Vision, Composition and Photography [Reprint 2021 ed.] 9783112419663, 9783112419656

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Ernst A. Weber

Vision, Composition and Photography With 60 exercises, 83 color and 338 black-and-white illustrations

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Walter de Gruyter Berlin New York 1980

Author: Ernst A.Weber Professor of Photography Department of Visual Communication Hochschule der Künste Berlin Einsteinufer 4 3 - 5 3 D-1000 Berlin 10 Title of the original German language edition: Ernst A. Weber Sehen, Gestalten und Fotografieren Walter de Gruyter, Berlin • New York 1979 Copyright© 1978 by Walter de Gruyter, Berlin English translation from the German original: Rolf Fricke Rochester, New York Assisted by Dr. Harold Borgstedt University of Rochester, New York All unidentified photographs are by the author. The photographs were made with miniature and medium-format cameras manufactured by Leitz, Nikon, Rollei, Hasselblad and Linhof. Black-and-white pictures were made with Agfa and Kodak films, color pictures were made exclusively with Kodak films. Cover and overall design: Ernst A. Weber, Berlin. Graphic design based on sketches by the author: Gunter Spielvogel, Berlin. Typesetting and printing: Mandruck München Graphicolor GmbH & Co. KG, München. Binding: Lüderitz & Bauer Buchgewerbe GmbH, Berlin.

Library of Congress Cataloging in Publication Data Weber, Ernst A.: Vision, composition, and photography. Translation of Sehen, Gestalten und Fotografieren. Bibliography: p. Includes index. 1. Composition (Photography) I. Title. TR179.W413 770'.1 '1 80-21480 ISBN 3-11-006903-2

CIP-Kurztitelaufnahme der Deutschen

Bibliothek

Weber, Ernst A.: Vision, composition and photography / Ernst A. Weber. [English transl. from the German orig.: Rolf Fricke]. - Berlin, New York: de Gruyter, 1980. Dt. Ausg. u. d. T.: Weber, Ernst A.: Sehen, Gestalten und Fotografieren. ISBN 3-11-006903-2

Copyright © 1980 by Walter de Gruyter, Berlin • New York All rights, including the right for reproduction and distribution as well as translation, are reserved. No part of this work may be reproduced in any manner (by photo-copying, microfilming, or other methods) without written permission from the publisher, nor may it be adapted, reproduced or disseminated with the aid of electronic systems. Printed in Germany

Contents 1 2 2 2

26 29 32

1 Vision and Composition Visual Communication A Brief History of Imagery Have People Always Seen the Way We Do Today? The Mechanization of the Graphic Arts The New Significance of Images Seeing and Perceiving The Physiology of Vision The Eye The Retina The Lens The Iris Light and Dark Adaptation The Visual Pigments Spatial Seeing Perception of Motion The Eyes and the Brain The Eyes and the Brain Classify and Select Image Stabilization Orientation by Selection Optical Memory The Eye is not an Objective Instrument Gestalt and Perception Psychology Total Field Gestalt The Figure-Ground Relationship Depth Perception on Two-Dimensional Surfaces Perspective Overlaps Texture Gradient Illumination Aerial Perspective Culturally Conditioned Vision The Visual Pathway in Viewing Pictures Information Theory The Emotion Thesis Pictorial Composition

35 36 38

2 Picture Analysis: Black-and-White Technique of Picture Analysis Figure-Ground

3 4 6 6 6 7 8 8 9 9 10 10 11 12 12 14 14 14 15 15 15 16 22 22 24 24 24 24 24 25

40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 101 102 103 105 105 105 109 110 110 110 111 111 112 113 113 114

Contrasts Informational Value Similarity Illumination Side Lighting Back Lighting Eye-Level Perspective Worm's Eye View Bird's Eye View Fore-, Middle-, and Background Texture Gradient Silhouettes Aerial Perspective Planes Strong Lines Horizontals Diagonals Verticals Counter-Diagonals Right Angles Arches Circles Symmetry Golden Section Total Sharpness Selective Focus Blurred Motion Square Format Horizontal Format Vertical Format 3 Seeing and Composing in Color Light and Color The Theory of Color Vision Additive Color Mixing Subtractive Color Mixing Complementary Colors The Definition of Colors The Color of Light Color Temperature The Classification of Color Sensations The Systematic Nomenclature of Colors Color Contrasts Color Harmonies The Subjective Response to Colors Color Permanence The Psychology of Colors

117 118 119 120 122 124 126 128 130

4 Picture Analysis: Color Simultaneous Contrast Successive Contrast Quality Contrast Complementary Contrast Color Hue Contrast Light-Dark Contrast Cold-Warm Contrast Quantity Contrast

133 134 136 138 140 142

5 Compositional Technique Correct Position Correct Focal Length Correct Perspective Correct Filter Correct Timing

145 150 152 154

6 Summary 60 Exercises Bibliography Index

IV

Vision and Composition

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A Brief History of Imagery The extent to which vision and design are dependent upon our evolution and education can be shown by a brief historical review. Man has an ancient and fundamental need to communicate what he sees and experiences in his dealings with the world by means of images. Visual communication began as far back as the late paleolithic age, 35,000 to 10,000 years ago, when man first conveyed his impressions by means of images. The impressive cave drawings and colorful cave paintings made by hunting tribes of northern Spain, southern France and north Africa date from that time.

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The "great buffalo" was painted on the ceiling of the cave at Altamira near Santander in northern Spain approx. 15,000 years ago. (According to S. Giedion in "The Evolution of Art")

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Although speech was already in use, images are the only permanent means of communication to survive from this period. Writing was not perfected until 3000 years B.C., by the Sumerians. It developed in several stages from the original pictographs to abstract symbols - an evolution that can also be found in the earliest writings of other cultures. The Egyptians perfected their writing in this manner, progressing from pictures to hieroglyphs; Chinese writing also evolved from pictures to ideograms to today's abstract symbols. The original, pictographical approach to writing lost its importance as a means of communication when the first alphabet with relatively few abstract symbols was created, presumably by the Phoenicians around 1500 B. C. Since then images have assumed an independent position as a means of artistic expression, alongside sculpture. Have people always seen the way we do today? In the higher cultures the evolution of writing was undoubtedly accompanied by conscious visual education. Surviving sculpture and early architecture are convincing proof of the high creative and artistic level of these eras. Despite the many accomplishments of architecture, pictorial representation of threedimensional space on two-dimensional planes - i.e. perspective - remained an unsolved problem until the Italian renaissance in the 15th century. Until then no culture rendered space in a natural, visually correct manner in its pictorial representations, and most primitive cultures of the present still retain the flat technique of depicting objects and space. That technique can also be observed in drawings by today's children. It took the renaissance with its fondness for logic and objectivity in science and the arts for man to see the world as it really was. Paintings of the renaissance period owe their powerful realism to the ability of artists to render threedimensional space in two-dimensions in correct perspective, a technique that was enhanced by the simultaneous discovery of another technique - that of painting with oils. For the first time, an equal degree of perfection was achieved in depicting form, color and space.

This couple is part of a festive group on a limestone relief at the tomb of Ramses (1400-1362 B. C.) in Thebes, Egypt.

200- to 400-year-old Indian petroglyphs on Newspaper Rock in Indian Creek State Park in the state of Utah, U.S.A.

A woodcut made by Albrecht Durer in 1525 shows a drawing machine designed to produce correct perspective.

Drawing without perspective by a 10-year-old girl showing a recording session in aTV-studio in 1971. (Drawing: H. Hofmeister)

Earlier periods lacked such balanced perfection. Even though sculpture and vase-painting reached a peak during the Greek classical period, works of art no longer achieved the same degree of perfection during the centuries that followed, when the application of color was dominant in painting. Color often took precedence over form. The first color photographers were confronted by the same problem. Even today, they do not always seem to succeed in bringing color and form into optimum harmony. Apparently the changeover from a black-and-white photography of forms to a color photography of planes requires a longer process of learning and adapting.

The Mechanization of the Graphic Arts With his invention of movable type, Gutenberg mechanized the art of writing as early as the 15th century. The ability to produce pictures mechanically, i.e. photography, can be attributed to knowledge gained in the natural sciences from the 17th to the 19th century. It enabled anyone, regardless of his drawing talents, to produce an image by optical-chemical means. The art of recording an image, like the art of reading and writing before it, became accessible to a large segment of the population. The invention of photography by Niepce in 1826 caused an acceleration of successive styles and trends in the creative arts that still continues today. A striving for realism dominated the arts up to that time. The sudden emergence 3

Woodcut showing a typesetting and printing shop of the 17th century.

These pictograms replace a virtual jungle of multi-language signs, greatly facilitating the orientation of air travellers. (Frankfurt Airport; Design: Otl Aicher)

ing moved away from realism. As a result there has been one "ism" after another, and the photographic realism of the early seventies reminds one of the very beginning of the entire cycle. Economic necessities nearly caused the complete replacement of drawings and paintings by photography as a medium of documentation. Thus, pictorial representation has kept pace with advances in technology and with the contemporary demand for speed.

Photograph made in 1895: the author's grandparents.

of a technique for producing ultra-realistic images, however, changed that tendency. Artists regarded it as a threat to their function as visual chroniclers, portrait painting was largely replaced by photography, and landscape paint4

The New Significance of Images Despite the inroads photography has made into professions and hobbies, documentation and research, and technology and science, images will never entirely replace words and writing. Still, the growing volume of information reaching the public through television, motion pictures, and photography clearly shows the increasing significance of images as a means of communication. This convenient way of absorbing information is very appropriate to an era in which nobody thinks he has enough time. The adage "a picture says more than a thousand words" is still valid. During recent Olympic games and at international airports pictorial symbols were used to replace multi-language signs in order to prevent a Babylonian language confusion - a significant contribution towards faster information. Good, appropriate images are a universal

language for which there are hardly any "illiterates".

5



Seeing and Perceiving

The Physiology of Vision The preceding brief review was intended to describe the historical evolution of images. Before delving into our main subject, however, we must define and understand the visual prerequisites for creativity and photography: vision in all its aspects. Only if we fully understand the possibilities and capabilities of our visual system can we utilize it to optimum advantage in photography and composition. The eyes are the sensory organs with which humans perceive those impressions of their environment that are most important to the preservation of their lives. The seeing process is, however, not limited to the optical system alone. During the seeing process, the other senses touch, smell, taste and hearing - as well as the memory are constantly brought into play, drawing comparisons for the purpose of registering and classifying. This highly complex physiological-psychological process enables us to recognize our surroundings, to understand and to evaluate them. In her textbook on "The Science of Creativity" Ruth Schwarze states that perception by our senses takes place in the following proportions: 78% through seeing 13% through hearing 3% through touching 3% through smelling 3% through tasting 6

Our memory retains 40 percent of what we see, and 20 percent of what we hear. How does the apparently so simple seeing process actually work? In order to better understand its complexity, it is useful for us to consider the structure and function of the human eye. The Eye The human eye is often compared to a camera. Since the latter was designed according to the principles of the eye, certain parallels do indeed exist. Light reflected from an object passes through the cornea of the eye with only minor refraction. Next, it travels through the anterior chamber and the opening of the iris (the pupil), reaching the lens, which serves to focus or "accommodate". The lens forms a sharp image of the object by refracting the light rays, which pass through the vitreous humor to reach the retina. There are two kinds of light sensors, or photo-receptors, in the retina: the so-called cones and rods. The picture formed on the retina is a reduced, inverted, reversed, and curved image of the original object. The imageforming process of a camera is basically similar, but the similarity between the eye and the camera ends here. Through its lens, a camera forms an image of a

Horizontal cross-section of the human right eye: 1 optical axis, 2 fovea or yellow spot, 3 blind spot, 4 optical nerve, 5 sclera, 6 choroid layer, 7 retina, 8 anterior chamber, 9 cornea, 10 lens, 11 iris, 12 ciliary muscle, 13 vitreous humor.

Photographically reproduced i m a g e of reality

Diagram of the formation of a photographic image in a camera.

LIGHT Messages f r o m the o t h e r senses

Comparison with memorized experiences

Information processing by nerves

Central processing unit

Mechanical switching organs

Nerve filters and switches

Image of reality p r o d u c e d by eyes a n d brain

Diagram of information processing by eyes and brain (According to Schober and Rentschler in "Optical Illusions in Science & Art").

scene directly on light-sensitive film. The picture remains latent, becoming visible and permanent only after development. In the visual process, however, only momentary images, lasting a fraction of a second, are formed on the photo-receptors by light stimuli, and are constantly erased, to be followed by other equally short-lived images. To the eye, light is nothing more than a form of energy that is capable of performing work. By a chemical-electrophysiological process, the eye converts light energy into "coded" signals for the brain. These signals are transmitted to the visual centers in the brain by means of millions of fine nerve fibers bundled to form the optical nerve. The brain decodes the signals by comparing them with stored patterns, ultimately to

recognize and to perceive the objects in the environment which originated the stimuli. The decoding process also inverts and reverses the images. The Retina Even though it is located apart physically, the light-sensitive retina constitutes a portion of the brain. It consists of several interconnected layers. Light must first pass through the frontal layer of nerve fibers and several layers of cells before it reaches the cones and rods located behind those layers. The point on the retina where all the nerve fibers join to form the optical nerve, and where the latter leaves the eye towards the rest of the brain, is the blind spot, where no 7

The above diagram of the human retina shows the structures that light 1 has to penetrate: vitreous humor 2, nerve fibers 3, ganglion cells 4, dendritic spreads of the bipolar cells 5, the bipolar cell bodies 6, the second dendritic spread 7, the ganglion cell layer 8, before it impinges on the wedge-shaped cones and rods 9. The pigmented epithelial layer 10 can be considered to represent an anti-halation layer for the elimination of internal reflections. In the area of the fovea there is very close coupling between cones and ganglion cells and their associated optical fibers, assuring the highest degree of visual acuity.

light stimuli can be received. The distribution and concentration of rods and cones embedded side-by-side in the retina are not uniform. In the region of the fovea in the center of the retina, where we have the greatest visual acuity, there is a high concentration of photo-receptors that consist exclusively of cones, which are responsible for bright and color vision. Towards its perimeter, the retina consists almost exclusively of rods. The latter serve for twilight vision, and they react only to differences in brightness. They react only to white, so that color cannot be perceived in this portion of the retina. Conversely, the fovea is nearly useless in twilight, because it is made up entirely of cones. That is why we try to see better in twilight by moving the eyes, thus imaging objects on periphereal regions of the retina which have a higher concentration of rods instead of the less sensitive cones. The extreme borders of the retina cannot even sense a moving stimulus, the latter merely produces an automatically compensating reflex action to move the eyes towards the object in order to image it on portions of the retina more suitably 8

Schematic representation of near and far vision. When the lens of the eye is accommodated to focus on the distant arrow, the ciliary muscle is relaxed and only the connecting fibers of the zona annularis maintain it in its slender form with minimum curvature. If, however, the lens is focused on the near arrow, the ciliary muscle contracts and forces the lens into its thicker, more strongly curved form. The annular fibers are thereby relaxed.

equipped for the prevailing conditions. The eye depends on the fovea when it concentrates on an object of interest that it wishes to see with maximum sharpness. The angle of vision at maximum sharpness is very small: it amounts to VA degrees, covering an area just under two square inches at a distance of 8 feet. The eye is constantly in motion, scanning objects one after another, thus creating an overall picture of the scene. The Lens At the same time, the eye is continually and automatically changing the curvature of its lens to achieve optimum sharpness. By adjusting the tension of a circular muscle called the ciliary muscle, the curvature of the lens can be changed so as to be more curved for near vision and less curved for distant vision. Thus, the human eye can focus almost instantly on objects at many distances, normally between 10 inches and infinity, and it is, therefore, far superior to even the most advanced camera. The Iris The aperture formed by the iris is called the pupil; it also performs important functions. The mechanical counterpart in a camera is the iris

diaphragm, which controls the amount of light passing towards the film. The iris in the eye performs a similar function, changing the diameter of its opening in response to nerve impulses reacting to brightness, operating within an effective aperture range of f/3 and f/12. But that is not its only function. The eye is capable of distinguishing a much larger brightness range of 1 to 100,000. The iris automatically reduces its aperture for near vision, thus providing a greater depth of focus - just like a stopped-down camera lens. Conversely, it opens up for viewing distant objects. The iris also changes under certain conditions not directly related to vision: it enlarges under great emotional stress such as joy or fear. Light and Dark Adaptation The intensity of the light stimulus is not the only important factor in its perception: another is its spectral composition. While the greatest sensitivity of cones is in the yellow-green region of the spectrum, rods are most sensitive to blue-green (cyan), even though they only sense black and white. This also explains the Purkinje phenomenon, which states that a red and a blue object of equal brightness will be perceived in that manner in daylight, but not at night, when the very same blue object will appear brighter to us than the red one, because rods are more sensitive to blue in dim light, while red is barely detected. Before it is able to recognize anything at all, the eye needs a certain amount of time for adaptation when changing from bright to dim light. The change from a dim area to a bright one requires an "adaptation time" of only 1 or 2 minutes; the opposite, a change from a very bright room to a very dim room, takes much longer, requiring up to 20 minutes to reach normal vision. Research into this phenomenon revealed that chemical reactions occur when light strikes the photo-receptors, causing physiological changes which, in turn, produce electrical signals which are transmitted to the brain. The Visual Pigments The adaptation to environments of different light intensity is accompanied by bleaching and regeneration of the visual pigments in the

The two curves show that the amplitudes and spectral sensitivities of the cones and rods are different for light of different wavelengths. Cones, which are responsible for daylight and color vision (broken line), have relatively low sensitivity, whereas rods, which are responsible for twilight and night vision (solid line), are ten times as sensitive. The cones are most sensitive in the yellowgreen portion of the spectrum, and the rods in the blue-green region.

photo-receptors. The visual pigment is a reddish liquid, which in the rods is called visual purple, or "rhodopsin". Light decomposes the visual pigments, simultaneously converting light energy into electrical impulses by a physico-chemical process. As a result, visual purple is bleached and has to be regenerated later during a dark interval. A similar energy conversion takes place in the cones, which are responsible for color vision, except that three different liquid pigments are involved. Each pigment is sensitive to a different third of the visible spectrum, so that there are separate blue-, green-, and red-sensitive cones. All the aforementioned parts of the visual process, involving the retina, the nerve cells, and the respective portions of the brain, serve to perceive brightness, color, depth and movement. While the first two properties can be registered with only one eye, perception of depth and movement requires the use of both eyes.

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Spatial Seeing The human visual apparatus functions on the basis of coordinated binocular, or "stereoscopic" vision. The eyes look in the same direction at any given time, and the brain combines the two resulting two-dimensional images, which differ because the eyes are differently located, into a single spatial impression. Space perception derives from the fact that the eyes, being on the average 65 mm (approximately 2%6 inches) apart, record an image from two different perspectives. Because of the relatively small base, as the distance between the pupils is called, spatially well differentiated depth perception ranges from approximately 25 cm to 50 m (10 inches to 160 feet). All spatial impressions beyond this range are based on estimates founded on past experience. Perception of Motion The perception of motion is of the utmost importance to us all, for it may signal danger. If, for instance, a speeding car suddenly appears in the distance while you are crossing an empty street, it is first detected by the peripheral portion of the retina. A nerve impulse immediately triggers a movement of the eye to position the center of the retina on the potential source of danger to perceive it sharply and clearly. Such movement is made possible by a set of six muscles attached to the eye. The eyes are constantly in motion of various kinds: while following a moving object, eye movement is smooth and uniform; on the other hand, while scanning objects, the eyes make short, quick dashes across them. A third, continuous automatic rapid scanning movement, also called saccadic movement, is necessary for fatigue-free viewing.

Schematic diagram of the visual fields of the human eye: the top figure shows the horizontal fields of the left and the right eye, identified by different crosshatching; the center figure shows the vertical field of both eyes. The bottom figure shows the range of spatial perception, or stereoscopic viewing, which occurs in the central portion where the crosshatchings overlap. Each eye covers a horizontal angle of approximately 150°, but the zone of spatial perception is limited to 120°. These dimensions cover only those regions within which optical stimuli are registered. Truly sharp vision occurs only within an angle of approximately IV20, as one can see when one fixes point "O" in the top and center figures.

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Schematic diagram of the visual perception process from the eyes to the brain: the field of vision 1 is registered by the two vertical halves of each retina 2 and these signals are transmitted to the visual areas of the brain by two major groups of nerve fibers 3. The nerve fibers from the temporal half of each eye lead to the same respective side of the brain. The nerve fibers from the

nasal halves of the retinas, however, lead to the contralateral sides of the brain, through the optical nerve crossover 4. Each bundle of nerve fibers passes through a relay station, the lateral geniculate ganglion 5, before reaching the visual areas 6 in the two hemispheres of the brain. (According to Conrad Mueller and Mae Rudolph in "Light and Vision").

If we move our eyes so as to keep the image of a moving object on the same spot of the retina, the pictorial impression vanishes within a few seconds. The function of the rapid scanning motion of the eye seems to be to cause continuing minute displacements of the image on the retina, thus preventing adaptation and constantly producing new signals for the brain.

brain. The brain, too, is divided into two hemispheres, which are connected by a nerve bundle and by the optical nerve crossover. The two lobes of the brain, with direct and crossed nerve interconnections, provide the exchange and comparison, as well as the processing and feedback, of previously stored data and information gathered from other senses. Recently physiologists have even succeeded in locating functions of the seeing process in specific portions of the brain. If, for instance, an electrical stimulus is applied to a selected spot on the brain's cortex in the visual area, light flashes will be seen in certain locations of the visual field. When the stimulus is applied to a different spot nearby, the light flash will be seen in a different location. By stimulating other portions of the brain, one can even be made to see picture sequences and entire actions, just like excerpts from movies. At the same time, it was also learned that the coded language to which the eyes and the brain are "programmed" is highly differentiated and complex. Experiments have shown that certain moving shapes are registered by different brain cells, depending on the direction of movement and location. Therefore, it is assumed that certain cells react exclusively to movement, whereas other cells react only to shapes, and that the brain sees and thinks in

The Eyes and the Brain A horizontal cross-section of the eyes and brain promptly suggests an electrical wiring diagram. Such a comparison is not entirely unwarranted, because the operation of our complete visual system corresponds to that of an information gathering, comparing and data processing installation. Acquisition of data begins with the photoreceptors in the retina. The retina is divided vertically into two halves, and signals gathered by them are transmitted to the visual centers in the brain by two major groups of nerve fibers. The nerve fibers from the temporal half of each eye lead to the same respective side of the brain. The nerve fibers from the nasal halves of the retinas, however, lead to the contralateral side of the brain, through the optical nerve crossover. Each passes through a relay station, the lateral geniculate ganglion, before reaching the visual areas of the two hemispheres of the

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patterns of pictures, not in abstract details.

Geometric-Optical Visual Illusions In Perception From top to bottom:

The Eyes and the Brain Classify and Select This fact is supported by several discoveries. The eyes and the brain are able to accept a limited number of bits of information, which they instinctively supplement with the missing details to form an entity. On the other hand, the visual mechanism also functions in the opposite sense in a unique manner: in spite of the great multitude of stimuli that constantly impinges upon the visual system, it is capable of differentiating precisely between real signals and interference, thanks to a complicated filter-mechanism. Image Stabilization Another important component of the visual process is the stabilization of the image of our environment. Even when we are in continual motion, the image conveyed by the eyes and the brain does not appear to gyrate wildly or to sway in a blur. First movies made with a newly acquired camera that are imposed on us by well-meaning friends who filmed them "dynamically", i. e. without the benefit of a tripod, often border on physical torture. The motion of the camera makes the viewer feel that the ground is being pulled out from under his feet. Those bouncing pan shots, some too fast, others too slow, produce a slight nausea; excessive zooming compounds the discomfort by making our eyes flicker. The torture ends only when the movie is finished. What causes this discomfort? The movie camera is capable of objectively recording only that which is presented to it. Projection reproduces the recorded images faithfully and unchanged. The human visual process, however, includes an image stabilization feature that might be compared to a gimbal-suspended gyroscope, always positioning itself horizontally. In addition, the brain filters out any interferences, withholding them from our awareness.

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Line-and-Pattern Illusion by Zollner The diagonal lines appear to converge or diverge in pairs. This impression is further enhanced by the short lines at 45°, and these also appear to be misaligned. Closer inspection proves both impressions to be illusions. The left portion of the illustration was intentionally reproduced as a negative mode, and the right one as a positive to strengthen the effect even further. Length-and-Size Illusion by Miiller-Lyer When arrowheads are added to the ends of two lines of equal length, with one pair pointing inwards and the other outwards, the line with the inward-pointing arrowheads seems the longer of the two. Line-and-Pattern Illusion by Ehrenstein If a set of concentric circles is intersected by a concentric square, the sides of that square will appear strongly curved inwards. A check with a ruler quickly dispels that illusion. Line-and-Pattern Illusion: the Siemens Star Certain line patterns cause an impression of flickering, which is particularly evident in this pattern of lines converging in the center. A steady, rhythmic pulsation seems to occur around the center during observation. Length-and-Size Illusion: the Top Hat Both in the inverted "T" as well as in the top hat, the height will appear greater than the length of the base. Yet height and base are of the same length; our eyes tend to over-estimate vertical dimensions. Area-and-Size Illusion by Titchener The solid circle surrounded by smaller circles in the left portion of the illustration appears to be larger than the solid circle surrounded by larger circles on the right side. Yet they are of the same size. Size-and-Depth Illusion by Ponto If two lines of equal length are drawn horizontally between two vertical converging lines (like a railroad track leading away from the observer), the lower one will appear the shorter of the two. The reason is the size relationship upon which our perception system is based, according to which more distant objects of the same size must appear smaller. Space Illusion by Necker Both figures are representations of a cube, each seen from a different point of view. Because of its symmetrical lines, however, the left figure looks more like a hexagon divided into equal triangles. The right cube, perceived as a body, appears to change orientation when viewed for an extended time: the gray surface can be taken either as the front or the rear surface of that cube.

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Our optical perception is capable of utilizing mere fragments of information about familiar objects in order to identify them. Which of the first three figures already contains sufficient information to identify the subject?

Orientation by Selection Even though we are subjected to countless visual images every day, our eyes and our brains, and consequently our consciousness, register only what interests us or what we wish to see. This physical-mental selection process serves as a protective classifying mechanism for the differentiation between relevant and irrelevant information. Our visual environment is made up of what we want to see in it, not what it actually contains. Optical Memory The eye functions very precisely in comparing qualities such as hue, brightness or contrast at a given moment. For comparing current impressions with past ones, however, our optical memory proves unreliable, especially in the case of color and size. The Eye is not an Objective Instrument In spite of all the filtering and regulating mechanisms, the visual process is subject to errors and illusions; these become evident when we look at certain structures and geometric figures. Normally, we correctly perceive an object in our environment only if its image is large enough 14

on our retinas, and if it is viewed long enough in sufficient brightness, and if that object is clearly separated from its background. If these conditions are not met, difficulties occur in the visual process. In addition, visual problems arise when we view certain specific figures and patterns, for reasons which are not yet understood. As exceptional as these figures may seem when compared with our familiar seeing experience, they prove that we cannot always trust what we perceive with our visual sense.

Gestalt and Perceptual Psychology Having examined the physiological aspects of vision, we will now consider the psychological components of perception. We have already established that the eyes and the brain do not function like a camera which records a straightforward image. Our visual sense records no lasting images, whether short- or long-lived. The visual process is actually a constructive sequence, in which complete patterns are perceived and compared with patterns and experiences previously stored in the brain so that we can recognize and identify what we see. In 1886, the Austrian physicist, psychologist and philosopher Ernst Mach gave a significant impetus to the establishment of the school of Gestalt psychology by publishing his book on "The Analysis of Perception". He recognized that the overall form took precedence over other differentiating characteristics in perceiving relatively uncomplicated objects. Thus, in the case of a tree, the leaves, branches and trunk are not seen separately but as an entity as a tree. Later on, around 1910, the most important exponents of "Gestalt Psychology", psychologists Max Wertheimer, Wolfgang Kohler, and Kurt Koffka, defined the distinction between figure and ground as a significant criterion in Gestalt theory. Total Field (Ganzfeld) If we point a camera straight upwards towards the sky on a sunny but very hazy day and make an exposure, we will get a picture with a homogeneous (uniform) white area. We will call this kind of homogeneous area a "Total Field". What is the significance of such a total field in the perception process? If we close one eye and cover the other one with a diffuser such as opal glass, and then proceed to look at a projection screen that is being evenly illuminated by a red slide projected on it in a darkened room, that screen, after some time of continuous observation, will appear as a neutral gray. The same phenomenon occurs with other colors. What is the reason for this? When our field of vision is completely homogeneous, we are unable to recognize any distinguishing characteristics. If, however, an object, such as a raised hand, is placed in the colored projec-

An entity will dominate its individual components if the object being perceived is not too complicated. For that reason we do not see the leaves, branches, and trunk of this tree, we see it as an entity. The same applies to the dromedary.

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In order to perceive differences, the environment must be varied. There are no differentiating characteristics in the homogeneous area on the left. Conversely, the hand shown in the illustration on the right is quite distinct from the gray background, which means that it is differentiated from its background by shape and contrast.

tion beam, in front of the total field, the color will return. That leads to the following conclusion: to make distinctions while seeing, a heterogeneous (varied) environment is necessary. Our entire visual process is based on the fact that we continuously perceive differentiating characteristics and compare them with each other. An object can only be perceived when it stands out from its background because of some form of contrast. The borderline between the two delineates the external shape of that object. Form (Gestalt) In connection with picture analysis and thus with the creation of pictures, Gestalt psychology provides us with a number of insights into the way individual visual elements are spontaneously classified and grouped to form an entity (Gestalt). 15

The Gestalt constitutes a clearly recognizable entity, which is structured, self-contained and distinct. Related forms are perceived as entities. Their individual characteristics become secondary to an overall impression or form (Gestalt). The entity is different from the sum of its individual elements.

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Just how much the overall entity differs from the sum of its visual elements is proven dramatically by this representation of the Venus de Milo. Using many characters, the operator of a computer created this view of the torso of the famous Venus sculpture. One is able to discern either each individual letter, the individual visual element, or the grouping of these letters into an entity, the form (Gestalt). (Courtesy of the Computing Center of the Technical University of Berlin)

16

iillF* ttHH mìmmm Unlike the free-standing sphere in the right half of the above illustration, the sphere in the left square barely stands out as a figure from its background. If, however, we close our eyes a little (in effect reducing their apertures), the same sphere appears more distinctly. (From "Art and the Computer", by A. A. Moles)

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The Figure-Ground Relationship The most significant insight of Gestalt theory is its distinction between figure and ground. From the first moment we look at a scene or a picture, we instinctively select one object to serve as figure, with the rest of the scene becoming the background. The time required for this selection is only 1/ioo of a second. This initial phase of perception thus defines the difference between the figure (which seems more important to us) and the background (which seems less important). In the illustration of the heterogeneous field of view the silhouette of the hand is clearly discernible as a figure against a light field or ground; this is an unambiguous example of a figure-ground relationship. The differentiation between figure and ground is subject to the following factors: 1. The figure must stand out from the ground. 2. The smaller area is usually seen as the figure, and the larger one as the ground. 3. Figure and ground cannot be perceived simultaneously. 4. Adjacent, similar visual elements are combined into a figure. 5. Symmetrical and contained shapes tend normally to be perceived as figures. 1. The figure must stand out from the ground. Considering the large number of objects that enter our field of vision when we scan our environment, some of them overlapping and concealing each other, our system of perception

Because of the profusion of blossoms, the figure-ground relationship of the picture on the left is disturbed. In the close-up on

the right, however, the blossoms stand out well as figures from their ground. Less often means more.

The large number of picture elements of similar value in the illustration on the left, the intertwined portions of the roots of a tree, preclude a clear figure-ground relationship.

By comparison, the drinking man in the right illustration clearly stands out as a figure from the ground.

has a remarkable ability to separate and distinguish individual objects. In distinguishing figure from ground we also assign isolated visual elements to the objects they are meant to represent. The figure-ground relationship is rarely as clear and obvious in the multi-faceted world around us as it is in the illustration of the silhouette of a hand. Far more frequently, the essential figure and the ground that serves as its setting are felt to be rather less distinct,

perhaps even to merge. Sometimes, whether from an excess of visual elements in the subject or from poor technical reproduction, this can go so far as to frustrate the figure-ground distinction altogether, robbing the picture of recognizability and impact.

17

The illustration on the left shows a free-standing sphere, which, unlike the one on the right, can hardly be recognized because of "optical noise". If, however, we close our eyes a little (in effect reducing the aperture), it too will stand out as a figure from the ground. (From "Art and the Computer" by A. A. Moles).

Our perceptual system continually strives for simplicity, regularity, clarity, lucidity, and order. For that reason, Gestalt psychology defines as "impact" (Prägnanz) the perception of an object in the simplest form that can be recognized in relation to its circumstances. The significance of the figure-ground relationship in perception goes beyond mere visual differentiation; it also includes a weighting differentiation. The figure-ground relationship constitutes an evaluation pattern applied to the field of visual perception, serving to distinguish the relevant from the irrelevant. In acoustics, the conversation at one's own table in a restaurant could be compared to the "figure" relative to the "ground" of the unintelligible mixture of voices of the other guests, which are merely perceived as neutral ambient sound. The figure-ground relationship has its parallel in acoustics as the signal-to-noise ratio. If the sound level produced by the other guests increases to the point where it exceeds the threshold of tolerance, so that one's own words can no longer be understood, then the ground relationship is altered and the ground begins to compete with the figure. One's own conversation becomes difficult to comprehend

Optical noise is an interference factor that makes the perception of visual information more difficult, whether from insufficient sharpness, as in figure 1, poor quality of the raster in figure 2, or a raster that is too coarse in figure 3. In each of these three examples, recognition and clear evaluation of the picture are hindered, as one can see by comparing them with the correct reproduction shown in figure 4.

18

In a random street scene, different objects will constitute the figure to passers-by, depending on their inclination, intention, and interests. For instance, someone who is in a hurry to get to the airport only has eyes for a taxi. The clock is important to the

because of the increased "noise": there is interference. In acoustic transmission of information, every undesired signal (noise) constitutes interference; the lower the noise level, the clearer the transmission of the information. A similar relationship exists in the optical field: "optical noise" is considered an interference when insufficient sharpness, poor contrast, or low resolving power and excessive graininess affect the quality of a picture. The recognizability of the information in the picture becomes more difficult, the figure-ground relationship is disturbed. In addition to a busy subject, or a poor technical reproduction, the figure-ground relationship is at the mercy of further variables. In a random situation, different observers of the same scene will select different picture elements as figure and as ground. The explanation for this lies in the difference among individuals in their character, moods, interests, knowledge and cultural background. The above sequence of figures is intended to illustrate this statement. 2. The smaller area is usually seen as the figure, and the larger one as the ground. The smaller the extent of an area, the more likely it is to be perceived as the figure, and the remaining area as the ground. Naturally, contrast plays an important role in this process. Black-and-white constitute the greatest possible brightness contrast and, therefore, the best figure-ground relationship. However, good recognizability not only depends on contrast, but also on the sizes of

young man who is eager to be on time for his date. The motorist who is worried because his fuel tank is nearly empty is relieved to find the service station. The tired tourist happily drags himself and his luggage to the hotel he has been craving.

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The photograph of an eye was digitized with a computer and a programmed picture-reading device, i. e. it was divided into a pattern of square dots of varying size and brightness values. While the range of gray tones remains unchanged, the size of the square dots decreases from left to right and from top to bottom, whereas the resolution increases. In the bottom row the dot pattern becomes less and less discernible, and the pictures begin to look like halftones. The same occurs when the top row is viewed from a very great distance, except that now the resolving power decreases. That shows that the optimum dot size for an illustration must always be selected in relation to the anticipated viewing distance. (Photo courtesy of the Society of Photographic Scientists and Engineers, U.S.A.)

the contrasting areas. 3. Figure and ground cannot be perceived simultaneously. There are pictures and geometric shapes in which an inversion of the figure-ground rela-

While the figure in illustration 1 is indicated weakly by lines, it stands out more strongly in illustration 2 because of the effect of contrast, creating a better figure-ground relationship. In illustration 3 the black Maltese cross is most clearly recognized as the figure on a white ground, and thus has the best attention value and the best figure-ground relationship.

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Even though both figures are identical and, when viewed individually, present a clear figure-ground relationship, the one on the right is felt to have the greater impact, because it stands out better from the surrounding large area.

Since all the bars are of equal width, both the white as well as the black ones can be deemed to be the figure. If neither figure is significantly different from the other in size or relevance, then the figure-ground relationship undergoes constant change.

Left: While viewing the spots that are evenly arranged in a square, one instinctively tends to arrange them. W e see either horizontal or vertical rows of dots, or we see squares made up of four dots each.

In this pattern the figure-ground relationship vacillates owing to the increasing width of the white and black bars as they approach the center, where their width is identical.

Right: Even though this arrangement is also square, one sees vertical rows of dots. This impression stems from the fact that the dots are closer vertically than they are horizontally. According to the Gestalt law of proximity, two or more visual elements situated closely together are perceived as a pattern or grouping.

The same occurs in the checkerboard pattern. On the left side, the white squares constitute the figure, whereas on the right side, the black squares stand out as the figure. In the center, where the squares are of the same size, the figure-ground relationship is ambiguous.

tionship occurs after prolonged observation. The best known example for this phenomenon is the picture of a vase published in 1915 by the Danish psychologist Edgar Rubin. It shows both a white vase on a black ground as well as two black human profiles against a white ground. Yet it is impossible to perceive both

Left: Within the large triangle made up of six dots, we recognize four smaller ones, each one made up of three dots. Right: Even though the eight dots together form a circle, upon closer observation we discover that four of the dots form a vertically positioned square, and the other four dots a diagonally positioned one.

figures (vase and profiles) simultaneously; they can only be seen alternately. How can this

phenomenon be explained? Gestalt psychologists are of the opinion that our visual perception system identifies objects on the basis of their contours. But a contour line can delineate both the area or figure to its left as well as the one to its right. Since in this case both solutions are possible, and both appear logical and simple, the figure-ground relationship reverses itself. An ambiguous figure-ground relationship exists whenever several perceptual possibilities have equal relevance. Even though ambiguous figures have a certain attraction, they lack impact. 4. Adjacent, similar visual elements are combined into a figure. Parts of a picture that are located closely together or that resemble each other tend to be perceived as a unified figure. A very simple and convincing example is the illustration published by Kurt Koffka in 1922, which shows eight parallel vertical lines. When the initial impression of eight black lines on a white background subsides, one begins to see four rods, separated from each other by distances greater than their thickness. Thus, by mental arranging, a figure-ground relationship has been created, and now the rods constitute a figure that stands out from its ground. How did this come about? The closer individual picture elements are located to each other, the more readily they will be grouped into a figure. By shading the space between pairs of lines that are close together, thus increasing the contrast, the figure-ground relationship can be further enhanced. Even so, it is not possible to see the four pencil-blackened rods and the white spaces simultaneously as figures.

In these two illustrations, at first sight one sees the vase, but only a moment later the two facing profiles become apparent. The inversion of the tonal values hardly makes any difference. A picture loses impact when figure and ground can be chosen from various possibilities.

The rods formed by visualizing the black lines in groups of two constitute a figure on a white ground. If the space within each pair of lines is darkened with a pencil, the figure-ground relationship is enhanced because of the increased contrast.

o o o o o o o o o o o o o o o o oo ooo o o o o o The letters "hdkb" in the logo of the Berlin Institute of Arts are formed by closely spaced dots. In the three illustrations above, contrast increasing from left to right improves the legibility and thus the figure-ground relationship. (Design Helmut Lortz)

Left: Even though the three incomplete black discs and the three angles only suggest an outline, one alternately recognizes either a six-pointed star or two triangles. Our perceptual system combines even incomplete picture elements into an entity. In the perception of the triangles, the increased contrast creates an apparent depth in which the triangle delineated by the black dots is perceived as the lighter one, located above the other triangle delineated by the three angles, and it thus becomes the figure. (According to Kanisza) Right: Incomplete figures or writings are easily recognized and read as entities when there is sufficient continuity. (Basle Fair)

21

The four hearts arranged around a white cross will not be perceived as individual figures, but as an entity: a clover leaf. The same applies to the illustration on the right, in which we mentally group tear-shaped figures arranged radially around a central dot into an entity: a blossom.

A figure cannot be perceived without a ground. Geometrical shapes or patterns that are completely or nearly self-contained tend to form a figure. In this process, the distance between individual visual elements and their similarity decisively influence their grouping into a figure. 5. Symmetrical and contained shapes tend to be perceived as figures. Symmetrical objects can be divided vertically or horizontally without the individual visual elements in both halves losing their correspondence of shape and size. Symmetrical shapes have a very balanced effect; they have a strong character (Gestalt), which produces a clear, immediately recognizable figure-ground relationship. However, because of their regularity, simplicity, balance, and order, they also have a high degree of redundancy - of the familiar, superfluous, and repetitious. Depth perception on two-dimensional surfaces Aside from very special methods of reproduction such as stereoscopic or holographic image recording, true image depth is not reproducible. All other methods of reproduction for visual communication, like prints, drawings, paintings, photographs, movies or television, are always merely two-dimensional: they only have vertical or lateral extension, but no depth. Our perception of reality is therefore not adequately reproduced by any of these media. Even so, we often experience pseudo three22

dimensionality when viewing two-dimensional pictures, such as photographs. What causes such apparent depth? Recent observations and investigations have shown that the impression of depth is not exclusively dependent upon stereoscopic viewing. The latter accelerates depth perception and enhances the ability to judge distances with greater accuracy, but this is limited to a range of 10 inches to approximately 164 feet because of the small separation between our eyes. Seeing depth with only one eye is of added importance for viewing and evaluating pictures. Its feasibility is largely of psychological origin, and it depends on education and on the learning of important reference points. There are six determining factors in this phenomenon: 1. 2. 3. 4. 5. 6.

Perspective Overlaps Texture Gradient Illumination Aerial Perspective Culturally Conditioned Vision

1. Perspective Since we usually do not stand parallel to objects in our environment that are situated at various distances from one another, we most likely perceive them from an oblique angle. This results in slanted and converging lines, like those in a picture taken with the camera pointed upwards at a tall building. According to the laws of perspective, with which we are familiar through education, we can gain significant guidelines from such views. We learn that straight, parallel lines converge in a point at infinity. Therefore, distant objects will become smaller and distorted when drawn in perspective. In spite of that distortion, our perception also tells us that forms and sizes are constant. This mechanism of constance is based on stored prior experience, and it enables us to estimate the size of all other things in our surroundings by comparing them to familiar objects. Looking at each column from top to bottom, these illustrations are examples of the following topics: 1 perspective; 2 overlaps; 3 texture gradient; 4 illumination; 5 aerial perspective; 6 culturally conditioned vision.

Left: In a test, the rendition of the elephant on the left was preferred by African children and adults to the customary Western top view of that animal. Right: The stylized bear drawn by Tsimshian Indians of British Columbia's coastal region is an example of the high artistic level achieved with such "fold-out" renditions. (From "Pictorial Perception and Culture" by Jan B. Deregowski, Scientific American, November 1972).

2. Overlaps When two or more objects in a picture overlap we deduce that the partially hidden objects must be located behind those that are covering them. 3. Texture Gradient Structures like brick walls, columns, and windows converge with increasing distance, and this indicates depth. 4. Illumination Illumination, by creating shadows, greatly contributes to the impression of depth. 5. Aerial Perspective Because atmospheric haze intensifies with distance, more distant objects become progressively lighter and more bluish. 6. Culturally Conditioned Vision The pictorial symbols mentioned on page 4, intended to prevent enormous language confu24

sion at international airports and at Olympic Games, are not necessarily intelligible to everyone. They too require a minimum of visual education, because persons from different cultures do not interpret pictures in the same way. By the time children learn to read and write, they have already gone through a period of learning how to read pictures, beginning at approximately 114 years of age. At that stage they learn to identify things reproduced in a picture with the real objects. With increasing age and additional education comes an expanded ability to see and think in terms of abstract, keyed pictures and codes, because that is exactly what diagrams, maps, wiring plans and technical drawings are. All of them amount to coded pictures, and to understand them we must learn special codes. The same applies to the viewing and understanding of photographs. Education influences and molds our way of viewing. It teaches us to see three dimensions in a two-dimensional picture when that picture contains any or all of the above-mentioned factors that suggest depth. The extraordinary paintings by primitive people teach us that there are other ways of expressing and seeing pictorial representations than those familiar to our Western cultural sphere. From the Maoris of New Zealand to the Indians of British Columbia, there is one characteristic

that is common to all primitive people: they do not see and draw pictures of objects with the same perspective to which we are accustomed. People who are used to that kind of visualization, which is different from ours, therefore have difficulty identifying objects depicted in perspective. In his article "Pictorial Perception and Culture", published in Scientific American in November 1972, psychologist Jan B. Deregowski describes the difficulties William Hudson had in his work for the National Institute for Personnel Research in Johannesburg with tests for South African Bantu workers involving the evaluation of pictures with perspective. The tests were intended to determine to what extent the African native was able to associate the perspective of the line drawing with depth in the depicted scene. The results - including those from other parts of Africa - showed that both children and adults had difficulties gaining the impression of depth of space from the line drawings. While these difficulties varied in degree, they were present in nearly all levels of education and population. The Visual Pathway in Viewing Pictures Knowledge of the visual habits of future viewers is undoubtedly indispensable in composing effective photographs. Because there is still no consensus regarding the exact mechanism of our visual perception process, physiologists as well as psychologists constantly strive to support new theories and to gain important new knowledge by means of objective tests. In this context it is interesting to mention the results of investigations with which David Noton and Lawrence Stark continued the work of other researchers who had similar results, as described in the article "Eye Movements and Visual Perception", which was published in Scientific American in June 1971. Under laboratory conditions, test persons were shown line drawings of geometric subjects subtending a viewing angle of about 20°, which were projected on a rear-projection screen. The viewers' eye movements were tracked and recorded with a special instrument using magnetic tape, so that they could be recalled at will. Results of this test showed that corners and angles are the most significant characteristics

The scanning pattern of a test subject viewing a picture of Nefertiti was recorded by Alfred L. Yarbus of the Institute for Studies in Information Processing in Moscow, using an instrument designed especially for this purpose. The eyes apparently do not wander at random across the picture, they systematically and repeatedly scan each picture element. It is noteworthy that corners and angles are viewed with special attention. (From "Eye Movements and Visual Perception" by David Noton and Lawrence Stark, Scientific American, June 1971).

for recognition and for storing in the brain's memory. The scan path followed a specific pattern which varied from person to person, and from test picture to test picture. Complex test objects required a longer viewing time than simple ones. Researchers concluded that the visual perception process functions in two different ways. One is the rapid visual scanning of the object and the assembly of individual familiar visual elements into an entity in the brain. (This process could also be called the entity method). The other is a systematic point-by-point scanning with a certain sight and motion rhythm (Feature Ring), which analyzes the unfamiliar elements. With the latter thesis, researchers are in apparent conflict with Gestalt theory. That contradiction is resolved, however, when Gestalt theory is limited to continually perceived visual elements that are well established in memory, and if the analytical scanning method is applied only to complex, less familiar visual elements. With this approach, the two theories complement rather than contradict each other.

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Information Theory When Gestalt psychology was introduced early in the 20th century, It was based on discoveries in the sciences made at the end of the 19th century. Later it was occasionally criticized for relying too much on subjective feelings, which were difficult to measure. Information theory, as founded by the American mathematicians R. A. Fisher, C. E. Shannon and N. Wiener in the

TRANSMITTER

« - I CHANNEL

Repertory of the transmitter

1 RECEIVER

Repertory of the receiver

Signals from the transmitter are understood by the receiver when they correspond, at least in part, to his font of knowledge or repertory. Understanding - Indicated by the shaded portion of the diagram - takes place proportionately to the extent that the repertory of the transmitter overlaps that of the receiver. As the receiver's capacity to understand increases, his repertory grows, eventually matching that of the transmitter. The process of continually collecting new data and knowledge can be called the learning process.

Indifferent because of lack of understanding Too demanding, too unfamiliar Optimal, because understandable and new

Interesting because new

0%

Indifferent because of boredom

The curve represents the information value of a message. Information content is inversely proportionate to redundancy. It reaches an optimum exactly in the middle between the two extremes. The intelligibility of any message depends on its redundancy. 100% originality would meet with the same incomprehension as would 100% redundancy, the one by overtaxing the receiver, the other by boring him.

26

middle of the 20th century, has sought to correct this weakness. The tumultuous development of the electronic news media and the rapid spread of datastoring and processing computers required a theoretical foundation. The latter was provided by information theory towards the end of the forties. Information theory is based on the premise that messages, whether in words or in pictures, are sent by a transmitter to a receiver by means of a physical channel. The message is made up of symbols that are contained in the repertory of the transmitter as well as in that of the receiver. It is sent with a certain system, a code, which the receiver will understand if it is contained in his repertory. The content, the substance of a message is derived from the relationship of the unfamiliar - the new - to the familiar and superfluous, the so-called redundance. The information value depends on the balance between these two extremes. Excessive novelty will meet with as much rejection because of unfamiliarity as an excess of familiar information would because of indifference. Therefore, in an optimal message, the emphasis will fall slightly more on novelty rather than familiarity in order to elicit interest and attention. The difference between the new and the familiar constitutes the information content or information increment for the receiver. This is the point where Gestalt and information theory border on each other. French psychologist and sociologist Abraham Moles established numerous connections between the two theories, thus confirming the validity of Gestalt laws for information theory as well. Summarizing and simplifying the Gestalt laws, they comprise the more or less familiar portion of a visual message, the redundant, in a clearly recognizable form (Gestalt) that results from classifying and grouping the individual visual elements. In this way the information is made The degree of complexity of a picture, the number of different visual elements of which it is composed, influences its information value. The latter increases with increasing complexity. In the six examples, the degree of complexity increases from subject to subject. From top to bottom: (page 26) fence posts in the snow; dried soil; rounded lava rocks; (page 27) inner yards in Cordoba, Spain; Westminster Bridge and Parliament Building in London; skyscrapers in New York.

27

TRANSMITTER

CHANNEL

RECEIVER

A pictorial message cannot be an absolute copy of reality, because there is a relationship between transmitter and channel - object, photographer, and photograph - which is affected by the subjectivity of the photographer, the way he sees things. It is

left to the receiver - the viewer - to gauge, again subjectively, the degree of conformity between reality and reproduction and to evaluate the picture. (According to G. Jäger in "Generative Photography").

easy to understand. The unforeseen, less easily understood portion of a message, its original or novel content, cannot be quantified according to Gestalt laws, but in information theory it is measurable in "bits", the unit for the smallest amount of information. Human absorption capacity is about 16 bits per second. For composing a picture, it is not necessary to express its original or new content in numerical values, therefore it will not be taken into account at this stage. It suffices that

novelty value is recognized and taken into account as a determining factor. What significance do Gestalt and information theory have in particular for the composition of pictures? Gestalt theory teaches us that, by classifying and grouping, our visual perception system constantly strives to simplify the recognition and understanding of our surroundings, so that we can more easily orient ourselves in them.

In viewing this pattern, we instinctively try to establish an order within it. Analyzing it, we see that it contains a complex variety of shapes. The basic elements are the black and white triangles, which can be combined into pyramids, cubes, rhombus, stars, and hexagons.

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Information theory teaches us to adjust opposite components of information, such as the new and the familiar, in such a way in relation to each other that a message will result that is both understandable and interesting. While Gestalt theory provides for formal aesthetic evaluation of pictures, information theory applies to the evaluation of the original or novel content. There is no unqualified yardstick for this, because something that is new to one person may be long familiar to another. Originality depends significantly on the font of knowledge and experience of the viewer.

The Emotion Thesis There is one determining factor that does not receive its proper due in either theory, and that is the emotional content of pictures. While it is even more difficult to measure than the other factors, it plays a most effective role. This category covers pictures that make an impression on the viewer, not because of their outstanding composition, nor because of their information content, but because of a quality that appeals to his feelings. Pictures which strongly influence emotion in this manner, however, are extremely rare. They fascinate either because of their uncommon beauty, or because of their repulsive ugliness. The intensity of this impression depends decidedly on the viewer's sensitivities. Summarizing, it can be stated that, basically, pictures can be evaluated according to three categories: 1. Pictures largely conveying information 2. Pictures largely aesthetic in nature 3. Pictures largely conveying emotions This does not mean, however, that only one of these categories may be recognizable in a picture in order to create attention and interest in a viewer. Rather, pictures that contain portions in two or all three categories can be most effective. A picture intended to convey information does not have to be completely free of aesthetics or emotion. On the other hand, pictures that contain none of these three categories-nor a combination of them - leave the viewer indifferent, apathetic. Pictorial messages of that nature are failures.

These photographs are intended to represent each of the three categories of picture evaluation: the top photo, showing a laboratory procedure, is informative; the center photo, composed of only a few elements, is an example of an aesthetic picture, and the bottom one, gracefully romantic, appeals to the emotions.

29

Picture Perceived by eyes and brain Reaction of emotions Initiation of associations Evaluation Agreement Rejection Comparison J with knowledge) Initiation of associations

Comparison with reactions of other senses Comparison with all stored experiences

30

The two sample photographs should help to explain the emotion thesis. The "pretty" picture from the Caribbean evokes romantic associations: we can hardly wait to go there ourselves. In the "repulsive" picture one can almost hear the shot and see the man

T h e sequence of viewing and perceiving a picture: Starting with the three categories of picture evaluation - Information theory, Gestalt theory, and Emotion thesis, the diagram shows the various dependencies and cross-connections that can become effective during this process.

collapsing in the very next moment to die in a pool of blood on the ground. (Vietnam 1968, Execution of a Vietcong officer in civilian clothes by the Saigon Police Chief in an open street. Photo courtesy Associated Press, Frankfurt).

6. Similarity with objects familiar to us contributes to recognition and therefore to faster comprehension and information processing. Thus the necessity of redundancy.

Pictorial Composition

7. The degree of complexity of a picture must be neither too low (understimulation) nor too high (overstimulation). 8. Aesthetic evaluation of each and every picture is always different from individual to individual, and it is governed by emotions. It depends significantly on the viewer's consciousness, his font of experiences, and his sensitivity. 9. Formalism and fads are ephemeral. Technical manipulation cannot compensate for a lack of originality.

Every composition is based on order. As we have learned from the laws of Gestalt psychology and information theory, this can be achieved in many ways. It results both from the grouping of similar things and from the emphasizing of opposites. Order is not the same as unrestricted monotony; tensions and contrasts in shapes and colors also create order. It is based on an aesthetic balance which establishes harmony out of complexity, contradiction, and dynamism. The following points provide important suggestions for good picture composition: 1. The (picture) signals must be clearly distinct from "optical noise". 2. A clearcut figure-ground relationship contributes to the impact of a picture message. 3. Ambiguous figure-ground relationships that could lead to optical deceptions should be avoided. 4. The area relationship of light-dark or color contrasts is of great importance. 5. In addition to the formal figure-ground relationship, psychological figure-ground weighting is very important, because every visual perception is judged immediately as pleasing or displeasing. A neutral evaluation would mean no reaction at all. 32

10. Illumination, perspective, overlapping, and texture gradient serve to convey an apparent feeling of depth on a two-dimensional surface. 11. An unfamiliar perspective serves to liven up the picture. 12. The conscious use of strongly directional lines and a format adapted to the subject increase the effect of the picture. What practical application can be derived from the above in composing a picture? Theories should always be taken as guidelines, not as infallible recipes. Nevertheless, realizations and points of view gained from the theories explained above are extremely useful in composing optimal pictures. The path to optimal picture composition goes by way of consistently executed picture analysis. Anyone who knows how to examine a picture for its specific effect by dividing it into its individual elements of composition and using them to derive its aesthetic coherence and legitimacy will also succeed in creating good pictures himself. For that reason, a number of selected photographs will be analyzed according to the factors that we have established. These analyses will individually examine relevant factors of picture composition and point out the interplay of qualities that affect each other.

The most important criteria for the analysis of picture composition are: 1. Figure-ground relationship and contrasts 2. Informational value and similarity 3. Illumination and depth 4. Strong lines and picture format In the first picture analysis this technique will be demonstrated in detail; all subsequent picture examples will be treated more succinctly. A page is devoted to each of the characteristic elements. Each element of composition is assigned a graphic symbol with a heading, the "Symbol Index". The symbol index has two functions. First, it helps in finding the desired place while thumbing through the book; second, the symbols appear again in the heading over every row of pictures at the bottom of the left page. Here they point out the individual elements of composition that play an important role in that picture's composition; this makes long explanatory texts unnecessary. Furthermore, the reader is encouraged and enabled to analyze actively. Once he understands the principle, he can analyze his own and other photographs according to the same method. He is thereby led to greater insight into effective picture composition and to an enhanced sensitivity, so that he is able to improve the quality of his own pictures. The first section of picture analysis takes into account those elements of composition that are of fundamental importance to both blackand-white as well as color photographs, whether in still or motion pictures. Elements of composition that are particularly important to color photographs are treated in detail in the color section of the book. The concluding chapter "Compositional Technique" once more recalls the factors of photographic technique that significantly affect picture composition.

Each of these four pictures is characteristic of one of the summarized criteria of analysis. From top to bottom: 1. Figureground relationship and contrasts; 2. Informational value and similarity; 3. Illumination and depth; 4. Strong lines and picture format.

33

Picture Analysis: Blackand-White

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Technique of Picture Analysis

1. Figure-Ground Relationship and Contrasts Because of its contrasting silhouette effect, the statue of Atlas clearly stands out as a figure from the lighter ground. The subject divides into dark, medium, and light tonal value contrasts. The smaller area is the figure, the larger one the ground. 2. Informational Value and Similarity The modern statue of Atlas stands in front of Rockefeller Center in New York City. The stylized body in combination with the repeating circles and ellipses shows redundant and familiar things, which contribute to the rapid comprehension of the picture. 3. Illumination and Depth Incident light from the upper left brings out the details of the statue. The area of the sky is broFigureGround

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Side Lighting

ken up by clouds. Unfortunately the buildings appear flat, not 3-dimensional. The worm's eye view that is the basis of this picture does not permit any other view of the buildings. The depth is due to the silhouette effect of the main subject and to the separation of the picture into fore-, middle-, and background. Converging lines and the decreasing size of windows convey the impression of height. 4. Strong Lines and Picture Format The figure consists of circles and ellipses and of the counter-diagonal of the raised right arm. The ground is made up of diagonals and counter-diagonals of the skyscraper and the flagpole in the left foreground. It is important that the side of the building that rises diagonally in the lower right corner of the picture counterbalances the skyscraper that towers over everything. The head is at the golden section, and thus at the right place. Sharpness is centered on the statue, but the background is clearly recognizable. Because of the dominating circular shape of the figure, only the square format was appropriate. Compositional elements that make up this picture: Figure-Ground Silhouettes Contrasts Texture Gradient Informational Value Diagonals Similarity Counter-Diagonals Side Lighting Circles Worm's Eye View Golden Section Fore-, Middle-, Sharpness and Background Square Format

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Silhouettes

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decisive influence on its recognizability. The smaller area is usually seen as the figure, and the larger one as ground. The clearer the composition, the easier the picture is to understand. Less often means more!

The most important part of any picture is a clearly recognizable center of (picture) interest. It can consist of one or several objects, and it constitutes the figure. The rest of the picture is the (back) ground. If the center of interest stands out clearly from its surroundings, the picture has a good figure-ground relationship, and the picture will be readily recognized and understood. If it can be discerned from its surroundings only with difficulty, then the figureground relationship is poor. The picture will then lose expressiveness and attention value. The size of the area of the figure, its make-up and its contrast with the ground also have a

Similarity

Picture Analysis Figure-Ground and Contrasts The subject of the drinking man is made up of only a few picture elements and it stands out well as a figure from its ground. In the distribution of contrasts, the light and middle tonal values predominate. Informational Value and Similarity The picture shows a street worker in Old Castille drinking from a typical Spanish unfired clay jug. The two arms holding the jug form two similar, almost identical right angles. They furnish an animating contrast of shapes in relation to the repetitive round areas of the jug and the head. Illumination and Depth The sun, high in the sky and covered by clouds, produces soft shadows and gives good depth to the forms and structures of the subject. Strong Lines and Picture Format Right angles, verticals, diagonals, and counterdiagonals dominate the picture. Ellipses and circles provide an alternate contrast. The original square picture format is best suited to this subject, because a rectangle would crop out important picture details.

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Contrasts

By means of contours, contrasts form the image of objects. They are the basic ingredient for any picture, and therefore they are one of the most important creative elements. With a distribution of one third each of light, medium, and dark contrasts, picture composition is perceived as varied and harmonious. A picture with only light or only dark tonal values can also be very attractive. However, a picture that consists only of medium tones appears uninteresting, because it lacks sufficient visual stimulation. A picture that consists primarily of only one tonal value is called a high-key subject when that tone is light, and it is a low-key subject when the predominant tonal values are dark.

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Side Lighting

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Worm's Eye View

Picture Analysis Figure-Ground and Contrasts The three buildings rising towards the sky stand out clearly as the figure from the ground of the sky. The lamppost serves only as a foreground subject. The distribution of contrasts is handled in the "classic" manner. Light, medium, and dark tonal values fill a third each of the subject. Informational Value and Similarity Unlike the feeling of sameness that predominates in New York's office buildings, these three buildings from different eras convey an impression of the variety of architectural styles. There is similarity and repetition both in the vertical as well as in the horizontal arrangement of windows. The silhouette of the lamppost serves to accentuate the upward thrust of the buildings. Illumination and Depth Light coming in from the right clearly defines each building. The bright contours of the lamppost separate it from the fronts of the buildings. This lends spaciousness and depth to a subject of flat surfaces. Strong Lines and Picture Format Lines converging towards the top, as seen from a worm's eye view, strengthen the feeling of height. The impact of the descending counterdiagonal of one of the buildings is balanced by the cross-beam that supports the lamps. The vertical format supports the impression of height.

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CounterDiagonals

Informational Value

The informational value of a picture results from the variety of its individual visual elements - its degree of complexity - and from the proportion of the new and unexpected to the familiar - its novelty value. But neither of these criteria is constant. Instead, they depend on the individual font of knowledge and experience. A subject that consists of only a few elements is grasped and understood more rapidly than a subject crammed with picture elements, which is also not necessarily the more interesting one. Both a lack as well as an excess of picture elements or novelty can cause rejection by the viewer, either because of disinterest or because of lack of understanding. Picture Analysis Figure-Ground and Contrasts The researcher stands out well as a figure from gpi>

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the ground. While his head and hands are well differentiated from the light window, the white laboratory coat provides good separation from the dark surroundings. Informational Value and Similarity This laboratory scene, in which fluorescin is applied to contact lenses under strong UVillumination and intense heat generation, has sufficient compositional elements and enough of the new and unexpected to be interesting. Similarity is found in the repetition of round shapes in the UV-lamp and the head, and in the many right angles, which in turn provide the contrast of shapes. Illumination and Depth The picture is illuminated by the UV-lamp in the left foreground, and by diffuse daylight entering through the window. Depth is created by the division into fore-, middle-, and background: UV-lamp, researcher, and view through the window. Strong Lines and Picture Format The UV-lamp in the left foreground, the bottle in the researcher's hands, and his head form a diagonal. The researcher is placed at the golden section and thus at the right spot in the picture. Since the plane of optimum sharpness is at the bottle, the wiring and valves in the foreground are only reproduced as unsharp vignettes. This considerably enhances the depth effept of this subject. The square picture format captures the researcher engrossed in his work and provides an informative overview of the arrangement of the working area.

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Similarity

Picture elements that are similar to one another in expression, shape, color, location, quantity, or contrast, provide balance and recognizability to a picture. Picture elements that resemble each other enable the viewer to grasp them more quickly and to concentrate more on the novelty of the picture. Similarity and the necessary repetition of individual picture elements can lead to the redundant (superfluous). However, a certain measure of redundancy is desirable in pictorial information, because it serves to couch the new and unexpected with the already familiar, and thus to make it more easily understood. Picture Analysis Figure-Ground and Contrasts The silhouettes of the persons stand out clearly

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from the bright design panels in the background. The picture consists of about twothirds light, and one-third dark tonal values. There are hardly any medium tones. Informational Value and Similarity The photograph shows a group of students in a lively discussion in front of their work. In spite of the varied picture elements, the picture's message can be considered successful. Seven persons in the foreground happen to be standing in front of seven designs in the background. There is agreement in quantity, but not in shapes. The checkerboard pattern of one of the designs is repeated on the pullover of one of the women. Illumination and Depth Side light entering from the left and the contrast formed by the silhouettes of the students against the background create a distinct feeling of depth. Strong Lines and Picture Format A pattern is formed on the light background by the horizontal and vertical lines of the eight squares, each of which contains a graphic design. The heads form a semicircle. A dynamic feeling is generated by the blurred images of the two students moving out of the picture, contrasting with the static background. A person on the left side of the picture, and another one on the right side has one arm in an angled position, giving the picture a certain completeness and symmetry. The horizontally arranged subject is best reproduced in a horizontal format.

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In addition to the contrasts that are formed by different colors in the object, illumination is the most important creative element in photography, which is a way of "drawing" with light. It determines to a large extent whether a real object when reproduced in two dimensions on a flat surface will appear to have depth. Soft, diffuse light makes objects appear flat, leaving contours as the principal recognizable feature. Hard, directional light, on the other hand, emphasizes shapes and structural details with its strong shadows, creating an impression of depth. The mood of the picture can also be strongly influenced by illumination, in which both the direction of that illumination and, especially in the case of color photography, the color of the light play an important role.

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Eye-Level Perspective

Picture Analysis Figure-Ground and Contrasts The contours of the structure and the palms in the foreground stand out very well from the background of the sky. Light and medium values predominate in the tonal value contrasts. Informational Value and Similarity The tower of Belem, which is located near the mouth of the Tejo river, was built as a fort in 1515 to protect the access to the harbor of Lisbon, and it is regarded as an important example of the Manuel style. Similarity and repetition are provided by the palm trees and the many smaller vertical towers and the battlements. Illumination and Depth The comparison of the two photographs, one taken with side lighting, and the other with diffuse daylight, convincingly demonstrates the difference illumination makes in pictorial effect. While the picture taken with diffuse light allows only the outline of the fort to be recognized, the strong side light emphasizes every shape and detail of the structure. The impression of depth is markedly greater with such dramatic lighting. The difference between the two kinds of lighting is especially apparent in the reproduction of the bay in the center of the tower. The palm trees serve to divide the picture into fore-, middle-, and background. Strong Lines and Picture Format Verticals dominate this subject. Both the shady side of the tower and the silhouettes of the palm trees contribute to that effect. The square picture format suits this motif best.

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Side Lighting

Photography with direct frontal lighting yields very flatly illuminated pictures. This is not so bad in color photography, because different colors give life to the picture. In black-andwhite photography, however, especially when it involves a subject without great tonal contrasts of its own, this type of lighting is particularly unsuited. By moving around the subject by just a few steps, the photographer can change his position in such a way that side lighting will produce much better depth. This is true for both black-and-white as well as color. Picture Analysis Figure-Ground and Contrasts Both the bell tower as well as the dome of this small church stand out well from their surroundings. The figure in this picture consists

not of one object, but of both of these structures, which were recorded in complementary tonal values. While not physically, thematically they form a unit. Contrast distribution is about one-third each light, medium, and dark. Informational Value and Similarity The church in Oia on the island of Santorin is a typical example of the style of architecture that predominates to this day on the Greek islands of the Cyclades. It can only be reached by way of the stairs and roofs of the houses that are virtually glued to the precipitous slopes. The picture is composed of a variety of triangles and angles, the very elements of shape that have the greatest attention value in our system of visual perception (see page 25); therefore it is visually stimulating. In addition, there is repetition in some of the rounded shapes. Illumination and Depth This picture is vibrant because of its lighting. The variety of picture elements and the illusion of depth created by the strong side light and the overlapping planes virtually invite the eyes to wander down those stairs and across the roofs. Strong Lines and Picture Format In spite of the profusion of lines, the eyes are always led to the picture's center of interest, the ambiguous figure. Depending on whether we consider the picture as left- or rightoriented, either half of the figure, the bell tower or the dome, is situated at the golden section. The choice of the vertical format augments the depth of the picture.

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Back Lighting

If side lighting has the advantage over diffuse or frontal lighting of increasing the illusion of depth, this applies to an even greater degree to pictures taken against the light. But as the pictorial impact increases, so do the difficulties in managing light that is directed at the camera. The principal object and the surroundings illuminated by oncoming light have to be measured separately and the resulting values have to be matched to the range of the film that is being used. Picture Analysis Figure-Ground and Contrasts The silhouettes of the two old women stand out strikingly as the figure from the predominantly light tonal values of the picture. Even though there are two separate persons, they must be

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regarded as a unit from the point of view of composition. Very careful reproduction of the contrast range keeps the shadows from appearing as parts of the silhouettes. Informational Value and Similarity The morning chat between two old ladies at the harbor of San Sebastian in Spain takes place in front of the city's skyline with the foothills of the Pyrenees visible in the background. There is a unifying similarity between the two persons facing each other. A mirror-image repetition occurs in the two shadows pointing at the viewer. The two posts on the left side of the picture repeat this theme. Illumination and Depth The oncoming light makes the distant mountains disappear in the aerial perspective. It also creates a light fringe around the head cloth, the hair, the folded hands, and the left foot of the lady standing on the left, dramatically separating the two persons from the background. The shining sea and the bright platform further enhance the illusion of depth. Strong Lines and Picture Format This subject is dominated by verticals formed by the two ladies, their shadows, the posts, and the pillars of the railing. A contrast is provided by the horizontal line of buildings, which is repeated several times by the cracks in the cement. The harbor and the platform each provide a diagonal on the right side. The center of interest, the two profiles, are situated at the golden section. The vertical format should emphasize the vertical lines.

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Eye-Level Perspective

According to the laws of optical reproduction, which also apply to our eyes, the further away an object is located, the smaller will be its image. At eye-level perspective, the impression of depth results from the fact that the point of view of the observer and the center of perspective of the object are at the same level. The lines converging towards that center of perspective make all objects within that cone of lines appear gradually smaller, thus creating the impression of depth and shape.

Picture Analysis

Figure-Ground and Contrasts Because of the complex structure and the constantly changing contrasts, the aqueduct does not stand out distinctly as a figure from the ground. The distribution of contrasts is approximately one-third each in the light, medium,

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Side Lighting

and dark tones. Informational Value and Similarity The aqueduct of Segovia in Spain was built over 2000 years ago by the Romans in order to bring water from the mountains across a wide valley into the city. The lower portion of the entire structure is built with granite blocks without the use of cement. Only the portion at the top was restored with the aid of cement. Similarity is provided by the repeating arches, the vertical pillars, and their horizontal shadows. The two diagonals are strong guiding lines leading towards the center of perspective of the subject. A repetition of the structure can be recognized in the rectangles formed by the shadows and in the roof shingles. Illumination and Depth Side lighting models the forms and textures of the aqueduct in a way that could hardly be stronger. Eye-level perspective makes the structure appear natural, and it also conveys its magnitude. The impression of depth is significantly emphasized by the converging lines of perspective. This impression is further supported by the texture gradient formed by the meeting of the vertical pillars with their horizontal shadows. Strong Lines and Picture Format This picture is created by the diagonal, vertical, and horizontal lines, which form a multitude of angles and triangles. They almost smother the rounded shapes. The subject was photographed with a vertical format to underscore the height of the structure.

Texture Gradient

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Vertical Format

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Worm's Eye View

Pictures taken with an unusual perspective generate more attention than those taken at eye-level. The surprise factor provided by an uncommon perspective should be utilized much more frequently, but there is a certain limit that should not be exceeded. Images that are too unusual induce rejection because they are not understood. Because of the very low picture-taking position of a worm's eye view, the horizon and the center of perspective of the picture move to a location above their usual eye-level position. Photographs taken from such a low perspective can make the objects seem very tall, towering, or even oppressive.

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Picture Analysis Figure-Ground and Contrasts The light columns stand out well as figure from the ground of the dark sky. The tonal value contrasts are mostly in the light and medium ranges. Only the shadows provide a relatively small portion of dark tones. Informational Value and Similarity The Doric capitals and columns are shown in a detail photograph of the Parthenon of the Acropolis in Athens. The sparse use of different visual elements makes it possible to grasp the picture at a glance. There is a similarity between the triangles formed on the one hand by the wall on the left and the crossbeam, and on the other by the three capitals. Illumination and Depth Light coming in from the top right causes shadows that create good modelling. The worm's eye view makes the subject appear to be free-standing in space. The illusion of depth is further enhanced by the small clouds that loosen up the sky. Strong Lines and Picture Format Diagonals coming from the upper and lower left point like arrows at the outermost column, acting as guiding lines towards the center of interest, the Doric capital located at the golden section. The vertical shadows on the right column hint at its height, which the picture does not show.

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Bird's eye views, like worm's eye views, are not among the everyday ways of seeing and viewing things. Therefore, they attract more attention than eye-level pictures. Because of the elevated picture-taking position of a bird's eye view, the center of perspective and all lines in the subject leading to it are moved towards the lower edge of the picture. The impression of endless depth that this creates can be accentuated significantly by the use of wideangle lenses (the shorter the focal length, the greater the effect). The use of side lighting in this picture reinforces the impression of reality because of the good modelling of the objects. Picture Analysis Figure-Ground and Contrasts In a complex subject with this many elements, the figure-ground relationship is bound to be

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Side Lighting

ambiguous. In general, however, the sea of buildings stands out from the ground separated by water. Contrasts are varied and divided roughly into one-third each light, medium, and dark tones. Informational Value and Similarity The view is from Rockefeller Center in New York City, looking towards the Grand Central, Pan-Am, and Chrysler buildings, the East River, and Brooklyn in the background. In the conglomeration of buildings there are examples of every size and style. Similarity and repetition can be found in the types of buildings, and in the formal picture elements such as diagonals, verticals, and texture gradients. Illumination and Depth Strong light coming from the right side and the picture's sharpness make the corners and façades of all the buildings clearly regognizable in spite of the apparent chaos. To recreate the impression of depth and confusion that an observer experiences at that site, the bird's eye view and a wideangle lens were used for this picture. Strong Lines and Picture Format In spite of the profusion of picture elements, lines, angles, and triangles can be clearly recognized in this subject. Dominating skyscrapers accentuate the verticals, but the canyons formed by the streets underscore the diagonals and counter-diagonals. The background is limited by the calming line of the horizon. To emphasize depth, the picture was taken in the vertical format.

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Fore-, Middle-, Background

A well-defined arrangement of a subject into fore-, middle-, and background is a compositional element that fosters the illusion of depth. A foreground silhouette offsetting the main s u b j e c t - t h e f i g u r e - in the middle ground, with the location recognizable in the background, is a classic solution that has been used for a very long time for the reproduction of landscapes. But the division of space into fore-, middle-, and background is not restricted to conventional landscape pictures; in every type of photograph it leads to a more pronounced depth effect, and thus to a more realistic reproduction of the subject. Picture Analysis Figure-Ground and Contrasts The silhouette of the cart in the left foreground

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stands out very well from the background. However the principal subject is not the cart, but the farmer standing on the thresher. He stands out well as the figure from the ground because of the contrast between him and his animals and the surroundings. The village is both ground and background. In this subject, the light and medium tonal contrasts predominate. Informational Value and Similarity The picture shows a threshing area in a small village in Old Castille in Spain, where until recently the kernels of wheat were still separated from the spikes by the thousand-year-old method of using threshing sleds. There is similarity and repetition in the two carts, the animals, and the houses. Illumination and Depth The picture was taken around noon with nearly vertical sunlight flooding a vast, arid landscape. Natural contrasts and spatial arrangement create an effect of depth in spite of a light that is unsuitable for good modelling. In this instance, the noon-hour lighting is part of the composition. It is used to convey the merciless heat and dryness of this region. Strong Lines and Picture Format In spite of the pronounced vertical shape of the cart in the foreground, the picture suggests peace and spaciousness. This impression is reinforced by the far edge of the threshing area in the lower third of the picture, and by the division of the picture into nearly equal halves by sky and landscape. The expanse of sky is loosened up by clouds. The overall character of the picture radiates peace, and this is supported by the choice of a horizontal format.

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Horizontal Format

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Texture Gradient

Texture gradient is formed by the gradually decreasing spaces between equidistant vertical or horizontal objects as they recede into the distance, like telegraph poles along a country road, or windows in a row of houses. Using the principle of the conservation of size we sense a quite considerable depth to the picture, owing to the diminishing horizontal and vertical spaces between the wooden ribs. Picture Analysis Figure-Ground and Contrasts Based on the contrast of forms, the group of

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three shipbuilders, like a counterpoint, constitutes the figure that is essential to the picture. It is, however, overpowered by the pattern formed by the light and dark contrast of the ribs, and the very prominent light diagonal of the keel. The light-and-dark pattern created by side lighting on the ribs becomes tighter with distance, and it is the actual texture gradient. Light and dark tones prevail in the distribution of contrasts. Informational Value and Similarity In Peniche, on the western coast of Portugal, shipbuilders still master the art producing wooden fishing cutters by hand. Similarity is provided by the three individuals, by the repetitive shadow pattern of the ribs, and by the two horizontal beams that close the picture off at the top. Illumination and Depth Side lighting models each rib and the keel, making every detail stand out clearly. Both the diagonal leading into the picture, as well as the conspicuous texture gradient contribute to the illusion of depth. Strong Lines and Picture Format The picture is dominated by the light diagonal of the keel leading towards the center of interest. The arched ribs create a contrast of forms with the heavy straight diagonal and the two horizontal crossbeams. The vertical format adds further to the depth effect of this picture.

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Silhouettes

The silhouette effect of objects results from certain lighting conditions. With oncoming light and very weak illumination, only the outline of objects stands out from its lighter surroundings or background. Because of harsh contrast and limited gradation, details in the object can barely be perceived. The high contrast that exists between a silhouette and the surrounding picture area can contribute to both the impression of depth as well as to the figure-ground relationship.

Picture Analysis

Figure-Ground and Contrasts The goddess on the Victory Column stands out

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Back Lighting

clearly as the figure from the ground of the winter sky. The arm and sword of the cropped Bismarck statue do not compete with it in spite of their higher contrast. Approximately half the picture consists of medium, and about a quarter each of light and dark tonal values. Informational Value and Similarity The photograph shows a portion of the Victory Column in the Tiergarten in Berlin. Similarity is limited to the repetition of formal picture elements like verticals, diagonals, and counterdiagonals. Illumination and Depth Photographed against the sun with a long focal length, this subject conveys a good impression of depth despite the crowded space by clever distribution of contrasts. By overlapping each other, the unsharp bare branches in the foreground heighten the illusion of depth. Strong Lines and Picture Format The subject was photographed from a worm's eye view, and it is composed of verticals that connect the Victory Goddess with the column, and of repetitive diagonals and counter-diagonals. Since the brightest spot in a picture always catches the eye, the sun is in the right location: the golden section. Very bright tonal values should never be located directly at the borders of a picture because that leads the eyes out of the picture, destroying the integrity of the composition. With the use of the tall format, the verticals in this picture are especially emphasized.

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Another creative element that helps to simulate three dimensions in a two-dimensional photograph is aerial perspective. In landscape photography, the contrast of progressively more distant objects diminishes considerably with accumulating atmospheric haze and its inherent blueness. The most distant objects, usually houses or mountains, often end up merging completely with the blue of the sky. To the viewer, it conveys the impression of distance and space.

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Bird's Eye View

Picture Analysis Figure-Ground and Contrasts The contrasting dark mass of the mountains in the foreground stands out well as the figure from the ground. In this subject, the distribution of contrasts is about one-third each in the light, medium, and dark tones. Informational Value and Similarity The view from the top of Mont Blanc towards the East shows the dark mass of the Grand Jorasse in the center foreground, and in the middleground behind it, the Grand Combin. At the horizon, we can see, from left to right, the Weisshorn, the pyramid with the long slope, the Dom (Cathedral), the Taschhorn, the Mischabel group, and the Matterhorn. Similarity and repetition occur in the pyramidical peaks. Illumination and Depth Taken against the rising sun, this photograph magnifies the effect of aerial perspective. Only the silhouettes of the mountain tops protrude through the haze. Low-lying clouds in the valleys contribute to a sense of distance. Strong Lines and Picture Format The subject is dominated by the diagonals and counter-diagonals formed by the cone-shaped mountain tops. A weak horizontal is suggested by the chain of mountains in the middleground. In addition to the square format, a horizontal cropping would also suit this subject well.

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Back Lighting

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Square Format

Picture compositions that have no inherent depth need other compositional elements in order to achieve an interesting and stimulating effect. A plane is an entity with only two dimensions: its length and its width. In addition to light and dark contrasts and varying colors, linear structures or geometric figures can also be utilized to enliven such pictures. Just as two lines converging at an acute angle form a triangle, the lines in a subject can form numerous shapes, from the rectangle to the polygon to the circle.

Picture Analysis Figure-Ground and Contrasts In terms of space, the figure cannot be distinguished from the ground in this picture. By virtue of its contrast, however, the dark diagonal and vertical figure stands out well. Contrasts are represented in equal amounts in all three tonal ranges. Informational Value and Similarity Photographed in the State of Utah near Moab, the aerial picture shows large lye basins for the production of potash through the evaporation of water. There is similarity between the lines and the planes they delineate. Illumination and Depth In spite of the side light coming from the right, there is no discernible depth in this picture; it appears absolutely flat. Strong Lines and Picture Format In addition to the tonal contrasts, the lines and the planes formed by the basins enliven this photograph. The diagonal and the counterdiagonal lead the eye to the rounded end of the dark basin, which is located near the golden section. To render the varied shapes of the planes as large as possible, a horizontal format was selected.

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Horizontal Format

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Strong lines are as important a compositional element as are illumination and perspective. Depending on the course of one or two lines, the message of a picture composition will vary. Lines can connect or separate. Whereas a straight line seems static or rigid, an angled or curved line conveys a lively and dynamic impression. When a number of lines meet, angles are formed, or squares, rectangles, triangles, or polygons. Lines do not necessarily always have to be directly visible in a subject. Instead, a picture is often effective because of implied, imaginary lines that connect several objects. Picture Analysis Figure-Ground and Contrasts In spite of the variety of compositional ele-

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Texture Gradient

ments in this subject, the persons on the stairs are well discernible as the figure from the ground. All three tonal ranges appear in approximately equal proportion. Informational Value and Similarity The photograph shows visitors on a staircase in a pavilion of the New York World's Fair. Similarity and repetition can be found in the persons and in nearly all groups of lines. Illumination and Depth Because of the diffuse daylight, the differentiation of individual objects takes place more by virtue of their contrasts than their illumination. There is also an impression of depth, created by perspective, fore-, middle-, and background, by texture gradients and by overlappings. Strong Lines and Picture Format Quite a number of picture elements contribute to the composition of this picture. The diagonal and curved lines of the stairs lead into the picture. The bright triangle formed in the middleground by a horizontal and by a counter-diagonal line creates a good contrast with the persons on the stairs. The diagonal upper balcony on the dark wall forms still another triangle with the counter-diagonal of the staircase. This triangle, however, loses its aggressive point to the protruding balustrade in the left upper third of the picture. The vertical white surface in the right upper third forms a contrast to the predominating horizontals and diagonals. The vertical is the only suitable format for this subject, because the depth effect would be lost without the powerful steps in the foreground.

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CounterDiagonals

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Vertical Format

An uneven apportionment of sky and landscape in the ratio of 1:3 or 1:6 brings much more vitality to the picture.

A line that is parallel to the upper and lower borders of a picture has a static and passive effect on the viewer. It can suggest tranquility, but it can also be boring. The strongest horizontal in many pictures usually is - as the name implies - the horizon line. If the horizon is exactly in the middle, as unfortunately is often the case, it divides the picture in two halves, a dark lower half and a bright upper one. Such symmetry appears contrived and monotonous.

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Side Lighting

Picture Analysis Figure-Ground and Contrasts The light statue stands out well from the darker ground. Dark and medium tonal values predominate in the contrasts, creating a "heavy" mood. Informational Value and Similarity The 18 m (59-foot) long reclining Buddha at Polonnaruwa on Ceylon was sculpted on site from native granite in the 13th century. Similarity is created by the horizontal position of arms and legs. Illumination and Depth Side lighting from the upper left is largely scattered by the trees around the statue. Because of the weak shadows, there is only a mild feeling of depth. Strong Lines and Picture Format Horizontal lines, repeated at several levels of the picture, are predominant. The flowing folds of the intimated vestments run vertically and diagonally, creating a contrast with the strong horizontal lines. To emphasize the latter, the horizontal format was chosen.

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Diagonals

When a horizontal is tilted slightly, it becomes a diagonal. A diagonal suggests movement and yearning. If it runs from the lower left to the upper right, it is considered as positive by persons from Western cultures because of their accustomed direction of reading and writing. The opposite diagonal, on the other hand, is regarded as negative. Picture Analysis Figure-Ground and Contrasts In spite of the numerous subjects in this photo-

Similarity

Side Lighting

graph, the traffic on the bridge should be regarded as the figure, and the Parliament Buildings as the ground. Contrasts are evenly distributed, a third each in the light, medium, and dark tonal values. Informational Value and Similarity Westminster Bridge over the Thames, with the obligatory doubledecker bus and Parliament Buildings with Big Ben in the background, are a typical London subject. Similarity and repetition can be found in the many strong lines. Illumination and Depth Light coming from the left side brings out all details and structures sharply and recognizably. The pronounced fore-, middle-, and background contributes to the illusion of depth, as do the good distribution of contrasts, the many overlappings, the eye-level perspective, and the texture gradient. Strong Lines and Picture Format A variety of opposing linear elements are at work in the composition of this picture. Contrasts between the diagonal and the counterdiagonal, between the vertical and the horizontal, or between the right acute angle and the arches contribute a dynamic feeling to the picture. The eye is led to Big Ben, which is situated at the golden section. In order to fill the format pleasingly with the bridge and the Buildings of Parliament, the horizontal format was selected.

3

Eye-Level Perspective

Fore-, Middle-, Background

73

If a diagonal is tilted steeply, it becomes a vertical. A vertical suggests striving force, firmness and vitality. When several verticals located at different distances from the camera overlap, care must be taken so that they do not seem like extensions of each other. An annoying example is the tree or telephone pole that often appears to grow out of a person's head. Picture Analysis Figure-Ground and Contrasts In this photograph, the figure-ground rela-

74

tionship is ambiguous. The pedestrians, the lamp post, or the bus could be regarded as the figure. All of them are in a plane determined by sharpness and contrast. The distribution of contrasts is divided into equal thirds in the light, medium, and dark tones. Informational Value and Similarity The corner of Fifth Avenue and 50th Street in Manhattan is a busy crossing in New York City. There is similarity among the repetitive verticals, diagonals, and rectangles. Illumination and Depth Oncoming side lighting nicely segregates contours and forms from each other and contributes depth to the picture by silhouette effects and aerial perspective. Strong Lines and Picture Format The contrast distribution and the strong lines are dominated by verticals. The diagonal and counter-diagonal of the concrete canyon and the street converge at the center of perspective and accentuate the illusion of depth. The flag at the upper left is particularly important. It closes off the wedge of sky, which would otherwise lead out of the picture. The vertical format is intended to heighten the impact of the deep canyon formed by the tall buildings.

CounterDiagonals

When a vertical tilts to the left, it becomes a counter-diagonal. Most people from Western cultures associate a feeling of falling or descending with counter-diagonals. Orientals, being accustomed to a different direction of reading and writing, may interpret the counterdiagonal as positive. Picture Analysis Figure-Ground and Contrasts The three washerwomen stand out well as the figure from the ground. Dark and medium

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Side Lighting

tones predominate in the contrasts. Only a few bright spots enliven the picture. Informational Value and Similarity Three women do their laundry on the banks of the Douro at Porto in northern Portugal. Similarity can be found among the women, the pieces of laundry, and between the pan and the large loop in the lower right corner. There is continuity in the activities of the washerwomen. Illumination and Depth Light coming from the upper right assures good separation of the figure from the ground, and it also provides crisp reproduction of picture details. Bird's eye view and shadows are responsible for the depth effect in this photograph. Strong Lines and Picture Format The counter-diagonal that runs through the entire subject would slice the picture in half if the dividing line were not bridged by the washerwomen. The white line along the upper embankment forms a triangle with the counterdiagonal that points at the center of interest, the standing woman. In addition to the real triangles in this picture, there are also several "optical" triangles, for instance: pan, standing woman, and iron loop; pan, round bundle of white laundry at the edge of the pier, and white towel with chunk of soap. The linear configuration of this picture demanded a vertical format.

Bird's Eye View

Horizontals

•

The convergence of a horizontal and a vertical line form a right angle. While the horizontal seems static and tranquil, the vertical is arousing and dynamic. Therefore these two directions are contrary to each other in character and pictorial effect. In a right angle, both forces become effective - those of the horizontal as well as those of the vertical. That is why it has a partially static and partially dynamic significance. This is illustrated by the accompanying photograph. While the lower portion of the woman's body is in a restful position, her upper half rises vivaciously.

FigureGround

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Picture Analysis Figure-Ground and Contrast The contrasts created by the illumination provide a good separation of figure from ground. The distribution of tonal ranges is approximately one-quarter light, one-quarter medium, and one-half dark. Informational Value and Similarity In this rear view of a female nude with side lighting, there are repetitions of horizontal, vertical, and diagonal lines, and of some highlights. Illumination and Depth The body's shapes are pleasingly modeled by the side lighting, and they stand out well from the dark background because of the distribution of light and shadow. The contrast between light and dark enhances the modelling effect, because the light shapes stand out, while the dark ones recede. Strong Lines and Picture Format Right angles certainly do not always have to seem harsh and edgy. Aside from the recognizable horizontals and verticals in this illustration, there is also a wealth of flowing lines and curves. The nicely formed back line is repeated in the structures of the rock in the background. As a contrast to these curves there are several triangles formed by the body's contours. The horizontal format is most appropriate for this nude as it fills the entire frame.

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The arch, a symmetrical figure, consists of a continuous, uniformly curved line. An arch usually suggests a connection, like the arches of a bridge connecting the two banks of a river. Picture Analysis Figure-Ground and Contrasts In spite of the dominating silhouette of the arch in the foreground, the building complex in the background is the figure. It contrasts well with the foreground and moderately with the light sky. Medium and dark tone values predominate

Worm's Eye View

in the distribution of contrasts. Informational Value and Similarity The modern City Hall of Toronto was designed by the Finnish architect Viljo Revell. The two curved administration buildings rise from the flat foundation around the lens-shaped assembly hall. The reflection of the tall buildings in the pond loosens up that large area. The pattern of arches is repeated three times: in the concrete arches in the foreground; in the dome of the assembly hall; and in the two curved skyscrapers. Verticals are repeated in the buildings and in the flagpole, horizontals in the far side of the pond and in the platform atop the foundation. Illumination and Depth The illusion of depth is produced primarily by the contrast between objects. Diffuse light coming from the left, the silhouette effect, overlapping elements, the worm's eye view, and the division into fore-, middle-, and background reinforce the feeling of depth. Strong Lines and Picture Format Nearly all vertical and horizontal lines and arches lead to the assembly hall situated at the golden section, where it forms the center of interest. Verticals create a good contrast of forms with the static horizontals, thus counterbalancing their effect. The square format is preferable for rendering the arches and skyscrapers.

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Side Lighting

•

Golden Section

Circles

The circle is a closed and complete basic shape. Its center is equidistant from any point on its circumference. It conveys a sense of protective cover. If it is stretched into an oval, it loses its central severity and unity. In an oval, either the horizontal or the vertical aspect predominates; therefore it can have a static and passive effect, or a striving and active one.

Picture Analysis Figure-Ground and Contrasts This subject has an ambiguous figure-ground relationship. To many observers, the three small reproductions at the bottom of this page appear convex (raised), yet they see the larger picture on the page to the right as concave (deep). After prolonged viewing, those impressions may even reverse themselves. Contrast distribution is divided approximately evenly among light, medium, and dark tones. Informational Value and Similarity This picture of a staircase in an office building has a large amount of redundancy. Circles, ovals, squares, and triangles are repeated frequently. Illumination and Depth The subject is illuminated by diffuse daylight coming from the right. The bird's eye view makes the circles appear smaller the further away they are, thus giving the flat character of the geometric shapes and patterns an effect of depth. Strong Lines and Picture Format The subject includes a multitude of geometric shapes and patterns. Gentle curves form a contrast with harsh squares, triangles, and rectangles. The nearly square vertical format shows the important elements to their best advantage.

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Symmetry

Symmetry results from the repetition of identical picture elements by line-ups, rotation, or mirror images. Symmetrical reproductions are severe, clear, peaceful, and easily comprehended. For that reason, they may occasionally seem dull. Picture Analysis Figure-Ground and Contrasts Because of the line-up and frequent repetition of similar picture elements, this subject has an ambiguous figure-ground relationship. The path is the figure, everything else the ground.

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Contrasts

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Medium and dark tones are predominant in the contrast distribution. Informational Value and Similarity The photograph shows a path in the park of Charlottenburg Castle in Berlin. The nearly mirror-image symmetry of the two rows of trees produces a repetition of the subject to the right and left of an imaginary vertical axis. Illumination and Depth Hazy autumn light evenly illuminates the scene, creating no accents. Only the contrasts of objects produces a differentiation between individual picture elements. An effect of depth is achieved by the eye-level perspective, by the texture gradient, and by overlapping elements. The impression of symmetry would be perfect if the light sky above the path were covered by more branches, forming the same gray tones of the surroundings. Instead, there is rivalry between the two brightest areas in the picture: the four windows in the center, and the white opening towards the sky. Strong Lines and Picture Format Severe diagonals, counter-diagonals, and verticals dominate the picture. The irregularly shaped branches and boughs are perceived more as patterns than details, and they form a contrast to the strong lines. The impression of symmetry is strengthened by the horizontal format of this photograph.

3

Eye-Level Perspective

Photo: Dieter Schultz

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Golden Section

Creating a pictorial composition with an arrangement less severe than outright symmetry calls for asymmetry. The latter appears lively, harmonious, and casually arranged. A form of balanced asymmetry used especially often in picture composition is the principle of the golden section. The center of interest, the important picture element, is placed at a distance of about one-third of the height or width from the picture's vertical or horizontal edge. (A more precise definition is not necessary for our purposes.)

Worm's E y e View

Picture Analysis Figure-Ground and Contrasts The relatively small image of the woman with a basket stands out clearly as the figure from the ground. Contrast distribution is about an even third each of light, medium, and dark tones. Informational Value and Similarity A woman, carrying a basket on her head, ascends a staircase. There is similarity in the contrast and in the shapes of the two walls. The two dynamic triangles formed by these walls in turn contrast with the often repeated, nearly horizontal, static steps. Illumination and Depth Sunlight is nearly vertical. Thus the illusion of depth is generated less by the illumination than by the contrast between surfaces, the strong lines, and the texture gradient. The two dark walls form a canyon that rises along the medium tones of the stairs. Striving for the light area of the sky, the contrasting dark form of the woman approaches the top of the stairs. Strong Lines and Picture Format The dark shadow of the left wall, aided by the shadow of the lamppost cast on the stairs, and the guiding lines formed by the railing, lead the eyes towards the golden section, to the woman on the stairs. To accentuate the steepness and height of the stairs, the vertical format was chosen.

Texture Gradient

•

Total Sharpness

Total sharpness, extending over the entire depth of the photograph, has a definite influence on the effect of the picture. It is informative and straightforward, but it can also be cold and sterile. Its conscious use depends on the intended effect of the picture. Subjects whose pictorial content are designed to demonstrate or convey information about technical and scientific equipment virtually demand total sharpness. But that does not preclude the use of total sharpness to suggest a certain mood, such as that of the crisp, clear winter scene shown on the next page.

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Contrasts

8

Back Lighting

3

Eye-Level Perspective

Picture Analysis Figure-Ground and Contrasts The figure-ground relationship in this picture is not clear. If any, the trees in the left and right foreground might be regarded as the figure, and the rest of the subject as ground. This impression is reinforced by the contrast formed by these trees and their surroundings. Informational Value and Similarity This winter landscape was photographed against the light on a frosty and sunny day in the Dolomites. Total sharpness emphasizes the biting cold feeling suggested by this wintry subject. Similarity and repetition are provided by the ice-covered trees. Illumination and Depth Oncoming light creates the bright fringes around the contours of the evergreen on the left and the deciduous tree on the right, making them stand out from the rest of the scene. As through a portal, they lead the eyes towards the woods in the middle ground. In addition to the path leading up to those woods, oncoming light, the silhouettes in the foreground, and the aerial perspective in the upper right contribute towards the impression of depth. Strong Lines and Picture Format Although verticals formed by contrasts dominate the scene, it is the diagonal of the winding path that gives this photograph the impression of depth and which leads the eyes to the area of the golden section. The most effective cropping is that of a nearly square rectangle.

Fore-, Middle-. Background

Verticals

•

89

Picture Analysis

The human eye can only see an angle of about 11/2 degrees at maximum sharpness. It is only because our eyes are constantly scanning our surroundings that we gain the overall impression of sharpness. Since we cannot see our environment sharply to its full extent with a single glance, it is understandable that a photograph with selective focus can also be attractive. By preferential reproduction of the important picture element, selective focus makes the latter stand out as the figure from its natural surroundings, the ground.

FigureGround

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Figure-Ground and Contrasts The contrast and sharpness of the light statue very effectively lift it from the ground of medium tones that surround it. Informational Value and Similarity The bust of Claudius Cesar is part of a row of personalities from world history that lines the garden side of Charlottenburg Castle in Berlin. Similarity can be found in the pose and material of the busts, as well as in the shape of the pedestals. Illumination and Depth Light entering from the upper left creates a good separation of the statues from the façade of the castle. The photograph was taken with a 500 mm telephoto lens, which gives the impression that the statues are shoulder-to-shoulder, even though they are actually about 33 feet apart. The long focal length foreshortens the depth on one hand, and enhances the effect of selective focus on the other. Because of the unsharp images of the statue in the foreground and those in the background, the one of Claudius Cesar stands out clearly because of its sharpness. Strong Lines and Picture Format Verticals, although not quite straight, predominate in this picture. Formed by the heads, a counter-diagonal leads towards the center of perspective at the lower right edge of the picture. The tops of the pedestals form a weak horizontal. The vertical format is best suited to convey this subject.

CounterDiagonals

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Blurred Motion

Unlike motion pictures, still pictures cannot reproduce movement directly. But two simple technical tricks can convey the impression of motion in a photograph. The first is to use a shutter speed that is too slow to freeze the action, thus yielding a blurred object in front of a sharp background. The other is to pan the camera along with the object in the direction of its motion, creating a sharp object in front of a blurred background. The safest method of capturing the optimum picture is to make a series of exposures with different shutter speeds.

Picture Analysis Figure-Ground and Contrasts Because of motion blur and tonal contrast, the cartwheeling acrobat stands out well from the dark background. Contrasts are distributed evenly by a third each of light, medium, and dark tones. Informational Value and Similarity The Hassani troupe of Moroccan acrobats demonstrates its whirlwind feats at a performance of the Hagenbeck Circus in Berlin. The impression that the acrobat in the foreground is actually moving is further enhanced by the intent observation of his partners in the background. There is similarity in the costumes and in the postures of the troupe. Illumination and Depth Because the performing member is highlighted by the spotlight, the others that are waiting behind him seem to recede even further into the background. A clear separation of fore-, middle-, and background is created by the distribution of contrasts. This contributes to the impression of depth in the photograph. Strong Lines and Picture Format Verticals predominate in this picture. The cartwheeling acrobat is at the golden section, thus attracting immediate attention. The effective vertical format was cropped from the original horizontal photograph. Photo: Peter Adler

Fore-, Middle-, Background

The cropping of a well-composed subject should begin with the making of the original photograph by choosing an appropriate focal length and a suitable subject distance. Basically, there are two picture formats available to us: the rectangle and the square. The square has the advantage over the rectangle in that it can subsequently be cropped into a vertical or a horizontal format. As an abstract geometric form with identical sides, the square lacks tension; it seems static. But as soon as its area is filled with a pictorial composition, the latter will influence the character of the square. Picture content and format have direct effects on each other. Picture Analysis Figure-Ground and Contrasts The persons walking towards the left and the seated woman constitute the figure in this pho-

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Side Lighting

tograph. The silhouette of the couple walking towards the right merely represents the foreground. Contrasts are distributed evenly as one-third each in the light, medium, and dark tones. Informational Value and Similarity Taken at the Swiss EXPO in Lausanne, this photograph shows visitors in front of the "Alert Switzerland" pavilion. This motif could hardly be visualized better than by the pointed, repelling, tank-obstacle-like concrete pyramids. Similarity can be found in the persons and in the constantly repeated pyramids. Illumination and Depth Side lighting from the upper left effectively models each of the many pyramids. The light ground allows the persons to stand out clearly. The deep shadows and the silhouettes in the foreground strengthen the effect of depth. Strong Lines and Picture Format The lighting creates a large number of aggressive triangles on the pyramids. However this effect is attenuated by the calm, nearly horizontal line that runs across the bottom quarter of the photograph, and by the weak diagonal formed by the shadow in the foreground. As demonstrated by the smaller pictures below, a vertical or a horizontal cropping very definitely influences the directional trend of the photograph. While the vertical format makes the subject appear very tall, a horizontal cropping makes it seem disproportionately long. Only the square framing of the photograph correctly conveys the original visual impression.

Fore-, Middle-, Background

across the direction of the format reduce the effect of that format. An elongated cropping radiates tranquility and wide open spaces.

Horizontal Format

By elongating the horizontal lines of a square it becomes a horizontal rectangle. The latter has a much more viable shape compared to the placid, equilateral square. Adapting the format to the content of the picture significantly enhances the impact of that picture. A horizontally oriented subject is strengthened considerably in its implied or visible directional trend by an extreme horizontal cropping. The greater the difference between the width and the height of the format, the more attention will be drawn by that picture. Lines and forms that run

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Back Lighting

Picture Analysis Figure-Ground and Contrasts The two dromedaries stand out clearly as the figure from the lighter ground. Medium and dark tones predominate in this picture. The lightest area of the photograph is located directly across from the darker of the two animals. Not only does this increase the effect of contrast, it also leads the eyes towards the center of interest. Informational Value and Similarity Two dromedaries wander across the Moroccan Sahara shortly before sundown. Similarity and repetition can be detected in the two animals as well as in the silhouettes of the two mountains. Illumination and Depth The late evening light - shining at the camera reproduces the objects as silhouettes with hardly any shadow detail. The dromedaries stand out very well from the desert and the sky, thus contributing to the feeling of depth. Strong Lines and Picture Format Other than the undulating lines of the horizon, the only other line pattern is that of the two animals, which are vertical. In viewing this scene, the extended horizontal format, aided by the direction of the animals' motion, suggests a feeling of wide open spaces.

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Horizontals

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Vertical Format •

The rectangle is the most commonly used picture format. Depending on the subject, it can be used either vertically or horizontally. In the vertical position, it conveys an impression of strength and activity, as compared to the tranquil and spacious mood of the horizontal format. The more extreme the proportions of the rectangle, the more pronounced will be these impressions.

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Picture Analysis Figure-Ground and Contrasts The silhouette of the walking woman stands out well as the figure from the ground. Contrasts are divided approximately evenly in onethird each of light, medium, and dark tones. Informational Value and Similarity The photograph shows a fisherwoman in Nazaré, Portugal, who manages to walk gracefully towards the village fountain while carrying a large jar on her head and a wooden bucket on her arm. There is similarity in the rounded shapes of the head and the jar. A repetition of lines occurs in the legs and in the right arm. Illumination and Depth Side lighting coming from the right brings out the details and contributes to the impression of depth. Strong Lines and Picture Format The subject forms a triangle pointing upwards, and the round jar at its apex creates a counterpoint. The jar also provides a contrast of shapes with the straight contours of the triangles. The erect posture of the walking woman is accentuated by the narrow vertical format.

Seeing and Composing in Color

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Most persons sense color rather than consciously perceiving it. That is true for both lay people as well as for so-called professionals, who are involved with colors in their jobs. All sorts of subjects are taught to children in schools, even singing and gymnastics; but seeing, especially seeing color, is neglected, and not just in schools for general education. Even institutes for higher education in the arts offer little in the way of objective, scientifically based color instruction; handed-down, antiquated, and subjective concepts seem to prevail. We can only perceive color in the presence of light. But what exactly is color? It is a very narrow portion of the very broad spectrum of electro-magnetic waves. This spectrum extends from the shortest waves, the gamma rays of merely 1/1,000,000 nanometers, to the longest waves such as alternating currents with wavelengths of several kilometers. Within that huge range lies the narrow band that is visible to the human eye. The visible spectrum covers wavelengths from 400 to 700 nm (1 nm = 1 nanometer, which is one millionth of a millimeter; 1 millimeter = 0.03937 inches). Light is transmitted both in the form of vibrating waves radiating in all directions as well as in the form of minute (corpuscular) energy particles called light quanta or photons. The very fact that we can perceive light is due to the nature of our seeing organs and our 102

Infrared

6

Gamma Rays Cosmic Rays The wavelength spectrum of electro-magnetic radiation.

brains, which are equipped as special receptors for this purpose. In the sequence of steps that constitute the seeing process, the radiation energy of light first produces a physicalchemical stimulus on the retinas of our eyes. This is converted into a physiological excitation that is transmitted to the brain in the form of coded electrical signal impulses. There the latter are compared with past and present stimuli and associations in the process of being transformed into psychological impressions. The eye can sense light as direct radiation, like sunlight. When light strikes an object, it is partially absorbed, partially broken up and scattered. But only the reflected portion of the originally colorless light is perceived by the brain as the color of the object. Sunlight - as in median daylight - can be considered as white light because it has a spec-

When white light, which contains all colors, strikes a blue object, only the blue component is reflected while all other colors are absorbed by the blue color of the object.

Breaking up a beam of white light by means of a prism produces a spectrum of all the colors contained in white light. (Photo: Courtesy Eastman Kodak Company, Rochester, N.Y., U.S.A.)

Left: The illustration shows the Young-Helmholtz color theory, according to which there is a separate type of receptor for each of the blue, green, and red components of light.

Left: The luminous, colorful televison image results from additive color mixing, in which thousands of minute blue, green, and red dots are projected onto the receiver phosphors of the picture tube.

Right: According to the Hering theory of color vision, there are three types of receptors, each of which reacts to two colors: yellow and blue, green and red, and black and white. Whereas the yellow-blue and the green-red receptors function only in the onoff (either-or) mode, and only for one color at a time, the blackwhite receptors are capable of reacting to both colors simultaneously to produce an impression of gray.

trum of evenly distributed energy: all colors of the visible spectrum are present with equal intensities. As far back as 1666, the English physicist Isaac Newton succeeded in dividing daylight into its spectral components by means of a prism. Newton also recognized that objects in nature appear to have a certain color only because they absorb a portion of the impinging radiation, reflecting the remaining wavelengths. The Theory of Color Vision Newton already anticipated the existence of photo receptors (light sensors) in the eye,

Right: Color printing employs the principle of subtractive color mixing. A pattern of different-sized dots, derived from each of three color separations, is applied to the white paper surface separately in each of the three complementary colors yellow, magenta (purple), and cyan (blue-green). This principle is used in both letterpress as well as in offset printing. In the area where the full dots overlap because of the displaced orientation on the individual plates, subtractive color mixing takes effect. In the lighter areas however, where the colored dots are much smaller and not individually resolved by the eyes, a so-called "optical color mixing" takes place, which basically corresponds to additive color mixing.

which react to colors. He interpreted color perception as a process that involves the eyes as well as the brain. But it was not until Thomas Young (1773-1829) and Hermann Helmholtz (1821-1894) that a theory of color vision was founded. According to the Young-Helmholtz theory of color vision, the light-sensitive cones in our retinas are of three separate types, each react103

ing to one of three ranges of the visible spectrum. One type of cone reacts to the shortwave blue range, another to the medium-wave green range, and the third one to the long-wave red range of the spectrum. Other color sensations are created by the stimulation of two color receptors. Yellow, for instance, results from the equal stimulation of the red and green receptors. All other colors are generated by similar means. The intensity of the stimulus of these receptors determines whether the colors appear lighter or darker. A strong, equally distributed stimulus of all three types of receptors creates the impression of white, a weak stimulus of all three receptors results in an impression of gray. Black results from the absence of any stimulus to the receptors. Black can only be perceived in connection with, or after the impression of other colors; its intensity grows with the contrast it forms with its surroundings. But this theory too has weaknesses, as it cannot explain all phenomena associated with color vision. An opponent of this theory, which seemed to be so simple and logical, was the German physicist and physiologist Ewald Hering (1834-1918). In contrast to the above theory, he proceeded on the following assumption: while we do register colors with only three types of receptors, the latter cannot themselves perceive colors directly. Nor are they connected directly with the brain; instead they convey their perceptions to the brain via three so-called color coders, which can only distinguish pairs of complementary colors. A color coder is capable of transmitting the stimulus of a color only by the on/off method. Only the black-white coder can transmit black and white signals simultaneously, creating the sensation of gray. The perception of colors: Based on the assumption that we are equipped with three types of color receptors, each sensitive to one-third of the visible spectrum, different colors are created by stimulating various combinations of these three receptors, as follows: White: all three types of receptors; Yellow: the green and the red receptors; Cyan: the blue and the green receptors; Magenta: the blue and the red receptors; Red: the red receptors; Green: the green receptors; Blue: the blue receptors; Black: none of the receptors.

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But this theory too cannot be accepted without reservations. Even though the color coder thesis is supported by the phenomenon of subsequent contrast described on page 112, it does not explain many other problems, such as the question why color coders function in the on/off mode and black/white coders do not. To this day there is still no agreement as to which theory is correct. Recent research appears to support the assumption that color vision takes place according to a partial combination of both theories. The Young-Helmholtz theory seems to offer the more plausible explanation. In any case, a convincing technical analogy can be found in the working principle of color television. The luminous color television image results from thousands of blue, green, and red light beams that are projected on the receiving phosphors on the inside surface of the television set's picture tube. Additive Color Mixing Let us leave the general theoretical controversy to its own devices and instead pose a concrete question that can be verified by anyone. Is it really true that the multitude of colors in our surroundings can be composed by mixing just three primary colors? This can be proven by a simple experiment. Using three slide projectors with equal light intensity, a blue, a green, and a red slide are projected on a white surface in a darkened room as shown in the illustration on the next page. If we overlap, or add, three light beams, each in one of the so-called additive primary colors blue, green, and red, the beams will intersect to produce three lighter mixed colors as follows: blue and green produce cyan, green and red yield yellow, and red and blue produce magenta. The area intersected by all three beams will be white. This proves that white light is made up of the three additive primary colors blue, green, and red, and that a combination of two of the additive primary colors produces a subtractive primary color. All other color hues can be generated by mixing the three additive primary colors in different proportions. Black results when no light at all is projected on the screen.

Gray results when all three additive primary colors are projected with low intensities. Since additive color mixing is based on the projection of colored light, in practice it can only be used in color television. Color photography and color printing use subtractive color mixing exclusively. Subtractive Color Mixing As the title implies, this involves the subtraction or removal of certain colors from white light or white reflecting surfaces. This principle too can best be demonstrated by an experiment. On a white illuminated surface (such as a lightbox), place three filters, one each of the colors yellow, magenta, and cyan, as shown in the illustration on the next page. The darker colors red, blue, and green are produced in those areas where the filters intersect, subtracting their respective colors from the white; in this way red is produced from yellow and magenta, blue from magenta and cyan, and green from cyan and yellow. Where all three filters overlap all colors are subtracted, leaving black. The areas that were not covered by any filter at all remain white. Gray will result when filters with less density are used. Upon closer inspection we recognize that the resulting darker mixed colors blue, green, and red are identical to the additive primary colors. All other hues of color can be produced by using filters of different densities in the subtractive primary colors. Since a color print is based on a white reflective surface, and a transparency on a clear surface, only subtractive color mixing can be utilized in color photography. That means that colors are subtracted from the white or transparent image carrier by the filter action of the color dyes in the image. Complementary Colors In additive color mixing, starting with colorless black, all other hues of colors can be produced by mixing varying amounts of light in the three primary colors of blue, green, and red (the principle of color television). Mixing equal amounts of the three basic additive colors yields colorless white. Mixing only two additive primary colors produces a subtractive primary 105

Left: Additive color mixing. Top: Overlapping projection of the colors blue and green produces cyan; similarly, green and red produce yellow; red and blue result in magenta, while blue, green, and red add up to white. Bottom: Individual projectors cast blue, green, and red light on the screen. Right: Subtractive color mixing. Top: By placing yellow and magenta filters on top of each other, red is formed; overlapping magenta and cyan filters produce blue; and cyan and yellow filters combined will yield green. In the area where all three filters overlap, all colors are absorbed, resulting in black. Bottom: Three filters, one each for the colors yellow, magenta, and cyan, are placed in the white light beam of a projector.

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color. If an additive primary color is mixed with a subtractive primary color that consists of the other two additive primary colors, they will combine into white. That supplementary color is called a complementary color. The three additive primary colors are also the complementary colors for the respective subtractive primary colors, and vice-versa, when properly combined. In additive color mixing, colored light rays that supplement each other to create white light are designated as complementary.

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The complementary color for blue is yellow. Yellow results from adding red and green. Therefore blue complements it to form white. The complementary color for green is magenta. Magenta is created by adding red and blue. Therefore green complements it to form white. The complementary color for red is cyan. Cyan results from adding blue and green. Therefore red complements it to form white. In subtractive color mixing, all color hues of the visible spectrum can be created from colorless white by mixing transparent color dyes (pigments) in the three subtractive primary colors yellow, magenta, and cyan. Combining all three

Left: Complementary colors for the additive primary colors. Right: Complementary colors for the subtractive primary colors.

subtractive primary colors yields colorless black (the principle of color photography and color printing). If a subtractive primary color is mixed subtractively with an additive primary color from the remaining third of the spectrum, they combine to form black. In subtractive color mixing, transparent color dyes (pigments) that supplement each other to form black are designated complementary. The complementary color for yellow is blue. Subtractively produced blue consists of cyan and magenta. Therefore yellow complements it to form black. The complementary color for magenta is 107

Color Theory at a Glance The relationship between the visible color spectrum, additive color mixing, and the subtractive primary colors is clearly demonstrated in the accompanying illustrations showing the phases in the creation of a ring-shaped color spectrum.

Phase 1 A white truncated hollow cone is placed on a white surface in a darkened room. This hollow cone is first illuminated by a spotlight with a filter of the additive primary color blue.

Phase 2 The same cone is now illuminated by another spotlight with a filter of the additive primary color green, except that the new spotlight is displaced by 120° from the first one.

Phase 3 A third spotlight is now used to illuminate that hollow cone through a filter of the additive primary color red, but displaced by another 120° from the second spotlight. Figures 1, 2, and 3 show the cone illuminated by each monochromatic light source as described above, with shadows of the same respective color.

Phase 4 When two additive primary colors are projected on the hollow cone simultaneously, for instance blue and green, a partial spectrum of blue-cyan-green is formed on the outer surface of the cone. At the same time, elliptical patches of the additive primary colors are formed on the bottom surface inside the cone. The outside shadows cast by the cone will also be of the additive primary colors blue and green.

Phase 5 The same procedure is repeated with the additive primary colors green and red. A partial spectrum of green-yellow-red is formed on the exterior surface of the hollow cone, while on the interior bottom surface elliptical patches of the additive primary colors red and green appear.

Phase 6 Now the procedure is repeated with the additive primary colors red and blue.

Phase 7 When all three additive primary colors blue, green, and red are projected on the hollow cone simultaneously, a perfect circular spectrum is created on the outer surface of the cone. Elliptical patches of the additive primary colors blue, green, and red appear on the inside bottom surface of the cone. These patches are clearly separated by dark areas that are not illuminated by any of the three colored light beams. On the outside bottom surface, crescent-shapes of the subtractive primary colors yellow, magenta, and cyan appear opposite their corresponding additive primary colors on the near inside of the hollow cone. Figure 7 contains the entire color theory at a glance.

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green. Subtractively produced green consists of cyan and yellow. Therefore magenta complements it to form black. The complementary color for cyan is red. Subtractively produced red consists of yellow and magenta. Therefore cyan complements it to form black. The Definition of Colors In dealing with the entire complex subject of colors, the greatest difficulty is the precise, unmistakeable designation of different color hues. There is hardly another segment of science with such a chaotic multiplicity of names. Artists, fashion designers, graphic designers, physicists, color photographers, to name only a few - all have different ways of naming the very same color. Advertising people consider this an opportunity, and they create wondrous, exoticsounding names for certain colors. What really

is the color of your Bahia-blue automobile? This confusing multiplicity of names can be attributed to a deficiency in our language, which provides only six names for different colors with which to describe the more than 100,000 individually distinguishable shades of colors. As an example, let us divide the circular spectrum into twelve separated segments. For practical considerations, we will limit ourselves to twelve colors. Six of these colors have already been named: the additive primary colors blue, green, and red, and the subtractive primary colors yellow, magenta, and cyan. The six middle tones that result from a mixture of equal amounts of adjacent additive and subtractive primary colors are named according to the principle used in defining intermediate directions on a compass: blue-cyan, cyangreen, green-yellow, yellow-red, red-magenta, and magenta-blue.

Left: The color hexagon with the three additive and the three subtractive primary colors is arranged so that opposing colors are complementary. Right: This circle was expanded into twelve colors. Six additional hues were obtained by mixing equal amounts of the adjacent primary colors shown in the hexagon on the left illustration. Opposing colors in the new figure are also complementary.

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Color Temperature Physically white light has a color temperature of 5000 Kelvin. Color temperature such as that of temperature radiating bodies like the sun or an incandescent bulb is measured in degrees Kelvin, whose scale begins with absolute zero at minus 273 Celsius. The concept of color temperature covers both the visual appearance of a color hue being radiated as well as the temperature in degrees Kelvin to which the so-called "black body" must be heated in order to emit light of that same hue. The Classification of Color Sensations Basically, we perceive three different aspects of color:

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1. The hue of the color 2. The brightness of the color 3. The saturation of the color 1. Color hue is the most distinctive property that we perceive in energy radiated by a light source, or in wavelengths reflected by an object. The duration of the stimulus is a determining factor in the perception of a color hue. The light stimulus must be longer than a specific threshold of duration in order to produce a sensation of color; if it is too short, it will merely produce a sensation of brightness.

From top to bottom: Spectral energy distribution of light sources with color temperatures of 3200 Kelvin and 5500 Kelvin. The T at the end of the curve designates daylight, and the K incandescent (tungsten) light. Spectral energy distribution of a fluorescent light source (neon tube) with a non-continuous color spectrum. Color temperatures of sunlight at different times of the day.

The Color of Light Precise determination of color is possible only under white light. White light contains all spectral ranges and therefore lets colors appear neutral. If the 110

2. Color brightness is the descriptor for the manner in which a color appears to us, whether it is lighter or darker, whether it is closer to white or to black. Perception of color brightness is determined mainly by the intensity of the stimulus and by the unequal sensitivity of the retina to radiation of different wavelengths. That is why yellow appears to us to be brighter than blue. 3. Color saturation is the measure of purity of a color. A fully saturated color is free from any additive; it is neither bleached nor blackened.

The saturation of a color is influenced by the length of observation. A prolonged stimulus reduces the saturation; excessive or insufficient intensity erases the saturation. The Systematic Nomenclature of Colors So-called color systems for the precise statement of color descriptions and color definitions have been proposed as early as 1593 by Giambattista della Porta. The three determining criteria for color perception, color hue, color brightness, and color saturation, were already known. The relationships and connections between these three factors could be adequately demonstrated only by means of a threedimensional body. Therefore, all that was needed was a practical and easy-to-understand color system. The inventiveness and accumulated knowledge of generations of artists, scientists and users of colors over the years has produced no less than three dozen of the most abstruse and complicated color systems. For practical purposes, the most useful color system was devised by the American painter Albert Henry Munsell (1859-1918). Munsell arranged his color system in the form of a spherical "color tree". An eleven-step gray scale is arranged along a colorless vertical axis, or the trunk. Individual spectral colors, or color hues, are spread out on twenty branches arranged radially around that trunk. Color brightness of each hue increases vertically from bottom to top. Color saturation increases horizontally from the center, or the trunk, towards the outside, or the periphery. Thus it is possible to define a specific color hue exactly by its relationship to the others. A system of numbers permits each color hue to be determined by its place and location. The color triangle published by the International Illumination Committee in 1931 is not nearly as clear, nor as easy to understand. Since its use requires complicated calculations, it appears to have been devised exclusively for mathematicians and physicists.

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By means of a three-dimensional body, the Munsell "Color Tree" permits the qualitative analysis of colors with respect to their hue, saturation, and brightness. In Munsell terminology, the latter are called "hue, chroma, and value".

lates them to their multicolored environment, and this relationship can significantly alter the appearance of the colors. Thus we never perceive colors as abstract or isolated, independent and plane phenomena; instead we become conscious of them as influenced and altered by their relationships, strengthened or weakened by contrasts. The perception of contrasts for the classification and rapid clarification of what is being seen is one of the most significant characteristics of our sense of sight. Color contrasts can be classified in eight categories: 1. 2. 3. 4. 5. 6. 7. 8.

Simultaneous Contrast Successive Contrast Quality Contrast Complementary Contrast Color Hue Contrast Light-Dark Contrast Cold-Warm Contrast Quantity Contrast

Color Contrasts The perception of objects around us is not a simple, but a very complex process. It involves not only the recognition of colors and shapes of individual objects, it also simultaneously re111

1. Simultaneous contrast is perceived most clearly when two color hues are compared with a neutral gray. The gray patch in one hue will take on a slight tint from the other one.

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2. Successive contrast is perceived when one observes a picture for a prolonged time (at least 20 to 30 seconds) without interruption, then immediately looks at a white surface. A negative image of the original picture will appear in its complementary colors.

Color Harmonies The influence of contrast phenomena on colors depends on their quantitative and qualitative relations to each other. Therefore, perceptions gained from reactions to color contrasts are important to the composition of color harmonies. If a color picture is to appear harmonious and balanced, its colors have to be arranged in a meaningful manner according to similarity and contrast. Otherwise the natural rhythm of perception is disturbed, and the color picture appears as too gaudy or too garish. A picture with too many colors should be attenuated by using neutral color hues, or be compensated by employing an additional, even stronger contrast with colorless hues such as black and white. The eye always searches for order and harmony. The perception of harmony appears to occur when all hues in a color composition add up to a medium gray value. This sounds like a paradox, especially in the evaluation of colors. But the phenomenon of successive contrast can be considered as a confirmation of that statement. Upon prolonged viewing, every hue, including black and white, produces an afterimage of its respective complementary color. Only medium gray remains medium gray. In relation to colors, the terms "color harmonies" and "harmonious" have various meanings: they may denote related colors as well as contrasting colors. There are five main rules for color harmony: 1. Utilize as few different color hues as possible;

3. Quality contrast represents the relationship and effects between different shades of the same color hue.

2. When several color hues are used, either select related colors that are nearby on the color ring, or 3. Choose a composition with complementary colors.

4. Complementary contrast shows how the side-by-side positioning of two surfaces with complementary colors increases the perceived color effect of both surfaces. 112

4. A high color brightness should be used together with a low color brightness, with the high-brightness surface being offset by a three to four times greater surface of low brightness. 5. An area with high color saturation should be compensated by an area with lower color saturation. Here, too, the relationship in sizes could be 1:3 or 1:4. The Subjective Response to Colors Color creates an apparent change in the size of a shape. Of two identical surfaces, one with a dark color, the other with a light color, the lighter one will appear the larger of the two. This impression is created by the fact that the brightness from the light surfaces or objects seems to spill over into the adjacent darker areas, thus making them appear larger. Colors also affect our impression of weight. Among objects of identical size, the darker ones will seem heavier than the light ones. The impression of space is also significantly affected by colors. Light-colored surfaces or objects will appear closer to an observer while dark ones seem further away than they really are. If, for instance, a slide with distinct red and blue areas is projected on a screen, the red areas seem to approach the observer, while the blue ones seem to recede. Another sense that is affected by colors is that of temperature. A room painted in cool colors like blue or green will more likely make us feel cold than one painted in warm colors like red or orange. A series of experiments has shown that test persons had the illusion of a temperature difference of an average of 2° to 3° Celsius.

5. Color hue contrast effects a substantial enhancement of our impression of color when all three subtractive primary colors or similar strong colors are used simultaneously in the same picture.

6. Light-dark contrast represents the maximum polarization between two color hues with respect to their visual brightness.

7. Cold-warm contrast denotes the greatest polarity between two color hues relative to their psychological effect, i. e. cold or warm.

8. Quantity contrast refers to the relationship between two adjacent disproportionate areas of strongly contrasting colors. 113

In a comparison of two circular areas of equal diameters, their sizes will appear different when one is dark and the other light. Because of irradiation, the light circle in a dark field will appear larger than the dark circle in a light field.

Color Permanence Colors, once perceived, are immediately associated and compared with those stored in our memory of earlier visual experiences. Thus we know that grass is green, blood is red, and paper is white. The phenomenon of color permanence results in our perceiving the color of an object as relatively unchanged even when the illumination has changed. Even when the color hue is objectively changed by replacing daylight with incandescent illumination, we still perceive the page of a book as being white. The same applies to the remaining colors under similar changes of illumination. Our perception appears to remove the overall color cast by means of a filter effect controlled by our brain. This again demonstrates that our perception combines a number of sensations into a single impression in order to help us recognize things and to help us orient ourselves in our surroundings. The Psychology of Colors The effect of colors on our emotions changes from person to person. It depends to a large extent on cultural background, education, age, sex, and on currently prevailing opinions. On the one hand, the emotional effect of colors is affected by very definite individual notions that are related to earlier experiences. On the other hand it is also based on color symbolism handed down over the centuries. Throughout all Western cultures, for instance, black is regarded as the color of mourning, while in India and in China that emotion is symbolized by white. In the past, colors had a much more 114

definite meaning and social significance than today. In Europe, crimson was reserved for the ruling class, and the clergy preferred violet. In the middle ages, prostitutes in Germany had to wear yellow clothes for identification, while at the same time yellow was the color for emperors in China. Because of our education and our conditioning, certain colors have a specific effect on us. We would never touch the red hot heating coils of a sun lamp with our fingers. The glowing red immediately and instinctively signals caution, danger. The same reaction occurs when we see red blood on the white shirt of an accident victim. Under such circumstances, based on prior experience, we automatically associate red with caution and danger. That is why red and green were chosen as international symbols in traffic signals. Periodic tests with human volunteers of various ages have shown that the preference for certain colors changes with the stages of the person's life. The very same persons preferred different colors when they were children of up to 12 years of age than they did when they were adolescents of up to 18 years of age, and that preference changed again at an age over 35. Today some psychologists even believe that they can derive conclusions about a person's character from the choice of colors of that person's clothes or from the person's preferred combination of colors. However, a considerable amount of skepticism is appropriate, because those conclusions rely too much on assumptions and hearsay. There are still no objective measuring techniques to verify these theories. All the important aspects of seeing and perceiving color have now been discussed. How then does picture composition in color differ from that in black-and-white? The most significant difference is the greater information content of a color picture as compared with one in black-and-white. Color pictures differentiate, intensify, define and specify to a far greater degree than is possible in black-and-white. A color picture appears considerably more realistic and it appeals to our emotions, whereas the more abstract blackand-white picture works on our intellect. Therefore, color pictures are easier to "read".

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These three illustrations demonstrate how much more information is contained in color pictures as compared to black-andwhite ones. Top: The picture with the sailboat conveys the romantic mood quite well, but it is far more effective in color. Center: This picture is relevant only in color. The black-and-white version does not enable us to realize that the algae that grow in a geyser are that colorful. Bottom: The difference in the photomicrographs of cells is even

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more striking. While we are hardly able to discern the shades of gray in the black-and-white picture, the color image permits us to make a precise differentiation. Fluorescence microscopy with Akridine-Orange, 800x. The intensity of the red color is an indication of the level of the RNS content in the body of the cell, and the intensity of the yellow color is a measure of the level of the DNS content of the nucleus of the cell. (Photomicrograph by Dr. H. W. Kolmel)

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Creating pictures in black-and-white depends primarily on seeing shapes made up of contrasts, while in color it depends more on seeing color areas formed by color contrasts and color harmonies. However this does not mean that the fundamentals of black-and-white picture composition are not valid for color composition. In a color picture, the criteria of figure-ground relationship, informational value, depth, and strong lines are as important as they are in a blackand-white picture, except that additional, colorrelated parameters such as color contrasts and color harmonies have to be taken into account as well. Here are the most important criteria for the analysis of color pictures: 1. 2. 3. 4.

Figure-ground and color contrasts Informational value and similarity Depth and illumination Strong lines and picture format

The classification of pictures according to their pictorial content applies equally to color and black-and-white pictures. We differentiate between: 1. Pictures largely conveying information 2. Pictures largely of an aesthetic nature 3. Pictures largely conveying emotions

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Picture Analysis: Color

: Simultaneous Contrast •

Colors grouped together on a surface influence one another, either standing out in contrast or merging in similarity. Simultaneous contrast is especially effective with light and medium tones. A comparison of two color hues with colorless gray shows that very clearly. When a neutral gray area is surrounded by two different color hues, the portion of gray surrounded by one color will appear to have a cast of the other color, and vice-versa. Simultaneous contrast results from the fact that, when two or more color areas are being observed, contrasts are enhanced or diluted because of adaptation or fatigue of the sight pigments in the receptors of our eyes. This contributes significantly to the improvement of perception. Contrast phenomena help us to absorb the multitude of our visual impressions, to sort and summarize them, to select details, and to separate important from unimportant elements. Angles, corners, and contours of colored or neutral areas have a greater informational value for our system of perception than areas of the same shape and color hue or contrast. It is the contour that determines the shape of things, not the volume contained by that contour.

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Successive or follow-up contrast is perceived when we stare at a picture for a prolonged time (at least 20 to 30 seconds) without interruption, and then look at a white surface. For a few moments, we will see a negative afterimage in complementary colors. According to the Young-Helmholtz theory of color, the explanation for this phenomenon as well as for simultaneous contrast can be found in the sequence of reactions in our optical system of perception. Large differences in brightness and in colors cause a progressive decomposition of sight pigments in the receptors, leading to their fatigue. When we change our glance from a picture to a neutral white surface, thus interrupting the optical stimulus, regeneration of the consumed sight pigments sets in immediately. The afterimage that we see is negative because those dyes that were consumed less during the viewing of the preceding picture continue to act vigorously until they have adapted to their new subject, the neutral white surface. The Hering color vision theory attributes the formation of the negative afterimage to a brief shift in the signals to the brain. Since each pair of colors, yellow und blue as well as red and green, is connected to only one color coder, one portion of the color coders is briefly disconnected at the termination of a visual stimulus, while the other portion continues to function briefly, producing the afterimage in complementary colors.

Quality Contrast

A picture composed of only one color hue, or of related colors, can be most effective. Quality contrast refers to the relationship and effects between individual shades of a single color hue, or between related colors that are located closely to each other in the circle of colors. Quality contrast can be demonstrated most convincingly by the use of a single color hue in all its shades, from the darkest (closest to black), to the purest, and to the brightest (closest to white). A multitude of color harmonies can be created by utilizing this type of contrast, for instance by combining a low brightness of one color hue with a high brightness of another color hue, or by combining a low saturation with a high saturation. Quality contrast is characterized by its pleasing and disciplined color effect.

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Picture Analysis Figure-Ground and Color Contrasts The contours of the nude stand out well as a figure from its ground because of its partly lighter and partly darker surroundings. In addition to the quality contrast, the picture's composition is also enhanced by light-and-dark, cold-warm, and quality contrasts. Informational Value and Similarity The structure of the picture of a female nude on the beach is nearly symmetrical. The greatest similarity can be found in the related colors. From the warm, reddish skin tones to the slightly colder, greenish sand color, all shades on the scale of the yellow-brown hue are represented. The red ribbon stands out as a small color accent, like a counterpoint, and enlivens the picture. Illumination and Depth Light coming from the right side creates depth for the shapes of the body. The light-and-dark contrast makes the body stand out from the darker and more distant background, making it seem closer and free-standing. Strong Lines and Picture Format The picture is dominated by the vertical character of the body. The gentle hint of an S-curve formed by the neck and the spinal column enlivens the surface of the back. The patch of dry sand near the right hip forms an arch that complements the round shape of the body and loosens up the otherwise uniform background. The dark, nearly horizontal shadow in the upper third of the photograph does not disturb the composition. The vertical format was selected to accentuate the posture of the body.

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a quiet and balanced effect, but they can also appear dynamic or aggressive.

Picture Analysis

Complementary Contrast

The effect of contrast in a picture is always determined by the largest color differential, enhancing the latter's luminance and color effect. Depending on the color hues, not only is a complementary contrast created, but also a light-and-dark and a cold-warm contrast. The ratios of the areas of the pairs of complementary colors play a decisive role in the harmony of a composition of complementary colors. In a combination of green-red, it is sufficient if the areas are of the same size. The combination cyan-red, however, requires an area relationship of 2 to 1, and blue-yellow an even greater ratio of 3 to 1. This means that, in order to create an impression of harmonious colors, the areas covered by these colors must be so proportioned as to add up to a neutral gray. Compositions with complementary colors can have

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Light-Dark Contrast

Cold-Warm Contrast

Figure-Ground and Color Contrasts Because of the complementary contrast between the magenta ball and the green deck, the former stands out very well as the figure from the ground. (This subject would be completely ineffective as a black-and-white photograph because the equivalent gray values of the various colors would result in a nearly uniform dark gray.) In addition to the complementary contrast, the light-and-dark and cold-warm contrasts are also involved in the structure of this picture. Informational Value and Similarity The magenta ball is a net-marking buoy on the deck of a fishing trawler. Similarity and repetition can be found in the curves of the ball and its complementary-colored shadow. The counter-diagonal of the light gunnel near the top of the picture is repeated frequently in the pattern of the deck planks. Illumination and Depth The illumination in this picture, photographed in the rain, comes exclusively from a gray, overcast sky. The weak shadows of the anchor and the ball create an impression of depth. The ropes and chains lying on the deck create overlaps that suggest depth. Strong Lines and Picture Format This subject, composed of only a few picture elements, is enlivened a little by the counterpoint formed by the ball with the faint diagonal lines of the deck planks. The location of the buoy in the golden section is retained only when the square format of the original photograph is maintained.

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color hue contrast have a lively and friendly character.

Color Hue Contrast

The simultaneous use of many strong colors can easily make a picture appear busy and fragmented. Limiting the colors to just three hues, perhaps even the three subtractive primary colors, produces a significant increase in the impact of the picture. The color contrast provided by yellow, magenta, and cyan may appear loud; on the other hand it is friendly and cheerful. Its effect can be softened by contrasting neutral tones like black and white. A triple combination of blue, green, and red is less strident. As we deviate from the subtractive primary colors the picture will appear progressively quieter and calmer. The three color hues do not necessarily have to be distributed in equal amounts; it is quite appropriate for one or two colors to be predominant. Pictures based on

Light-Dark Contrast

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Cold-Warm Contrast

Complementary Contrast

Picture Analysis Figure-Ground and Color Contrasts Because of the strong color contrast, the striking red-and-white striped rudder stands out in the picture. The subject vibrates with its brilliant colors, which closely approximate the subtractive primary colors. In addition to the color hue contrast, the light-dark and the coldwarm contrast can clearly be noticed. Informational Value and Similarity The lateral and vertical controls of a vintage sports aircraft were photographed in New Hampshire, U.S.A. Similarity and repetition appear in the lines and in the areas of color. Illumination and Depth We can tell from the shadow of the cable and the elevator that the light is coming from the upper right. Except for the stabilizer and elevator, which are attached to the fin at a right angle, all color surfaces are in one plane. Strong Lines and Picture Format The right angle formed by the two bands of blue creates a contrast with the diagonal red and white stripes. There is a yellow triangle above and another one below the blue right angle. The shadows of the rounded edges of the rudder and the elevator create two additional dark triangles in the lower portion of the picture. The strong black lines created by edges or shadows contribute to an interesting division of space. The square format in no way weakens the effect of the lively picture content, which seems to transcend its borders.

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than they really are. A picture created with the use of light-dark contrast has a three-dimensional and dynamic effect.

Light-Dark Contrast

Light-dark contrast constitutes the strongest extremes between two color hues, as far as their visually perceived brightness is concerned. The strongest contrast of this type occurs between black and white. But similarly strong contrasts occur in the colors too, for instance between yellow and blue. This kind of contrast has an even stronger impact between the bright color yellow and colorless black. Light-dark contrast is usually present in a picture along with one or more of the other contrasts. Bright colors seem to strive for the foreground, while the dark ones seem to recede into more distant planes in space. Because of spillover (irradiation), with which bright areas seem to invade darker ones, they appear larger

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Cold-Warm Contrast

Picture Analysis Figure-Ground and Color Contrasts Selective focusing on the bee makes the latter become the figure and the remaining subject become the ground. The color contrast between yellow as the brightest color and black as the darkest constitutes nearly extreme opposition. In addition to the light-dark contrast, cold-warm contrast can also be detected. Informational Value and Similarity The picture, photographed against the light, shows a bee collecting nectar. Similarity and repetition can be found both in the various shapes as well as in the colors. The picture area is enlivened by the repetition of the round shapes of the flowers, their rings of petals, and the stems. Illumination and Depth The strong color contrast is further enhanced by photographing against the light. Thus the yellow blossoms stand out brightly from the plane of the dark background. The vignetting by the unsharp foreground strengthens the impression of depth even more. Strong Lines and Picture Format In addition to the yellow and brown dabs of color of the flowers, the vertical and diagonal stems enliven the picture area. The horizontal format was cropped from the original square format.

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colors are predominantly in the cold range, but when the colors are mostly warm the subject appears close and exciting.

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Cold-Warm Contrast

It may seem strange to use terms like cold and warm in connection with the perception of color. But there is a reason for the comparison of the effect of color with the feeling of temperature. We consider predominantly blue-green colors as cold, and yellow-red colors as warm. In addition, there is also a colder or warmer impression created between related colors. The feeling of depth in a picture can be strongly influenced by the judicious use of cold or warm colors: warm tones stand out, cold ones recede into the background. Cold-warm contrast seldom appears by itself; it usually appears together with light-dark contrast. Pictures that contain predominantly cold-warm contrasts have a remote and soothing effect when their

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Complementary Contrast

Picture Analysis Figure-Ground and Color Contrasts The brown-skinned fishing boy stands out clearly as the figure from the ground of the blue-green water. The cold-warm contrast is even repeated three times in this subject: 1. Between the boy's body and the ocean; 2. Between the loincloth and the ocean; 3. Between the lobster and the boy's body. In addition to the cold-warm contrast, the composition also includes light-dark contrast, complementary contrast, and quantity contrast. Informational Value and Similarity A Tamil boy near Jaffna in Ceylon proudly displays a lobster that he caught himself. There is similarity in the forms and posture of the boy and the still living lobster. Illumination and Depth Because of the color contrasts, the nearly vertical illumination is not disturbing. The warm red-brown body of the boy stands out spacially from the colder, blue-green plane of the sea. Strong Lines and Picture Format The vertical of the standing boy dominates the picture. The angled arms and the stretched antenae of the lobster, however, add a linear contrast to the predominant verticals, thus adding life to the picture area. The narrow vertical format was selected to emphasize the upright position of the boy.

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Quantity Contrast

Quantity contrast results from the relationship of two very unequal areas of strongly contrasting color hues. The unbalanced size relationship of those two areas and the position of the smaller one with the strong color differential create vigorous tension. In a nearly monochromatic picture, a spot with a complementary or sharply contrasting color is as effective as the dot on an "i". The position of this colored spot, however, is of the utmost importance in the overall composition. The location in the golden section is particularly advantageous, but in some subjects the central position also works quite well. Quantity contrast gives the picture a certain surprise or startling effect.

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Quality Contrast

Picture Analysis Figure-Ground and Color Contrasts The tall tank on the right stands out clearly as the figure from the surrounding picture area. This is due primarily to the circular red area, rather than the overlapping shapes or the shadows. This small red area forms such a pronounced color contrast with the many large light-colored areas that surround it that it becomes the center of attention. In addition to the quantity contrast, this subject also involves quality, simultaneous, light-dark, and coldwarm contrasts. Informational Value and Similarity This tank installation is located near the TransCanada Highway in the Province of Alberta. Similarity and repetition can be found in the large rectangular shapes of the tanks, in their triangular tops, and in the uniform color hue. Illumination and Depth Light entering from the right side creates shadows that give depth to each tank in this colored high-key subject. The lowest tank constitutes the foreground, the tallest one is the middleground, and the one situated slightly further back on the left is the background. Strong Lines and Picture Format The obtuse triangle and the diagonal ladder enliven the otherwise static rectangles of the tanks. In spite of the interruption by the trade name, the red circle in the golden section remains an entity because of its black outline. To strengthen the effect of the picture, a horizontal composition was cropped from the original square format.

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Compositional Technique

Correct Position

The effect of a picture hinges on finding the correct picture-taking position. This is demonstrated by the five different views of the sculpture by Gaston Lachaise displayed in the Albright Knox Museum in Buffalo, N.Y. Picture number 1 was taken in diffuse daylight, using a wideangle lens. The bright area just below the left knee is distracting. Picture number 2 was taken from a greater distance with a telephoto lens. In this view, the bright entrance area in the background is even more disturbing, but the proportions of the woman are reproduced more naturally and with less distortion thanks to the longer focal length. The head and torso are considerably more slender than in the wideangle view. Picture number 3 was taken with the same focal length, but from a different position. The plant in the lower right is distracting, and the pose is not pleasing from this angle. Picture number 4 was taken from still another position, still with the same telephoto lens. The dark areas on both sides of this view are disturbing; the arrangement of the body is also awkward. The large photograph on the next page was taken from an even greater distance with a still longer focal length. To eliminate the bright light spots, only a portion of the sculpture was photographed. Here the figure stands out well, with good depth, from the quiet background, aided by the bright contour lines.

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The correct focal length enables the photographer to achieve the intended picture from a given position. What factors are relevant in the selection of a focal length? The right focal length must bridge the existing subject distance to capture the desired cropping. For pictures in the winding narrow streets of the older section of cities or in the cabin of an airplane the subject distance is usually much too short for a proper reproduction of the scene with the normal focal length. In order to capture a greater angle of view, we use a shorter focal length, or a wideangle lens. For photographing wild animals in nature, or for distant objects, we select a telephoto lens with a long focal length, which has a narrow angle of view, and which records the subject in a larger size on the film. To find the most suitable focal length for a particular subject, it is best to try several lenses while constantly observing the image in the viewfinder. Zoom lenses have the advantage over lenses with fixed focal lengths that they eliminate the time-consuming lens changes, because their focal length can be varied continuously over a range between 1:2 to 1:5. It is

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Side Lighting

Bird's Eye View

important to note that, in a photograph of an object taken from the very same position with a wideangle, normal, or telephoto lens, the perspective does not change; only the field covered by each lens is different.

The four views of "Spider Rock" in Canyon de Cheily National Monument in the state of Arizona, U.S.A. were taken from the exact same spot with lenses of 50, 120, 250, and 500 mm focal length. The most convincing impression of vastness and depth of that canyon is conveyed by the wideangle picture on the upper left. The other photographs, made with longer focal lengths, differ only in scale, not in perspective.

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3

3 Correct Perspective

The perspective is correct when it satisfies the creative intention of the photographer. Like the selection of an appropriate focal length, choosing the proper perspective is an individual, subjective decision which must, however, take into account the laws of optical imaging. In reproducing an object in the foreground in exactly the same size with wideangle, normal, and telephoto lenses by changing the taking position, the perspective and the size relationship between fore-, middle-, and background are changed. If we wish to have a distant object appear as small as possible, we would select a wideangle lens with an extremely short focal length. If, on the other hand, we want to include the distant background effectively in the composition of the picture, then we would choose a telephoto lens with a very long focal length. Using the first approach, a cramped cabin on a ship can be made to look like a spacious first class suite; the second technique can be used during a photo safari to make the tiny lions and Kilimanjaro appear close enough to touch.

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By changing lenses and the distance of the camera from the "Hercules" sculpture on the grounds of the National Gallery in Berlin, that sculpture is reproduced in the same size in every photograph. However the Matthài Church in the background appears

to be increasingly closer to the sculpture as we change to ever longer lenses: 50,120, 250, and 500 mm. This alters not only the perspective, but the size relationship between fore- and background as well.

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Blue haze causes a color cast in scenic photographs. That haze consists of miniscule particles of water, which partly reflect polarized skylight, covering all colored objects. When the direction of the photograph forms a 90° angle with the direction of the sunlight, the blue cast can be removed with a polarizing filter. This filter is rotated in front of the lens while observing the image in the viewfinder until the effect reaches a maximum. This eliminates the polarized light, and colors will be reproduced in the picture in their original intensity. The two picture examples were taken from Dead Horse Point State Park in Utah, U.S.A. in the direction of the Colorado river and Canyonlands. The photograph on the left was taken without a polarizing filter, and the resulting bluish cast makes it unacceptable. The picture on the right was taken immediately after the one on the left, but this time a polarizing filter was used, which shows the landscape in its natural colors.

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For every subject - excluding those that can be photographed anytime - there is an ideal time for a picture. This optimum time is determined not only by prevailing illumination, time of day, season, or weather, but also by momentary or coincidental events or changes within the subject. That is why it is worthwhile always to take more than just one picture of a given subject. Under certain circumstances it is desirable to make a series of photographs over a short or a long period of time. One of the pictures from this series is likely to capture just the right, most representative moment. With the objective of obtaining a night-time picture of a tall building that seems to hang from "suspenders" in Vancouver in the Province of British Columbia, a series of photographs was made over a period of one hour. Picture number 1 was taken while there was still daylight. While the skyscrapers glow in the red light of the setting sun, the streets are already immersed in the gloom of dusk. It was still too early for a night picture. Photograph number 2, taken a little later, while falling within the "blue hour", still is not a night scene. Picture number 3, however, does convey the impression of a

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Light-Dark Contrast

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real night photograph. But it was taken in late twilight, after all the lights had been turned on. If it had been taken even later, in complete night time, we would only recognize illuminated windows and street lights. All other details would disappear in complete darkness.

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Summary

A Brief History of Imagery Man has an ancient and fundamental need to communicate what he sees and experiences in his dealings with the world by means of images. Despite the many accomplishments of architecture, pictorial representation of three-dimensional space - i.e. perspective - remained an unsolved problem until the Italian renaissance in the 15th century. The growing volume of information reaching the public through television, motion pictures, and photography clearly shows the increasing significance of images as a means of communication. The Physiology of Vision During the seeing process, the other senses touch, smell, taste, and hearing - as well as the memory are constantly brought into play, drawing comparisons for the purpose of registering and classifying. A momentary image, lasting only a fraction of a second, is formed by light stimuli on the eye's photo-receptors during the seeing process, and these fleeting images are constantly being erased and followed by new ones. Even though it is located apart physically, the light-sensitive retina constitutes a part of the brain. The distribution and concentration of rods and cones embedded side-by-side in the retina are irregular. While the greatest sensitivity of cones is in the yellow-green region of the spectrum, rods on the other hand are most sensitive to blue-green (cyan), even though they only sense black and white. Because its angle of sharpest vision is very small (1.5 degrees), the eye is constantly in motion, systematically scanning individual objects in order to create an overall image of the scene. The eye constantly and automatically changes the curvature of its lens to achieve optimum sharpness. The human visual apparatus functions on the 146

basis of coordinated binocular, or "stereoscopic" vision. The eyes and brain are able to accept limited bits of information, which they intuitively supplement with missing details to form an entity. A great variety of stimuli constantly impinges upon the eye, and our seeing mechanism is capable of differentiating precisely between real signals and interference because of a complex steering and counter-steering arrangement. Even when we are in constant motion, the image generated by the eyes and the brain does not appear to gyrate wildly or to sway in a blur. Our visual environment is made up of what we want to see in it, not what it actually contains. Gestalt and Perception Psychology The seeing process is a constructive sequence, in which complete patterns are perceived and compared with patterns and experiences previously stored in the brain in order that we can recognize and identify what we see. An object can only be perceived when it stands out from its background by virtue of contrast. The differentiating borderline also constitutes its external form. The form (Gestalt) constitutes a clearly recognizable entity, which is structured, self-contained, and clearly distinct from its surroundings. The entity is different from the sum of its individual visual elements. The most important tenet of form (Gestalt) theory is the distinction between figure and ground, which is subject to the following criteria: 1. The figure must stand out from the ground. 2. The smaller area is usually seen as the figure, and the larger area as the ground. 3. Figure and ground cannot be perceived simultaneously. 4. In particular, similar visual elements that are located closely together are combined into a figure. 5. Symmetrical and contained shapes tend

normally to be perceived as figures. Our perception system continually strives for simplicity, regularity, clarity, lucidity, and order. For that reason, Gestalt psychology defines as impact the perception of an object in the simplest form that can be recognized in relation to its circumstances. The figure-ground relationship constitutes a pattern applied to the field of visual perception, serving to distinguish the relevant from the irrelevant. A figure cannot be perceived without a ground. Geometrical shapes or patterns that are entirely or nearly self-contained tend to form a figure. In a random situation, different observers of the same scene will select different picture elements as figure and as ground. Good recognizability depends not only on contrast, but also on the sizes of the contrasting areas. An ambiguous figure-ground relationship always exists when several perceptual possibilities have equal relevance. Even though ambiguous figures have a certain appeal, they lack impact. The following factors contribute to an impression of depth in a picture: 1. 2. 3. 4. 5. 6.

Perspective Overlaps Texture Gradient Illumination Aerial Perspective Culturally Conditioned Vision

Education has influenced and molded our way of viewing; it has taught us to see three dimensions in a two-dimensional picture when any or all of the above factors are recognizable in the scene. Corners and angles are the most significant signals for the perception of objects. Gestalt theory teaches us that, by classifying and grouping, our visual perception system constantly strives to simplify the recognition and understanding of our surroundings, so that we can more easily orient ourselves in them.

Information Theory

Information theory teaches us to adjust opposing components of information, such as the new and the familiar, in relation to each other in such a way that a message will result that is both understandable and interesting. The content, the substance of a message is derived from the relationship of the unforeseen, the new, to the familiar and superfluous, to the so-called redundance. While Gestalt theory provides for formal aesthetic evaluation of pictures, information theory applies to the evaluation of the original or novel content. However, there is no absolute yardstick for this, because something that is new to one person may be long familiar to another. Originality depends significantly on the font of knowledge and experience of the viewer.

The Emotion Thesis

There is one determining factor that does not receive its proper due in either Gestalt or information theory, and that is the emotional content of pictures. While that content is even more difficult to measure than the other factors, it plays a most effective role. This category covers pictures that make an impression on the viewer, not because of their outstanding composition nor because of their information content, but because of a quality that appeals to emotion. Summarizing, it can be stated that pictures can be classified in three basic categories: 1. Pictures largely conveying information 2. Pictures largely aesthetic in nature 3. Pictures largely conveying emotions

Picture Composition

The following points provide important suggestions for good pictorial composition: 1. The (picture) signals must be clearly distinct from "optical noise". 2. A clearcut figure-ground relationship contributes to the impact of a picture message. 3. Ambiguous figure-ground relationships that could lead to optical deceptions should be avoided. 147

4. The area relationship of light-dark and of color contrasts is of great importance. 5. In addition to the formal figure-ground relationship, psychological figure-ground weighting is also very important, because every visual perception is evaluated immediately as pleasing or displeasing. A neutral evaluation would mean no reaction at all. 6. Similarity with familiar objects contributes to recognition and thus to faster comprehension and information processing. Thus the necessity of redundancy. 7. The degree of complexity of a picture must not be too low (understimulation) nor too high (overstimulation). 8. Aesthetic evaluation of each and every picture is always different from individual to individual, and it is determined by emotions. Such evaluation depends significantly on the viewer's consciousness, his font of experiences, and his sensitivity. 9. Formalism and fads are ephemeral. Technical manipulation cannot compensate for a lack of originality. 10. Illumination, perspective, overlapping, and texture gradient serve to convey an impression of depth on a two-dimensional surface. 11. An unfamiliar perspective serves to enliven the picture. 12. The conscious use of strongly directional lines and a format adapted to the subject enhance the effect of the picture. Consistently executed picture analysis is the way to learn optimum picture composition. The most important criteria for the analysis of picture composition are:

400 to 700 nm (1nm = 1 nanometer, which is one millionth of a millimeter; 1 millimeter = 0.03937 inches). Visible light is transmitted both in the form of vibrating waves radiating in all directions as well as in the form of minute (corpuscular) energy particles called light quanta or photons. Sunlight - as in median daylight - can be designated as white light because it has a spectrum of evenly distributed energy: all colors of the visible spectrum are present with equal intensities. A c c o r d i n g to the Young-Helmholtz theory of color vision, the light-sensitive cones in our retinas are of three separate types, each reacting to one of three ranges of the visible spectrum. One type of cone reacts to the short-wave blue range, another to the medium-wave green range, and the third one to the long-wave red range of the spectrum. Additive color mixing is based on the mixture of colored light in the three additive primary colors blue, green, and red. Subtractive color mixing is based on the subtraction or removal of the subtractive primary colors yellow, magenta, and cyan from white light. In additive color mixing, colored light rays that supplement each other to create white light are designated complementary. In subtractive color mixing, transparent color dyes (pigments) that supplement each other to form black are designated complementary. In dealing with the entire complex subject of colors, the greatest difficulty is the precise, unmistakeable designation of color hues. Precise evaluation of color is possible only under white light.

Figure-ground relationship and contrasts Informational value and similarity Illumination and depth Strong lines and picture format

The concept of color temperature covers both the visual appearance of a color hue that is being radiated as well as the temperature in degrees Kelvin to which the so-called black body must be heated in order to emit light of that same hue.

Seeing in Color The visible spectrum covers wavelengths from

Color hue is the color that we perceive in energy radiated by a light source, or in

1. 2. 3. 4.

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wavelengths reflected by an object.

the lighter one will appear the larger of the two.

Color brightness is the descriptor for the manner in which a color appears to us, whether it is lighter or darker, whether it is closer to white or to black.

Colors also affect our impression of weight. Among objects of identical size, the darker ones will seem heavier than the lighter ones.

Color saturation is the measure of purity of a color. A fully saturated color is free from any additive; it is neither bleached nor blackened.

Our impression of space is also significantly affected by colors. Light-colored surfaces or objects will appear closer to an observer, while the dark ones will seem further away than they really are.

Color Contrasts Simultaneous contrast is perceived most clearly when two color hues are compared with a neutral gray. The gray patch in one hue will take on a slight tint from the other one.

Another sense that is affected by colors is that of temperature. A room painted in cool colors like blue or green will more likely make us feel cold than one that is painted in warm colors like red or orange.

Successive contrast is perceived when one observes a picture rigidly for a prolonged time (at least 20 to 30 seconds) without interruption, then immediately looks at a white surface. A negative image of the original picture will appear in its complementary colors.

Colors, once perceived, are immediately associated and compared with those stored in our memory of earlier visual experiences.

Quality contrast represents the relationship and effects between different shades of the same color hue. Complementary contrast shows how the sideby-side positioning of two surfaces of complementary colors increases the perceived color effect of both surfaces. Color hue contrast causes a substantial enhancement of our impression of color when all three subtractive primary colors or similar strong colors are used simultaneously in the same picture. Light-dark contrast represents the maximum polarization between two color hues with respect to their visual brightness. Cold-warm contrast denotes the greatest polarity between two color hues relative to their psychological effect, i. e. cold or warm. Quantity contrast refers to the relationship between two adjacent areas of disproportionate size and of strongly contrasting colors. The Psychology of Colors Color creates an apparent change in the size of a shape. Of two surfaces of the same size, one with a dark color, the other with a light color,

The effect of colors on our emotions is not the same for all persons. It depends to a large extent on cultural background, education, age, sex, and on currently prevailing opinions. Picture Composition in Color The most significant difference between picture composition in color or in black-and-white is the greater information content of the color picture. Color pictures differentiate, intensify, define, and specify to a far greater degree than is possible in black-and-white. A color picture appears considerably more realistic and it appeals to our emotions, whereas the more abstract black-and-white picture works on our intellect. Therefore, color pictures are easier to "read". The most important criteria for the analysis of color pictures are: 1. 2. 3. 4.

Figure-Ground and Color Contrasts Informational Value and Similarity Depth and Illumination Strong Lines and Picture Format

The classification of pictures according to their pictorial content applies to color pictures too. We differentiate between: 1. Pictures largely conveying information 2. Pictures largely of an aesthetic nature 3. Pictures largely conveying emotions 149

60 Exercises

The following photographic subjects are to be translated into pictures:

These 60 exercises will give the reader an opportunity to expand his newly acquired knowledge and apply it to his own pictures.

1. Homogeneous Field of View Heterogeneous Field of View Clearcut Figure-Ground Relationship Ambiguous Figure-Ground Relationship Poor Figure-Ground Relationship

As is clearly shown by the pictures and text on the preceding pages of this book, each individual element of composition has a particular significance. By practicing the use of specific creative elements in the composition of a picture, the photographer will sharpen his visual sensitivity. Each exercise consists of a photograph and the subsequent analysis of the picture. It is important that the subject of the exercise should be clearly recognizable in the photograph. The exercises are grouped in blocks of six subjects each, in order of increasing complexity. It is recommended that this sequence be observed. The greatest progress in learning is achieved by proceeding step by step. In the beginning, no more than six of the subjects should be photographed and analyzed, in order to detect possible errors in time, and to avoid them in the future. The exercises are suitable for individual self-study as well as for use with photographic groups or school courses. Whether the photographs should be in the form of transparencies or prints is up to each individual. For use in study groups, however, transparencies (slides) are more convenient, because they can be projected and then jointly analyzed by a larger number of participants. A 20-exposure film is recommended for each group of six subjects so that at least three exposures are available for each subject. Later, as the photographer's experience and confidence increase, a 36-exposure film can be used to photograph 12 subjects. 6 to 12 weeks will probably be necessary to complete all 60 exercises. The analysis is an essential part of each exercise, as it forces the photographer to take a critical view of his own pictures. It also serves as a means of monitoring his own progress in picture composition.

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2. Perspective Overlaps Texture Gradient Illumination Aerial Perspective Information Content 3. Degree of Complexity Aesthetic Content Emotional Content Tonal Value Contrasts Similarity Depth 4. Frontal Lighting Side Lighting Back Lighting Eye Level View Bird's Eye View Worm's Eye View 5. Fore-, Middle-, and Background Silhouette Planes Horizontals Diagonals Verticals 6. Counter Diagonals Right Angles Arches Circles Symmetry Golden Section 7. Total Sharpness Selective Focus Blurred Motion Square Picture Format Horizontal Format Vertical Format

8. Monochromatic Color Picture Multichromatic Color Picture Simultaneous Contrast Complementary Contrast Quality Contrast Light-Dark Contrast 9. Cold-Warm Contrast Quantity Contrast Color Brightness, high/low Color Saturation, high/low Depth Impression through Color, near/far Size Impression through Color, large/small 10. Weight Impression through Color, light/heavy Correct Position Correct Focal Length Correct Perspective Correct Filter Correct Timing

Bibliography

Gregory, Richard L. The Intelligent Eye New York: McGraw-Hill, 1970

Anderson, Donald The Art of Written Forms New York: Holt, Rinehart and Winston, 1969

Haber, R. N. and M. Hershenson The Psychology of Visual Perception New York: Holt, Rinehart and Winston, 1973

Arnheim, Rudolf Art and Visual Perception Berkeley, Calif. : University of California Press, 1969

Hedgecoe,John The Art of Colour Photography London: Mitchell Beazley Publishers, 1978

Arnheim, Rudolf Visual Thinking

Katz, David Gestaltpsychologie Basel - Stuttgart: Schwab & Co., 1969

Berkeley, Calif.: University of California Press, 1972 Bense, Max Einführung in die informationstheoretische Ästhetik Hamburg: Rowohlt Taschenbuch Verlag, 1969 Berlyne, D. E. Aesthetics and Psychobiology New York: Meredith Corporation, 1971 Bleckwenn, Ruth und Beate Schwarze Gestaltungslehre Hamburg: Handwerk und Technik, 1975 Eastman Kodak Encyclopedia of Practical Photography New York: Amphoto, 1977 Feininger, Andreas Principles of Composition in Photography New York: Amphoto, 1973 Forgus, R. H. Perception New York: McGraw-Hill, 1966 Gerritsen, Frans Farbe Ravensburg: Otto MaierVerlag, 1975 Gibson, E. J. Principles of Perception Learning and Development New York: Appleton-Century-Crofts, 1969 Gombrich, E. H. Art and Illusion Princeton, N.J.: Princeton University Press, 1969

Koffka, K. Principles of Gestalt Psychology New York: Harcourt Brace and World, 1963 Lewinski, J. and B. Clark Blickpunkt Farbe Düsseldorf: Wilhelm Knapp Verlag, 1977 Mante, Harald Farbdesign in der Fotografie Ravensburg: Otto MaierVerlag, 1970 Metzger, Wolfgang Gesetze des Sehens Frankfurt: Verlag Waldemar Kramer, 1975 Meyer-Eppler, W. Grundlagen und Anwendungen der Informationstheorie Berlin: Springer-Verlag, 1969 Moles, Abraham A. Informationstheoretische und ästhetische Wahrnehmung Köln: Verlag M. DuMont Schauberg, 1971 Mueller, Conrad and Mae Rudolph Light and Vision New York: Time-Life Books, 1969 Patterson, Freeman Photography & the Art of Seeing Toronto: Van Nostrand Reinhold, 1979 Time-Life Books Color, Life Library of Photography New York: Time-Life-Books, 1971

Gombrich, Hochberg and Black Art, Perception and Reality John Hopkins University Press, 1972

Vernon, M. D. Experiments in Visual Perception Harmondsworth: Penguin Books, 1966

Gregory, Richard L. Eye and Brain New York: McGraw-Hill, 1966

Weber, Ernst A. Farbfotopraktikum Berlin: Walter de Gruyter, 1971

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Yarbus, Alfred L. Eye Movements and Vision New York: Plenum, 1967 Zakia, Richard D. and HollisTodd Color Primer I & II Dobbsferry, N.Y.: Morgan & Morgan, 1974 Zakia, Richard D. Perception and Photography Englewood Cliffs, N.J.: Prentice-Hall, 1975 Zusne, L. Visual Perception of Form New York: Academic Press, 1970

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Index Absorption of Information 4 Accommodation 6 Adaptation 9 , 1 1 Adaptation Time 9 Additive Color Mixing 1 0 3 , 1 0 5 , 1 0 6 , 1 0 7 Aerial Perspective 22, 2 4 , 6 4 Aesthetics 28 Aesthetic Content 2 9 , 3 2 Airport 4 , 2 4 Alphabet 2 Altamira 2 Amount of Information 28 Angle of View 10 Anterior Aqueous Chamber 6 Arches 80 Area 19 Associations 102 Attention Value 20

Back Lighting 50 Bipolar Cells 8 Bird's Eye View 56 Bit 28 Blind Spot 6 Blurred Motion 92 Brain 7 , 1 1 , 1 2 , 1 4 , 1 5 , 1 0 2 , 1 0 4 Brain Lobes 11 Brightness Sensation 10 Brightness Value 19

Camera 6 , 9 , 1 5 Cave Drawings 6 Channel 2 7 , 2 8 Ciliary Muscle 6 , 8 Circles 82 Circular Spectrum 108,109 Clarity 17 Code 24, 27 Cold-Warm Contrast 1 1 1 , 1 1 3 , 1 2 8 Color 102 Color Brightness 110,113 Color Cast 114 Color Coders 104 Color Contrasts 111,116 Color Harmony 112 Color Hue 1 1 0 , 1 1 1 , 1 1 4 Color Hue Contrast 1 1 1 , 1 1 3 , 1 2 4 Color of Light 110 Color Permanence 114 Color Printing 103,105 Color Saturation 110,113 Color Vision, Color Seeing 8, 102, 103, 104,114 Color Sensations 1 0 , 1 0 2 , 1 0 4 , 1 1 0 Color Symbolism 114 Color Temperature 110 Color Theory 108 Color Tree 111 Complementary Colors 1 0 5 , 1 0 7 , 1 0 9 Complementary Contrast 1 1 1 , 1 1 2 , 1 2 2 Complexity 2 7 , 3 2 Composition 28, 32

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Composition Technique 33 Conditioning 114 Constance Mechanism 22 Contour Line 20 Contrasts 1 9 , 3 3 , 3 6 , 4 0 , 1 1 4 Contrast Effect 20 Cornea 6 Correct Filter 140 Correct Focal Length 136 Correct Perspective 138 Correct Position 134 Correct Timing 142 Cortex 11 Counter-Diagonals 76 Creating 6 Criteria for Analysis 33 Culturally Conditioned Vision 2 2 , 2 4 Cyan 103,109

Dark Interval 9 Data Processing Installation 11 Decoding Process 7 Dendritic Spreads of the Bipolar Cells 8 Depth 3 3 , 3 6 , 1 1 6 Depth Perception 22 Deregowski, Jan B. 25 Diagonals 72 Distance Differentiation 22 Distant Viewing 8 Documentation 4 Dot Size 19

Ehrenstein 12 Electrical Stimulus 11 Elements of Composition 3 2 , 3 3 Emotion 28 Emotional Content 29 Emotion Thesis 2 9 , 3 0 Entity 16 Entity Method 25 Evaluation Pattern 18 Eye 6 , 7 , 1 1 , 1 2 Eye-Level Perspective 52

Feature Ring 25 Feedback 11 Feelings 29 Field of View 1 0 , 1 1 , 1 2 , 1 6 Field of Visual Perception 18 Figure-Ground Relationship 16, 17, 18, 20,21,22,32, 33,36,38,116 Filter Effect 114 Fisher, R.A. 26 Fore-, Middle-, and Background 58 Form (Gestalt) 15,16 Fovea 6 , 8

Ganglion Cells 8 Gestalt Law 20, 27, 28 Gestalt Psychologist 1 5 , 2 0 Gestalt Psychology 1 5 , 2 6 , 3 2 Gestalt Theory 15,16, 2 5 , 2 7 , 2 8 , 3 0 Golden Section 86 Gutenberg 3

Gyroscope 14 Helmholtz, Hermann von 103 Hering, Ewald 104 Hieroglyphs 2 Horizontals 25 Hudson, William 25 Horizontal Format 96 Ideograms 2 Illiterates 5 Illumination 22,24,33,36,46,116 Illusions in Perceptions 12 Image-Forming Process 6 Image of Environment 14 Image Stabilization 12 Impact 17,21 Impulse Signals 9,102 Information 28 Information Content 27,29 Information Processing 7 Information Signals 7 Information Theory 26, 27, 28, 30, 32 Informational Value 26, 27, 33, 36, 42, 116 Initial Perception Phase 16 Iris 6,9 Iris Aperture (Pupil) 9 Irradiation 114 Kanisza 21 Kelvin 110 Köhler, Wolfgang 15 Koffka, Kurt 15,21 Lateral Geniculate Ganglion 11 Layer of Pigmented Epithelium 8 Light 102 Light and Dark Adaptation 9 Light-Dark Contrast 111,113,126 Light Energy 7,9 Light Quanta 102 Light Sensors 6,8 Light Stimulus 9 Lucidity 17 Mach, Ernst 15 Magenta 103,109 Messages 27 Moles, Abraham 27 Movement Rhythm 25 Müller, Lyer 12 Munsell, Albert H. 110,111

Nanometer 102 Near Viewing 8 Necker 12 Nerve Cell Layer 8 Nerve Fibers 8,11 Nervelmpulses 9,10 Nerve Strands 7 Newton, Isaac 103

Niépce 3 Noise 12 Noton, David 25 Object Color 103 Olympic Games 4,24 Optical Color Mixing 103 Optical Nerve 6, 7 Optical Nerve Crossover 11 Optical Noise 18,32 Order 17,32 Original Content 28 Overlaps 24 Patterns 15,21 Perception 28,32,114 Perception Possibilities 21 Perception Process 15,25 Perception Psychology 15 Perception System 6,17, 20, 21, 22, 28 Perspective 2,22,32 Physiology of Seeing 6 Photography 3,4 Photography of Forms 3 Photography of Planes 3 Photo Receptors 6,7,11 Picture Analysis 32, 33, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 120, 122, 124, 126, 128,130 Picture Composition 29,32,116 Picture Elements 17,21 Picture Format 33,36,116 Picture Idea 28 Picture Message 28 Pictorial Symbols 4 Planes 66 Point of Convergence 22 Ponto 12 Porta, Giambattista della 111 Psychology of Colors 114 Pupil 6 Purkinje Phenomenon 9 Quantity Contrast 111,112,120,130 Radiation Energy 102,110 Reality 28 Receptors 9,103 ReceptorTypes 104 Recipient 27,28 Redundance 26,27 Regularity 17 Renaissance 2 Repertory 26,27 Research 4 Resolving Power 19 Retina 6,7,8,9,10,11,14,102,104,110 Retina Halves 11 Rhodopsin 9 Right Angle 78 Rods 6,9 Rubin, Edgar 19

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Saccadic Eye Movements 11 Scan Path 25 Science 4 Scientific American 25 Sculpture 3 Seeing Movement 10 Seeing Problems 14 Seeing Process 6, 7,12,15,102 Selective Focus 90 Sender 27,28 Sensing Organ 6 Sensitivity 29,33 Shannon, C. E. 26 Sharpness of Vision 8 Side Lighting 48 Siemens Star 12 Signals 12 Signal-to-Noise Ratio 18 Silhouettes 62 Similarity 32,33,36,44,116 Simplicity 17 Simultaneous Contrast 111,112,118 Spacial Impression 10 Spacial Seeing 10,22 Spectral Energy Distribution 111 Spectrum 102,103 Square Format 94 Stark, Lawrence 25 Stereoscopic Seeing 19,22 Strong Lines 32,33,36,68,116 Style Changes 3 Substance 27 Subtractive Color Mixing 103,106,107 Successive Contrast 104,111,112,119 Symbol Index 33 Symmetry 22,84

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Television 4,22,105 Tendency to Arrange 20 Texture Gradient 22,24,60 Titchener 12 Tone Range 19 Top Hat 12 Total Field 15 Total Sharpness 88 Venus de Milo 16 Vertical Format 70 Verticals 74 Visual Communication 2 Visual Pigments 9 Visual Purple 9 Viewer 28 Viewing Angle 25 Viewing Distance 19 Vitreous Humor 6,8 Wavelength Spectrum 102 Way of Viewing 24 Wertheimer, Max 15 Wiener, N. 26 Worm's Eye View 54 Writing with Pictures 2 Young, Thomas 103,104 Zöllner 12