence Examination continued

integrated use 5.FE.1

laboratory organisation 3.1.4–5

light sources 5.FE.6, 5.FE.8, 5.FE.10, 5.FE.11, 5.FE.26, 5.FE.32–8

condensation 5.FE.30

low contrast 5.FE.20

contaminants 4.2, 5.FE.21

process details 5.FE.12–13

contact marks 4.51 currency 4.29

date of introduction 2.3.3

effectiveness 5.FE.1, 5.FE.3, 5.FE.11, 5.FE.14

equipment 5.FE.6–7, 5.FE.35–7 faint marks 5.FE.15, 5.FE.30 filters

background fluorescence 5.FE.18 discharge lamps 5.FE.37

filtered arc lamps 5.FE.37

illumination light transmission

practicality 5.FE.3, 5.FE.14, 5.FE.42 process overview 5.FE.1

processed fingermark examination 5.FE.2, 5.FE.10, 5.FE.28–9

safety

door interlocks 3.1.5, 5.FE.12 hazards 5.FE.5

laboratory organisation 3.1.4–5

5.FE.11

sequential processing 4.2, 5.FE.2

mercury vapour tubes 5.FE.38

5.FE.14, 5.FE.35, 5.FE.36

Superglue Fluorescent Dye Staining 5.SFDS.2, 5.SFDS.16

optical density (OD) 5.FE.39

surface distortion 5.FE.16

selection 5.FE.7, 5.FE.8, 5.FE.10,

targets 4.60

practicality 5.FE.42

5.FE.26, 5.FE.43–6

theory 5.FE.39–46

grease contamination 4.23, 4.34 human eye 5.FE.47, 5.FE.48

imaging systems 3.3.18, 5.FE.46–7 initial examination 5.FE.2, 5.FE.9, 5.FE.27, 5.FE.38

Home Office January 2014

foot protection 3.2.11

initial assessment 2.1.3, 2.1.6, 2.1.9

food wrap see cling film footwear marks

Acid Dyes 4.51

blood interpretation 4.58

evidence recovery overview 7.18–19 Lifting 5.Lif.2

force policy constraints 2.1.3, 2.1.13 forensic evidence

environmental effects 2.1.4, 2.1.6, 2.2.17, 2.2.21–5, 2.4.2, A.2.10

preservation 2.1.3, 2.1.4–5, 7.5

viewing filters 5.FE.11, 5.FE.39

surface types 5.FE.1 theory 5.FE.23–49

transparent items 5.FE.22

2.4.11

Fluorescence Examination 5.FE.1

scene treatment 5.FE.14

overview 5.FE.1, 5.FE.3–4

Fingermark Evidence Recovery Plan

food fats contamination 4.23, 4.34, 4.48

interaction with investigative process

scene treatment 5.FE.1, 5.FE.3,

low contrast 5.FE.20

Fluorescent Superglue Fuming 6.2.8

light sources 3.2.15, 3.2.16

5.FE.19

labelling systems, light sources

Fluorescent Dye Staining

2.1.3

storage 2.1.4–5, 2.4.12, 3.1.3, 3.3.12

Indandione 6.1.25

Iodine Fuming 6.1.32 Lifting 7.9

manual usage guide 1.19

Monochromatic Illumination 5.MI.1 Multi-Metal Deposition (MMD) 5.MMD.1

Multi-Spectral Imaging 5.MSI.1 Ninhydrin 5.Nin.1

Numberplate Splitting 5.NS.1

overview of other evidence types 7.1 Physical Developer 5.PD.1

Physical Developer Enhancement 5.PDE.1

time effects 2.1.2, 2.1.4, 2.1.6, 2.2.17,

Powder Suspensions 5.PS.1

types overview 7.1

preservation 2.1.4–5

2.2.18–20, 2.4.2

forensic evidence integration Acid Dyes 5.AD.1

Acid Dyes (methanol-based) 6.3.2 Adhesive Tape Removal 5.ATR.1 Basic Violet 3 (BV3) 5.BV3.1

case studies A.1.2–3, A.1.5–6, A.1.7, A.1.10, A.1.14

Powders 5.Pow.1

process selection 4.51

sequential processing 2.1.12, 2.1.14 Small Particle Reagent 5.SPR.1 Solvent Black 3 5.SB3.1 Soot Removal 5.SR.1

Superglue Fluorescent Dye Staining 5.SFDS.1

wavelength selection 5.FE.8, 5.FE.9,

Colour Filtration 5.CF.1

Superglue Fluorescent Dye Staining

wood 4.30

DFO 5.DFO.1

Superglue Fuming 5.SF.1

5.FE.10, 5.FE.29, 5.FE.32–3

fluorescent powders 5.Pow.3, 5.Pow.4 fluorescent stains see Superglue

complex items 4.51 DMAC 6.1.14

ESDA 5.ESDA.1

(propanol-based) 6.1.56

Thermal Coating Removal 5.TCR.1

IND.13

Fingermark Visualisation Manual

Index

IND.14

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. forensic evidence integration continued Vacuum Metal Deposition (VMD) 5.VMD.1

freezer spray 5.ATR.2, 5.ATR.5, 5.ATR.6,

Genipin 6.2.9

friction ridge skin 2.2.3

GHS (Globally Harmonised System)

5.ATR.8

FTIR 6.2.2

fume cupboards

drying of items 3.3.13

Visual Examination 5.VE.1

process requirements 3.1.7

water-based Acid Dyes 6.1.2

regulations 3.2.3

Forensic Evidence Recovery Plan see also

specifications 3.1.6, 3.1.9

Fingermark Evidence Recovery Plan CCTV guidance 7.7

coordination approach 2.0.1, 2.1.1,

2.1.2, 2.5.1, 4.51 see also forensic evidence integration

costs 2.1.15

usage guidance 3.1.9–10

fume extraction see local exhaust ventilation

Fuming Orange™ 6.2.8 furniture 4.30

definition GLO.2

G

manual usage guide 1.4

galvanisation 4.18

initial assessment 2.1.6 overview 2.1.11

planning for other requirements 7.1 resources 2.1.15

review 2.1.11, 2.1.13 safety 3.2.1

Forensic Evidence Recovery Strategy

galvanic silver deposition 6.2.7

review 2.1.11, 2.1.13

6.2.2

Home Office January 2014

laboratory equipment 3.1.13–14, 3.2.24, 3.3.5

processing charts 4.6 water exposure 4.6

glass-fibre brushes 5.Pow.7

glass transition temperature 5.ATR.5, 5.ATR.9, 5.NS.7

glassware washing 3.1.8, 3.1.12, 3.3.2–3 glazes on ceramics 4.6

Globally Harmonised System (GHS) 3.2.20, 3.2.30–2

gloves, safety 3.2.9–10, 3.2.13, 3.3.11

contact angle 2.2.16

contact environment 2.2.16

contact pressure 2.2.14–15, 2.5.16

information maximisation 2.2.4

Fourier transform infrared spectroscopy

labelled bottles 4.53, A.1.11–12

generation of fingermarks

gelatin lifts 5.Lif.2, 5.Lif.6, 5.Lif.8–9, 7.13

initial assessment 2.1.9 planning for other requirements 7.1

case studies A.1.11–12

gloss-painted surfaces 4.17

contact time 2.2.16

overview 2.1.11

3.2.20, 3.2.30–2

glass

gelatin lifting sheets 5.ESDA.4

constraints 2.1.11 definition GLO.2

gentian violet see Basic Violet 3

contaminants 2.2.8, 2.2.12–13 overview 2.2.1, 2.2.2 skin properties 2.2.3

substrate properties 2.2.5, 2.2.15 sweat 2.2.8–12, 2.2.12 types 2.2.6–8

genetic information see DNA evidence

glovemarks 7.20–1

GLP (Good Laboratory Practice) 3.3.2 goggles

gold/zinc Vacuum Metal Deposition CAS number 5.VMD.6

evaporation vessels 5.VMD.5 overview 5.VMD.2

process details 5.VMD.7–8

processing problems 5.VMD.11–16 reverse-developed marks 2.5.15, 5.VMD.18

theory 5.VMD.17–19

Good Laboratory Practice (GLP) 3.3.2 grading schemes A.2.11, A.2.13

granular powders 5.Pow.3, 5.Pow.9, 5.Pow.11

grease contamination

age of mark 2.3.10 case studies A.1.8

category A processes 2.3.5

category B processes 4.61–2

category C processes 4.61–2

combined with blood contamination 4.54

Fingermark Evidence Recovery Plan 2.4.10

dark adaptation 5.FE.7, 5.FE.12

Infrared Reflection 5.IRR.7

safety 3.2.8, 3.2.17

process selection, non-porous

Fluorescence Examination 5.FE.43–5 gold 3.1.18, 4.18

overview 4.57

substrates 4.23

gold/cadmium Vacuum Metal Deposition

process selection, porous substrates

gold (III) chloride 5.MMD.4, 5.MMD.6,

process selection, semi-porous

‘gold’ powder 5.Pow.2, 5.Pow.9

processing charts key 1.13

6.5.2

5.MMD.7, 5.MMD.9

gold Single Metal Deposition 6.2.14

4.34

substrates 4.48

temperature effects 2.3.10

IND.14

Fingermark Visualisation Manual

Index

IND.15

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. grease contamination continued washing glassware 3.3.3 water exposure 2.3.10

solutions 3.2.23

transport regulations 3.1.16

handwriting 7.12

hard specular lighting

application examples 5.VE.9, 5.VE.10, 5.VE.14

greyscale images 3.3.20

equipment 5.VE.4, 5.VE.14

groomed fingermarks A.2.7

theory 5.VE.27

greyscale inversion 2.5.20

guideline expiry periods, solutions 3.3.7 Gun Blueing 6.1.24

gunshot residue (GSR) 7.2 guttering 4.9

H

Haem Reagents 6.4.6, 7.18

haemoglobin 5.AD.14, 5.DFO.13 hairs

DNA evidence 7.10, 7.22

evidence recovery overview 7.22–3 skin analysis 4.46

sweat glands 2.2.8

hand protection 3.2.9–10, 3.2.13, 3.3.10 handling

chemicals 3.2.23

effectiveness 3.3.1

laboratory organisation 3.1.3

minimising damage 2.1.4, 2.1.15, 3.3.11, 4.3, 4.24

mixtures 3.2.23

porous substrate with blood contamination 4.33

post-processing 3.3.14, 3.3.15 Home Office January 2014

Iodine Fuming 6.1.34

legislation 3.0.1, 3.1.1 Lifting 5.Lif.5

light sources 3.2.14–17, 3.2.34–5

Monochromatic Illumination 5.MI.3 Multi-Metal Deposition (MMD) 5.MMD.3, 5.MMD.4

set-up 5.VE.14

Multi-Spectral Imaging 5.MSI.3

hazards see also risks

Ninhydrin Enhancement 6.3.11

Acid Dyes 5.AD.3, 5.AD.4–5

Acid Dyes (methanol-based) 6.3.4 Adhesive Tape Removal 5.ATR.4 air depletion 3.2.18

Basic Violet 3 (BV3) 5.BV3.4

Ninhydrin 5.Nin.3–4

Numberplate Splitting 5.NS.3 overview 3.2.1

Physical Developer 5.PD.3–4

Physical Developer Enhancement 5.PDE.4

category F processes 6.5.2

Powder Suspensions 5.PS.4

classification 3.2.6

process selection constraints 2.1.14

chemicals 3.2.20–7, 3.2.30–3 Colour Filtration 5.CF.4

Control of Substances Hazardous to

Health (COSHH) regulations 3.2.7

definition 3.2.6

DFO 5.DFO.3–4 DMAC 6.1.15

ESDA 5.ESDA.3

flammable liquids 3.1.15, 3.2.18–19 Fluorescence Examination 5.FE.5 glove usage 3.2.9–10, 3.2.13 HFE7100 5.Nin.12

identification 3.2.6, 3.2.12

identification symbols 3.2.21, 3.2.30–3 Indandione 6.1.26

Infrared Reflection 5.IRR.3

Powders 5.Pow.6 regulations 3.2.6

Superglue Fuming 5.SF.3

UVC Reflection 5.UVCR.4

Vacuum Metal Deposition 5.VMD.3 Visual Examination 5.VE.3

water-based Acid Dyes 6.1.5

HDPE see high-density polyethylene

health and safety see also hazards; risks

Acid Dyes 5.AD.1, 5.AD.3, 5.AD.4–5, 5.AD.10

Acid Dyes (methanol-based) 6.3.4 Adhesive Tape Removal 5.ATR.1, 5.ATR.4, 5.ATR.8

Adhesive Tape Removal category B process 6.1.12

Basic Violet 3 (BV3) 5.BV3.1, 5.BV3.3, 5.BV3.4, 5.BV3.13

chemicals storage 3.1.15

Colour Filtration 5.CF.1, 5.CF.3–4, 5.CF.8

scene treatment overview 3.1.16–17

context 1.2

Silver Nitrate 6.1.50

DFO 3.2.18, 5.DFO.1, 5.DFO.2–3

signal words 3.2.21

Small Particle Reagent 5.SPR.3–4 solutions 3.2.22

Solvent Black 3 5.SB3.3 Soot Removal 5.SR.6 spillages 3.2.28

storage conditions 3.1.3

storage of forensic evidence 3.2.12 Superglue Fluorescent Dye Staining 5.SFDS.4, 5.SFDS.5

Superglue Fluorescent Dye Staining (propanol-based) 6.1.58

control measures 3.2.7 DMAC 6.1.14, 6.1.15

Earth and Mud Removal 6.1.22 electricity supply 3.2.4

equipment 3.2.3, 3.2.4

ESDA 5.ESDA.1, 5.ESDA.2–3

Fingermark Evidence Recovery Plan 2.4.11

Fluorescence Examination

door interlocks 3.1.5, 5.FE.12 hazards 5.FE.5

light sources 3.2.15, 3.2.16

IND.15

Fingermark Visualisation Manual

Index

IND.16

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. health and safety continued

overview 5.FE.1, 5.FE.3–4 scene treatment 5.FE.14

viewing filters 5.FE.11, 5.FE.39

fume cupboards 3.1.9–10 Gun Blueing 6.1.24

housekeeping 3.2.5

Indandione 6.1.25, 6.1.26

Infrared Reflection 3.2.16, 5.IRR.1, 5.IRR.2, 5.IRR.3, 5.IRR.6

Iodine Fuming 6.1.32, 6.1.33–4 Iodine Solution 6.1.41

laboratory organisation equipment 3.1.8

Natural Yellow 3 6.1.43

Ninhydrin 3.2.11, 3.2.18, 5.Nin.1, 5.Nin.2, 5.Nin.3–4, 5.Nin.12

Ninhydrin Enhancement 6.3.10, 6.3.11 Numberplate Splitting 3.2.18–19, 5.NS.1, 5.NS.2, 5.NS.3

Oil Red O 6.1.44

5

Monochromatic Illumination 5.MI.1, 5.MI.2, 5.MI.3, 5.MI.6

Multi-Metal Deposition (MMD) 5.MMD.1, 5.MMD.3–4

Multi-Spectral Imaging 5.MSI.1, 5.MSI.2, 5.MSI.3, 5.MSI.8

Home Office January 2014

hazards 3.2.18, 5.Nin.3, 5.Nin.12, 6.1.26, 6.3.11

Ninhydrin solution preparation 5.Nin.8

Physical Developer 5.PD.3–4

training 3.1.2, 3.2.23

Physical Developer Enhancement 5.PDE.1, 5.PDE.4

post-processing 3.2.1

Powder Suspensions 5.PS.1, 5.PS.3– 4, 5.PS.11

responsibilities 3.2.2, 3.2.22

manual usage guide 1.4

(propanol-based) 6.1.56, 6.1.58

Thermal Coating Removal 5.TCR.1,

3.2.7–12

3.2.6, 3.2.14–15

light sources 3.2.6, 3.2.14–17, 3.2.34–

Superglue Fluorescent Dye Staining

5.Nin.7, 6.1.28

DFO solution preparation 5.DFO.7

personal protective equipment (PPE)

process selection constraints 2.1.14

Lifting 5.Lif.1, 5.Lif.4–5

5.SFDS.1, 5.SFDS.3–5

CAS numbers 3.1.19, 5.DFO.6,

Ninhydrin Enhancement solution

overview 3.1.1, 3.2.1, 3.2.2

Leuco Crystal Violet (LCV) 6.1.42

Superglue Fluorescent Dye Staining

alternative names 3.1.19

Superglue Fuming 5.SF.1, 5.SF.2–3,

Palladium Deposition 6.1.45

Powders 5.Pow.1, 5.Pow.2, 5.Pow.5,

legislation 3.0.1, 3.1.1, 3.2.2–3, 3.2.4,

5.SR.16

specialists 3.1.2, 3.2.6

HFE7100

overview 3.0.1, 3.1.1, 3.2.1

Fingermark Evidence Recovery Plan 2.4.11

Soot Removal 5.SR.1, 5.SR.5, 5.SR.6,

5.Pow.6, 5.Pow.14

Radioactive Sulphur Dioxide 6.1.46 reviews 3.2.2, 3.2.22

Scanning Electron Microscopy 6.1.47 Scanning Kelvin Probe 6.1.48

scene treatment overview 3.1.1, 3.1.16–17, 3.2.6, 3.2.24

Silver Nitrate 6.1.49, 6.1.50

Small Particle Reagent 5.SPR.1,

5.SF.7

5.TCR.2–3

UVC Reflection 3.2.16, 5.UVCR.1,

5.UVCR.2, 5.UVCR.3–4, 5.UVCR.5, 5.UVCR.8

Vacuum Metal Deposition 5.VMD.3 Vacuum Metal Deposition (VMD) 5.VMD.1

ventilation 3.2.3, 3.2.23

Visual Examination 5.VE.1, 5.VE.2, 5.VE.3, 5.VE.22

waste management 3.2.4, 3.2.28–9

water-based Acid Dyes 6.1.2, 6.1.4–5, 6.1.11

water supply 3.2.4

wavelength selection 3.2.15 work flow 3.2.5

Health and Safety at Work etc Act (1974)

water contamination 5.DFO.10, 5.Nin.13

high-density polyethylene (HDPE) 4.7, 4.10

high intensity light source (HLS)

examination see Fluorescence Examination

high pressure mercury vapour discharge tubes 5.FE.38

high-value items

effect on process selection 4.2 storage 3.1.3

history

age of mark 2.2.17 definition GLO.2

effect on process selection 1.11 processing charts key 1.15

record keeping 2.4.3, 2.5.4, 3.3.10

3.2.2, 3.2.6, 3.3.2

Home Office Fingerprint Source Book

3.2.2, 3.2.14, 3.2.20

hotplates 5.MMD.5

5.SPR.2, 5.SPR.3–4, 5.SPR.10

Health and Safety Executive (HSE) 3.2.1,

5.SB3.9

heptane tape removal 6.1.12

Solvent Black 3 5.SB3.1, 5.SB3.2–3,

preparation 6.3.14

HFE71DE 3.1.19, 5.DFO.6, 5.DFO.7

A.2.1

housekeeping 3.2.3, 3.2.5

Howie laboratory coat 3.2.9

IND.16

Fingermark Visualisation Manual

Index

IND.17

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. HPS 6.2.17

HSE (Health and Safety Executive) 3.2.1, 3.2.2, 3.2.14, 3.2.20

‘huffing’ 5.Pow.18–19

human eye, Fluorescence Examination 5.FE.47, 5.FE.48

humidity

degradation of forensic evidence 2.1.5

IFRG (International Fingermark Research

communications 2.5.7–8, 2.5.9,

image capture see imaging

competence 3.3.22

image cube 5.MSI.5, 5.MSI.6, 5.MSI.7,

context 3.3.16

Group) A.2.5

image compression 3.3.21 5.MSI.9

image enhancement

definition GLO.2 digital 2.5.20

lighting techniques 4.2, 5.CF.2

low temperature fluorescence 5.FE.30

development ovens 5.Nin.19

image management 3.3.16, 3.3.24

fingermarks generation effect 2.2.16

images

effect on Powders 5.Pow.18 persistence effects 2.2.23

Superglue Fuming cabinets 5.SF.4, 5.SF.9, 5.SF.10, 5.SF.13

Hungarian Red 6.4.2

hydrofluoroether see HFE7100

image processing see image enhancement compression 3.3.21 definition GLO.2

digital image enhancement 2.5.20

digital transfer 2.5.9, 3.3.21, 3.3.23, 3.3.25

hydrogen chloride fuming 6.5.2

file formats 3.3.20–2

hydrogen sulphide fuming 6.5.2

master copy 3.3.22, 3.3.24

hydrogen fluoride 6.5.2

2-hydroxypropane-1,2,3 tricarboxylic acid see citric acid

hyperspectral imaging see Multi-Spectral Imaging

I

identification

communications 2.5.4

comparison process 2.5.1, 2.5.2–3, 2.5.10, 3.3.16

definition GLO.2

Home Office January 2014

2.5.15, 2.5.20, 3.3.23, 3.3.25

complex marks 3.3.16 contrast limitations 4.3

cross-referencing 2.5.7

Lifting 5.VE.9

lighting techniques 5.VE.9, 5.VE.13 visualisation 2.2.27

1,2,3-indantrione see Ninhydrin

labelling systems 3.3.18

master copy 3.3.22, 3.3.24 optimisation 3.3.22

post-processing 3.3.22–3 purpose 3.3.16

recording in sequential processing

2.3.7, 2.4.3, 2.4.4, 2.5.4, 4.3, 4.10

resolution 3.3.19

scale requirements 2.5.5, 3.3.16, 3.3.17, 3.3.18, 3.3.25

working copy 3.3.22, 3.3.24

2.3.7, 2.5.4, 4.3, 4.10

generation 2.2.6, 4.16

integrity of evidence 3.3.10

printing 3.3.23

resolution requirements 3.3.19

impressions

incident light 5.VE.26

equipment 3.3.17–18

standard requirements 3.3.16

recording in sequential processing

impregnated sheets (DMAC) 6.1.19

effectiveness 3.3.1, 3.3.16–25

management 3.3.16

quality loss 2.5.7, 2.5.9

5.UVCR.10, 5.UVCR.13

wet surfaces 4.3

imaging chain 3.3.21 imaging systems

digital image capture 3.3.17–19, 3.3.24

Indandione 6.1.25–31

information maximisation 2.2.4, 2.2.29, 2.4.4, 2.5.4, 2.5.7

information review 2.1.3, 2.4.11, 2.4.14 Infrared Reflection

application examples 4.60 case studies A.1.13

date of introduction 2.3.3

effectiveness 5.IRR.1, 5.IRR.2, 5.IRR.6 emission of radiation definition 2.2.30 equipment 5.IRR.4, 5.IRR.9–11 integrated use 5.IRR.1 limitations 5.IRR.10

practicality 5.IRR.2, 5.IRR.6 process details 5.IRR.5

process overview 5.IRR.1

safety 3.2.16, 5.IRR.1, 5.IRR.2, 5.IRR.3, 5.IRR.6

stability during capture 3.3.17, 3.3.18

Fluorescence Examination 3.3.18,

scene treatment 5.IRR.1, 5.IRR.2,

work flow 3.3.21

Infrared Reflection 3.3.18, 5.IRR.9–10

surface types 5.IRR.1

storage 3.3.25

working copy 3.3.22, 3.3.24

imaging see also interpretation

audit trail 2.4.3, 2.5.4, 3.3.22–3, 3.3.24

5.FE.46–7

Multi-Spectral Imaging 5.MSI.4, 5.MSI.10

UVC Reflection 3.3.18, 5.UVCR.5,

5.IRR.6

targets 4.60

theory 5.IRR.7–11

IND.17

Fingermark Visualisation Manual

Index

IND.18

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. initial assessment

definition GLO.2

forensic evidence integration 2.1.3, 2.1.6

importance of 2.1.1 outcomes 2.1.7–10

overview of process 2.1.6

inks 7.12, 7.13

integration of forensic evidence Acid Dyes 5.AD.1

Acid Dyes (methanol-based) 6.3.2 Adhesive Tape Removal 5.ATR.1 Basic Violet 3 (BV3) 5.BV3.1

case studies A.1.2–3, A.1.5–6, A.1.7, A.1.10, A.1.14

Colour Filtration 5.CF.1

Multi-Metal Deposition (MMD) 5.MMD.1

Multi-Spectral Imaging 5.MSI.1 Ninhydrin 5.Nin.1

Numberplate Splitting 5.NS.1

overview of other evidence types 7.1 Physical Developer 5.PD.1

Physical Developer Enhancement 5.PDE.1

Powder Suspensions 5.PS.1 Powders 5.Pow.1

preservation 2.1.4–5

process selection 4.51

sequential processing 2.1.12, 2.1.14 Small Particle Reagent 5.SPR.1 Solvent Black 3 5.SB3.1 Soot Removal 5.SR.1

Iodine Fuming 6.1.32 Lifting 7.9

manual usage guide 1.19

Monochromatic Illumination 5.MI.1

Home Office January 2014

information requirements 2.5.15

calibration 3.3.2, 3.3.6

mirrored marks 2.5.14, 2.5.17–18

competence requirements 3.1.2

overview 2.5.1

definition GLO.2

reverse-developed marks 2.5.15–16

effectiveness 3.3.2, 3.3.3

sequential processing 2.5.11

housekeeping 3.2.5

substrate effects 2.5.13–14

local force policy deviations 2.1.13

investigative process

process instructions requirements

constraints 2.1.1, 2.1.3

3.1.2

forensic evidence assessment 2.1.3

process validation A.2.1

limitations 2.1.1

record-keeping requirements 2.4.3,

overview 2.1.1, 2.1.2, 2.1.3

3.3.2

(propanol-based) 6.1.56

IR imaging see Infrared Reflection

Vacuum Metal Deposition (VMD)

initial assessment 2.1.3, 2.1.6, 2.1.9

ISO 17025

ISO 6706 3.1.14, 3.3.5

work flow 3.2.5

Fingermark Evidence Recovery Plan

Indandione 6.1.25

examination overview 2.5.10

distortions 2.5.19

Iodine Fuming 6.1.32–40

Superglue Fuming 5.SF.1

Fluorescence Examination 5.FE.1

ISO 4788 3.1.14, 3.3.5

5.SFDS.1

Superglue Fluorescent Dye Staining

DMAC 6.1.14

2.4.11

theory 5.PS.17

digital image enhancement 2.5.20

relationship to this manual 3.1.2

Superglue Fluorescent Dye Staining

ESDA 5.ESDA.1

constituents distribution 2.5.11–12

specifications 3.3.3

iodide toning 5.PDE.2, 5.PDE.7, 5.PDE.8,

complex items 4.51 DFO 5.DFO.1

interpretation

Thermal Coating Removal 5.TCR.1 5.VMD.1

Visual Examination 5.VE.1

water-based Acid Dyes 6.1.2

integrity of fingermark evidence 3.3.10– 15 see also preservation of forensic evidence

interfering substance removal 4.55

International Fingermark Research Group (IFRG) A.2.5

traceability 3.2.24, 3.2.25

5.PDE.12, 5.PDE.14

Iodine Solution 6.1.41

isononylphenol ethoxylate see synperonic

iron 4.18

isopropyl alcohol see 2-propanol

iron (III) nitrate nonahydrate 5.MMD.6,

5.MMD.8, 5.MMD.9, 5.PD.6, 5.PDE.6

iron oxide-based Powder Suspension

adhesive tape 4.39, 5.PS.15, 5.PS.16 alternative names 3.1.19, 5.PS.6 background staining 5.PS.16 CAS number 3.1.19

labelling systems 5.PS.5

process overview 5.PS.1, 5.PS.2

solution preparation 5.PS.7, 5.PS.8, 5.PS.13

N

item definition GLO.2

J

jewellery 4.18

JPEG file format 3.3.21

JPEG2000 file format 3.3.21

K

kitchen units

grease contamination 4.23 melamine 4.7

IND.18

Fingermark Visualisation Manual

Index

IND.19

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. knives 4.53, 4.54

L

labelling systems

Acid Dyes solutions 5.AD.5

Basic Violet 3 solutions 5.BV3.5 DFO solutions 5.DFO.4

hazardous chemicals 3.2.20–1, 3.2.24, 3.2.25

imaging 3.3.18

legislation 3.2.20–1

light sources 5.FE.8, 5.FE.11

marking up 2.5.5, 3.3.10, 3.3.13–14 Multi-Metal Deposition (MMD) solutions 5.MMD.4

Ninhydrin 5.Nin.4

Physical Developer 5.PD.4

Powder Suspensions 5.PS.5 regulations 3.1.16

Small Particle Reagent 5.SPR.4 Solvent Black 3 5.SB3.4

Soot Removal solutions 5.SR.6, 5.SR.8

Superglue Fluorescent Dye Staining 5.SFDS.5

labels 4.19, 4.32, 4.40

laboratory accreditation 1.2–3, 3.3.2, 3.3.6, A.2.1

laboratory coats 3.2.9

Home Office January 2014

laboratory organisation see also

equipment; Good Laboratory Practice costs 3.2.2

‘dry’ areas 3.1.6, 3.1.7, 3.1.8

effectiveness overview 3.3.1–2 electricity supply 3.2.4 handling 3.1.3

optical processes 3.1.4

large item treatment 3.3.9, 3.3.13 laser glasses 5.FE.44

laser light sources 3.2.14–17, 3.2.34–5, 5.FE.11, 5.FE.35

latent fingermarks

age of mark 2.3.10

blood contamination on non-porous substrates 4.22

practicality 3.2.3

blood contamination on porous

safety

blood contamination on semi-porous

process types 3.1.7 equipment 3.1.8

substrates 4.33 substrates 4.47

Fingermark Evidence Recovery

chemical and physical process

legislation 3.2.2–3

contaminants 4.56, 4.57

Plan 2.4.11

overview 3.1.1, 3.2.1, 3.2.2

storage of forensic evidence 3.1.3 ventilation 3.2.3, 3.2.23 water supply 3.2.4

‘wet’ areas 3.1.6, 3.1.7, 3.1.8

laboratory treatment

constraints 2.1.15

definition GLO.2–3 effectiveness

chemicals 3.3.3–4

equipment 3.3.2, 3.3.5–6 overview 3.3.1–2

solutions 3.3.7–9

planning 2.4.12

practicality 2.4.12

laboratory trials A.2.2, A.2.9–12

lacquer-coated wallpapers 4.42

laminated floors, melamine facings 4.7

overview 5.CPP.1

definition GLO.3

effect of drying items 4.3 filters 2.2.29

generation 2.2.8, 2.2.12–13

grease contamination on non-porous substrates 4.23

grease contamination on porous substrates 4.34

grease contamination on semi-porous substrates 4.48

Lifting 4.3

limitations on PVC 4.13

processing charts key 1.13

latex 4.15

latex, liquid 5.SR.7, 5.SR.12, 5.SR.16

laurylamine acetate see n-dodecylamine acetate

Lawsone 6.4.3

LCV see Leuco crystal violet

LDPE see low-density polyethylene lead 4.18

lead powder 6.5.2 leather 4.44

leatherette 4.13, 4.44

LEDs (light emitting diodes) 5.FE.36 LEL (lower explosive limit) 3.2.18

lenses, image capture 3.3.17, 3.3.18

Leuco Crystal Violet (LCV) 6.1.42, 6.4.6 Leuco Malachite Green 6.4.6 leukocytes 5.AD.14

LEV (local exhaust ventilation) 3.1.8, 3.1.9, 3.1.10, 3.1.11, 3.2.3, 3.2.23

lever marks 7.24 Lifting

adhesive tape 5.Lif.2, 5.Lif.6, 5.Lif.8–9 aluminium powder 5.Lif.13, 5.Lif.15, 5.Lif.17, 5.Pow.2, 5.Pow.10

background 5.Lif.17

case studies A.1.8, A.1.13

combined with Fluorescence Examination 5.FE.22

temperature effects 2.3.10

communications 2.5.6

visualisation 2.2.26, 2.2.27, 2.2.29,

date of introduction 2.3.4

treated marks 2.2.29 4.60, GLO.4

water exposure 2.3.10

contrast optimisation 2.5.8 effectiveness 5.Lif.1, 5.Lif.2, 5.Lif.4, 5.Lif.12

IND.19

Fingermark Visualisation Manual

Index

IND.20

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. Lifting continued

epoxy resin 5.Lif.3, 5.Lif.7, 5.Lif.10 equipment 5.Lif.6–7

flake powders 5.Pow.2, 5.Pow.19 footwear marks 7.18, 7.19

gelatin lifts 5.Lif.2, 5.Lif.6, 5.Lif.8–9, 7.13

granular powders 5.Pow.3, 5.Pow.11, 5.Pow.19

image transfer 2.5.9

integrated use 5.Lif.1, 7.9

laboratory organisation 3.1.7 lighting techniques 5.VE.11 limitations 4.3

magnetic powders 5.Pow.3, 5.Pow.12, 5.Pow.19

silicone rubber casting compound

Monochromatic Illumination 5.MI.9

lower explosive limit (LEL) 3.2.18

Soot Removal 5.SR.3, 5.SR.7,

power requirements 2.2.31, 5.FE.34

luminol 6.4.6

5.Lif.3, 5.Lif.6, 5.Lif.10 5.SR.10–12

surface damage 4.3

surface types 5.Lif.1, 5.Lif.2 theory 5.Lif.16–17

visualisation 5.Lif.9

light adaptation 5.FE:48, 5.FE:49

light boxes 5.VE.5, 5.VE.17, 5.VE.30, 5.VE.32

light emitting diodes (LEDs) 5.FE.36

light guides 3.1.14, 5.FE.35, 5.FE.37 light sources

legislation 3.2.14–15

proximity 5.VE.9, 5.VE.25

risk group classification 3.2.14, 3.2.34–5

safety 3.2.6, 3.2.14–17, 3.2.34–5

metal flake powders 5.Pow.2,

light spectrum 5.CF.9

post-processing 5.Lif.11

lighting techniques

5.Pow.10, 5.Pow.19

light tent 5.VE.30

Multi-Spectral Imaging 5.MSI.4–5 process selection 2.2.31, 4.2 theory 2.2.30, 5.VE.23–34

UVC Reflection 5.UVCR.13

Visual Examination 5.VE.4–8, 5.VE.13–

5.VE.9–10

magnetic granular powders 5.Pow.4,

limitations 2.1.1, 2.1.13, 4.2

linear variable filter 5.MI.4, 5.MI.9 lipid reagents

category B processes 6.1.23, 6.1.44 category C processes 6.2.11

category E processes 6.4.4

safety 5.Lif.1, 5.Lif.4–5

scene treatment 5.Lif.4, 5.Lif.12

sequential processing 2.3.8, 5.Lif.3

Home Office January 2014

diffusion 2.2.31

Fluorescence Examination 5.FE.6,

5.FE.8, 5.FE.10, 5.FE.11, 5.FE.26, 5.FE.32–8

Infrared Reflection 5.IRR.4, 5.IRR.8–9

light source proximity 5.VE.9, 5.VE.25

5.Pow.9, 5.Pow.12, 5.Pow.15

magnetic powder applicators (wands) 5.Pow.8, 5.Pow.15

magnetic stirrer plates 3.3.8

Magnetite see iron oxide-based Powder Suspension

liquid nitrogen 3.1.19, 3.2.10, 3.2.18–19,

MALDI-MSI (matrix assisted laser

liquid measuring 3.3.5

5.ATR.2, 5.NS.3, 5.NS.5

5.CF.10–13

process selection 4.3

5.Pow.9, 5.Pow.12, 5.Pow.15, 5.Pow.18

magnification 5.FE:49

process details 5.Lif.8–10 process overview 5.Lif.1

magneta flake 5.Pow.3, 5.Pow.9

liquid latex 5.SR.7, 5.SR.12, 5.SR.16

Local Water Authority 3.2.28

Colour Filtration 5.CF.2, 5.CF.5, 5.CF.6,

macro lenses 3.3.18

magnetic flake powders 5.Pow.3,

beam size 2.2.31

problems 5.Lif.13–15

M

5.VE.11

Visual Examination, untreated marks

practicality 5.Lif.4, 5.Lif.12

5.VE.24

lysochromes 5.SB3.14

magazines 4.36–7, 4.54

local exhaust ventilation (LEV) 3.1.8,

5.Pow.11, 5.Pow.12, 5.Pow.19

LumiCyano™ 6.2.8

21

Visual Examination, treated marks

angle of illumination 2.2.31, 5.VE.9,

Powders 5.Pow.2, 5.Pow.3, 5.Pow.10,

Fingermark Visualisation Manual

Index

3.1.9, 3.1.10, 3.1.11, 3.2.3, 3.2.23

long-pass filters 5.FE.40, 5.IRR.11

maintenance of equipment 3.3.2, 3.3.6 desorption/ionisation-mass spectral imaging) 6.2.10

maleic acid

alternative names 3.1.19, 5.PD.6 CAS number 3.1.19, 5.PD.6

long-sightedness 5.FE:49

hazard labelling 5.PD.4

low-density polyethylene (LDPE) 4.10,

solution preparation 5.PD.7, 5.PD.8

loops 2.5.2 4.14

low pressure mercury vapour tubes 5.FE.38, 5.UVCR.9, 5.UVCR.12, 5.UVCR.14

Physical Developer theory 5.PD.19 solution problems 5.PD.14–15

manual overview 1.2–6 mark see fingermarks

IND.20

IND.21

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. marking up

definition GLO.3

integrity of fingermark evidence 3.3.10 labelling systems 2.5.5, 3.3.13–14 options 2.5.5

masking complex items for targeted

processing 2.4.10, 4.53, A.1.10, A.1.12

masking tapes 4.39

mass balances 3.1.14, 3.3.5–6, 3.3.8 mass spectrometry, SIMS 6.2.13

master copy image 3.3.22, 3.3.24 matt-painted surfaces 4.31 maturity bar

definition 1.8

processing charts 1.9, 1.13, 1.16

Technology Readiness Levels (TRLs) A.2.4

MDF 4.30

measuring equipment 3.1.14, 3.3.5–6, 3.3.26

melamine 4.7

meniscus 3.3.5

mercury and chalk powder 6.5.2

metal evaporation see Vacuum Metal Deposition

metal flake powders 5.Pow.2, 5.Pow.9, 5.Pow.10, 5.Pow.18

Home Office January 2014

Physical Developer Enhancement 5.PDE.14

date of introduction 2.3.3

process details 5.MMD.10–11

Dyes, methanol-based

equipment 5.MI.4, 5.MI.9

methanol-based protein stains see Acid 1-methoxy-2-propanol see PGME

1-methoxynonafluorobutane see HFE7100

methyl nonafluorobutyl ether see HFE7100 5-methylthioninhydrin (5-MTN) 6.4.3, A.2.8

micelles 5.PD.19, 5.SPR.12 mirrored marks

definition GLO.3

interpretation 2.5.14, 2.5.17–18

mixtures

commercial mixtures 3.3.3

5.MI.7, 5.MSI.10, 5.MSI.11

effectiveness 5.MI.1, 5.MI.2, 5.MI.6 integrated use 5.MI.1

practicality 5.MI.2, 5.MI.6 process details 5.MI.5

process overview 5.CF.1, 5.CF.2, 5.MI.1

safety 5.MI.1, 5.MI.2, 5.MI.3, 5.MI.6 scene treatment 5.MI.2, 5.MI.6 surface types 5.MI.1 targets 4.60

theory 5.MI.7–9

MoS2 see molybdenum disulphide

definition 3.3.7, GLO.3

MTF (modulation transfer function) 3.3.19

handling 3.2.23

Mud Removal 6.1.22

effectiveness 3.3.3 safety 3.2.22

specifications 3.3.3

storage 3.2.24, 3.2.26

modulation transfer function (MTF) 3.3.19

Deposition; Single Metal Deposition

compared to Colour Filtration 5.MI.7

mirrored marks 2.5.17

5.DFO.13, 6.3.6

methanol 3.2.26, 5.DFO.6, 5.DFO.7,

metadata 7.8

metal deposition see Multi-Metal

application examples 4.60

post-processing 5.MMD.12

MMD see Multi-Metal Deposition

metal corrosion 2.2.20, 4.18

Monochromatic Illumination

laboratory organisation 3.1.7

compared to Multi-Spectral Imaging

metal oxidation 4.18

mercury vapour tubes 5.FE.38, 5.UVCR.9, 5.UVCR.12, 5.UVCR.14

money see currency

mobile phones 2.1.12, 7.8, 7.9, A.1.10 moisture content of paper 5.ESDA.12 molybdenum disulphide 5.SPR.5, 5.SPR.6, 5.SPR.11, 5.SPR.12

molybdenum foil 5.VMD.5

mud 4.50, 4.57, 7.26

Multi-Metal Deposition (MMD) age of mark effect 2.3.13 chemicals 5.MMD.5 cling film 4.14

practicality 5.MMD.2

process overview 5.MMD.1 safety 5.MMD.1, 5.MMD.3

solution preparation 5.MMD.7–9 solution problems 5.MMD.13

surface types 2.3.14, 5.MMD.1 target properties 2.3.5

temperature effects 2.3.11

theory 5.MMD.14, 5.MMD.15 water exposure 2.3.12

Multi-Spectral Imaging

application examples 4.60 case studies A.1.14

compared to Colour Filtration 5.MSI.10

compared to Monochromatic

Illumination 5.MI.7, 5.MSI.10, 5.MSI.11

date of introduction 2.3.3

effectiveness 5.MSI.1, 5.MSI.2, 5.MSI.8

contaminants 2.3.5

equipment 5.MSI.4–5, 5.MSI.11–12

effectiveness 5.MMD.1

practicality 5.MSI.2, 5.MSI.8

date of introduction 2.3.4 equipment 5.MMD.5

integrated use 5.MMD.1

labelling solutions 5.MMD.4

integrated use 5.MSI.1

process details 5.MSI.6–7 process overview 5.MSI.1

IND.21

Fingermark Visualisation Manual

Index

IND.22

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. Multi-Spectral Imaging continued

safety 5.MSI.1, 5.MSI.2, 5.MSI.3, 5.MSI.8

scene treatment 5.MSI.2, 5.MSI.8

age of mark effect 2.3.13

sequential processing 2.3.8, 5.Nin.20

effect on persistence 2.2.18, 2.2.19

background development 5.Nin.15–17

solutions preparation 5.Nin.8

processing charts 1.9

alternative names 3.1.19 cadmium toning 6.5.2 CAS number 3.1.19

case studies A.1.1, A.1.3, A.1.4, A.1.6, A.1.12

surface types 5.Nin.1

target properties 2.3.5, 2.3.6 targeted processing 4.53

category F processes 6.5.2

theory 5.MSI.9–13

colour cancellation 5.CF.6

theory 2.3.15, 5.Nin.19–20

compared to DFO 5.Nin.20

thermal paper blackening 5.Nin.18

multiple donor studies A.2.9, A.2.11

N

nanoparticles 5.MMD.14, 6.2.16

a-naphthoflavone 6.1.32, 6.1.36, 6.1.37, 6.1.41

National Fingerprint Search System 2.5.9, 2.5.10

Natural Yellow 3 6.1.43, A.2.8 NBD chloride (4-chloro-7-

nitrobenzofurazan) 6.4.3

near IR imaging see Infrared Reflection negative images 2.5.20 negative marks

definition GLO.3 generation 2.2.7

visualisation 2.2.27

new fuschia 6.2.3

new magenta 6.2.3 newspaper 4.25

night blindness 5.FE.49 Nile Red 6.2.11 Ninhydrin

Home Office January 2014

chemicals 5.Nin.7

colour enhancement 5.CF.7, 5.CF.11 contaminants 2.3.5

dark-coloured paper 4.28 date of introduction 2.3.4

effectiveness 5.Nin.1, 5.Nin.2, 5.Nin.12

equipment 3.1.8, 3.1.10, 5.Nin.5–6

Fluorescence Examination 5.FE.31 grease contamination 4.34

integrated use 5.Nin.1

labelling solutions 5.Nin.4

laboratory organisation 3.1.7

Monochromatic Illumination 5.MI.7–8 Multi-Spectral Imaging 5.MSI.6, 5.MSI.12

post-processing 5.Nin.11

practicality 5.Nin.2, 5.Nin.12 process details 5.Nin.9–10 process overview 5.Nin.1

safety 3.2.11, 3.2.18, 5.Nin.1, 5.Nin.2, 5.Nin.3, 5.Nin.12

scene treatment 5.Nin.2, 5.Nin.12

secondary processing charts 4.6–23

normal diffuse lighting

application examples 5.VE.9, 5.VE.10, 5.VE.16

temperature effects 2.3.11

surface types 5.MSI.1 targets 4.60

primary charts 4.5

solution problems 5.Nin.13–14

equipment 5.VE.4, 5.VE.7, 5.VE.16

temperature problems 5.Nin.17,

set-up 5.VE.16

5.Nin.19

thermal paper 4.26 ThermaNin 6.2.18

theory 5.VE.29

notch filters 5.FE.40

Numberplate Splitting chemicals 5.NS.4

condensation 5.NS.5

water exposure 2.3.12, 2.3.15

effectiveness 5.NS.1, 5.NS.2

Ninhydrin Enhancement (Zinc Toning)

equipment 5.NS.4

chemicals 6.3.13

integrated use 5.NS.1

effectiveness 6.3.10

laboratory organisation 3.1.7

equipment 6.3.12

post-processing 5.NS.6

integrated use 6.3.10

practicality 5.NS.2

post-processing 6.3.16

process details 5.NS.5

process details 6.3.15

process overview 5.NS.1

process overview 6.3.10

safety 3.2.18–19, 5.NS.1, 5.NS.2,

safety 6.3.10, 6.3.11

5.NS.3

solution preparation 6.3.14

scene treatment 5.NS.2

surface types 6.3.10

surface types 5.NS.1

nitric acid fuming 6.5.2

nitrogen (liquid) 3.1.19, 3.2.10, 3.2.18–19, 5.ATR.2, 5.NS.3, 5.NS.5

Nominal Ocular Hazard Distance 3.2.17 non-porous substrate

category B processes 4.61

category C processes 4.61 definition 1.9, 4.4, GLO.3

theory 5.NS.7

NY3 6.1.43

nyctalopia 5.FE.49 nylons 4.7

O

O-tolidine 6.5.2

IND.22

Fingermark Visualisation Manual

Index

IND.23

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold.

oblique lighting

5.VE.11, 5.VE.13

equipment 5.VE.4, 5.VE.5, 5.VE.13 set-up 5.VE.13

theory 5.VE.24, 5.VE.26

OECD Principles on Good Laboratory Practice 3.3.2

oil contamination 4.23, 4.34, 4.48 Oil Red O 6.1.44

open-beam examination 5.FE.12

satin 4.38

CAS number 3.1.19

sequential processing 2.3.7, 2.3.8,

trace evidence 7.26

overview 5.BV3.2

process selection 2.2.31, 4.2, 4.60

Tables are in italics.

application examples 5.VE.9, 5.VE.10,

overview 5.1, 5.OP.1

4.2, 4.50, 5.OP.1

target properties 2.3.5

optical radiation 2.2.24, 3.2.14–17, 3.2.34–5

optical storage media 7.9 organic waste 3.2.28

ORO (Oil Red O) 6.1.44

ortho-phthaladehyde 6.4.3 osmium tetroxide 6.5.2

oven recovery time, Ninhydrin 5.Nin.6, 5.Nin.19

operating procedures 2.5.4, A.2.15

ovens see development ovens

optical brighteners 5.FE.32, 5.FE.38

oxidising chemicals 3.1.15

operational trials A.2.2, A.2.14 optical density (OD)

equation 5.FE.39

laser light sources 5.FE.11 viewing filters 5.FE.39

optical filters 3.3.18

optical processes see also Colour

Filtration; Fluorescence Examination; Infrared Reflection; Monochromatic

Illumination; Multi-Spectral Imaging; UVC Reflection; Visual Examination body fluids evidence 7.5 complex items 4.50

fingermark properties 2.2.28

forensic evidence integration 7.1, 7.11 information maximisation 2.4.4 laboratory organisation 3.1.4 Home Office January 2014

oxidation of metals 4.18

silk 4.38

Palladium Deposition 6.1.45 paper

case studies A.1.14

photographic flash for fluorescence

Ninhydrin 5.Nin.9

Physical Developer problems 5.PD.14–15, 5.PD.19

processing charts 4.25–9, 4.36–7

patent fingermark definition GLO.4 PD see Physical Developer

PD toning see Physical Developer Enhancement

permits to work 3.2.7

drug contamination 7.15

forensic evidence storage 2.1.4, 2.4.12, 3.3.11–12

Perma Blue 6.1.24 persistence

age of mark 2.2.17

environmental effects 2.2.17, 2.2.21– 5, 2.4.2

overview 2.2.1

substrate 2.2.17, 2.2.18–20

hard plastics 4.8

personal protective equipment (PPE)

soft plastics 4.10

PET see poly(ethylene terephthalate)

mirrored marks 2.5.17 tapes 4.19, 4.21, 4.40

painted surfaces gloss 4.17 matt 4.31

solution preparation 5.BV3.7, 5.BV3.8

moisture content 5.ESDA.12

document evidence recovery 7.12–13

P

cling film 4.14

process details 5.BV3.11 Photo-Flo 3.1.19

PE see polyethylene

cellophane 4.43

post-processing 5.BV3.12

complex items 4.54

ozone exposure 5.UVCR.4

packaging

labelling solutions 5.BV3.5

3.2.7–12, 3.2.17, 3.2.18, 3.3.11

photogrammetry 7.6

examination 5.FE.38

phthalates 4.13

Physical Developer

age of mark effect 2.3.13, 2.3.20

background development 5.PD.13–14 case studies A.1.9 chemicals 5.PD.6

cloudy solution 5.PD.12 contaminants 2.3.5

date of introduction 2.3.4 effectiveness 5.PD.1 equipment 5.PD.5

faint marks 5.PD.16

grease contamination 4.34

Infrared Reflection 5.IRR.5, 5.IRR.7 integrated use 5.PD.1

labelling solutions 5.PD.4

laboratory organisation 3.1.7

marbling from dust contamination 5.PD.18

PGME 5.SB3.5, 5.SB3.6, 5.SB3.14,

post-processing 5.PD.10, 5.PD.17

Phenol-based Basic Violet 3

process details 5.PD.9

5.SB3.15

background staining 5.BV3.19

practicality 5.PD.2

process overview 5.PD.1

IND.23

Fingermark Visualisation Manual

Index

IND.24

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. Physical Developer continued

processing problems 5.PD.11–18 safety 5.PD.3–4

solution preparation 5.PD.7, 5.PD.8 surface types 5.PD.1

target properties 2.3.5

theory 5.PDE.14

polyacetals 4.7

definition GLO.3

polybutadiene 4.15

physical processes

fingermark properties 2.2.28

forensic evidence integration 7.1 information maximisation 2.4.4 overview 5.1, 5.CPP.1 surface effects 2.2.32

target properties 2.3.5

polyamides 4.7

polycarbonate 4.7

PolyCyano UV™ 6.2.8

polyester brushes 5.Pow.7 polyesters

film for ESDA 5.ESDA.4, 5.ESDA.8 processing charts 4.7

temperature effects 2.3.11

pigment black 11 see iron oxide-based

poly[ethylcyanoacrylate] 5.SF.11

water exposure 2.3.12

planning see Fingermark Evidence

poly(ethylene terephthalate) (PET) 4.8

blue toning 5.PDE.2, 5.PDE.11,

plasticised polyvinylchloride (PVC) 4.13

theory 2.3.20, 5.PD.19

Physical Developer Enhancement 5.PDE.14

chemicals 5.PDE.6

date of introduction 2.3.4 effectiveness 5.PDE.1 equipment 5.PDE.5

integrated use 5.PDE.1

iodide toning 5.PDE.2, 5.PDE.7,

5.PDE.8, 5.PDE.12, 5.PDE.14

laboratory organisation 3.1.7 post-processing 5.PDE.13 potassium iodide 4.28

Powder Suspension Recovery Plan

plasticisers, Vacuum Metal Deposition effect 5.VMD.19, 5.VMD.20

plastics

cling film 4.14

hard packaging 4.8

identification symbols 4.7, 4.8, 4.9, 4.10, 4.11, 4.13

laboratory equipment 3.1.14, 3.3.5 rigid see rigid plastics soft packaging 4.10 texture 4.7

practicality 5.PDE.3

platelets 5.AD.14

process overview 5.PDE.1

PMMA see polymethylmethacrylate

process details 5.PDE.11–12 safety 5.PDE.1, 5.PDE.4

solutions preparation 5.PDE.7–10

sulphide toning 5.PDE.2, 5.PDE.9, 5.PDE.10, 5.PDE.12, 5.PDE.14

surface types 5.PDE.1

Home Office January 2014

platinum 4.18

polarised light 5.VE.34

polarising filters 3.3.18, 5.VE.7–8, 5.VE.21, 5.VE.34

policy constraints 2.1.3, 2.1.13 pollution 2.2.25

polyethylene (PE) 4.10, 4.42 polyisoprene 4.15

polymeric ‘papers’ 4.12, 4.25, A.1.13 polymethylmethacrylate (PMMA) 4.7 polypropylene (PP)

biaxially oriented polypropylene (BOPP) 4.12

processing charts 4.7, 4.10

polystyrene (PS) 4.7, 4.8, 4.11

polyvinylchloride (PVC) 4.13, 4.14 pores 2.2.9, 2.5.11 porosity

effect on persistence 2.2.18

effect on process selection 2.2.33, 4.1 wood 4.30

porous substrate

category B processes 4.61

secondary processing charts 4.25–34

positive marks

definition GLO.3

generation 2.2.7–8

post-processing

Acid Dyes 5.AD.9

Acid Dyes (methanol-based) 6.3.9 Adhesive Tape Removal 5.ATR.7 Basic Violet 3 (BV3) 5.BV3.12 DFO 5.DFO.9 DMAC 6.1.21

ESDA 5.ESDA.6

handling 3.3.14, 3.3.15 imaging 3.3.22–3

Indandione 6.1.31

integrity of fingermark evidence 3.3.14, 3.3.15

Iodine Fuming 6.1.40 Lifting 5.Lif.11

Multi-Metal Deposition (MMD) 5.MMD.12

Ninhydrin 5.Nin.11

Ninhydrin Enhancement (Zinc Toning) 6.3.16

Numberplate Splitting 5.NS.6

Physical Developer 5.PD.10, 5.PD.17 Physical Developer Enhancement 5.PDE.13

category C processes 4.61

Powder Suspensions 5.PS.10

effect on persistence 2.2.18

safety 3.2.1

definition 1.9, 4.4, GLO.3 primary charts 4.24

processing charts 1.9

Powders 5.Pow.13

Silver Nitrate 6.1.55

Small Particle Reagent 5.SPR.9

IND.24

Fingermark Visualisation Manual

Index

IND.25

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. post-processing continued

Solvent Black 3 5.SB3.8

Superglue Fluorescent Dye Staining 5.SFDS.11

Superglue Fluorescent Dye Staining (propanol-based) 6.1.63

Superglue Fuming 5.SF.6

Thermal Coating Removal 5.TCR.6

Vacuum Metal Deposition 5.VMD.10 waste management 3.2.28–9

category E processes 6.4.8

solution preparation 5.PS.7, 5.PS.8,

integrated use 5.Pow.1

colour enhancement 5.CF.12

spot tests 4.37, 4.39

Lifting 5.Pow.2, 5.Pow.3, 5.Pow.4,

date of introduction 2.3.4

target properties 2.3.5, 2.3.6

chemicals 5.PS.6

contaminants 2.3.5

effectiveness 5.PS.1, 5.PS.3, 5.PS.11 equipment 5.PS.5

grease contamination 4.23, 4.48 Infrared Reflection 5.IRR.7 integrated use 5.PS.1 iron oxide-based

adhesive tape 4.39, 5.PS.15, 5.PS.16

water-based Acid Dyes 6.1.10

alternative names 5.PS.6

potassium bromide 3.1.19, 5.PDE.6,

labelling systems 5.PS.5

postage stamps 4.19 5.PDE.9, 5.PDE.10

potassium ferricyanide 3.1.19, 5.PDE.6, 5.PDE.9, 5.PDE.10, 5.PDE.14

potassium iodide 3.1.19, 4.28, 5.PDE.6, 5.PDE.7, 5.PDE.8

Powder Suspensions

as additional process 4.2

adhesives with semi-porous backings 4.39, 5.PS.15

age of mark effect 2.3.13

background development 5.PS.14, 5.PS.16

carbon-based 5.PS.1, 5.PS.2, 5.PS.17 carbon-based Powder Suspension 5.PS.6

case studies A.1.1, A.1.3, A.1.6, A.1.7, A.1.9, A.1.10, A.1.12

Home Office January 2014

5.PS.12–13, 5.SFDS.8, 5.SFDS.9

surface types 2.3.14, 5.PS.1 temperature effects 2.3.11 theory 2.3.16, 5.PS.17

titanium dioxide-based 5.PS.1, 5.PS.2, 5.PS.6, 5.PS.17

Lifting 5.Lif.2, 5.Lif.3, 5.Lif.9, 5.Lif.16 lighting techniques 5.VE.11 post-processing 5.PS.10

practicality 5.PS.3, 5.PS.11

printed paper and card 4.37

magnetic flake powders 5.Pow.3, 5.Pow.9, 5.Pow.12, 5.Pow.15, 5.Pow.17

metal flake powders 5.Pow.2,

5.Pow.18

category F processes 6.5.2

theory 5.PS.17

lighting techniques 5.VE.11

age of mark effect 2.3.13

background development 5.Pow.17,

process overview 5.PS.1, 5.PS.2

laboratory organisation 3.1.7

5.Pow.19

magnetic granular powders 5.Pow.3,

case studies A.1.3, A.1.4

5.PS.8, 5.PS.13

5.Pow.10, 5.Pow.11, 5.Pow.12,

water exposure 2.3.12, 2.3.16

Powders

background staining 5.PS.16

solution preparation 5.PS.7,

laboratory organisation 3.1.7

category E processes 6.4.7 contaminants 2.3.5, 5.Pow.17, 5.Pow.18

date of introduction 2.3.4

effectiveness 5.Pow.1, 5.Pow.2, 5.Pow.3, 5.Pow.4, 5.Pow.14, 5.Pow.18

equipment 3.1.8, 3.1.13, 5.Pow.7–8 Fluorescent powders (category C) 6.2.12

5.Pow.9, 5.Pow.12, 5.Pow.15 5.Pow.9, 5.Pow.10, 5.Pow.17

post-processing 5.Pow.13

practicality 5.Pow.5, 5.Pow.14 process details 5.Pow.10–12 process overview 5.Pow.1

processing problems 5.Pow.15–17 reading list 5.Pow.20

safety 5.Pow.1, 5.Pow.2, 5.Pow.5, 5.Pow.6, 5.Pow.14

scene treatment 5.Pow.1, 5.Pow.5, 5.Pow.14

sequential processing 5.Pow.4

surface types 2.3.14, 2.3.21, 5.Pow.1, 5.Pow.17, 5.Pow.18

process details 5.PS.9

footwear marks 7.18

target properties 2.3.5

PVC 4.13

glovemarks 7.20

theory 2.3.21, 5.Pow.18–19

process overview 5.PS.1 safety 5.PS.1, 5.PS.3–4, 5.PS.11 scene treatment 5.PS.1, 5.PS.3, 5.PS.11

sequential processing 5.PS.2

glass 4.6

granular powders 5.Pow.3, 5.Pow.7, 5.Pow.11

‘huffing’ 5.Pow.18

Infrared Reflection 5.IRR.7

temperature effects 2.3.11 uPVC 4.9

water exposure 2.3.12

PP see polypropylene

IND.25

Fingermark Visualisation Manual

Index

IND.26

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Contents

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. PPE (personal protective equipment) 3.2.7–13, 3.2.17, 3.2.18, 3.3.10

practitioners

communications

image transfer 2.5.9

images 2.5.7–8, 2.5.9, 2.5.15, 2.5.20, 3.3.23, 3.3.25

lifts 2.5.6

marking up 2.5.5

overview 2.5.1, 2.5.4

competence 3.1.2, 3.3.2, 3.3.22 definition GLO.3 fatigue 5.FE.49

investigative process overview 2.1.3 manual usage guide 1.2

safety responsibilities 3.2.2, 3.2.22 visual ability 5.FE.49

visual attention 5.FE.49

pre-humidification 5.ESDA.12 precipitation 5.Nin.14

preferential solubility 5.SB3.14

preparation processes see also Adhesive Tape Removal; Numberplate Splitting; Soot Removal; Thermal Coating Removal

complex items 3.3.13, 4.50 definition GLO.3

effectiveness 3.3.13

information maximisation 2.4.4 large items 3.3.9, 3.3.13 Home Office January 2014

overview 2.4.4, 2.4.5, 4.55, 5.1, 5.PP.1 sequential processing 4.3, 5.PP.1

Technology Readiness Levels (TRLs) A.2.3

preservation of forensic evidence 2.1.3,

process charts see processing charts

presumptive tests 7.4, 7.5

process instructions

2.1.4–5, 7.5

primary charts

non-porous substrate 4.5 overview 4.1

porous substrate 4.24 selection 1.10

semi-porous substrate 4.35

supporting information 1.11

Principal Component Analysis 5.MSI.13 print see fingerprints printed surfaces

currency 4.29

document evidence recovery 7.12 Infrared Reflection 5.IRR.6 paper 4.25, 4.36–7

soft plastic packaging 4.10

Superglue Fluorescent Dye Staining 5.SFDS.2, 5.SFDS.14

printing images 3.3.23 process

chemical, definition GLO.1 definition GLO.3

optical, definition GLO.3

physical, definition GLO.3

preparation, definition GLO.3

process category

classification table 2.3.2 definition GLO.3

process effectiveness see effectiveness Acid Dyes 5.AD.8

process selection decisions 1.15 Silver Nitrate 6.1.54

Small Particle Reagent 5.SPR.8

solutions standard preparation 3.3.8 solutions standard usage guidelines 3.3.9

Acid Dyes (methanol-based) 6.3.8

Solvent Black 3 5.SB3.7

Basic Violet 3 (BV3) 5.BV3.9–11

Superglue Fluorescent Dye Staining

Adhesive Tape Removal 5.ATR.6 Colour Filtration 5.CF.7

Soot Removal 5.SR.9–15 5.SFDS.10

DFO 5.DFO.8

Superglue Fluorescent Dye Staining

ESDA 5.ESDA.5

Superglue Fuming 5.SF.5

Indandione 6.1.30

usage guidance 1.16–17

DMAC 6.1.20

Fluorescence Examination 5.FE.12–13 Infrared Reflection 5.IRR.5 Iodine Fuming 6.1.38–9

ISO 17025 requirements 3.1.2 laboratory organisation 3.1.7 Lifting 5.Lif.8–10

Monochromatic Illumination 5.MI.5 Multi-Metal Deposition (MMD) 5.MMD.10–11

Multi-Spectral Imaging 5.MSI.6–7 Ninhydrin 5.Nin.9–10

Ninhydrin Enhancement (Zinc Toning) 6.3.15

(propanol-based) 6.1.62

Thermal Coating Removal 5.TCR.5 UVC Reflection 5.UVCR.6–7

Vacuum Metal Deposition 5.VMD.7–9 Visual Examination 5.VE.12

water-based Acid Dyes 6.1.9

process optimisation A.2.8

process selection see also processing charts

complex items 4.49–54

constraints 1.11, 2.1.13–15, 4.2

contaminant considerations 4.56

decision making 1.4, 2.4.7–8, 2.4.14, 4.3

Numberplate Splitting 5.NS.5

forensic evidence integration 4.51

Physical Developer Enhancement

Lifting 4.3

Physical Developer 5.PD.9 5.PDE.11–12

Powder Suspension 5.PS.9 Powders 5.Pow.10–12

high-value items 4.2

manual usage guide 1.4 overview 4.1

resource constraints 2.1.15, 2.4.13

IND.26

Fingermark Visualisation Manual

Index

IND.27

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold.

Dye Staining

chemicals 6.1.60

Tables are in italics.

effectiveness 6.1.56

process selection continued

substrate 1.15, 2.2.32, 4.1, 4.2 test marking 2.4.9

time constraints 2.1.13, 2.4.13

process validation A.2.1, A.2.2, A.2.5, A.2.6, A.2.15

processing charts

definition GLO.3

Fingermark Evidence Recovery Plan

R

options 6.1.57

radiation emission 2.2.30, 3.2.15

radiation absorption 2.2.30

Registration, Evaluation and Authorisation

safety 6.1.56, 6.1.58

re-humidification before Powders

solution preparation 6.1.61

REACH (Registration, Evaluation and

surface types 6.1.56

propanone see acetone

5.Pow.18

Authorisation of Chemicals) regulations 3.2.20

receipts

non-porous substrate 1.9, 4.5–23

protein stains see Acid Dyes

overview 4.1–2

Prussian Blue 5.PDE.14

porous substrate 1.9, 4.24–34

primary charts 1.10, 1.11, 1.13, 4.1, 4.5, 4.24, 4.35

secondary charts 1.11, 1.12–13, 4.1, 4.6–23, 4.24–34, 4.36–48

semi-porous substrate 1.9, 4.35–48 sequence options 4.2

usage guidance 1.9–15

PGME

3.2.18, 3.3.11

proximity of light source 5.VE.9, 5.VE.25 Prussian Red see potassium ferricyanide PS see polystyrene

pseudo-operational trials A.2.2, A.2.13 pulling and prising 5.ATR.2, 5.ATR.6, 5.ATR.10

PVC see polyvinylchloride Pyrex® glass 3.1.13–14

processing troughs 5.DFO.5, 5.Nin.5,

Q

2-propanol 6.1.60, 6.3.13

quality of images 2.5.7, 2.5.9

6.1.27

propanol-based Superglue Fluorescent Home Office January 2014

initial recording 2.2.2, 2.5.2

RAW file format 3.3.21, 3.3.22

range of donors studies A.2.10

protective equipment 3.2.7–12, 3.2.17,

options in process instructions 1.9–15

2.5.10

forms 2.2.2

process overview 6.1.56

process details 6.1.62

high-value items 4.2

modifications 2.4.7–8

comparison process 2.5.1, 2.5.2–3,

reflectivity 2.2.30

reactivity of substrates 2.2.20

forensic evidence integration 4.51

compared to fingermarks 2.2.1

Radioactive Sulphur Dioxide 6.1.46

propylene glycol monomethyl ether see

2.4.5–8

reference prints

post-processing 6.1.63

sequential processing 6.1.57

complex items 4.52–4

Illumination

equipment 6.1.59

integrated use 6.1.56

sweat 2.3.6

Quaserchrome see Monochromatic

quality documents 2.5.4

quartered fingermarks A.2.8

readership 1.2

DFO blackening 5.DFO.12

Ninhydrin blackening 5.Nin.18 processing charts 4.26

Thermal Coating Removal 5.TCR.1, 5.TCR.5, 5.TCR.7

recirculatory systems 3.2.23

record keeping see also audit trail communications 2.5.4

equipment 3.3.2, 3.3.6

imaging during sequential processing 2.3.7, 2.5.4, 4.3, 4.10

refractive index 2.2.30

of Chemicals (REACH) regulations 3.2.20

release paper 5.ATR.5, 5.NS.4 reproduction of images 2.5.9 research

effectiveness A.2.11

guideline documentation A.2.5 laboratory trials A.2.9–12

methodology caution A.2.6 operational trials A.2.14 overview A.0.1, A.2.1

process optimisation A.2.8

process validation A.2.1, A.2.2, A.2.5, A.2.6, A.2.15

pseudo-operational trials A.2.13 publication of process A.2.15 spot tests A.2.7

Technology Readiness Levels (TRLs) A.2.1, A.2.2

integrity of evidence 3.3.10

resolution of images 3.3.19

requirements overview 2.4.3

resource constraints 2.1.15, 2.4.13

reference prints 2.2.2

risk assessments 3.2.7, 3.2.15

solution preparation 3.2.24, 3.2.25

resolution of mass balances 3.3.5

respiratory protective equipment (RPE) 3.2.11, 3.2.22

IND.27

Fingermark Visualisation Manual

Index

IND.28

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. reverse-coloured marks see reversedeveloped marks

reverse-developed marks contaminants 2.5.16 definition GLO.3

deposition pressure 2.5.16

ring lights 5.VE.4, 5.VE.16, 5.VE.29

Physical Developer Enhancement

S

risk assessments 3.1.16–17, 3.2.6, 3.2.7,

Powders 5.Pow.6

safety see also hazards; risks

risks see also hazards

public exposure 3.1.16

Acid Dyes 5.AD.1, 5.AD.3, 5.AD.4–5,

Solvent Black 3 5.SB3.3

Acid Dyes (methanol-based) 6.3.2,

rinsing, targeted processing 4.53 3.2.15

Acid Dyes 5.AD.4–5

Acid Dyes (methanol-based) 6.3.4 Adhesive Tape Removal 5.ATR.4, 5.ATR.8

5.PDE.4

process selection constraints 2.1.14 Silver Nitrate 6.1.50

Superglue Fluorescent Dye Staining

(propanol-based) 6.1.58

Adhesive Tape Removal category B

Superglue Fluorescent Dye Staining

Superglue Fuming 2.5.16

context 1.2

Superglue Fuming 5.SF.3

definition 3.2.6

Vacuum Metal Deposition 5.VMD.3

Vacuum Metal Deposition 2.5.15, 5.VMD.18

reverse-direction marks see mirrored marks

reverse-oriented marks see mirrored marks

ridge detail

control 3.2.7

DFO 5.DFO.3 DMAC 6.1.15

ESDA 5.ESDA.3

Fluorescence Examination 5.FE.5, 5.FE.39

blood-mark interpretation 4.58–9

Indandione 6.1.26

definition GLO.4

Iodine Fuming 6.1.34

contrast optimisation 2.5.8 feature distribution 2.2.3 features 2.5.2, 2.5.3

incomplete prints 2.5.10 Lifting 4.3

patterns 2.5.2

rough surfaces 2.2.15

Infrared Reflection 5.IRR.3 legislation 3.0.1, 3.1.1, 3.2.7

light sources 3.2.14–17, 3.2.34–5 manual usage guide 1.4

Monochromatic Illumination 5.MI.3 Multi-Metal Deposition (MMD) 5.MMD.3

substrate effects 2.5.13–14

Multi-Spectral Imaging 5.MSI.3

wet surfaces 4.3

Ninhydrin Enhancement 6.3.11

uniqueness 2.2.3

rigid plastics processing charts 4.7 rigidity of substrate 2.2.5

Home Office January 2014

Ninhydrin 5.Nin.3

Numberplate Splitting 5.NS.3 overview 3.2.1

6.3.4

Adhesive Tape Removal 5.ATR.1,

Basic Violet 3 (BV3) 5.BV3.4 Colour Filtration 5.CF.4

5.AD.10

5.SFDS.4

interpretation 2.5.15–16 substrate 2.5.15

S2N2 6.2.15

5.ATR.4, 5.ATR.8 process 6.1.12

UVC Reflection 5.UVCR.4

Basic Violet 3 (BV3) 5.BV3.1, 5.BV3.3,

Visual Examination 5.VE.3

Body Decomposition Residue Removal

water-based Acid Dyes 6.1.5

rods, eye structure 5.FE.48

rotary sample holders 5.VMD.5 roughing pumps 3.1.12 roughness

effect on fingermark generation 2.2.5, 2.2.15

effect on process selection 1.15

visualisation effectiveness 2.2.15, 2.2.32, 2.3.9

RPE (respiratory protective equipment) 3.2.11, 3.2.22

rubber 4.15

rubbing, Soot Removal 5.SR.3, 5.SR.13– 14, 5.SR.17

Ruhemann’s Purple 5.Nin.19, 6.3.10 ruthenium tetroxide 6.5.2

5.BV3.4, 5.BV3.13 6.1.13

chemicals storage 3.1.15

Colour Filtration 5.CF.1, 5.CF.3–4, 5.CF.8

context 1.2

control measures 3.2.7

DFO 3.2.18, 5.DFO.1, 5.DFO.2–3 DMAC 6.1.14, 6.1.15

Earth and Mud Removal 6.1.22 electricity supply 3.2.4

equipment 3.2.3, 3.2.4

ESDA 5.ESDA.1, 5.ESDA.2–3 Europium Chelate 6.1.23

Fingermark Evidence Recovery Plan 2.4.11

Fluorescence Examination

door interlocks 3.1.5, 5.FE.12 hazards 5.FE.5

IND.28

Fingermark Visualisation Manual

Index

IND.29

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Multi-Spectral Imaging 5.MSI.1,

Solvent Black 3 5.SB3.1, 5.SB3.2–3,

satin-painted surfaces 4.38

Natural Yellow 3 6.1.43

Soot Removal 5.SR.1, 5.SR.5, 5.SR.6,

SB3 see Solvent Black 3

laboratory organisation 3.1.4–5

Ninhydrin 3.2.11, 3.2.18, 5.Nin.1,

specialists 3.1.2, 3.2.6

overview 5.FE.1, 5.FE.3–4

Ninhydrin Enhancement 6.3.10, 6.3.11

Illustrations and figures are in bold. Tables are in italics. safety continued

light sources 3.2.15, 3.2.16 scene treatment 5.FE.14

viewing filters 5.FE.11, 5.FE.39

fume cupboards 3.1.9–10 Gun Blueing 6.1.24

housekeeping 3.2.5

Indandione 6.1.25, 6.1.26

Infrared Reflection 3.2.16, 5.IRR.1, 5.IRR.2, 5.IRR.3, 5.IRR.6

Iodine Fuming 6.1.32, 6.1.33–4 Iodine Solution 6.1.41

laboratory organisation equipment 3.1.8

Fingermark Evidence Recovery Plan 2.4.11

overview 3.1.1, 3.2.1, 3.2.2

5.MSI.2, 5.MSI.3, 5.MSI.8

5.Nin.2, 5.Nin.3–4, 5.Nin.12

Numberplate Splitting 3.2.18–19, 5.NS.1, 5.NS.2, 5.NS.3

Oil Red O 6.1.44

overview 3.0.1, 3.1.1, 3.2.1

Palladium Deposition 6.1.45

personal protective equipment (PPE) 3.2.7–12

Physical Developer 5.PD.3–4

Physical Developer Enhancement 5.PDE.1, 5.PDE.4

post-processing 3.2.1

Powder Suspensions 5.PS.1, 5.PS.3– 4, 5.PS.11

Powders 5.Pow.1, 5.Pow.2, 5.Pow.5, 5.Pow.6, 5.Pow.14

legislation 3.0.1, 3.1.1, 3.2.2–3, 3.2.4,

process selection constraints 2.1.14

Leuco Crystal Violet (LCV) 6.1.42

responsibilities 3.2.2, 3.2.22

3.2.6, 3.2.14–15

Lifting 5.Lif.1, 5.Lif.4–5

light sources 3.2.6, 3.2.14–17, 3.2.34– 5

manual usage guide 1.4

Monochromatic Illumination 5.MI.1, 5.MI.2, 5.MI.3, 5.MI.6

Multi-Metal Deposition (MMD) 5.MMD.1, 5.MMD.3–4

Home Office January 2014

Radioactive Sulphur Dioxide 6.1.46 reviews 3.2.2, 3.2.22

5.SB3.9 5.SR.16

Superglue Fluorescent Dye Staining

5.SFDS.1, 5.SFDS.3–5, 5.SFDS.12

Superglue Fluorescent Dye Staining

5.SPR.2, 5.SPR.3–4, 5.SPR.10

Scanning Electron Microscopy (SEM) 6.1.47

scene treatment

Thermal Coating Removal 5.TCR.1, 5.TCR.2–3

training 3.1.2, 3.2.23

UVC Reflection 3.2.16, 5.UVCR.1,

5.UVCR.2, 5.UVCR.3–4, 5.UVCR.5,

5.UVCR.8

Vacuum Metal Deposition 5.VMD.3 Vacuum Metal Deposition (VMD) 5.VMD.1

ventilation 3.2.3, 3.2.23

Visual Examination 5.VE.1, 5.VE.2, 5.VE.3, 5.VE.22

waste management 3.2.4, 3.2.28–9

water-based Acid Dyes 6.1.2, 6.1.4–5, 6.1.11

work flow 3.2.5

Small Particle Reagent 5.SPR.1,

scanners, flatbed 3.3.17, 3.3.19

5.SF.7

Superglue Fuming 5.SF.1, 5.SF.2–3,

scene treatment overview 3.1.1, 3.1.16–17, 3.2.6, 3.2.24

scaling 2.5.5

Scanning Kelvin Probe (SKP) 6.1.48

water supply 3.2.4

Silver Nitrate 6.1.49, 6.1.50

scales see mass balances

(propanol-based) 6.1.56, 6.1.58

Scanning Electron Microscopy 6.1.47 Scanning Kelvin Probe 6.1.48

saturated solutions 3.3.7, GLO.4

wavelength selection 3.2.15 Safety Data Sheets (SDS) 3.2.20–1, 3.2.26

saliva 7.4–5

salts in fingermarks 2.3.6, 5.SF.11

scene management 2.1.5

Acid Dyes 5.AD.3, 5.AD.10

Adhesive Tape Removal 5.ATR.3, 5.ATR.8

Basic Violet 3 5.BV3.1, 5.BV3.3 Basic Violet 3 (BV3) 5.BV3.13 case studies A.1.8

Colour Filtration 5.CF.1, 5.CF.3, 5.CF.8 constraints 2.1.15 definition GLO.4

ESDA 5.ESDA.2, 5.ESDA.7

Fluorescence Examination 5.FE.1,

5.FE.3, 5.FE.14, 5.FE.35, 5.FE.36

Infrared Reflection 5.IRR.1, 5.IRR.2, 5.IRR.6

Lifting 5.Lif.4, 5.Lif.12

Monochromatic Illumination 5.MI.2, 5.MI.6

Multi-Spectral Imaging 5.MSI.2, 5.MSI.8

Ninhydrin 5.Nin.2, 5.Nin.12 planning 2.4.12

IND.29

Fingermark Visualisation Manual

Index

IND.30

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. scene treatment continued

Powder Suspensions 5.PS.1, 5.PS.3, 5.PS.11

Powders 5.Pow.1, 5.Pow.5, 5.Pow.14 practicality 2.4.12

secondary ion mass spectrometry (SIMS)

effect of supporting information 1.11

secretory glands 2.2.8–9, 2.2.10

Forensic Evidence Recovery Plan

6.2.13

segregation of chemicals 3.2.26, 3.2.28 selectivity of processes A.2.9 selenic acid 6.5.2

Sellotape 4.40 see also adhesives with cellulose backings

safety overview 3.1.1, 3.1.16, 3.2.6,

SEM (Scanning Electron Microscopy)

Small Particle Reagent 5.SPR.2,

semen

3.2.24

5.SPR.10

Solvent Black 3 5.SB3.2, 5.SB3.9 Soot Removal 5.SR.5, 5.SR.16

Superglue Fluorescent Dye Staining 5.SFDS.3, 5.SFDS.12

Superglue Fuming 5.SF.2, 5.SF.7

UVC Reflection 5.UVCR.2, 5.UVCR.8 Visual Examination 5.VE.2, 5.VE.22 water-based Acid Dyes 6.1.4

SDS (Safety Data Sheets) 3.2.20–1, 3.2.26

sebaceous glands 2.2.8, 2.2.10

sebaceous sweat category A processes 2.3.5, 2.3.6 see also sweat

second generation reproductions 2.5.9 secondary charts

non-porous substrate 4.6–23 overview 4.1

porous substrate 4.25–34 selection 1.11, 1.12–13

semi-porous substrate 4.36–48

Home Office January 2014

6.1.47

fluorescence 5.FE.9

forensic evidence recovery 7.4–5

semi-porous substrate

category B processes 4.62

Fluorescence Examination 5.FE.2 2.1.12, 2.1.14

imaging

audit trail 2.4.3

at each stage 2.3.7, 2.4.3, 2.4.4, 2.5.4, 4.3

process selection 4.3

interpretation requirements 2.5.11 Lifting 5.Lif.3

multiple donor studies A.2.11 Ninhydrin 2.3.8, 5.Nin.20

optical processes 2.3.7, 4.2, 4.50, 5.OP.1

category C processes 4.62

optimisation 2.4.8

effect on persistence 2.2.18

Powders 5.Pow.4

definition 1.9, 4.4, GLO.4 primary charts 4.35

processing charts 1.9

secondary processing charts 4.36–48

sensitivity of processes A.2.9, A.2.10

sequential processing see also processing charts

Acid Dyes 2.3.8, 5.AD.2

Acid Dyes (methanol-based) 6.3.3 alternative routes 1.14

ballistics forensic analysis 2.1.12, 7.3

Powder Suspensions 5.PS.2 preparation processes 4.3, 5.PP.1 research A.2.11–12

rules 2.3.7–8, 2.4.7, 4.52 solvents 2.3.7

Soot Removal 5.SR.4

split fingermarks A.2.12

Superglue Fuming 2.3.8

Thermal Coating Removal 5.TCR.1

Vacuum Metal Deposition 5.VMD.2 water-based Acid Dyes 6.1.3

Basic Violet 3 5.BV3.2

shoes 4.15

definition GLO.4

short wave IR imaging see Infrared

complex items 4.52 DFO 2.3.8

DNA evidence 2.1.12, 2.1.14, 7.11

short-pass filters 5.FE.41 Reflection

short wave UV imaging see UVC

Reflection

shutter release cables 3.3.17

silicone release paper 4.53, A.1.10

silicone rubber casting compound 5.Lif.3, 5.Lif.6, 5.Lif.10, 5.SR.7, 5.SR.11

silk-painted surfaces 4.38 silver 3.1.19, 4.18

silver bromide 5.PDE.14 silver chloride 6.1.49

silver deposition, electroless 6.2.7 silver iodide 5.PDE.14 silver nitrate

CAS number 3.1.19, 5.MMD.6, 5.PD.6, 6.1.52

category B process 6.1.49–55 development theory 5.PD.19

labelling systems 5.MMD.4, 5.PD.4 processing problems 5.PD.11–12, 5.PD.14

solution preparation 5.MMD.8,

5.MMD.9, 5.PD.7, 5.PD.8, 6.1.53

silver Vacuum Metal Deposition CAS number 5.VMD.6

evaporation vessels 5.VMD.5 overview 5.VMD.2

process details 5.VMD.7, 5.VMD.9

processing problems 5.VMD.12–16 theory 5.VMD.20

SIM cards 7.8, A.1.10

SIMS (secondary ion mass spectrometry) 6.2.13

Single Metal Deposition 6.2.14 single step superglue 6.2.8

IND.30

Fingermark Visualisation Manual

Index

IND.31

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. skin

properties 2.2.3

as substrate 4.46

sweat physiology 2.2.8–9

SKP (Scanning Kelvin Probe) 6.1.48 Small Particle Reagent

temperature effects 2.3.11

definition 3.2.22, 3.3.7, GLO.4

Superglue Fluorescent Dye Staining

water exposure 2.3.12

DMAC 6.1.18

water-based Acid Dyes 6.1.8

theory 5.SPR.12 SMD 6.2.14

soda-lime glassware 3.1.13

sodium chloride in fingermarks 2.3.6, 5.SF.11

sodium citrate 5.MMD.4, 5.MMD.6, 5.MMD.7, 5.MMD.9

age of mark effect 2.3.13

sodium hydroxide 3.1.20, 5.PDE.4,

contaminants 2.3.5

sodium hypochlorite 3.1.20, 5.PDE.6,

effectiveness 5.SPR.1, 5.SPR.2,

soft boxes 5.VE.5

chemicals 5.SPR.5

date of introduction 2.3.4 5.SPR.10

equipment 5.SPR.5

Infrared Reflection 5.IRR.7 integrated use 5.SPR.1

5.PDE.6

5.PDE.7, 5.PDE.8 see also bleach

soft specular lighting

advantages 5.VE.28

application examples 5.VE.9, 5.VE.10, 5.VE.15

labelling solutions 5.SPR.4

disadvantages 5.VE.28

Lifting 5.Lif.2, 5.Lif.3

set-up 5.VE.15

laboratory organisation 3.1.7 lighting techniques 5.VE.11

equipment 5.VE.6, 5.VE.8, 5.VE.15 theory 5.VE.28

DFO 5.DFO.4, 5.DFO.7

effectiveness 3.3.3, 3.3.7–9 expiry periods 3.3.4, 3.3.7 handling 3.2.23 hazards 3.2.22

Indandione 6.1.29

labelling systems 3.2.24, 3.2.25 large items treatment 3.3.9

Multi-Metal Deposition (MMD) 5.MMD.4, 5.MMD.7–9

Ninhydrin 5.Nin.4, 5.Nin.8

Ninhydrin Enhancement (Zinc Toning) 6.3.14

Physical Developer 5.PD.4, 5.PD.7 Powder Suspensions 5.PS.5, 5.PS.12–13

preparation guidelines 3.3.7–8 re-use 3.3.4

record keeping 3.2.24, 3.2.25

Silver Nitrate 6.1.53

Small Particle Reagent 5.SPR.4,

post-processing 5.SPR.9

software for analysis, Multi-Spectral

process details 5.SPR.8

soil 4.50, 4.57, 6.1.22, 7.26

Solvent Black 3 5.SB3.4, 5.SB3.6,

safety 5.SPR.1, 5.SPR.2, 5.SPR.3–4,

solutes 3.3.7, GLO.4

Soot Removal 5.SR.6, 5.SR.8

practicality 5.SPR.2, 5.SPR.10 process overview 5.SPR.1 5.SPR.10

scene treatment 5.SPR.2, 5.SPR.10

solution preparation 5.SPR.6, 5.SPR.7 solution problems 5.SPR.11

surface types 2.3.14, 5.SPR.1 target properties 2.3.5

Home Office January 2014

Imaging 5.MSI.9, 5.MSI.12–13

solubility 3.3.7, 5.SB3.14 solutions

Acid Dyes 5.AD.5, 5.AD.7

Acid Dyes (methanol-based) 6.3.7

Basic Violet 3 (BV3) 5.BV3.5, 5.BV3.7, 5BV3.8

commercial solutions 3.3.3

5.SPR.6, 5.SPR.7, 5.SPR.11 5.SB3.10, 5.SB3.15

specifications 3.3.3

standard preparation method 3.3.8 standard usage guidelines 3.3.9 storage 3.2.24, 3.2.26, 3.3.7

Superglue Fluorescent Dye Staining 5.SFDS.5, 5.SFDS.8

(propanol-based) 6.1.61

Solvent Black 3

age of mark effect 2.3.13 alternative names 3.1.20

background staining 5.SB3.12 CAS number 3.1.20 chemicals 5.SB3.5

colour enhancement 5.CF.6 contaminants 2.3.5

date of introduction 2.3.4

effectiveness 5.SB3.1, 5.SB3.2, 5.SB3.8

equipment 5.SB3.5

faint marks 5.SB3.11

integrated use 5.SB3.1

labelling solutions 5.SB3.4

laboratory organisation 3.1.7 large item treatment 3.3.9 post-processing 5.SB3.8

practicality 5.SB3.2, 5.SB3.9 process details 5.SB3.7

process overview 5.SB3.1

rinsing problems 5.SB3.13

safety 5.SB3.1, 5.SB3.2, 5.SB3.9

scene treatment 5.SB3.2, 5.SB3.9 solution preparation 5.SB3.6

solution problems 5.SB3.10–11 surface types 2.3.14, 5.SB3.1 target properties 2.3.5, 2.3.6 temperature effects 2.3.11 theory 5.SB3.14–15

IND.31

Fingermark Visualisation Manual

Index

IND.32

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics.

equipment 5.SR.7

stickers 4.19, 4.32, 4.40

limitations 4.2

laboratory organisation 3.1.7

sticky tape removal see Adhesive Tape

optical processes 2.2.28

integrated use 5.SR.1

Solvent Black 3 continued

method options 5.SR.3

Solvent Red 27 6.1.44

process details 5.SR.9–15

water exposure 2.3.12

solvents

Acid Dyes post-processing 5.AD.9

solvents continued

Adhesive Tape Removal 5.ATR.2, 5.ATR.10

Adhesive Tape Removal category B

practicality 5.SR.5, 5.SR.16 process overview 5.SR.1

safety 5.SR.1, 5.SR.5, 5.SR.6, 5.SR.16 scene treatment 5.SR.5, 5.SR.16 sequential processing 5.SR.4 solutions 5.SR.6, 5.SR.8 surface types 5.SR.1 theory 5.SR.17

process 6.1.12

specialists, safety 3.1.2, 3.2.6

5.BV3.13

spectrum 5.CF.9

Basic Violet 3 post-processing definition GLO.4

Drug Removal 6.2.5

sequential processing 2.3.7

spectroscopy, ATR-FTIR 6.2.2 specular lighting

theory 5.VE.24, 5.VE.27, 5.VE.28 UVC Reflection 5.UVCR.10

Solvent Black 3 post-processing

specular reflection 2.2.30, 5.VE.28

storage see chemicals

split depletion series A.2.10

5.SB3.8

Superglue Fluorescent Dye Staining post-processing 5.SFDS.11

Superglue Fuming post-processing 5.SF.6

water-based Acid Dyes postprocessing 6.1.10

soot contamination 4.57, 5.SR.2 Soot Removal

chemicals 5.SR.7

coverage levels 5.SR.2

effectiveness 5.SR.1, 5.SR.5, 5.SR.16 Home Office January 2014

spillages 3.2.28

‘sticky-side powder’ 6.4.8 Removal

stir bars 3.3.8 storage

chemicals 3.1.15, 3.2.24, 3.2.26–7, 3.3.4

equipment 3.1.14

forensic evidence 2.1.4–5, 2.4.12, 3.1.3, 3.3.12

images 3.3.22, 3.3.25

storage media 7.8, 7.9 street furniture 4.18

styrene-butadiene 4.15

substrate see also surfaces

definition GLO.4

effect on process selection 2.2.30, 2.2.32, 2.2.33, 4.1, 4.2

emissivity 2.2.30 2.2.23, 2.2.24

fingermark generation effect 2.2.5, 2.2.6–7, 2.2.15

stamps (postage) 4.19

fluorescence 2.2.30

Standard PPE 3.2.7

identification 1.9

Standard Operating Procedures 2.5.4 stearic acid 5.Pow.18 steel 4.18

reflectivity 2.2.30

reverse-developed marks 2.5.15 rigidity 2.2.5

semi-porous see semi-porous substrate

separation 4.52, 4.55

texture 1.15, 2.2.5, 2.2.15, 2.2.30, 2.2.32, 2.3.9

transparency 2.5.14, 2.5.17 wetability 2.2.19

sulfourea see thiourea

environmental effects 2.2.21, 2.2.22,

stainless steel 4.18

reactivity 2.2.20

condition 2.2.5, 2.2.17

complexity 2.4.10

staining solutions

water-based Acid Dyes 6.1.8

porous see porous substrate

Sudan Black see Solvent Black 3

elasticity 2.2.5

Acid Dyes 5.AD.7, 5.AD.14

persistence 2.2.17, 2.2.18–20

colour 2.2.30, 2.2.33

spot tests A.2.2, A.2.7

SPR see Small Particle Reagent

non-porous see non-porous substrate

fluorescence theory 5.FE.31 interpretation 2.5.13–14 laboratory trials A.2.10

Sudan Red 5B 6.1.44

sulphide toning 5.PDE.2, 5.PDE.9, 5.PDE.10, 5.PDE.12, 5.PDE.14

5-sulphosalicylic acid dihydrate 3.1.20, 3.3.3, 5.AD.6, 5.AD.11, 6.1.7

sulphur dioxide, radioactive 6.1.46 sunlight effects 2.2.24

Superglue Fluorescent Dye Staining

background staining 5.SFDS.15 Basic Red 14

CAS number 5.SFDS.7

Fluorescence Examination 5.FE.10, 5.FE.28–9

overview 5.SFDS.2

solution preparation 5.SFDS.8

IND.32

Fingermark Visualisation Manual

Index

IND.33

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Contents

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. Superglue Fluorescent Dye Staining continued

Basic Yellow 40

background staining 5.SFDS.15 CAS number 5.SFDS.7

faint fluorescent marks 5.FE.15 Fluorescence Examination 5.FE.10, 5.FE.28–9

overview 5.SFDS.2

solution preparation 5.SFDS.8 transparent items 5.FE.22

case studies A.1.10, A.1.12

category B process see Superglue Fluorescent Dye Staining, propanol-based

chemicals 5.SFDS.7 cling film 4.14

date of introduction 2.3.4

effectiveness 5.SFDS.1, 5.SFDS.3, 5.SFDS.12

equipment 3.1.11, 5.SFDS.6 ethanol-based

overview 5.SFDS.2

solution preparation 5.SFDS.8, 5.SFDS.9

expanded polystyrene 4.11

Fluorescence Examination 5.FE.10, 5.FE.28–9

integrated use 5.SFDS.1

labelling solutions 5.SFDS.5 Home Office January 2014

laboratory organisation 3.1.7 post-processing 5.SFDS.11

practicality 5.SFDS.3, 5.SFDS.12 process details 5.SFDS.10

process overview 5.SFDS.1

processing problems 5.SFDS.13–15 propanol-based

chemicals 6.1.60

effectiveness 6.1.56 equipment 6.1.59

integrated use 6.1.56 options 6.1.57

post-processing 6.1.63 process details 6.1.62

process overview 6.1.56 safety 6.1.56, 6.1.58

sequential processing 6.1.57 solution preparation 6.1.61 surface types 6.1.56

PVC 4.13

rubber 4.15

safety 5.SFDS.1, 5.SFDS.3–5, 5.SFDS.12

scene treatment 5.SFDS.3, 5.SFDS.12 solution preparation 5.SFDS.8, 5.SFDS.9

surface types 5.SFDS.1 theory 5.SFDS.16 uPVC 4.9

water-based

overview 5.SFDS.2

solution preparation 5.SFDS.8, 5.SFDS.9

Superglue Fuming

age of mark effect 2.3.13 CAS number 3.1.20

case studies A.1.6, A.1.10, A.1.12 category E process 6.4.5 chemicals 5.SF.4

colour enhancement 5.CF.12

targeted processing 4.53

temperature effects 2.3.11 theory 2.3.16, 5.SF.11–13

UVC Reflection 5.UVCR.9 vacuum 6.4.5

Visual Examination 5.VE.11, 5.VE.20 water exposure 2.3.12, 2.3.16

contaminants 2.3.5

superglue stains see Superglue

effectiveness 5.SF.1, 5.SF.2, 5.SF.7

superglue wands 6.5.2

date of introduction 2.3.4

equipment 3.1.8, 3.1.11, 5.SF.4 fabrics 4.41

faint marks 5.SF.9

Fluorescence Examination 5.FE.15, 5.FE.21, 5.FE.22

grease contamination 4.23

humidity 5.SF.4, 5.SF.9, 5.SF.10, 5.SF.13

integrated use 5.SF.1

laboratory organisation 3.1.7

Fluorescent Dye Staining

surfaces see also substrate colour 2.2.30, 2.2.33 complexity 2.4.10 definition GLO.4

delamination during lifting 5.Lif.14 distortion during Fluorescence Examination 5.FE.16

effect of printing 4.10

effect on process selection 1.15, 2.2.32, 4.1, 4.2

Lifting 5.Lif.2

fingermark generation effect 2.2.5,

practicality 5.SF.2, 5.SF.7

fluorescence 2.2.30

process overview 5.SF.1

history 2.1.6

post-processing 5.SF.6 process details 5.SF.5

process problems 5.SF.8–10 quantities required 5.SF.13

reverse-developed marks 2.5.16 safety 5.SF.1, 5.SF.2–3, 5.SF.7

scene treatment 5.SF.2, 5.SF.7 sequential processing 2.3.8

surface types 2.3.14, 5.SF.1 target properties 2.3.5

2.2.6–7

fluorescence theory 5.FE.31 initial assessment 2.1.6

interpretation 2.5.13–14 laboratory trials A.2.10 Lifting damage 4.3

Powder theory 5.Pow.18, 5.Pow.19 reflectivity 2.2.30

roughness 1.15, 2.2.5, 2.2.15, 2.2.30, 2.2.32, 2.3.9

IND.33

Fingermark Visualisation Manual

Index

IND.34

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. surfaces continued

visualisation effects 2.2.29, 2.2.30 wet surfaces 4.3

surgical tape 4.32

sweat see also latent fingermarks age of mark 2.3.10

category A processes 2.3.5, 2.3.6 composition 2.2.10–11 distribution 2.5.11

latent fingermarks 2.2.8, 2.2.12 physiology 2.2.8–9, 2.3.6, 4.46 process selection 4.57

temperature effects 2.3.10 visualisation 2.2.26, 2.3.6 water exposure 2.3.10

synperonic N 3.1.20, 5.PD.6, 5.PD.7

T

Tagged Nanoparticles 6.2.16

tapes 4.19, 4.21, 4.39, 4.40 see also Adhesive Tape Removal

targeted processing 4.53, 4.54, 4.57 tarnish 4.18

tartrazine 6.4.2

Technology Readiness Levels (TRLs) A.2.1–4, A.2.5

temperature

distortion of marks 2.5.19

fingermark generation effect 2.2.16 fire risks 3.2.18

Home Office January 2014

persistence effects 2.2.22, 2.4.2

visualisation effectiveness 2.3.9, 2.3.10, 2.3.11, 2.3.17–19

test marking 2.4.9

testing of new processes see research tetraaminobiphenyl TAB 6.4.6

tetrachloroauric acid see gold (III) chloride tetramethylbenzidine (TMB) 6.4.6 textiles 4.41, 7.16–17

texture

definition GLO.4

substrate effect on fingermark generation 2.2.5, 2.2.15

visualisation effects 2.2.30, 2.2.32, 2.3.9, 2.3.21

TFD 6.2.17 theory

Acid Dyes 2.3.18, 5.AD.14

Adhesive Tape Removal 5.ATR.9–10 Basic Violet 3 (BV3) 5.BV3.20 Colour Filtration 5.CF.9–13

dark adaptation 5.FE:48, 5.FE:49 DFO 2.3.17, 5.DFO.13

Fluorescence Examination 5.FE.23–49 Infrared Reflection 5.IRR.6–11 Lifting 5.Lif.16–17

lighting techniques 2.2.30, 5.VE.23–34 Multi-Metal Deposition (MMD) 5.MMD.14, 5.MMD.15

Multi-Spectral Imaging 5.MSI.9–10 Ninhydrin 2.3.15, 5.Nin.19

Numberplate Splitting 5.NS.7

Physical Developer 2.3.20, 5.PD.19

Physical Developer Enhancement 5.PDE.14

Powder Suspensions 2.3.16, 5.PS.17 Powders 2.3.21, 5.Pow.18–19

Small Particle Reagent 5.SPR.12 Solvent Black 3 5.SB3.14–15 Soot Removal 5.SR.17

Superglue Fluorescent Dye Staining 5.SFDS.16

Superglue Fuming 2.3.16, 5.SF.11–13 Thermal Coating Removal 5.TCR.8 UVC Reflection 5.UVCR.9–11

Fingermark Visualisation Manual

Index thermal paper

DFO blackening 5.DFO.12 DMAC 6.1.14–21

Ninhydrin blackening 5.Nin.18 process selection 4.26 theory 5.TCR.8

Thermal Development 6.2.17 ThermaNin 6.2.18

ThermaNin 6.2.18

thiocarbamide see thiourea

thiourea 5.PDE.4, 5.PDE.6, 5.PDE.9, 5.PDE.10, 5.PDE.14

Vacuum Metal Deposition 2.3.19,

third generation reproduction 2.5.9

Visual Examination 5.VE.23–34

TIFF file format 3.3.21, 3.3.22

5.VMD.17–21

Thermal Coating Removal

darkening of processed items 5.TCR.7 effectiveness 5.TCR.1 equipment 5.TCR.4

integrated use 5.TCR.1

laboratory organisation 3.1.7 post-processing 5.TCR.6 practicality 5.TCR.2

process details 5.TCR.5

process overview 5.TCR.1

safety 5.TCR.1, 5.TCR.2–3 scene treatment 5.TCR.2

thrombocytes 5.AD.14 tilt-shift lens 3.3.17

tilting benches 3.1.4

time constraints 2.1.13, 2.4.13

time resolved fluorescence 5.FE.24 tin 4.18

titanium 4.18

titanium dioxide-based Powder

Suspension 5.PS.1, 5.PS.2, 5.PS.6, 5.PS.17

TMB (tetramethylbenzidine) 6.4.6 toning see Physical Developer Enhancement

sequential processing 5.TCR.1

toolmarks forensic evidence 7.24–5

theory 5.TCR.8

torches, LED 5.FE.36

surface types 5.TCR.1

Thermal Development 6.2.17

thermal expansion coefficient 5.ATR.9, 5.NS.7

tools 4.18, 4.30

toxic chemicals storage 3.1.15, 3.2.26 toxilic acid see maleic acid

trace evidence 7.26–7, A.1.5–6, A.1.7

IND.34

IND.35

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. traceability 3.2.24, 3.2.25

training 3.1.2, 3.2.23, 3.3.2, 3.3.22

uniform diffuse lighting

application examples 5.VE.10, 5.VE.17 set-up 5.VE.17

trans-1,2 dichloroethylene 5.DFO.6

United Kingdom Accreditation Service

transfer paper 5.BV3.6, 5.BV3.11,

unplasticised polyvinyl chloride (uPVC)

transmitted radiation 2.2.30, 5.VE.32,

untreated marks

transfer of marks 2.5.17–18 5.BV3.17–18 5.VE.33

transparent items

Fluorescence Examination 5.FE.22 interpretation 2.5.14, 2.5.17

treated marks

lighting techniques 5.VE.11 visualisation 2.2.29

Triton® X-100 5.PS.6, 5.PS.7, 5.PS.8, 5.PS.12, 5.SFDS.7, 5.SFDS.9

TRLs (Technology Readiness Levels) A.2.1–4, A.2.5

tungstomolybdic acid 6.4.4

Tween® 20 3.1.20, 5.MMD.6, 5.MMD.9 twilight vision 5.FE.48 typeface defects 7.12 tyres 4.15

U

UK national fingerprint database 2.5.5, 3.3.19, 3.3.22

UKAS (United Kingdom Accreditation Service) 3.1.2

‘UnDo’ 6.1.12

Home Office January 2014

(UKAS) 3.1.2 4.9

lighting techniques 5.VE.9–10 visualisation 2.2.29

untreated metals corrosion 2.2.20, 4.18 untreated wood 4.30 uPVC 4.9

urea 2.3.6 urine

fluorescence 5.FE.9

forensic evidence recovery 7.4–5

UVA mercury vapour lamps 5.FE.38 UVC Reflection

application examples 4.60

combined with Fluorescence Examination 5.FE.22

date of introduction 2.3.3

effectiveness 5.UVCR.1, 5.UVCR.2

equipment 5.UVCR.5, 5.UVCR.12–14 integrated use 5.UVCR.1 practicality 5.UVCR.2

process details 5.UVCR.6

process overview 5.UVCR.1

safety 3.2.16, 5.UVCR.1, 5.UVCR.2,

5.UVCR.3–4, 5.UVCR.5, 5.UVCR.8

Lifting 5.Lif.3, 5.Lif.10

targets 4.60

over-development 5.VMD.12,

surface types 5.UVCR.1

equipment 5.VE.5, 5.VE.17 theory 5.VE.30

scene treatment 5.UVCR.2, 5.UVCR.8

theory 5.UVCR.9–11

V

Vacuum Metal Deposition

adhesives with semi-porous backings 4.39

age of mark effect 2.3.13 case studies A.1.12

lighting techniques 5.VE.12 5.VMD.14

plastics packaging 4.8, 4.10 post-processing 5.VMD.10 process details 5.VMD.7–9

processing problems 5.VMD.11–16 PVC 4.13

reverse-developed marks 2.5.15, 5.VMD.18

category E process 6.4.5

safety 5.VMD.3

chemicals 5.VMD.6

silver

category F processes 6.5.2 cling film 4.14

contaminants 2.3.5, 5.VMD.19, 5.VMD.21

date of introduction 2.3.4

equipment 3.1.8, 3.1.12, 5.VMD.4–5 fabrics 4.41

faint marks 5.VMD.11, 5.VMD.13, 5.VMD.14, 5.VMD.16

gold/zinc

CAS number 5.VMD.6

evaporation vessels 5.VMD.5 overview 5.VMD.2

process details 5.VMD.7–8 reverse-developed marks 5.VMD.18

theory 5.VMD.17–19

grease contamination 4.23, 4.48 Infrared Reflection 5.IRR.7

laboratory organisation 3.1.7

sequential processing 5.VMD.2 CAS number 5.VMD.6

evaporation vessels 5.VMD.5 overview 5.VMD.2

process details 5.VMD.7, 5.VMD.9 theory 5.VMD.20

surface types 2.3.14

target properties 2.3.5, 2.3.6 targeted processing 4.53

temperature effects 2.3.11, 2.3.19 theory 2.3.19, 5.VMD.17–21 water exposure 2.3.12

Vacuum Metal Deposition (VMD) effectiveness 5.VMD.1

integrated use 5.VMD.1

process overview 5.VMD.1 safety 5.VMD.1

surface types 5.VMD.1

vehicle plate splitting see Numberplate Splitting

IND.35

Fingermark Visualisation Manual

Index

IND.36

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. ventilation

examination rooms 3.1.5 flammable liquids 3.2.18

local exhaust (LEV) 3.1.8, 3.1.9, 3.1.10, 3.1.11, 3.2.3, 3.2.23

safety requirements 3.2.3, 3.2.23

viewing filters

background fluorescence 5.FE.18 camera filters 5.FE.46

discharge lamps 5.FE.37 eyewear 5.FE.43–5

filtered arc lamps 5.FE.37

illumination light transmission 5.FE.19 labelling systems 5.FE.11 low contrast 5.FE.20

mercury vapour tubes 5.FE.38 optical density (OD) 5.FE.39 practicality 5.FE.42

selection 5.FE.7, 5.FE.8, 5.FE.10, 5.FE.26, 5.FE.43–6

theory 5.FE.39–46

vinyl see plasticised polyvinylchloride vinyl-coated wallpapers 4.42 visibility 2.2.26

visible fingermark

definition GLO.4

visualisation 2.2.26, 2.2.27

visors 5.FE.45

visual ability 5.FE.49

visual attention 5.FE.49 Home Office January 2014

optical processes 2.2.28, 2.2.29,

HFE7100 contamination 5.DFO.10,

case studies A.1.3, A.1.6, A.1.7, A.1.8,

printed surfaces 4.10

laboratory organisation 3.1.6, 3.1.8,

cold case review A.1.11

surface effects 2.2.29, 2.2.30, 2.2.32

Powders theory 5.Pow.18

Visual Examination

2.2.31

application examples 4.60

research A.2.11–12

A.1.9, A.1.13

contrast optimisation 4.2

date of introduction 2.3.3

effectiveness 5.VE.1, 5.VE.2, 5.VE.22 equipment 5.VE.4–8

integrated use 5.VE.1

visible fingermark 2.2.26, 2.2.27

VMD see Vacuum Metal Deposition volume crime

constraints 2.1.13 definition GLO.4

lighting selection 5.VE.9–11

vulcanised rubber 4.15

practicality 5.VE.2, 5.VE.22

W

process overview 5.VE.1

wands (magnetic powder applicators)

scene treatment 5.VE.2, 5.VE.22

washing

lighting techniques 5.VE.13–21 process details 5.VE.12

safety 5.VE.1, 5.VE.2, 5.VE.3, 5.VE.22 sequential processing 4.2 surface types 5.VE.1 theory 5.VE.23–34

visualisation

category A list 2.4.5 complexity 2.0.1

contrast optimisation 2.2.28 definition 2.4.4, GLO.4

fingermark properties 2.2.26 footwear marks 7.18

forensic evidence integration 7.1 imaging 4.3

information maximisation 2.2.29, 2.4.4, 2.5.7

laboratory organisation 3.1.4–5

latent fingermarks 2.2.26, 2.2.27

wallpapers, non-paper-based 4.42 5.Pow.8, 5.Pow.15

glassware 3.1.8, 3.1.12, 3.3.2–3 Physical Developer 5.PD.17

Soot Removal 5.SR.4, 5.SR.15, 5.SR.17

washing solutions

Acid Dyes 5.AD.7, 5.AD.14

water-based Acid Dyes 6.1.8

waste management 3.2.4, 3.2.28–9 water see also condensation

adhesive tape 5.BV3.16, 5.FE.30 contrast optimisation 4.3 effect on glass 4.6

exposure effects 2.2.21, 2.2.23, 2.3.9, 2.3.10, 2.3.12, 2.3.15–16, 2.4.2

Fluorescence Examination 5.FE.30

5.Nin.13 3.2.4

processing charts key 1.15

purification systems 3.1.8, 3.1.12 rinsing, targeted processing 4.53 Solvent Black 3 rinse problems 5.SB3.12

sweat composition 2.2.11

Water Authority 3.2.28

water-based Acid Dyes chemicals 6.1.7

compared to category A 5.AD.3, 6.1.2 effectiveness 6.1.2, 6.1.4, 6.1.11 equipment 6.1.6

integrated use 6.1.2 options 6.1.3

post-processing 6.1.10

practicality 6.1.4, 6.1.11 process details 6.1.9

process overview 6.1.2

safety 6.1.2, 6.1.4–5, 6.1.11

scene treatment 6.1.4, 6.1.11 sequential processing 6.1.3 solution preparation 6.1.8 surface types 6.1.2

water-based Superglue Fluorescent Dye Staining

overview 5.SFDS.2

post-processing 5.SFDS.11 process details 5.SFDS.10

IND.36

Fingermark Visualisation Manual

Index

IND.37

Contents

this Safe and Effective Process Category A Category B-F Integrating 1 About Manual 2 Forensic Evidence 3 Implementation of 4 Selection 5 Processes 6 Processes 7 Forensic Recovery Processes Processes

Appendices

Glossary

Index

Illustrations and figures are in bold. Tables are in italics. water-based Superglue Fluorescent Dye Staining continued

solution preparation 5.SFDS.8, 5.SFDS.9

wavelength selection

Fluorescence Examination 5.FE.8,

5.FE.9, 5.FE.10, 5.FE.29, 5.FE.32–3

process selection 2.2.31 safety 3.2.15

Wavelet Scalar Quantisation (WSQ) file format 3.3.21

wax 4.16

weighing equipment see mass balances weighing liquids 3.3.5

Lifting 5.Lif.9

white wet powder see titanium dioxidebased Powder Suspension

whorls 2.5.2

wind effects 2.2.24

window frames 4.9, 4.17

witness statements 2.1.3 wood, untreated 4.30 Woods glass 5.FE.38

work flow 3.2.3, 3.2.5, 3.3.21 see also laboratory organisation

working copy image 3.3.22, 3.3.24

Workplace Exposure Limits (WELs) 3.2.20 wrapping paper 4.54

WSQ (Wavelet Scalar Quantisation) file format 3.3.21

welfare facilities 3.2.2

X

wet benches 3.1.6, 3.1.8, 3.1.11,

XRF (X-ray fluorescence) 6.2.19

WELs (Workplace Exposure Limits) 3.2.20 5.SFDS.6

wet powders see Powder Suspensions wet surfaces 4.3

wetability 2.2.19, 2.2.33

xenon discharge tubes 5.FE.37, 5.FE.38

Y

yoracryl red 4G see Basic Red 14

wheelie bins 4.7

Z

white granular powder 5.Pow.3 see also

zinc see gold/zinc Vacuum Metal

white gelatin lifting sheets 5.ESDA.4 granular powders

white light examination see Visual Examination

white magnetic powder 5.Pow.4, 5.Pow.9

Fingermark Visualisation Manual

Index

Zephyr-style brushes 5.Pow.7 Deposition

zinc chloride toning see Ninhydrin Enhancement

White Powder Suspension

colour enhancement 5.CF.12

Home Office January 2014

IND.37

ISBN: 978-1-78246-234-7