Color and Light in Painting 9780231879989

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COLOR IN

AND

LIGHT

PAINTING

COLOR

AND

IN

LIGHT

PAINTING

BY R O L A N D R O O D EDITED GEORGE

I

COLUMBIA

9

BY L.

STOUT

4

I

UNIVERSITY NEW

YORK

PRESS

COPYRIGHT COLUMBIA

UNIVERSITY

1941 PRESS,

NEW

YORK

FOREIGN AGENTS: O x f o r d University Press, H u m p h r e y Milford, Amen House, L o n d o n , E. C. 4, England, and B. I. Building, Nicol R o a d , B o m b a y , I n d i a ; Maruzen Company, Ltd., 6 Nihonbashi, T o r i - N i c h o m e , T o k y o , Japan MANUFACTURED

IN T H E UNITED STATES OF

AMERICA

Introduction

T

H I S B O O K i s good reading on a subject which might have been made deadly dull. It reaches the imagination and it does not neglect the intelligence. T h e student of art will recognize it as continuing a series notable for classic treatises like those of Cennino Cennini, Alberti, Leonardo da Vinci, Dürer, Pacheco, Pozzo, Sir Joshua Reynolds, Delacroix, Ruskin, and Sir Charles Holmes. In those and in many less famous, an artist attempts to deal with the rational basis of his work. T h e twenty years that have elapsed since Rood's work was done have left the great bulk of it still authoritative as theory. As a demonstration of the links between theory and experience, both in observation and in representation, it will never be out-dated. Probably it is in this respect that his work reaches its chief distinction. It stands for the late nineteenth century rather than for the post-war twentieth century, but it reaches out into the distant practices and into the far past of the art.

Anyone who takes pleasure in painting, and who may like to locate himself in the problems of representation, will find here a well-marked roadway. It is not only a book about painting; it is a book about the experience of vision. T h e parts of that experience are followed out and interpreted with care. T h e accumulation of evidence about what the eye can see is a kind of salvaging process. It brings on from childhood a memory of a possession which mature men have largely lost. In these pages, however, a mature man can recall, and perhaps in small part recover, a world where things that are seen furnish constant food for thought and for enchantment. T h i s is an adventure into the realm of present reality. T h e author of this book was born in Peace Dale, Rhode Island, April 8, 1863, the son of Ogden Nicholas and Matilde Prunner Rood. He was educated by tutors and later at the Morse School,

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INTRODUCTION

New York. In 1885 he was graduated from Columbia University with the degree, Ph.B. For about a year after that he roughed it in the West. T h e n he returned to New York and, during 1886 and 1887, was assistant to his father, a professor of physics at Columbia. T h e influence of his father must have been strong. Of Ogden Rood, President Nicholas Murray Butler said, " H e was a great scientific investigator and a character as quaint and charming as he was rugged. . . . His research laboratory was the real home of his mind and he lived the quiet, retired life of the typical scholar." Among physicists he is known for studies and innovations in many branches of the science. Among artists he is known as the author of Modern Chromatics, with Applications to Art and Industry, published in 1879 and republished two years later as Students' Text-Book of Color. He worked at drawing and painting as an avocation and was an honorary member of the New York Water Color Society. It is not surprising that the son should have turned to painting as a profession or that he should have carried into it an inquiring mind academically schooled and disciplined further in a physical laboratory. For many years after 1887, Roland Rood was in Europe studying and practicing his art. He returned to America in 1907 and established himself in a studio in New York. He did a number of landscapes but was chiefly active as a portrait painter. Photography was something of an interest with him and he published a number of articles about it. In 1 9 1 7 he married Mary Kain of New York. At the time of his death, which occurred suddenly on February 10, 1927, it was reported that he had been working for fifteen years on a book about color and painting. His widow was then ill at Saranac Lake. She gave what strength she had to the labor of sorting and typing his manuscript. He had left a great deal, much of it as miscellaneous notes and comments, penciled often on pieces of letter paper. Parts were ordered into a more complete treatise. Out of it all came a set of material of which this volume represents somewhat less than half. One can not know how the book would have been arranged if the author had lived to do that himself. Certainly it would

INTRODUCTION

vii

have been longer. It would have taken up questions that are not considered here—the handling of paint, its plastic character, glazes, composition, and design. In the process of assembling this part of the material for publication, I have done as little as I could with the manuscript originally composed. T h e first two chapters have only been treated for minor details of wording and punctuation. T h e later ones have more changes, largely to abbreviate long sentences and involved constructions. A few paragraphs which seemed unnecessary have been taken out. T h e diagrams are made from penciled sketches and from a few finished drawings. T h e footnotes are mine. Defects will, of course, be noticed. During the gap of twenty years since most of this was set down, there have been advances in the study of color, particularly in colorimetry and spectrophotometry. More is known now about color perception and about the history of painting practice. There have been refinements of aesthetic theory. Other defects, which can be easily overlooked, may come from the unfinished condition of the work. T h e "unities" in art and in nature listed in the first chapter were not yet systematically arranged and the appraisal of nature's use of such unities is left arbitrary. Some of the terminology is personal and had to be coined by the author to represent concepts for which there were no standard names. Such words as "phosco tone" have been left with the hope that they might have a meaning to someone. Others like "gradate," "fixate," "syncopated values," "staccato," and "shadows-looked-at," might have been changed by the author. As an unfinished writing, this has awkwardness in parts and some lack of clarity. T h e use of references is obscure and this only the author could have rightly completed. These minor shortcomings I have spoken about do not really detract from the work. In a way, they are part of its charm. They are part of its character of freshness and vitality. T h e book could not have been published without the work of Mrs. Roland Rood. In spite of illness which at times kept her from doing anything over months and years, she still managed

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INTRODUCTION

to get this done. Toward the end it became a struggle against time. At her death in the summer of 1940 she knew that it was to be printed. Miss Caroline Hazard, a cousin of Roland Rood, has helped in many ways to bring together the unfinished manuscript and to make it a publication for the use of many. GEORGE L .

Fogg Museum of Art Cambridge, Massachusetts 20, May 1941

STOUT

Contents

I. II.

I N T R O D U C T I O N , BY G E O R G E L. S T O U T

v

A T H E O R Y OF B E A U T Y

3

SENSATION

15

III.

A R B I T R A R Y VALUES

4s

IV.

SHADOWS AND I N H I B I T E D VALUES

61

P R O D U C T I O N OF C O L O R BY A D D I T I O N

85

V. VI. VII. VIII. IX.

X. XI.

B R O K E N COLOR AND L U S T E R

118

P R O D U C T I O N OF C O L O R BY S U B T R A C T I O N

144

L O C A L C O L O R AND SHADOW C O L O R

169

COLOR CONSTANTS—INDUCTION

AND

CONTRAST

202

A T T E N T I O N AND DRAWING

242

A T T E N T I O N , T H E O R E T I C A L A N D P R A C T I C A L 270 INDEX

289

COLOR IN

AND

LIGHT

PAINTING

I A Theory of Beauty

O

F T H E numerous theories of aesthetics many appear absurd, but at this stage of our knowledge no aesthetic theory should be ridiculed. For a long period we derided the alchemists for having attempted to convert the base metals into gold. Today we keep silent. Their method was scientific, trial and error, but they had a small foundation to start from. So it is with the aestheticians. Their foundation is, and can be, little more than their personal feelings, and sometimes the feelings of a few friends. A man may start with the assumption that the beautiful is absolute like the good and the true, and that it exists independently of man; but if Gothic cathedrals and Michael Angelo's sculpture and Beethoven's symphonies affect him in the same way as the stroking of velvet and the drinking of cold milk or whiskey and the smell of roses, then he can not hold to his thesis. The words he writes will be unintelligible; therefore, unconsciously perhaps, he will twist his argument to express his own hedonistic feelings, and in doing so produce a disjointed theory and make the valuable contribution of defining himself. That such contributions are highly desirable can not be gainsaid, since the question to what parts of the human make-up an aesthetic object appeals is far from being settled; and it is as necessary to understand the various types into which human beings are cast as to understand the make-up and machinery of the aesthetic object. The whole question of taste, which certainly is a vital one, revolves, I believe, more upon the strange way in which men's minds are made, than upon education, environment, and association. It must always be

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A THEORY

OF BEAUTY

remembered that it takes two to make the beautiful, the artist and the spectator—unless indeed we hold with Plato that there is absolute beauty independent of man. In the following chapters I shall repeatedly mention the word beauty. I shall talk at some length about the psychological factors related to it. I find that necessary, perhaps for the reason that this vague and overused word does finally stand as a symbol of the excellence which painters work for. Because I should not like to acknowledge that such excellence is explained by some of the mistaken concepts which are provoked by the word beauty, however, I am going to try to define what I mean by it. I shall try to make clear a theory which, wrong as it may be, can be set to work. I have no intention of attempting to speculate on the ultimate reality, for even if such a thing as absolute beauty exists, our minds are so hedged in by physical and psychological limitations that it would be incomprehensible to us. We can conceive it as existing, but our conception is emotional and not logical. Indeed our false conception of causality, of order, is one of the bases on which our larger concept of the beautiful rests; the whole existence of what appears beautiful to us is principally grounded on various limitations of mind— not on mind's virtues. This sounds as if my theory were intellectual in content and had little to do with the emotions. On the contrary; without the play of the emotions we should have beauty which would satisfy only the mathematical, machine type of man. I even admit that on occasions the coarse, brutal sensations of the body, in transmuted states, are felt aesthetically. As there are three viewpoints from which we habitually regard beauty-—the philosophical, the psychological, and the practical, and as I am dealing with beauty from all three points of view, I shall have to make three definitions. Philosophically, beauty is order. Psychologically, beauty is a subjective phenomenon caused by the projection of our pleasurable feelings, emotions, and sensations, the noblest as well as the meanest, the most spiritual as well as the most animal, into the so-called beautiful object. We confuse this projection with, and believe it to be a part of, the matter of the beautiful object. And just

A THEORY

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5

in proportion to the strength of this projection will the matter sink out of the field of attention into the background, and just so much be canceled. T h e beauty of nature and the beauty of art are substantially the same, and the principles that apply to the one apply to the other. T h e philosophical definition is sufficiently clear for the moment, and I shall postpone, a little, the practical one, but the psychological requires explaining, particularly the phrase, "the projection of our pleasurable feelings, emotions and sensations." Every process of the mind, of the nervous system, and of the rest of the physical system in functioning is capable of, and frequently gives rise to, pleasure, displeasure, or pain. T h e only exceptions to this are the functioning of some of the bodily processes situated in nerveless tracts, and the functioning of the subconscious mind—although for all we know much pleasure and pain may rise from the latter. Of course the object of the functioning is not to give pleasure and pain (that is, as we understand the processes), but the pleasure and pain are everlasting by-products. Be that as it may, we are everlastingly soaked in feelings and sensations. T h i s is easy to understand if we recall the continual functioning of memory, imagination, touching, or smelling, or the functioning of the will in triumphing over resistance, or the pain in bowing to defeat, or the pleasure of easy attention. T h e outcome of this everlasting pleasure-pain state is obvious. W e desire to continue the pleasure and to cut short the displeasure. But how? T h e answer is not so obvious. W e may not be in a position to continue the pleasure, or its continuance may exhaust us. What then? W e shall try to revive the feelings and sensations in our imagination. But there are many pleasurable feelings and sensations which either can not be revived in imagination, or of which the revivification is not satisfactory. There is a means, however, by which this revivification may be attained, and attained under such singular conditions that the revived feelings are made over; they are transfigured into a form which gives them a spiritual signification and pleasure whatever their origin. When there is presented to our senses any object which will

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stimulate any of our mental processes—attention, memory, imagination, tactual cognition, the built-up sense of order, the sense of flying, etc.—then will such processes function and there will be thrown off pleasurable or disagreeable feelings as by-products of that functioning. These feelings will be projected into the object, and if the stimuli are of such nature, and so disposed, as to stimulate the functions into throwing off only pleasurable feelings, then we shall say that the object into which we project these pleasurable feelings is agreeable to look at. And if this object is possessed of a large number of "according" stimuli, then will the processes work with great activity and in various manners and throw off a large number of different feelings, all of which will be projected into the object, and we shall call it beautiful. A well-formed oak is such an object; a well-executed painting is another. I have alluded to the sense of flying as if it were generally understood. This flying sense is no more or less than the sense of empathy we hear so much about. My explanation of it is this: * our gastronomic functioning in the act of swallowing, and our muscular processes in skating, sliding, swinging, swimming, gliding, and dancing, throw off as a by-product what may be called a gliding-flying sensation, and this sensation is, next to the sex sensations—to which some psychologists ally it —the most pleasurable one we can feel; and so ingrained in our mind is it that it forms just as much a part of mind as do the by-products of attention, or of the built-up sense of order. When we project this gliding-flying sensation into an object, we are said to be empathizing that object. I shall now give my practical definition of beauty. Beauty is an objective effect produced by the accordance of the physical appearances or existences through which the beautiful object is cognized by the mind through the eye, ear, and other senses. Physical appearances and existences are color, line, shape which includes space), sound, motion (which of necessity includes • T h e physiological and psychological description given here, like that in other places throughout this work, is probably fallacious according to theory that has developed since the time when this was written, but to leave it out would make a serious gap in the exposition of the author's ideas.

A THEORY

OF BEAUTY

7

time), and touch. All of these appearances or existences are stimuli, as psychologists call them, or unities, as I call them. All nature is clothed in them; I have included in my list all those stimuli through which we cognize the world outside of ourselves, with the exception of heat and other allied stimuli which I have not been able to connect with the aesthetic. My use of the term "accord," or "accordance," I cannot possibly define in a few words; it will take chapters to do so, for in that word, often lightly used, is included the whole of aesthetics. But I can say that it is the accordance of stimuli, as accidentally occurring in nature and as willfully and practically contrived by the art of man, that produces beauty. From this definition of beauty, which can be boiled down to the accordance of the ever-present stimuli in all matter, it must follow that as stimuli always act when we give them an opportunity to do so, and as accordance in nature is by chance, then from the doctrine of probabilities there must be continually more or less complete accordances and more or less complete fragments of beauty scattered haphazardly through nature. I may here remark that this chance presence of beauty continually surrounding us and continually impressed upon us would account for the ever-present aesthetic attitude (even if in most cases it is of a low order) of which we are undoubtedly possessed. T h e simple experiment of listening to a group of people talking and noting each occurrence of aesthetic approval or disapproval, will show how intertwined the aesthetic attitude is with all the other attitudes. We take it that even in business transactions not only must a letter be written in a legible (economic) style, but the appearance of the sheet—that is the spacing, placing, and lettering—must be agreeable to look at. Practically, accordance is produced by putting in order the stimuli or unities, and since in this chapter I attempt to prove nothing, I find it most convenient to give an outline of the method in the shape of propositions. A misconception of Schiller's play theory of art is known to us all.* I give the theory • Here a note by the author mentions Spencer as the most prominent of those who misunderstood Schiller, but any reference or any detailed explanation is lacking.

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itself in Schiller's own words and it constitutes my first proposition. I. " I n an artistic work of true beauty the content ought to be nil, the form everything; by form man is influenced in his entirety; by content in his separate faculties only. T h e secret of great artists is that they cancel matter through form; the more imposing the matter is in itself, the greater its obstinacy in striving to emphasize its own particular effect, the more the spectator inclines to lose himself immediately in the matter, so much more triumphant is the art which brings it into subjection and enforces its own sovereign power." II. All matter is sheathed in broken unities. I I I . When the unities are in accord matter is unified and canceled and there results beauty. IV. When an accord of unities encounters the obstruction of a counter-accord there results ugliness. V. When the unities are all in discord, each acting in opposition to, or differently from, the others, there is no unification and consequently no cancellation, and the result is matter or the commonplace. VI. When all the unities are in discord save one whose intention is carried through, there results a little unification and cancellation and a little beauty; if the intention of two is carried through, there results more beauty; if the intention of three is carried through, there results still more beauty; etc. V I I . T h e greater the number of unities clothing the matter, the greater may be the unification and cancellation or counter unification and obstruction and the greater the beauty or ugliness. V I I I . T h e more powerful the unities are, the more complete may be the unification and cancellation and the more excessive the beauty. I X . T h e most powerful unities are the spiritual unities which are non-existent in nature and are only at the command of the artist; and as almost all the unities at the disposal of nature are equally at the disposal of the artist, the artist can produce greater unification and cancellation and therefore greater

A THEORY

OF BEAUTY

9

beauty. It follows that: (a) the opposite of beauty is not ugliness b u t the commonplace, the self-assertion of matter; (b) n o excess of n u m b e r o r quality of unities acting in discord will increase the commonplaceness, for matter cannot become more material through insistence. I interrupt the propositions to give the unities. In the following table in the left column are those w h i c h art employs; and in the right c o l u m n are comments as to nature's share and use of them. The Unities in Art Grouping and massing Focal attraction Proportion Repetition Variety Alternation Interchange Symmetry and balance Harmony and contrast Succession, evolution of shapes Radiation and tangential juncture Outline Rhythm Touch (as in mosaic-handling) Line currents Composition T h e motif, fusion of contents (character) Stability Enframement Proportionate values T h e value-break (span of perception) Artificial systems of values Chiaroscuro Color gradation

The Unities in Nature Sometimes fairly well Sometimes indifferently; usually badly Never Poorly ordered Destructively overpowering in quantity Rarely and poorly ordered Rarely and poorly ordered Sometimes fairly well Sometimes moderately well Sometimes fairly well Often very well Never Poorly Never Often and well Rarely and badly Rarely but well Often and powerfully Never Incomparably better than a r t — perfectly Never Never Occasionally, and very well and powerfully Often and superbly—better than art

IO

A THEORY

The Unities in Art Color fusion (softness) Color saturation Color harmony T h e plastic contrasts Smoothness (texture) Natural tone Phosco tone Double tone Envelopment Obscurity and mystery Gauze (the drama) Transparency Varnish and glaze (plastic contrasts) Decay of medium T h e human unity, called expression or the soul, really the style or form The plane The sphere T h e cone The cylinder Weight (gravity)

OF

BEAUTY

The Unities in Nature Often and superbly Often and superbly Very rarely but sometimes well Always and perfectly Sometimes Far superior to art Never Never Occasionally; fairly well Often; only fairly well Never Rarely; not well Never Sometimes, poorly Never

Sometimes and perfectly Rarely but sometimes perfectly Rarely but sometimes perfectly Rarely but sometimes perfectly Volume Sometimes superior to art, someTime times inferior Sound Far superior to art Size Very poorly Very poorly Motion (usually none) Sometimes superior to art; sometimes inferior Contact (tactile) Sometimes superior to art; someIt will be noted that the above table merely a list of what times isinferior Nonewhich the artist employs, are generally termed the art means and it is easy enough to understand that through the use of these means the artist can translate nature into art. T o conceive of nature as employing the same means to produce its beauty is nearly impossible, but I intend, bit by bit, to prove that it does. T h e r e may seem another objection to the table. I state in

A THEORY OF BEAUTY my second proposition that all matter is sheathed in unities and among my unities we find cylinders, repetition, color, time and a most heterogeneous assortment of concepts. It is easy enough to understand how the trunk of a tree may be draped or sheathed in a cylinder, and in color, but how can it be clothed in time and repetition? It can be sheathed in repetition, as I shall later show, and as for time and some of the other unities, I hasten to point out that by matter I mean matter in its philosophic sense, not merely as the form of being or substance that is characterized by extension, inertia, weight, and so forth. In painting it may be the material world, and also movement and weight; in the drama it may be movement and sound and weight; in dancing, weight and inertia and gross matter; in architecture, extension, and so forth. Or, to put it another way, by matter I mean those contents which form the subject matter of the "object of art"; in music the subject matter is the musical notes which are partly unified by time and partly canceled by it. My table would fail to be a table if it did not enumerate all of the unities employed in all aesthetic production, for the simple reason that all the arts are merely different forms of one and the same spiritual manifestation, and what is true of one is true of the other and there are no exceptions. It will be seen that our familiar friends, unity, order, and several others have been dropped from the list. All of the unities I have given are unifiers; unity is not a stimulus, not an art means to an end, but is the end itself and so has no place among the means. And as for order, order is the final goal of the artist. Proposition III says: when the unities are in accord, matter is unified and canceled and there results beauty. If we analyze this proposition and the others which follow, we shall find that they seem to presume that the very fact of bringing the unities in which matter is sheathed into accord will at one and the same moment unify matter, cancel it, and produce beauty, and that therefore all the artist need know is how to bring the unities into accord. That is true; it is all he needs to know, but to know it means to know all art. My propositions are a trifle condensed, but by stating a final one I can somewhat fill the

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gaps and give a little clearer idea of what I am driving at and what I shall try to prove. X . When the unities sheathing matter are in accord, each with the other and each with all the parts of itself; when this accord within each unity obeys the law of the particular character of that unity; and when the expression of this character agrees with the expression of character in the other unities, then will the cognition of the sum total of the many agreeing intentions be satisfying to the physiological and spiritual demands of our nature, (a) T h e tension strains of attention and the sense of order—that portion of consciousness which may strive to comprehend a great law of order in the universe—are released by this agreement of order in matter. They encounter no objection from the ever critical judgment, and therefore none from the will. Both the judgment and the will retire, leaving the imagination and emotions full sway. T h e agreement of order in matter, by its agreement with the demands of the sense of order, plus relief from the tension strains, will be such a freedom from the continual criticisms of the judgment and from the continual cognition of disorder and from tension strains that there will result a pleasurable feeling in the mind, in consciousness, a feeling of delight through which the matter is seen as through a magic veil. Not merely will the relief from disorder and tension strain be pleasurable, but the pleasure will increase as the quantity of order increases. And thus the matter will be canceled, (b) When the critical judgment has been forced to retire, there results a state of mind, bordering on the dream state, where the judgment is paralyzed and where we accept all the nonsense of the imagination without criticism, (c) T h e evidence of order is cognized logically and sensationally, but when its cognition produces over-strong intellectual feelings these feelings will run over and out from the intellectual grasp into the well of emotions, where they will arouse the emotions which will blend in with and augment, while somewhat altering, the intellectual feelings, (d) And if the emotional well is very strongly appealed to, it will in its turn boil over and discharge itself into the fleshly body where it will

A THEORY

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13

arouse strong sensations, which, though different from either the intellectual or emotional feelings, will blend in with them and form one whole complex. This, from the richness of its make-up, will be stronger than merely intellectual cognition, or intellectual plus emotional feeling. Before closing this chapter let us glance once more at the table of unities which are the tools by means of which all the unification, cancellation, etc., is to be done. T h e y differ in their many qualities but are all appearances and states of matter. This may not seem so and therefore must be taken on faith until I demonstrate it. And all nature and matter are sheathed or clothed in one or another, or in many of them, and it is impossible for nature not to be clothed in them, for these unities are the different forms matter takes—matter can take no other. Therefore, these unities being aspects and appearances of nature, they are all stimuli more or less strong. They are always ready to act and do act when not rendered nil by a contradicting unity. But as the surface of nature is usually composed of an endless mass of contradictions, there is usually very little agreeing stimulation from it. If an agreeing stimulation is received by the aesthetically blind, then there is no response by the recipient and the matter of nature continues to appear to him simply as matter— as it always appears to him. Beauty is therefore a dynamic force always trying to assert itself through its unities. Put the unities in order and the beauty in the object (matter) becomes apparent. I do not mean, as it would appear from this, that beauty is objective in its nature; I mean that nature gives matter and that it gives also disordered unities. If these unities can be put in order, then will they act as powerful stimuli, so strong that the mind will set to work and with their aid cancel the matter and give birth to beauty. Beauty is subjective. But the artist always looks upon it as objective, and realizes that his function is to determine what are the unities sheathing nature and to order them, even if only in his mind; or to add such additional unities as are necessary; or to eliminate some unnecessary unities. A landscape may be very commonplace, but the artist sees that it is only necessary to sink it in

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chiaroscuro; or to leave the flat glaring light as it is and to carry through the intention of the pattern (ornament) of the leaves; or to carry out the character (motif) given by one single tree. T h e n will the landscape become transfigured and beautiful. For all practical purposes beauty is objective and alive and ever trying to assert itself to those who can see, and it is only needed that the artist break the deadlock of the unities (the stimuli) and it will be born. This is the only way for the artist to look upon nature. I shall always speak of beauty as objective, knowing that it is not. When an artist gets into difficulties with his picture or poem or play, he knows that the beauty is already there on his canvas or paper, but that there is something which prevents its revealing itself, and he wants to know what that is, and how to get rid of the obstruction.

II Sensation

I

H A V E S A I D that beauty is the resultant of the accord of sensations and ideas. If this is true, the logical way of proceeding will be first to determine what a sensation is. But as sensations are the effects of stimulation on the sense organs we shall have to study the receiver of stimulus, the sense organ, and the sensation all together. When one solid object is sharply struck by another, the motion is partly converted into a different kind of motion: the object vibrates. This vibration may not be visible to the eye but imparts itself to the air which is in contact with the objects thus producing waves of compacted air which, following in quick succession, radiate in every direction. Some of these waves are lost in space. Others fall on various objects; their movement, like the initial movement, is converted into air waves and heat, and so on until equilibrium is restored. Physics and popular language are apt to call these air waves sound, but they are not, they are merely matter in motion. These waves remain in motion, and they may strike on the drum of the ear, whereupon psychology changes their name from air waves into stimulus. But even this stimulus is not sound, it merely causes another form of vibration, a movement of the drum of the ear. T h e mechanical movements of the drum are converted into other movements, all easily followed by the anatomist, and then in some incomprehensible manner something is communicated through the nerve of the ear to the brain and then to consciousness. Consciousness experiences that which has and can have no existence outside of itself, namely the sensation of sound. But of what this

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SENSA TION

sensation is we know absolutely nothing. All the science and metaphysics in the world can tell us no more of what it is than of what consciousness is. T h e study of light gives the same result. In this case the body radiating the waves of motion makes use of the ether, but in a manner not so clearly understood as the mechanism of the sound waves. This motion, acting as a stimulus to the retina of the eye, produces there some other form of motion or chemical activity —which is also motion—and then in consciousness we experience the sensations of light and color. These are different from the original motion. So it is with radiant heat, which is a somewhat slower form of motion than light waves, and becomes translated in mind into the sensation of heat. Heat as such has no existence in nature—there it is only molecular motion. T h e sensations of taste, smell, pressure, cold, and so on are in the world outside of consciousness equally resolvable into motion. There is only motion in nature, motion of many kinds, and we name these different forms of motion by different names of forces. And also, of course, there is matter, even though it may be, as some tell us, merely motion got into a tangle. So we can say that nature consists of matter and physical force, and consciousness is ever filled with that which has no earthly connection with the physical world. There is no light in nature. We live, and walk, and do our work in unutterable blackness. Our usual saying is that within the skull all is dark, but in reality that is the only place where there is any light. Nature is lightless. T h e lightning flashes darkly, the thunder roars silently, and all things are without temperature. It is mind that has given nature her beautiful light and color, her cheering noises, her genial warmth, and her fragrant odors. Nature is a blank and incomprehensibly dreary desert, but as we spend all our time living within our bony skulls, we rarely discover the truth. Moreover nature has not even appearance. Things in nature have extension, direction, limitation, hardness, roughness, smoothness, weight, and many other qualities, but no appearance. There are two worlds. And the world within our minds is not, as we fondly think, a miniature copy of the world without.

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T h e r e almost seems to be no connection between the two. T h e y fall into such entirely different categories that many of those who think profoundly fail to see how we can bridge from the one to the other. A l l of this may seem apparent enough and so I shall explain that the reason for my insistence is that the study of art and aesthetics consists of a perpetual effort to perform this bridging between two worlds which are governed by laws incomprehensible to each other. Unless we awaken ourselves into a realization of these differences, we shall miss every point. Language unfortunately has been so constructed as to slur over and hide the differences as much as possible and to misrepresent this truth. Because of that, language can make false reasoning seem sound. Sometimes there appears to be a little similarity between the two worlds. W h e n on the back of our hand we lay a very light weight, we say we experience the sensation of contact, and when the weight is increased we experience the sensation of pressure. W e experience the gravity in the weight. When the weight and pressure are increased still more, we experience the sensation of pain, but there is no pain in the weight. Our tactual sense, however, gives the greatest correspondence between the two worlds, and if we were allowed but one sense organ, we could choose this as the most valuable. It may be asked then, how is it that when our sense organs give us sensations, experiences which we can in no way connect with nature, we are able at all to understand nature sufficiently to cope with existence. T h e answer is that the reason acts on these sensations in consciousness and, treating them as mere symbols, just as a mathematician treats his symbols, converts them into ideas. In that shape they become useful to us. But we must never fool ourselves into believing that even between ideas and nature there is any solid connection. There are many who, never having introspected themselves, fail to recognize some of the sensations as being such, and claim these sensations to be knowledge, ideas, thoughts, anything except the simple sensations they are. Many persons fail to understand that vision is largely sensational and that the sensations

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produced by patches of light falling on the retina are experienced in the same manner as the sensation of pressure in the viscera, contact on the skin, and odors in the nose and mouth. We accept the sensations produced on the skin and tongue and in the nose and throat and viscera as sensations and deny the same categories to the sensations of hearing and vision, because none of the bodily sensations arouse much reflection of any sort, whereas the sensations of hearing and vision, especially the latter, so instantly arouse the intellectual processes that we focus on what these processes bring into being and forget to note the sensations. A loud crashing noise produced by machinery will be painful, for the reason that it is so overbearing, and we can not help calling it a sensation. But when our friends make sounds with their throats, we accept these as language and fail to note the sensation because it so immediately arouses intellectual processes. Even when our friends get excited and shout, we do not recognize the sensation produced if we are interested in what they are shouting about. Only when interest flags do we experience an overpowering sensation. It is the same with vision. We look at objects and see them. T h a t is, as far as we are aware, the whole process. If we choose we can analyze these objects into various patches of color differently sized, shaped, and disposed, but we do not say that we experience any sensations as we do when we touch or when we smell. We seem simply to see objects and understand them. T h a t is true. But what does the understanding of an object mean? It means attention to the resultant of an intellectual process. W h e n we see an object and understand it, we are not experiencing the several sensations effected by the various color patches, which are b u t the symbols out of which the intellect constructs the complete object, or rather idea, but we are concentrating our attention on a completed and built-up thing. T h e sensations themselves, which are in part the materials out of which the intellect constructs the object, are no longer experienced, b u t sink into the background of consciousness. Putting all this in another way we can say: attention as a rule focuses on the sensations of touch, taste, smell, and heat, particularly the last three

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because these have so little meaning to detract attention from themselves, but attention focuses on the products built up from visual and auditory sensations because these usually have so much meaning attached. He can easily approach the matter experimentally. Let a man be blindfolded and gently touched in various ways and on various parts of the body by a variety of objects both dull and sharp, and both hot and cold. He will experience and know nothing except bodily sensations. T h e n let someone put in his hands various objects of a complicated construction, but objects he has seen. He will feel them all over but not recognize them at first. He will still distinctly experience the sensations of touch, but at the same time another element will enter his consciousness the element of an external reality, and even if he is performing the experiment self-consciously, the experiences of touch sensation will not occupy the whole field of consciousness. There will, if he persists sufficiently long, come moments when the sensations of touch will entirely disappear, and his consciousness will be filled with the cognition of a piece of matter, or with a solution (an idea) such as, " T h i s is a bathing suit," or, " T h i s is an egg-beater." In the blindfolded state the function of giving meaning to sensations of skin contact, a function which in the open-eyed state is partly accomplished by the interpretation of visual sensations, depends entirely upon the interpretation of tactual sensations, and attention is therefore detracted from these sensations to the ideas which they help to form. T h e blind, therefore, experience skin contact more as the cognition of things than as sensations. That sensations are habitually inhibited when their cognition is useless to us is realized when we consider the sensation continually produced in our noses by the air we breathe. T h e same is true with the circulatory apparatus. T h e sensations of contact of clothes and skin are inhibited. All this seems natural enough; in taste, touch, smell, feeling of heat and cold, the sensations themselves are important, whereas in seeing and hearing the ideas resulting from the sensations are important. James says that it is a general principle in psychology that consciousness

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deserts all process where it can no longer be of use.* No experimental psychologist fails to experience the sensations of weak visual stimulation, and painters are talking of them all the time, though they usually call them feelings. LIGHT

There are two worlds, the world of nature and the world of mind. One may speak of the sensation of light coming from a white cloud, but the cloud does not send out sensations, nor is it white. T h e cloud radiates light waves which fall into the eye —an interpreting or rather transmuting station—and are there translated into what psychologists call local signs. Those signs, or signals, are sent to the brain. There, this impulse finds its way into consciousness and is experienced for the first time as the sensation of white light. As the whole of aesthetics is founded on the assumption that there are two worlds, we must at the outset guard against confusion and devise terms which will safely lead us past pitfalls and which will, at the same time, be simple. Physics accepts sunlight reflected from a white cloud as its standard of pure white. T h e light falling from the blue sky into a room is not pure white because it is tinged with a little blue. This color, however, we fail to experience because we are so used to it. W e inhibit it. White light, acting as a stimulus to the retina of the eye, is experienced in consciousness as a pure and unmixed sensation, and we are not prepared to learn that when a beam of white light is passed through a prism it appears not to be pure at all; it splits up into red, orange, yellow, green, blue, violet, and lavender. How is it, then, that these several stimuli, acting simultaneously on the retina, cause such local signs to be sent to consciousness as to produce a sensation entirely different from that which any one of these, acting singly, would produce? This question has never been finally answered. It seems strange and finds no analogy in the functioning of the other sense organs. For one sensation to contradict and neutralize another is usual, but for two or more to combine into a • Like other quotations, direct and indirect, this carried with it no specific reference in the author's manuscript.

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totally different one showing no trace of its constituents seems unaccountable. Lemon juice, sugar, cold, wetness, all produce individual sensations when applied singly to the tongue; when applied together they produce the new sensation of lemonade, which, however, is analyzable (with practice), into its constituents. T h e bitter of coffee and the sweet of sugar to considerable extent neutralize each other, but the new sensation is a logical combination. Musical notes may be compounded with their overtones into single sensations, but these compounds are not pure sensations and can be split up. A large n u m b e r of musical notes sounded together will produce a new sensation, noise, which it is absolutely impossible to analyze, but—and this is important—when we experience such a noise, although acknowledging it to be a distinct sensation, we instantly recognize that it is not pure; whereas the first thing we feel regarding white light is its simplicity and purity. It is not necessary that all seven spectral color waves should impinge on the retina simultaneously to produce the sensation of white: ultramarine blue and yellow, or red and green, or yellow-green and violet, or orange and blue-green, and many other combinations stimulate the retina into transmitting such local signs as to cause the sensation of white in consciousness. And on the other hand a certain green and a certain red cause yellow, and a certain orange and violet cause red, and so on. It may be said then, in physical terminology, that white light is not white at all. It consists of colored lights of all descriptions, which, falling on the retina simultaneously, stimulate it in such a manner that it sends an altogether u n t r u e message to the mind, or else it sends the true message and the brain does the falsifying. T h a t the falsifying is done somewhere within the skull is very evident, for physics, as we have seen, proves beyond a shadow of doubt that white light has no existence. It is a creation of mind. T h e explanation of all these phenomena, as well as innumerable others, is attempted by the Young-Helmholtz, the Hering, the Ladd-Franklin, and numerous other theories, the first two being the most prominent. But they contradict one another, the

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Helmholtz theory flies in the face of accepted psychology, and they all fail to explain many phenomena like the one we have just touched on. Virtually, today after centuries of work, there may be said to be no agreement, that is no agreement on how mind experiences light and color. T h e theories on physical light, however, are sufficiently consistent to constitute a magnificent science. It is true therefore that we painters and aestheticians, whose interest, both practical and theoretical, lies in what we experience in consciousness, find ourselves without any working theory. Consequently the only thing we can do is to proceed without it, occasionally taking a glance at the theories when we feel they may be of assistance.* T h e loss of a theory such as the Young-Helmholtz or the Hering, is very slight because neither of them tries to solve the real and interesting problems: how is the mechanical or chemical activity of the retina converted into local signs or signals; what is a local sign; how does a local sign travel through the brain; and, above all, how is it converted into a sensation in consciousness; what is a sensation? T h e s e are the great questions beside which the problem of the particular mechanical activity of the retina sinks into insignificance. If Helmholtz and Hering and the others agreed with one another and with the empirical facts, we should still have no theory; we should scarcely be in the antechamber of the theory. WHITENESS AND NEUTRALITY

W h e n we look at nature we find (in physical terminology) that every object is colored, even if only very slightly. A l l the objects and various parts of the objects send to our eyes different quantities of light. Nature has a color element and a light-dark element, and these two elements are, with astonishing ease, sepa* Frequently in such connections as this the author is more contentious than analytical. It must be accepted as a consequence of the unfinished state of his work. Unfortunately, the reader is left without a very clear description of the theories discarded, b u t most of them are given in standard works on physics and optics. A l l of this part of the development can be clarified and brought up to date by a reference to the work of A r t h u r C. Hardy and the staff of the Color Measurement Laboratory, Massachusetts Institute of Technology, Handbook of Colorimetry (Cambridge: the Technology Press, >936).

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rated in mind, the one from the other. So easily is this separation made that it is consciously, as well as unconsciously, effected by everybody many times a day. T o separate the lights from the shadows seems logical because that is differentiating between very apparent quantities, but unconsciously to divorce the lightdark element from the color itself means disentangling a compound sensation without effort of thought. T h e singularity of our ability to differentiate between the color and the light-dark only becomes evident after reflection, and then leads to the suspicion that somehow consciousness always has two attitudes toward color: it experiences its color proper, and it experiences its light-dark element. When a black and white drawing is shown to children who are too young to perform the simplest operation in abstraction, they instantly recognize its meaning as do adults and always fail to note its absolute dissimilarity to nature. It may be argued that children understand outline drawings more easily than any other and that outlines are abstractions, but in reality outlines are the most concrete elements in visual perception. They are the sole things objects always possess, and it is just because outlines are the most concrete that the child understands. Modern physiological investigations tend to show that elemental vision is colorless vision; elemental eyes translate all differing qualities of stimulation into one quality of local signs which reaches the mind of the creature possessing the elemental eye as varying quantities of this one quality. But this quality, which may be what we call red or green for all we know, is perceived by the mind behind the eye as white. This, reflection will show us, must inevitably be so. Suppose nothing in the way of color save the sensation of red ever made its appearance in our consciousness. W e should then only distinguish between the differing quantities of this redness, namely the light-dark element. Never being able to compare the redness with other color sensations, we should never acquire the idea of color sensation. T h e concept of color itself would be missing in our mental make-up; the red sensation would merely mean light to us. And light without any quality attached is merely light of no, or of

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neutral, quality. And light which is neutral is white, of necessity, because white is the only neutral of which we can conceive. It may be asked, how is it that we human beings have come to adopt the bundle of light rays coming from the sun as our concept of white when we are capable of making comparisons of sensations? Why did we not adopt green? We adopted the particular sensation effected by sunlight because it is ever present; what we call color is the rarity. All colored objects whatever, under any and all circumstances, even in the dead of night, have a certain amount of white (usually a large amount) mixed with them. Our most vivid pigment mixtures are largely adulterated with white, and even the sun spectrum, as generally seen by us, contains white. White is the medium in which nature sinks all her colors. It is easy enough to get rid of yellow or blue or red or green, but no one ever, even in the dead of the night, buried in a black room with his eyes closed, can get rid of whiteness, for the simple reason that the constant activity of the retina, owing to the blood circulation it is said, always furnishes some white. Whiteness is merely the quality-less sensation produced by constant visual stimulation. Pass from daylight into a lamp-lit room; all is orange. Remain immersed sufficiently long and the whites will begin to assert themselves again. Look out of doors and note the bluish tone of everything. Go outdoors and it is gone. If the sun were to turn pea-green we should feel rather astonished at first, but undoubtedly after a period (it might be long) we should get used to it and it would appear white again. The trees and grass would follow suit, and all the other colors would change. T h e perception of color sensation is purely relative, and whiteness is naught but an idea. Whiteness, or white-black, is the idea of the predominant ever-present medium in which all other color is sunk, and as the light of the sun remains fairly constant, we never have occasion to change our idea of white and we come to regard it as being equally constant with the law of causality. But it is not. There is nothing farfetched in my reasoning. Our other senses act in the same manner. Air has no

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odor and water no taste only because the stimulation is everpresent. T o return to primitive sight. In such vision, as we have said, all the differing qualities of light waves are alike and receive but one response. T h e perception of color appears to be the work of a higher evolution, and an addition. T h e r e is, however, no evidence to lead us to believe that the eye, when it added its color susceptibilities, threw overboard its firmly established and individualized black-white perceptive functions. O n the contrary, both of the functions work side by side and appear as one, save at occasional moments when we seem to forget the color element and only experience the black-white. T h e latter we never lose for an instant; it is the fundamental, the basic form of light. T o those who object to my description of the evolution of the color sense, and to my drawing inferences from it, I shall say that whatever the evolution may have been, our color perception today acts in the manner I have described. BLACKNESS AND THE VIVID

Hering in his theory postulated four fundamental color susceptibilities of the retina—yellow, blue, red, and green. T h i s is all right enough from the painter's viewpoint. But he added white and black susceptibilities: namely, he placed white light and absolute blackness on a par with colored light and insisted that an image of some black object falling on the retina acts as a stimulant in identically the same manner as does white or red. W e are quite ready to agree with the white, but how can black, the absence of all motion, produce retinal activity? Hering insists that when we see a black area in nature, it produces a sensation just as positively as does a red area next to it. T h i s unquestionably is so, and every artist will enthusiastically agree with Hering that black areas in pictures act as forcefully as colored areas, and the reader can try it for himself by placing a square foot of very black paper or black velvet on a white wall in a medium light, and alongside of it—at a distance of two feet — a vermilion or other strongly colored square, and by glancing

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from one to the other. That the black is as sensational in its effect on consciousness as the color is indubitable. But both Leonardo and Helmholtz state clearly that black is the absence of all light. Both Leonardo and Hering as well as Helmholtz are right. T h e question simply resolves itself into: how can nothing produce a sensation? Very easily. Nothing produces a sensation more easily than nothing. Black produces a sensation but not the one psychology has been looking for—it produces the sensation of astonishment at the unexpected, at suddenly finding an area of nothing in a space that is all filled in with stimuli producing color. This astonishment is only experienced when the black area makes its appearance in a group of illuminated objects which we feel should logically all be illuminated. Nor do we usually experience astonishment when looking at very dark shadows, nor in the night, nor when we close our eyes, for then, expecting blackness, we cannot be astonished. But when I look at black velvet and suddenly see nothing, or when I look around my room and my eye falls on a piece of black lacquer so placed as to reflect no light, I experience a strong sensation. It is the nonfulfillment of confident expectancy that is astonishing. And this nonfulfillment upsets the judgment and there results a commotion in consciousness. Also, black to produce a sensation must be adulterated with as little white as possible. White takes the edge off the phenomenon with great rapidity. A blue-gray, half color and half white, is still a strong stimulus, but such a mixture of black and white is like well-watered milk. Black diluted with only as much white as is always contained in chrome yellow no longer acts as black. Every painter knows this. And the reason is that nothing ceases very quickly to be nothing if something is added to it. A very small quantity of white in black causes the mixture to be measured by mind as so-and-so much white—the void has lost its spell. This is why grays produce lukewarm sensations, as every tailor knows. There is next door to no potency in dark gray: it does not astonish, nor is the quantity of white in it sufficient to stimulate strongly.

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But, it will be asked, is not the sensation of astonishment so different from the sensation of color that we should instantly detect the disparity? In the first place black, as we have seen, only produces its peculiar sensation when pure or almost so, that is, when it is what we call "vivid." We have reason to believe that all vivid colors affect consciousness in such a manner that it acts emotionally—vivid red, vivid green, vivid black, are felt emotionally. And when sensations are felt emotionally they become very difficult to analyze. Secondly, I have often and distinctly felt the shock of astonishment when suddenly coming upon a large area of black, astonishment which I have never felt in the presence of colors. What holds for large areas holds for small, and I believe that if others introspect themselves they will get the same answer. Hering—I believe it was Hering—in his classification of color elements tabulates them into three sets: the red-green, the blueyellow, the black-white. This, altogether apart from my argument above, is necessarily fallacious. If we place a piece of black paper in sunlight and close by in the shadow a piece of white, it will be observed that the black scrap becomes whiter than the white one, and it is not difficult to juggle them around in lights and shadows of different strengths so as to get them to appear identical. But no amount of juggling in lights and shadows will ever make blue turn yellow or red turn green. T h e blackwhite belongs to a totally different category from the color elements. Leonardo had it right. White is all colors, black none; but having no psychological interest, he carried it no further. Painters, although they look at black as a color and use large and small areas of it in a nearly pure state to enrich the color scheme of their pictures, soon find something "weird" about it. When a man dressed in a coat of very black quality is placed in a studio side light of medium strength against a not very dark but shadowed background, it can be so arranged that the shaded side of the coat is darker than the background and the illuminated side lighter—which is quite normal and in nowise unpleasant to look at. But when the painter paints what he sees, taking due precautions to retain the true relations of light and

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dark, the whole thing will usually come out "all wrong"; the very quality the whole thing was done for, the richness, blackness of the coat, will all be gone, and in place there will be a coat with black enough shadows, but with chalky and offensively gray lights. T h e reason is that the painter's blackest black is the black on his palette, whereas the coat's blackest black is this same black blackened still more by being in shadow, namely many shades darker than the palette can go. But the painter can do no better than use his black pigment to copy the greater black of nature, and perforce must mix a fair amount of white with the black on his palette to obtain the light and half-light. It is this white which kills the sensation of nothingness in the painted coat. But no such thing ever happens when the coat or object is colored, for the simple reason that colors depend upon the color stimuli to produce their sensations and when the color is weakened too much by excessive white it is in large part replaced by the very white which weakens it, whereas the quantity of white sufficient to destroy the nothingness of black is no more than sufficient to produce a very weak, lukewarm sensation. Lukewarmness, although very agreeable in certain places, is exactly the opposite from what we expect of black, and we are disappointed and disgusted. It appears to have been Hering's fallacy that he mistook the subjective effect of contrast for an objective quality. A few experiments, tried thousands of times by others, may illustrate this. In my room, around the corner from the window, I hung a piece of black velvet a few feet in front of me so that it received no direct light. Shielding my eyes from the light, I looked at the velvet. It looked impenetrably dark. But as I continued to gaze, it lightened a little and I became aware of a few folds in the cloth and these became evident not because they darkened but because the rest lightened, owing to the expanding and accommodation of the pupils of my eyes to the general darkness. Then, in my direct line of vision over the middle of the velvet, but a foot nearer to myself, I introduced a square of white paper held at such an angle as to let it receive direct light. T h i s was easy to accomplish owing to the positions of the velvet and myself. I

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stared at the white. Instantly, like a descending wave, the velvet darkened still more, simply because of the accommodation of the pupil to the white. I continued to stare. T h e white dulled a little and the black lightened a little, unquestionably due to fatigue. Suddenly I removed the white paper, holding my eyes steady, and in a second or two saw an astonishingly black square on the velvet. A few trials however made it evident that the square was not so black in itself, but that the velvet around the square had lightened materially; it even looked gray, and it was this contrast which made the spectral image of the white square look so dark. In fact, the truly astonishing thing in this experiment is not the darkness of the afterimage of the white, b u t the lightness of the black surrounding the after image. Why should this lightness of the black occur? T h e dilation of the pupil on the removal of the white square would account for it only to a slight extent, but the gray disappears and darkens again when the effect of the afterimage has worn off. So it cannot be due to the dilation of the pupil and it cannot be due to successive contrast, because the same stimulus (or lack of stimulus), the black, is still acting on the same portion of the retina surrounding the spectral image, the conditions of the experiment being, as I have said, that the eyes shall not be moved. It must therefore be simultaneous contrast—that is, inducted contrast—and I believe the whole of this resolves itself into a question of contrast. As a next experiment, gazing into the dark velvet as before, I drew it to myself. It grew darker and darker, and as it almost touched my eyes I realized that the darkness was greater than any afterimage had been. I threw it over my head, and a greater blackness than all swept over my consciousness. As I sat there with the velvet pressed to my eyes a singular phenomenon took place. Everything remained the same. T h e blackness neither lightened nor darkened, but my opinion, my judgment regarding its blackness, altered materially, and I decided it was not so very dark after all and wondered why I had thought so. What had happened was this: mind judges the strength of a sensation by its vividness, and vividness is produced by the passing from one sensation to another. T h e greater the shock of the contrast

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of the sensations, the greater the vividness. But as in utter blackness there is no objective contrast, and as the memory image of daylight begins rapidly to fade, thus even eliminating the contrast between an image of mind and an objective fact, then consciousness, finding itself in a state where all possibility of the production of vividness is denied it, judges that the sensation is not so strong after all. It is for this reason that when the absolute blackness of the closed and shielded eyes is presented to vision, we deem it lighter than the gray-black of nature. But, it may be asked, how do I know that the darkness I experienced when first I threw the velvet over my head did not lighten? Because consciousness feels the weakening and strengthening of a sensation keenly. It is a psychological commonplace that a much smaller difference of sensation registers in consciousness when the sensation itself is changing than when it is successively compared with another sensation. Therefore black, as Leonardo and Helmholtz claim, is nothing, and white is everything. But from this we must not falsely conclude that black and white are the opposites of each other as is constantly premised. Everything and minus everything are opposites; and plus a billion dollars and minus a billion dollars are opposites; but a billion is not the opposite of nothing, namely zero. Opposites destroy each other and leave nothing, but white added to black only changes the sensation from one category to another, a thing that has no connection with annihilation as implied in opposites. In case the reason stated above as to why black produces a sensation may be objected to, I am giving the following physiological * explanation. When we look at a patch of color, we experience a sensation which, however, continues to weaken as we continue to look. When we suddenly turn from the patch to another of a different color, we experience a sensation which is particularly strong at the instant of making the change. Our attitude, or what psychology calls our attitude of attention, suddenly changes from one state of adjustment to another, and the • According to current knowledge in these fields, such comments on physiology and psychology may be quite out of date.

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change requires an effort. T h i s effort is felt in consciousness as a shock, and the greater the contrast between the two patches of color, the greater the necessary change in the attentive attitude, and the greater the shock. T h e shock when strong produces upon us the sensation of what we call vividness. Vividness is merely the effect produced by the sudden and violent adjustment of the attention to something new and different. Now the greatest possible change in attention that color can produce is caused by looking from bright light into blackness, from white paper onto black paper, and when we do so we feel that the black paper is producing the sensation, whereas in truth the sensation of vividness apparently effected by the black has not really been effected by the black itself but by the shock of changing the attentive attitude. T h e fallacy in everyday reasoning about sensation is the assumption that sensation can only be effected by stimulus. Sensation is usually effected by stimulus, but it is often effected by the change of action of the attentive apparatus, independently of stimulus. T h a t black in itself is incapable of producing any sensation is demonstrated by closing the eyes and shielding them under a black cloth. When this is done suddenly a shock is felt for an instant, and then all sensation dies out. And the reason we do not experience any sensation after the first adjustment is that the attention is no longer called into play simply because the blackness under the closed eyelid is all black and there is no possibility of a change of attitude. Therefore I conclude that the shock or sensation produced by black is the effect of the change of attentive adjustment from a stimulus to absence of all stimulus. I place more faith in this explanation than in the astonishment explanation. VALUES

Painters have given the name values to the light-dark element in nature. At first glance the term appears unfortunate for there are values of many kinds in nature, to say nothing of art. But confining ourselves to art, and particularly to the graphic arts, we find that the term seems appropriate. When we try to construct a scale of values of line, we find such insuperable difficulties that

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we quickly abandon the attempt; and although we can to a certain extent and in a rough way formulate values of color, in the end we find that it is only the light-dark element that easily and perfectly lends itself to the reduction to value scales. Also, as the light-dark element is the most important in painting, we feel that the painters are in their right when they say values pertain only to the black-white phenomenon. Wundt defines values as achromatic light, achromatic meaning non-colored, and a value system he calls a series of grades of brightness. I shall use all three terms as suit the occasion. Helmholtz has given us many measurements of brightness in nature. He tells us that the light of the sun is 150,000 times brighter than the light of the moon falling on a white surface; and white marble as painted in a picture is 10,000 to 20,000 times brighter than real marble in moonlight. T h e pure black on the palette is many times brighter than moonlight, and the painter's white falls far below the sun in values. And yet the painter's white pigment on his canvas often makes us strongly recall the sun in the heavens, and his grays take us into the dreamy moonlight. How is it done? It would hardly appear to be through imitating the strength of the brightness or weakness of the light in nature. Possibly the measurements of the relative values of nature overlook something. When we look at the sun or in its neighborhood, the pupil of the eye contracts to its smallest area, letting in the minimum quantity of light; and when we look at the moonlight falling on white walls, the pupil opens to its utmost, letting in the maximum of light; and as the relation of these two pupil areas is 1 to 50, we can divide the 150,000 by 50 which will give us a relational difference of 3,000. Again, we have two eyes within one. In what is called photopic, daylight vision, the cones in the retina are to the fore and do the work in translating the stimulus into local signs; and in scotopic, night vision, the cones sink into abeyance and the rods, which are many times more sensitive to light, receive the low illumination and in consequence the sensation of night light produced in consciousness does not appear weak at all. Therefore the 3,000 must be well divided again with the result that the

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most brilliant sunlight and soft moonlight fall within comprehensible relations to each other, even if not within the range of the palette. Still, however much the mechanism of the eye reduces value differences, it remains a fact that outdoor daylight is much more luminous than pigments indoors, and moonlight, even evening light, much darker. Therefore a sunlight picture is black as compared with real nature; and a moonlight representation, white. Further, even a painted copy of objects indoors fails—not because it falls below the objects' values, nor because it rises above, but because it does both. Except under most favorable circumstances, the light in the picture representing indoor lights will be darker than the lights of the objects themselves, and the shadows will be lighter. In other words, the range of interior values is greater than the gamut of the palette. T o illustrate this we will try to make a painted imitation of a man in a black coat and white collar. T h e black of the coat is of the same value as the black pigment, which can be demonstrated by smearing a little pigment on the coat, where it will disappear. But the coat has shadows which fall in value below its illuminated parts, and the only way the painter could reach these low values would be to make deep depressions, veritable holes in his canvas into which very little light could enter. T h e white collar on one side is turned directly toward the window and is much brighter than the white pigment representing it because this latter lies on the plane of the canvas which is parallel with the direction of the light coming from the window, or if the canvas is turned so as to face the window, the blacks become impossibly bright. A blond woman, draped in white, posed against a light background presents the most favorable condition for imitation because the range of values is small; and if the shaded side of the figure is illuminated by light reflected from a large white screen, the difference between the values of the highest lights and the shadows may be no greater than between white and black pigment. Yet the figure and draperies as a whole will be brighter than the imitation—a fact which may not be of much consequence—but the darker shadows of the white draperies, as copied

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by pigment closely approaching black, will appear false, heavy, and lightless; that is the lovely feeling of play of varying brightness, for which we like white draperies and other white objects, will all be gone. T h e only way white illuminated in the shadows by reflected light can be "imitated" is to paint the shadows fairly bright. In other words, the painter must restrict himself to the lighter values of his palette and this means that he is again forced into a smaller range of values than those of nature. Of course when white draperies are not illuminated in their shadows, then some of these can be painted almost black, but in such a case the natural range of values is greater than the palette, and we find ourselves where we started. I have just remarked that even relationally true values may fail in practice in that they do not imitate the lovely feeling of play of varying brightness. T h a t is a meaningless series of words but is one continually used by us all to express an idea. Possibly the secret of imitative values, Avhich we are in search of at this moment, may lie somewhere in "feeling," and the physicist's conception of how painters imitate and use values may be off the track. Helmholtz in telling us that sunlight is 150,000 times brighter than moonlight tells us a fact that is only true in the world of mathematics and physics; it is not true in psychology or aesthetics, or even in practical painting. I have already pointed out that through the mechanism of the eye this 150,000 is enormously reduced, but there are other reasons which make the measure of brightness totally meaningless. We might as well say that the strength of pure Chinese vermilion is twice the strength of sugar, and water of 78 degrees Fahrenheit equates the stimulation produced by the musical note G flat. T h e sensation produced by the stimulation of the sun is as totally different from that produced by moonlight as is the sensation produced by a plunge into the sea waves from that of a note of the nightingale. Moonlight soothes and lulls us into dreamland; the sun arouses to activity. T h e y belong to totally different categories and can not be compared. Because the stimulation of intense sunlight and soft moonlight both affect the organ of sight and are there

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both converted into local signs, which are translated into sensations in consciousness, it does not follow that these respective sensations belong to the same category any more than do the sensations of sweetness and liquidity because both are furnished by the tongue. They are different, and the reason that the sensations of varying brightness are all so habitually and confidently thrown into the same category is that a series of varying degrees of brightness can so easily be constructed. Every variety of brightness can so easily be catalogued and strung on this string that casual thought, holding that varying quantities of stimulations merely produce varying degrees of sensations, jumps to the conclusion that these sensations are all of the same quality. But they are not. W e need not go to the sun and moon to construct a series that will prove this; we need only make it from black velvet in shadow to white paper placed near the window, and we shall find that the two extremes produce two sensations whose "feel," so to speak, is so different that we refuse to class them together. An analogy to this is found in tactual stimulation. Increasing pressures on the skin produce the sensational series of contact, pressure, pain. Again, if on a winter day I stand close to a roaring fire, I feel pain; if I retire to a reasonable distance, I feel genial warmth; and when I step out-ofdoors into bitter cold, I again feel pain but of a different character from the first pain. If physics is right and reduction of stimulation merely produces reduction of sensation, why do I feel sensations of three different characters while the heat stimulus is being reduced? A physiological explanation is that different heat-sense-organs are affected by different degrees of heat; but physiological psychology, although it tells us that the photopic eye which sees daylight is not the scotopic eye which sees twilight or reduced daylight, does not sufficiently insist that this second eye responds to stimuli in such a different manner from the first eye as to produce in consciousness sensations of a different character. T h e sensations light produces on us distinctly change several times between the sun and moonlight—and the dark night produces still another sensation. Particularly is this change strongly felt

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when at twilight the photopic eye ceases to (unction and the scotopic eye takes its place. They are two different instruments; how can they be expected to function in the same way? It is, however, impossible to make a direct comparison between sensations effected by high and low degrees of illumination. When we suddenly pass from broad daylight into candlelight illumination, we at the first moment see only opaque shadows over all, with lights here and there glaring out of the blackness—and this is because we are still using our photopic eye. But it takes from twenty to forty minutes for the photopic eye to retire and be replaced by the scotopic eye, and therefore comparison must be made between sensations existing at the moment and memories of the others, which is not very satisfactory scientifically. If we can rely on painters, who have spent their lives studying such phenomena, we shall have it that when the scotopic eye has assumed the field it talks a somewhat different language from the photopic eye, and that to "imitate" these different sensations an entirely different painting technique must be employed. Physics, however, contents itself with making distinctions of differences of degree and assumes, with not always sufficient warrant, that the sense organs act consistently when affected by varying degrees of stimulation. T h e practical painter knows, or feels, all this and in his effort to "imitate" nature strives to imitate what he terms the "feeling of nature"—which of course has no existence but by which he means the varying sensation-combinations he experiences when looking at nature. And as he experiences one set of sensations in the interior of his studio and another outdoors on a gray day and another in sunlight and another at twilight and still again others in moonlight and the night, he does not look upon the values of nature as formulating themselves into one system of brightness, but rather he looks upon nature as appearing in different guises, each one of which produces its specific group of sensations, and it is these sensations he strives to "imitate" by devising means whereby the pigment on his canvas shall act as stimuli which will arouse in consciousness the same sensations

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he experiences w h e n regarding nature. A m o n g these p i g m e n t means he strives to create naturally full values, b u t whether his values and nature's correspond is totally uninteresting to him so long as he can devise such a formulation of values, and color, and t e x t u r e — a n d a lot of other qualities for the matter of t h a t — a s shall accomplish the desired result. T h e problem of imitation in painting then resolves itself into a psychological o n e — c a n a g r o u p of sensations, A , produced by a g r o u p of stimuli, Y , also be produced by a g r o u p of stimuli Y'? PROPORTIONATE VALUES AND PHYSICS It seems to many that if painting cannot produce the same quantity of brightness nature uses, that at least it can reproduce the same relation between the different degrees of brightness, and thus, although not exactly imitating nature, can obtain something w h i c h will cause m i n d to experience in a weaker form the same sensations as are effected by nature. T h i s reasoni n g is the basis on w h i c h is founded the famous French System of Proportionate Values taught in the academies the w o r l d over. It first made its appearance as a great force in France somewhere in the early part of the past century, although it was practiced l o n g before. If we paint a strip of canvas or paper gradating from black to snow white, the eye will be able to differentiate only 150 distinguishable degrees of brightness. Some calculations give 120 and others 180, and so w e shall assume the average. If w e attempt to make smaller distinctions, the j u d g m e n t vacillates or fails to discern altogether. B u t in a room, under ordinary illumination, the distinguishable values between the highest light and lowest shadow are easily as many as 300 to 500 and more, depending upon the illumination falling into the room. W h e n we look from the room at the sky, in place of hundreds w e can tabulate thousands of unquestionable value differences between the darkness of the interior and the white clouds. A n d the n u m b e r of visible values in any landscape far o u t n u m b e r s the painter's 150. H o w do proportionate values copy such dis-

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crepancies? T h e name of the system gives the key to its method of procedure. If, for example, there are 300 discernible values in the group of objects in nature to be imitated, every two values, contiguous in degree of brightness, must be copied by one degree in pigment. If there are 375 in nature every two and a half must be translated by one in pigment; and if nature's scale is 1,520, then each ten adjacent degrees must be imitated by one of the palette. Possibly the painter may not wish to use pure white or black, he may desire to limit himself to the middle of his gamut, say 75 distinguishable degrees, in which case the problem remains, as before, merely a matter of arithmetic. On the face of it, these proportionate reductions cannot be accomplished through scientific means. No painter ever lived who could tell how many degrees there are in nature, or what degree on his palette corresponded. His method of procedure is to place on his canvas a spot of low-valued pigment to stand for the deepest shadow, and a spot of bright pigment to stand for the highest light, and then to work between them relying on his "feeling" that the reduction will, after sufficient repainting, become proportionate. It cannot be done otherwise, and as the last court of judgment as to the truth of the proportionate reduction is and can only be the feelings of the painter, and those of the spectator, he very intelligently uses his feelings from the outset of the work. T h e idea underlying the method, it must be remembered, is a scientific, a mathematical idea, and permits of no favoring, of no massing, or elimination of any description other than that dictated by the system. The mind of the artist practicing proportionate values must be as a camera, and, singularly, the camera, when all due precautions are taken to eliminate its characteristic false color values, often succeeds better than the painter. Physicists may deny that the feelings must be relied upon to obtain the proportionate reductions and will show us apparatus whereby they may be exactly made. Without doubt; but these machines work so slowly that the man sitting for his portrait would have long since forgotten the painter's address, and the

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green leaves on the trees would have seared and blown away before the picture was completed.* There are several objections to the proportionate system. T h e results, with rare exceptions, seem very tame, as tame as our pet poodle when asleep. And they fill our minds with the uncomfortable question, why was the picture painted? Only once in a long while are the values in nature so related to each other that the proportionate system gives a lifelike result. One of the great drawbacks to the proportionate system appears to be the following: let us assume a specific case in which the value range of nature is ten times as great as that of the palette; then every ten discernible value distinctions in nature will be translated by one in pigment. But it happens over and over again that separations of objects and planes in nature are effected by as few as five or six or eight visible degrees of brightness—which is amply sufficient—but all of these small distinctions of brightness, according to the system, must be ignored as becoming invisible when reduced, or they must be massed in one value with the consequence that much that is clearly seen and necessary in nature is lost in the copy—and this loss may be vital. Also, many natural distinctions will be rendered so as to be barely discernible, and the copy will be lacking in the sharp and marked transitions of nature, and as sharp and marked transitions produce vividness and life, the copy lacking these appears very dull. There is one singular pitfall encountered in practicing the proportionate system—a pitfall of which the system's advocates seem so naively unconscious that they fall into it without ever realizing they have fallen. Watch the iris of the eye as it (the eye) roams over objects. T h e iris is as restless as a weather vane on a stormy day; one instant contracting, the next expanding; one instant protecting the retina from an excess of distressing light; the next letting in more light to clear the obscure shadows. But the iris does not work instantaneously; it opens and contracts with a deliberate movement, so that if it is adjusted • T h e kind of a p p a r a t u s referred to may be a colorimeter; whatever it is, the author's impatience with it has led h i m into a rather extravagant attack.

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to a light and we then suddenly look into a shadow, the shadow will grow appreciably lighter and lighter for a second or two, when the adjustment will be completed. O r if, on the other hand, we glance quickly into the shadow and as quickly turn the eye away again, we shall see only the shadow with the contracted pupil, and it will appear darker than when gazed at steadily for several seconds. W h i c h shadow is the true one from the standard of the proportionate system? Outdoors the dilation of the pupil on looking from sunlit white clouds to the shaded foreground is so great as to give two strikingly different values for the shadow, depending upon whether it is looked at instantaneously with contracted pupil, or deliberately with expanded pupil. Indoors the differences are not so large. W h i c h value should be chosen? T h e answer is not easy for the proportionist. T h e r e is another difficulty. W h e n shadows are glanced at with the contracted pupil they appear not merely dark but foggy, blurred, and mysterious. W h e n studied with dilated pupil they not only appear lighter, but the detail becomes more visible and sharpens. W h i c h is the true shadow? T h e preRaphaelite answers that to understand nature we must study her closely and carefully; but when we do so, the shadows will become the lighter (up to a certain point), and the faint shadows, "half-tones" as the painters call them, may become darker. A l l the relations become generally distorted. T h e impressionist answers, sometimes, that there can be permitted but one adjustment of the iris, otherwise the simplicity and unity of the light effect is lost and the objects cease to exist in atmosphere. Evidently our values are fast slipping away from us and are changing into other things which are not values. W e must hold firmly or they will be gone. W e will call upon the old-fashioned Claude Lorraine glass, which is nothing but a mirror in which lamp black is substituted for silver and which reflects so little light and reduces the range of luminosity so much that in viewing its reflections the differences between the pupil expansions are reduced to a minimum. A sunlit landscape seen in such a mirror appears as an ex-

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quisite miniature, but the foreground sunlit fields, as well as the shadows, wear an unnaturally dark aspect. We cannot suspect the glass of false proportionate reduction or false coloration. Any alteration introduced by the action of the iris is in the direction of lightening, rather than darkening, the foreground. Some, not all, of the older Dutch and Flemish painters of landscape, at about the period of Rubens, claimed such values to be proportionate values, to be the truly proportionate reduction of nature; and if Plato had been asked his opinion he would have been forced to endorse them as being the closest attainable approach to imitating nature, for imitation included his conception of art—at least according to some of his own statements. T h e public of today, however, fails to understand this system and claims that these dark colors do not give the sensations received from nature; and the artist of today puts the sun in his sky, and boldly paints the field underneath almost as light as the sun, and succeeds in producing some of the sensations nature produces. Swayed by the fallacy of today, he even confidently reasons that he has reduced nature proportionately. Further on we shall find more and equally insurmountable objections to the proportionate system, but the above are all we need bear in mind at present. Proportionate values are only an idea which it is well for the artist to hold firmly in mind to keep him from going too far off the track, and highly advisable to teach the young student, as such values form the basis of true values—values created by mind.

Ill Arbitrary Values

I

N T H E bedroom at night white, black, and all colored objects are equally black. When dawn enters, the white objects become visible, but their shaded sides remain almost black. T h e illuminated parts of the black, and darkly colored objects respond but slightly; therefore they too, particularly the blacks, remain almost invisible. This is so in all low illuminations, particularly if the source of light is very weak. A single candle illuminating a room produces a similar effect. T h e lights on the brightly colored objects separate clearly from the shadows because of the smallness of the candlelight. T h e shadows blend mysteriously into the dull lights on the darkly colored objects because these dull lights seem so much like shadows. CANDLELIGHT AND BLACK-SHADOW VALUES

In the daytime the candlelight effect can be imitated by cutting down the window light to a square foot, more or less, but the light outdoors must be fairly strong, and if the walls and general value of the room's contents are darkly colored so as to reduce their reflecting powers, the maximum effect is obtained. In addition to the black shadows, and their blending into the low-valued lights, the whole effect is one of translucency, as if one were seeing through an envelopment of some kind. This is particularly felt in the lower values, which sometimes seem almost vapory, the result of all this being a considerable air of mystery. T h e general effect is suggestive of a print from what is called "an underexposed and softly focused" photographic negative. Since such a negative is not exposed

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long enough for any of the shadows to "take," they all print equally black or dark, which means that all the shadows are of one value and the lights are of various values. T h e explanation of these phenomena, which for convenience I shall call "candlelight-values," appears to be the following: T h e planes of objects turned away from the source of light constitute their shadows, and if it were not that all objects have the power of reflecting some of the light falling upon them and reflecting it into the shadows of other objects, these shadows would always remain as black as night. All nature is illuminated by reflected and re-reflected light as well as by direct light. In fact, during the daytime there is only one source of direct light—the sun; all of the rest is reflection. Under candlelight illumination, the walls of the room and most of the accessories are more or less dark in color, and the source of direct light is small, the consequence being that reflections are cut down to a minimum and shadows remain almost unilluminated. Portions of lightly colored objects which receive no direct light and all of darkly colored objects are black—or very nearly so. Because the source of direct light is weak, the dark objects respond but slightly, and, as under ordinary illumination, what brightness they have is due not merely to direct illumination, but also to reflection. With the reflection eliminated we find them darker than we expect and in consequence, I suspect, judge them to be still darker. T h a t this is probably so is borne out by the fact that a prolonged study of a particular candlelight effect often causes us to modify our first decision regarding the lighter values of the darkly colored objects. But when we forget and come back to them again, this weird blackness is as striking as ever. Black draperies astonish us. T h e shadows, of course, are very black, but their lights, which receive the feeble direct illumination, are scarcely lighter. When such draperies are juxtaposed against white linen and flesh, both so light in their lights and so very dark in their shadows, we recognize the illumination so frequently used by the early Venetians in many of their portraits. I have referred to the lights of the whites and other lightly

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colored objects as if they were very light. T h e y seem so, we experience them in consciousness as being so, but it is an illusion, as our reason will point out, for a very low illumination cannot make anything very light. W e feel them as light owing to their contrast with the unexpectedly black shadows and to their contrast with all darkness and to their being the lightest objects in sight; they give us the sensation of great brightness and therefore they are very bright, and we shall paint them so. I have also referred to a feeling of translucency, as if we were seeing through a liquid, through an envelopment of some kind; and I have spoken of a vaporousness of the shadows and the weak lights, and have pointed out that these weak or deep lights blended or fused into the shadows, partaking of their character. All this is probably from psychological causes. T h e quantity or force of the light reflected from the deep lights is very small, and from the shadows almost nil; the two stimuli are much alike and, consequently, the two sensations. This is particularly true because luster, which is the almost invariable accompaniment of illuminated surfaces and is only slightly produced by weak light and in part distinguishes an illuminated surface from a shadow, is almost entirely absent in the deep lights; consequently the deep lights and the shadows are in mind accepted as being the same. So much for the explanation; now to take up the matter practically: candlelight illumination is particularly applicable to portraiture, especially of men, as the dark shadows accentuate the character markings so easily, and when the sitters are dressed in black, the black appears what we expect it to be, namely, rich black and not black and gray. Lightly colored draperies will, of course, be nearly black in their shadows, just as dark as black draperies, but the lights will not glare, and the colors will appear in their full strength, not washed out as in strong light. T h e sudden transitions from light to dark and dark to light give a feeling of great life and reality, for psychology tells us (as we have already noted) that the experience of vividness is produced not so much by the strength of an individual sensa-

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tion as by the shock of passing from one sensation to another; and the greater the difference between sensations, the greater the shock and vividness and life and feeling of reality produced. (Of course the sensations passed through must belong to the same category; to pass f r o m jet black to a high musical note is meaningless.) As I have said, the later Venetians used the illumination so frequently—as did also many of the older masters—that we have come to look upon it as the old-master-value system, but it is only one of the illuminations they employed. Some artists, R i b e r a and Caravaggio for example, exaggerated the blackness of the shadows to such an extent that we look at them and not into them. T h i s is a great blemish because when the shadows have lost their transparency they have lost their greatest virtue. In practical painting there are certain precautions to be taken about this kind of illumination. It is difficult to obtain exactly; usually something is wrong. Often stray light is thrown into the shadows, in which case a black cloth must be hung in such a position as to cut off this light. Again, the whites and flesh colors may be confused and appear darker and weaker than we should like to see them. Every full-fledged painter knows that, in copying such an exaggerated effect as this, the effect from its very exaggeration is apt to hold at its m a x i m u m for only a few minutes; the light fades, or reflections interfere, or the flesh tones glare too much. Physical considerations like these teach the painter rather to copy the idea in his mind than to copy what he sees, and his use of nature is to refresh the idea, to keep it alive. T h e idea in question at this moment is candlelight illumination and, although a daylight studio is more practical to work in, the true idea, the beautiful idea, is obtained by actually studying and dreaming over genuine candlelight. A n d this idea is translated into the " o b j e c t " that is painted in the daytime. T h e idea of candlelight illumination is that of solid, brilliant objects vividly looming out of a sea of rich mysterious shadows. How do proportionate values tally with candlelight values? It is the most propitious field for proportionate reduction that

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I know of. If the reduction loses some of the distinctions in the darks, the loss is not so great as might be, and the lights are so definite and clearly separated that they will reduce without much loss. But when everything is said, all that proportionate translation can obtain is an imitation of the one particular group of objects it operates on. T h e proportionate system is able to succeed with candlelight illumination because this kind of illumination exhibits one of those rare moments when nature has tumbled together so happy a combination of stimuli as to produce harmonizing sensations in the mind. I have taken the title, Candlelight Values, but I have written of candlelight illumination. If they are the same, how can a phenomenon be a system of values? One phenomenon cannot form a system, but if a phenomenon repeats itself in numerous ways, if it shows an underlying principle, a system can be based upon it. My object now is to discover the mental principle which parallels candlelight illumination, and on that to construct a value system. It is well known among painters that both light and dark shadows of near-by objects can be painted very dark and of the same value and color, and that if only the values and colors of the lights are retained, the effect will appear logical. But it is impossible to render nature by painting all the lights white or gray or of one color and by differentiating the shadows. Such a representation is meaningless. Let us approach the question experimentally. On a table pile a few wooden blocks variously colored, white, yellow, red, green, blue, and black, and let the window of the room, in which the experiment is tried, be fair sized, and the walls and furniture light in value. T h e shaded sides of the blocks are easily seen, and their values and colors easily distinguished. Each block consists of its light and shaded sides, and the two experienced together in consciousness constitute that specific block. Which is the more important element of the blocks, the light or the shadow? T h a t both are equally important would appear the appropriate answer. If, however, in a painted reproduction we correctly differentiate the lights but paint the shadows black—which negates all shadow values

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and shadow color save that of the black b l o c k — w e still retain meaning, whereas if we differentiate the shadows and paint all the lights w h i t e — w h i c h negates all the values and color in the lights except that of the white b l o c k — w e get nonsense. T h e result is exactly the same when we discard the color element and use black, white, and gray blocks. T h e laws of association explain this. According to these laws the phenomenon which I choose to call candlelight illumination is so continually seen and we are so accustomed to low illumination that we have fallen into the habit of regarding the illuminated part as the meaning of the object. W e disregard (inhibit) the shadows and, when they are all black, accept them. C o m m o n sense says that since nature never furnishes us with the opposite effect, we cannot understand it when painted. T h i s sounds plausible so far as it goes and physics upholds common sense. It recognizes no illumination in which differentiated colors all turn the same gray or white and leave their shadows differentiated. Even if we were to see achromatically, only the color element would be eliminated and the blackwhite element of the various colors of the blocks would stand in the same relation as before. It is for these reasons that the mind can and does believe a black-shadowed version of nature. But it does not at all follow that I have made my point. A passive acceptance does not constitute an active, aggressive function. It does not mean that mind seeks to force nature into a black-shadow pattern, or that the black shadow is one of the instinctive demands of the aesthetic attitude, and unless I can show this I can construct no system. W e may find help in the principles of sensation. Sensations are the strongest experiences we have in consciousness, and the first in life; they are the elemental experiences. T o a baby sensations are the whole world. Recalled ideas have not the intensity of direct sensations, nor has the imagination the power of producing so great a shock as sensation. T h e thwarted will may sometimes produce feelings in consciousness that are as strong as any sensations, but they are rare. A steady stream of sensations is the daily mental bread we live on. T o

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the plain mind sensations are life, and when these are lacking life sinks into a lethargy of dull feelings, into a drift of incoherent ideas. Sensations are pleasurable or painful. W e enjoy the taste of good food and are disgusted with bad food. W e suffer when the air is too hot or too cold, but spring breezes thrill us. T h e sensation of bodily exercise is exhilarating, overhard work is fatiguing. Monotony, repetition even of an agreeable sensation is boring, painful, because the attention, being held too long to the same experience, grows tired. W e demand variety for relief if for nothing else. But if the variety is too great, the attention again becomes strained from having too rapidly and frequently to change and adjust itself. A strong contrast of sensations is pleasant, a jump from hot soup to cold celery, sweet to sour, a low to a high note, black to white, because here we have variety accompanied by great contrast, and contrast, as we have seen, produces shock; and shock, vividness, and vividness, the feeling of life. T h e soup is hot, but we adjust ourselves—that is, the attention, the will, and all the automatic machinery of our mental and physical make-up combine into an attitude. This combination of mental and physical processes takes a stand, so to speak, resists the excessive heat of the soup, and we sip it with enjoyment and feel no shock or pain. But if we suddenly pass from hot to cold, our attitude is not prepared for the sudden change and we feel a shock. Shock produces the vivid, the intense, or rather is the vivid and the intense. And the vivid seems to be life. Absolute evenness, perfect sameness without interruption is an approach toward sleep, death; continual change points toward life, and continual and violent change toward intense and vivid life. So it is that great and sudden contrasts of values in nature as well as in painting produce a strong feeling of life; delicate contrasts, less life. T h e connection between the physical black shadow in nature and the black shadow in mind becomes apparent. A system of black-shadow values is agreeable to and desired by mind because it produces an effect of life which is the most intense

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craving of life itself. T h e way in which this craving works out in practice is often the following: the young draughtsman usually begins very timidly, but as soon as he gains a little courage he is overcome by the desire to reproduce life itself on his paper, and when he discovers that blackening his shadows will effect his desire he indulges in it until an understanding of proportionate values comes in to correct him. Many black-andwhite artists, although not blackening all their shadows, blacken many small shadows to produce relief, they say. It is true that a black shadow under the brow or nose or chin will "relieve" the features, but at bottom the painter's real motive is the realization of the life of nature. Some of the Italian pre-Raphaelites failed to achieve aerial perspective in their landscape paintings not because their lights are untrue, but because in their desire to imitate they imitated what to them, and to many of us today, seems nature's most important attribute, life, and life to them, as to all minds, meant strong contrast of sensations. Having achieved a parallel in their paintings to the sensation of life experienced in mind, they let the mist in the air go by the boards. If we study these particular pre-Raphaelite pictures we may not at first suspect candlelight values, but on closer inspection we find them. T h e reason we do not at first sight see them is that the illumination, which is in part invented, is so arranged as to cast the maximum of light and the minimum of shadow. T o bring out, to give brilliancy and life to each part by dwelling on the black shadow and thus to satisfy the instinct for the creation of life, is the key to the system. As the primitives practiced it, it runs somewhat into attentionized values, but in later, post-Renaissance periods we find many landscapes with large quantities of almost evenly valued, dark shadows and multi-colored lights. In figure work, particularly in portraiture, the system is at its best, and any interior can always be forced into it. T h e plain man is fascinated by black-shadow values unless the shadows obscure one side of the face or something he desires to see. When precautions are taken not to excite his aversions he will proclaim black shadows as being truer than proportionate

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values, for to him truth is not truth of aspect, but truth of sensation—and possibly he is not so wrong as is generally supposed. T o practice candlelight values from nature, precaution must be taken not to look into the shadows too closely, otherwise an attempt is made at differentiation and confusion sets in. When pure black pigment is employed in painting, more than a mere touch of it in the deepest shadows is apt to appear out of tone. This question of tone is very complicated and is explained further on. All I can now say is that it means putting things into their own atmosphere, and atmosphere, for various reasons, always appears slightly grayed. So when I say the preRaphaelites sometimes painted their shadows black, I mean they painted them of that value of dark gray which in relation to the tone of the picture appeared black—a little colored, of course. T h e black of the palette is one thing; it is smoothly varnished lampblack—and even that reflects some white light— b u t the black of mind is a relational quality depending largely on the tone of the picture. For example, a light-valued fresco may be painted in candlelight values with very black-appearing shadows, but these are shadows which in reality are half way between black and white pigment. When the painter has chosen the shadow value, it must be adhered to, and this means that although it may be painted a little lighter here and there, yet when its bottom (lowest value) is definitely given in one shadow, it must be duplicated in the others, and this because any greater depth will appear out of tone. It will j u m p out of atmosphere. Old-fashioned woodcuts and some etchings often beautifully illustrate the principles of candlelight values as applied to bright landscape and broad light. A good example of the black-shadow values is a certain class of landscapes. They represent a kind of twilight into which a nude figure is introduced. T h e nude is almost white except for dark shadows which connect it with the very dark landscape. In such painting some of the illuminated greens are made very dark, not much lighter than the shadows into which they blend, thus fulfilling the demands of candlelight illumination. Hen-

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ner's nymphs are of this type. T h e effect is seen occasionally in nature, or an approach to it sufficiently close to warrant the adoption of this value system—if any warrant is necessary. T h e forest interiors of Diaz are like this, although his theme is sunlight falling into an interior. T h e adoption of the system was very frequent with the romanticists, among them the Barbizon School. MOONLIGHT AND SCOTOPIC VISION

Moonlight is a clear-cut example of candlelight values. T h e moon is a small source of light; shadows scarcely receive reflections and are almost equally dark. In a landscape lights are variegated in value from a white house and half-lit sky down to the illuminated portions of shrubberies. T h e latter are confused with the shadows. Every candlelight law holds; but as moonlight is seen with the scotopic eye, the sensation it produces is entirely different from the artificial daylight version of candlelight illumination. It may be said that it is not scotopic vision which produces the dreamlike sensation, but that the relations of the parts of the whole scene give rise to ideas which we confuse with sensations. But when I confine my attention to a moonlit white wall, which certainly does not inspire romantic ideas, I experience a distinct sensation of solidity and transparency at the same moment, a sensation which I never experience when my eye is photopic. In actual candlelight illumination, that is, when the eye is half scotopic and half photopic, I experience this phenomenon to a slight extent. Moreover, in the practice of oil painting opaque pigment renders the sensation of night indifferently, whereas Whistler proved that glazing imitates it perfectly. T h e sensations produced by glazes and opacities are totally unlike each other. The matter of photopic and scotopic vision requires more explanation. T h e retina of the eye, under the microscope, presents an appearance, like velvet, of countless fibrils standing on end. Some of these fibrils are shaped like cones and others like rods. Just what part they play in receiving the stimulus of light and transmuting it into signs to be sent to the brain is not

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thoroughly understood, but it is known that when the light falling on them is strong, the rods, which appear to be oversensitive, retire; and when the light is weak, the rods come to the fore and the more obtuse cones retire. But the retirement and the coming forward are a slow operation, taking about forty minutes in its entirety. We often experience this slowness at twilight when we first turn on the artificial light. We say that we are not accustomed to the light, but in truth the rods have not had sufficient time to come to the assistance of vision. Night birds and night animals have retinas almost entirely without cones and are therefore adapted to see clearly only in the night. It is also known that night, scotopic, vision when the light is very weak, is a colorless vision. In fact, photopic (cone) vision and scotopic (rod) vision are two different forms of vision effected by two somewhat dissimilar sense organs. Why then should they produce sensations belonging to the same category? I believe that they do not. ELEMENTAL VALUES AND INFERENCE

In some of the paintings by Hogarth, T e r Borch, and many others, of the older as well as of the modern schools, the backgrounds behind the strongly illuminated figures are in a medium-dark shadow, but the deepest shadows introduced into these backgrounds are lighter than the dark accents in the foreground, whereas the illumination demands the reverse. T h e effect of this system is not of dust or tobacco smoke in the room, as that would also slightly gray the foreground, but is the effect of a quantity of atmosphere—distance and space between the figures and background—bought, however, at the cost of solidity. An exaggeration of this system causes the background to look unreal, false. A strong, concentrated, side light falling on billiard balls does not sink gradually into the shadow on the other side. There is a rapid jump from the light into a dark band which, as it recedes into the shadow, becomes a little lighter again on account of reflected light. If all reflections are cut off from the shadow, the jump appears even more abrupt. This sudden transition from light to shadow often distorts bil-

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liard balls lying on a table to such an extent that they look squashed in. And it is the same with bald heads, and rounded cheeks and necks. In fact all objects become distorted in concentrated light. This phenomenon of the sphere is easily explained by physical mathematics, and impressionism accepts it. Yet it need not be accepted. T h e shadow on the billiard ball can be painted to appear as gradually grading into darkness, a method of painting which restores its rotundity. One of the distinctive differences between modern impressionistic portraiture of women and that of some older schools, of the time say of Reynolds, is that the impressionist tells the truth of light and loses the shape, whereas Reynolds lies about the light and gives the truth of the softly rounded feminine form. Apparently there must be some principles in the mind which make us accept the untrue and unaccented gray background, and the rounded forms. T h e r e is one principle underlying the two phenomena. It is what logic calls "unconscious inference." This is the most elemental form of reasoning and is performed, as the term implies, unconsciously. In the present instance it says, "A surface gradually turning away from the light will gradually darken." This is simple and plausible, and all the skipped steps in reasoning are hidden. As nothing could be more gradual in its surface changes than a sphere, the light should melt gradually into the dark. T h e false inference regarding the interior background is not so simple. Elemental reason, which in part is inference, says, "Light receding into the darkness of the room gradually sinks into soft, dark gray, but never into black gloom. And also the foreground is bright and interspersed with black shadows and accents." This forms our indelible idea of an interior background and foreground and is derived from countless casual observations. T h e black accents in the background do not appear—to the casual observation—as dark as those in the foreground because they are contrasted with the general dark-gray mass of background, and this, according to the laws of contrast dulls and apparently lightens them. Those accents in the foreground, being contrasted with strong lights, appear darker than

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they are. But the fallacy of this reasoning is beyond the elemental mind, which is the aesthetic mind, and all the painter need do is to soften and blend the background, sufficiently lightening the darkest shadows, and it will retire. In its softness and in some other respects such a background carries out the laws of attention, but the lightened background accent and shadow belong to elemental values. Looking from a gloomy interior against the light does not give the converse, because the adjustment of the pupil to the light and the consequent obscuring of all the objects against the light produces a phenomenon outside of the group we are discussing.

There is another example of elemental values. A figure posed in front of a dark background usually presents some very light-valued edges and thus cuts clear from the background, but some of the old masters, Rembrandt for example, would often darken these edges considerably and thus produce the effect of the figure's sinking into the background. Nor can this lowering of values be due to the figure's being posed at the edge of a dark shadow, as advised by Leonardo, because these juncture shadows find no logical correspondence in that general value scheme. What they do is effectively to unite the figure with the background and to form a harmonious whole. Here again we have the inference of elemental reason that light sinks into dark and is joined into dark by gradual degrees. Turner sometimes practiced a system of values which so flagrantly defies physical laws of light that were it not for the evidence of his pictures we would deny the possibility of the method's producing unity. And yet so great is the unity that we cannot but feel that there must be some principles underlying the values or we should not accept them. Turner is like the magician, a wave of whose wand causes the large tree to spring instantaneously from the tiny clay pot and spread its majestic branches over our heads. We know the tree is not there, we doubt the pot, and have strong suspicions of the magician, but we experience the tree in consciousness and accept it. How is it done? We listen to the sophist, we accept as true

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premises we have denied all our life, we closely follow his handling of the logical machine, are blind to the sophistical sequences, uncategorical identities, and end by agreeing to impossible conclusions. T u r n e r surrounds the sun with deep crimson and purple clouds and at a little distance from them he paints in white clouds as bright as the sun. T h e distant mountain or cloud on the horizon against the sun is dark, as i t should be, but relieved against it are houses, or trees or sails, the sunlight falling full on them. Below these lights the ground or water or whatever it may be, as it approaches us, darkens, and then lightens—or darkens again if it chooses, entirely inadequate excuses being offered for the changes—and when we get to the foreground, the light falls from any direction and produces any value it pleases. T h e law underlying this system appears to be that light relieves dark, dark relieves light, light relieves dark, and so forth. It is needless to say that although light relieves dark, and dark relieves light, yet the continuously alternating series accompanied by the false values finds no correspondence in nature. T h e question therefore is, does it satisfy a principle in mind? It seems to satisfy the demand for contrast and the resultant vivid; and as it is so illogical, we unconsciously throw logic to the winds and enjoy, besides the vivid, certain aesthetic qualities which the slackening of the demands of logic render possible. T h e great advantages of this elemental system over a logical system are evident, for, besides relief, a harmonious balance of light and shade is easily created, variety and contrast of all kinds are easily introduced and discordant features eliminated. T h e insuperable objection to it, however, is that, save in the hands of a T u r n e r , its sophistry is so apparent that we fail to unite the contradictions and feel amused or irritated as the case may be. But T u r n e r did not rely on values as his binding unity; ornament, tone, color harmony, empathic line, and many other unities were the means whereby he consolidated, and so well did he consolidate that we never feel the falseness of his light and are carried into the land of dreams—as was his intention. T u r -

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ner often adhered faithfully to the physical laws of light, and my only object in speaking of his use of an elemental system is because I can find no better or more widely known illustration of the principle. Another elemental system which we can logically name the Constructive Values system, was largely used in primitive art and is constantly intertwined with modern values. A constructive value is such a value as assists in giving construction, shape, to matter, and never contradicts that shape. It is not what is termed "light and shade," but exists independently of shadow envelopment. Constructive values are the product of the elemental mind. T h e y lie in the folds and hollows and at the edges of things and always, with no exceptions, follow the intention of construction and constructive lines. SYNCOPATED VALUES

T h e r e are two worlds, the world of physical force and the world of mind. In the physical world values are ruled by mathematical law, in the spiritual world by sensation, feeling, and will. Proportionate values are altogether physical. Candlelight and black-shadow values occasionally find a fairly well defined counterpart in nature. Elemental values find a suggestive counterpart, but syncopated values find absolutely no correspondence and are therefore the most powerful and universal. T h i s system is created by the attention and the will. Attention, that process of mind which consciously attends to and brings into a clear focus in consciousness not merely the phenomena of nature without but also the phenomena of mind within, is much more restricted in its powers than the layman generally supposes. It can focus intently only on one unit, one tiny object or one sensation or feeling or idea at a time, and when it slightly relaxes and attempts to grasp a group it has great difficulty in holding in clear consciousness more than four or five or six units. If this number is increased, it comprehends them vaguely, confusedly, or not at all. Attention has another remarkable peculiarity. W h e n we present to it a diagram of equally spaced circles, the eye wanders over the circles for a time and

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there is possibly experienced a singular straining; then suddenly the multitude of circles appears to split into smaller groups. T h e reason of this is that the multitude baffles attention, which becomes distressed at its inability to grasp it in one conception, as one unit, and the attention or the will breaks up the combination into small comprehensible groups. Now, on this trait of attention are founded not merely syncopated values, but the musical bar, and to a certain extent color harmony, ornament, dancing, and some of the unities of proportion. Indeed it enters into all art. As it works out in painters' values, the attention, being distressed by inability to understand the numerous values a proportionate reduction presents, desires to simplify. Of itself, beyond the mere breaking up of a simple pattern, it has little power, and even if it had, the exercise of this power is accompanied by discomfort. Therefore, the artist, with deliberation and intent, reconstructs the whole scheme produced by proportionate reduction so as to conform to the demands of attention— or the span of perception as it is often termed—and in this way satisfies attention and relieves its discomfort and straining. T o take a concrete example, we shall imagine a landscape receding into the distance, the values becoming lighter and lighter as they go back. T h e artist masses and draws together, to a certain extent, all the sky and distance values, all the middle distance, and all the foreground, which will divide the whole landscape into three masses so clearly distinguished as to be easily held in attention. Further, the values within each division are syncopated in such a manner as to divide the large divisions into three or four or five smaller masses, which are also easily understood and as easily taken up in the larger mass. T h e result of this syncopating is that, although not one single value is proportionately true to nature—some of them being very wide of the fact—yet, because the attention is satisfied, there results such a feeling of peace that we entirely overlook the physical untruth. Applied to portraiture the system is worked as follows. T h e background may be conceived as one plane, as in elemental values; all the lights in the face are massed by leaving out the

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half shadows, or by lightening them, thus making a simpler and more evidently unified mass; the lights on dark hair, or other dark colors are all darkened; half-lights in shadows are subdued. Or no division in planes is made between the figure and background, and every part is reconstructed from the standpoint of values. But whatever is done, the values are juggled around with the intention of cutting the picture into a few large evident masses, masses which are again cut into smaller ones subject to the larger. This sketch is very short, but all we have to bear in mind for the moment is, first, that syncopation eliminates the verbosity and confusion of proportionate values; second, that it augments vividness and produces life because stronger and more sudden value contrasts can be produced; third, that it satisfies attention and the will, a satisfaction which appears in consciousness in the form of a pleasurable sensation of peacefulness; fourth, that to all, save the discerning artist, syncopated values appear true for the simple reason that mind accepts as truth those phenomena which conform to its dictates—dictates, as frequently as not, founded on its weaknesses—whereas it rejects, and even absolutely ignores, physical truth because it is usually incapable of understanding it. T H E DOUBLE ADJUSTMENT OF THE IRIS

T h e pupil of the eye accommodates itself to the quantity of light falling into the eye. A quick glance from the sun to the foreground gives a much darker foreground than is obtained by looking sufficiently long at it to let the pupil expand and take in more light. Our effort to decide which of the two methods of perceiving gives true proportionate values ended ambiguously. Having now studied a few of the mental systems, and having acquired a little understanding of their meaning, we are put in a position to observe that, the conception of proportionate values being purely physical, any alteration of them dictated by physiological or mental causes is in contradiction to their integrity, and, therefore, proportionate values can only be the resultant of a single adjustment of the iris. But in practice we find

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pictures exhibiting every degree of pupil adjustment, and probably almost all these pictures were executed in the sincere search after physical truth. T h e r e have been artists, however, who understood, or rather felt, the conflict between the two systems. Foremost among these in modern times was Turner. When he practiced the double adjustment system, he reproduced the clouds in values ranging from one quarter to one half of the gamut of his palette; and when he came down to earth, and his pupil dilated, he again painted "as he saw" with the consequence that sometimes his half lights on the ground were represented as being lighter than the sky shadows, whereas, in truth, they were the reverse. In spite of all their protestation against "false" values, the best of the impressionists of today do the same. An impressionist will place yellowish-white sun in the sky and use pure chrome or cadmium yellow in spots on the sunlit earth, whereas the camera, under properly guarded conditions, tells us that a proportionate reduction of the sun and the earth together looks very much like moonlight. But even if we, the cultured as well as the uncultured public, do not choose to accept T u r n e r or the impressionists, we accept something approaching them and agree that the false double adjustment value system is truer than the true physical system. "ATTENTIONIZED VALUES"

At present it is only necessary to point out that the attention has several moods and lays the basis for several systems of values. In its expansive mood of attempting to grasp firmly as many units as possible—and failing to hold more than five or six—it lays the basis on which syncopated values are founded. This Ave have seen. In its very contracted mood, in which it closely studies an object point by point, it lays the basis for what I call "attentionized values." In its intense endeavor to see point by point, it loses some large relations, overlooks others altogether, exaggerates, distorts, inhibits, and ends by presenting to mind that singular appearance which the pre-Raphaelites, Botticelli for example, so confidently presented in their pictures as being an imi-

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tation of nature. But strange as these values appear to many, and physically very untrue as mechanical measurements tell us that they are, yet our tactual sense, to which they make their appeal, says they are the truest of all. And again, attention in its indolent mood, when it wanders but is still awake, lays the basis for impressionistic drawing, and certain tricks of the attention make a basis for inhibited values.

IV Shadows and Inhibited Values

B

Y I N H I B I T E D values I mean a system founded on one of the numerous habits—tricks we m i g h t almost say—of the attention, namely the trick of being at times totally b l i n d to shadows. W e look at objects in a room illuminated by w i n d o w light and say that they are in light. T h e objects receiving n o direct light we say are in s h a d o w — m o r e or less deep. W e step o u t of doors and look at the house and into the w i n d o w and say that the outside of the house, even if there be no sunlight falling o n it, is in light, but that all inside is in shadow. W e stand in the sunshine and perceive that the side of the house, w h i c h w e said was in light, is now in shadow. Light and shadow are purely relative. Everything is in shadow save the sun. Everything is in light save the black of the blackest night. It is a question of contrast and not of quality. It is a question of more light and less light, that is, from the standpoint of physics, b u t not f r o m the standpoint of mind. Mind, from physiological causes, assumes a totally different attitude toward the darker parts. T h e sensation that the more highly illuminated part of an object produces is not merely a stronger sensation than that produced by the less illuminated part; it is a different sensation. T o understand this we must look into the mechanism of the eye. T h e iris automatically adjusts itself to the lightest light in the field of vision. Its first and strongest interest is to protect the retina from possible damage by too strong light. T h e r e f o r e , if in the field of vision there fall lights and shadows, the pupil lets in sufficient light to effect a clear vision of the lights, but not sufficient to see the shadows clearly. T h i s is easily proved experi-

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mentally. Face the window and note how blurred and vapory all objects in its direction are. With the hand shade the eyes from the strong light; the iris dilates and the blurred shadows clear and reveal unsuspected details. A hillside in the direction of the setting sun is a chaos of confused dark mists. Cut out the sun with the hand and after the lapse of a few seconds the hillside becomes marked with houses, roadways, and trees. W h e n shaded and softened electric lights, or Chinese candlelight lanterns which weakly b u t sufficiently illuminate a garden, are replaced by powerful and unshaded electric lights, although the latter actually illuminates more than the softer lights, the general effect produced is one of inky blackness. At the dimly lighted Paddington Station in London some years ago the demand for better illumination brought powerful arc lights and general invisibility. These may be extreme cases not applicable to ordinary vision. Besides, the light shining directly into the eye illuminates the liquid in the eyeball and this spreads a glittering veil over everything, particularly during the act of looking against the sun. T r y an experiment, taking precautions to guard the eyes from strong light. At night, at one end of a room place a lamp behind and a little to one side of your head—a position which will insure its sending no direct light into the eyes—and then study the lights and shadows in front of you. T h e lights appear dull. Now raise a sheet of white paper so that it reflects strongly onto the outlying retinal areas; instantly a veil of gloom will spread over all and still more confuse and blacken the dull lights. In ordinary daylight gaze into shadows, first, with the unprejudiced eye, and then through a tube of black paper or even the tube made with the fist. And finally (in a room), into the midst of a group of not brilliantly colored objects throw a white sheet. Each experiment gives the same result. I can think of only one exception, which, however, enforces the experiments. In the country at night it will often happen that in a soft and dreamlike landscape one solitary light appears in a distant cottage. Attention is continually drawn toward the light, but the iris does not adjust itself to it. T h i s is shown by the fact that cutting it out with the hand does not in the slightest degree illuminate or

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clear the dark landscape. Apparently it is a case where the attention is awakened and seeks to see into the mysterious shadows. T h e tiny spot of light is not sufficient to force the iris to act in opposition to the attention and it remains fully dilated. T h i s physiological phenomenon occurs in greater or less degree wherever there is light and shade. T h e psychological consequence is that the greater light and the lesser light (although physically only differing quantitatively) present to mind two different characters (qualities). T h e light is sharp, clear, and harsh. T h e shadow is obscure and nebulous. T h e light is prosaic, literal, factual. T h e shadow is elusive, soft, and fused; the eye easily sees through it—the attention not being arrested by sharp demarcations and accents—and the imagination comes into play, filling in vagueness to suit itself. I have several times alluded to the softness, blending, and fusion of shadows. T h i s now requires explanation. W e know that in the night all edges disappear. Objects turn into black and gray vapor. One can easily understand that insufficiency of light means a weak stimulus which may be strong enough to arouse the black-white mechanism of the eye without, however, being able to produce any color response. But why should everything appear out of focus? Certainly the objects in nature remain as clear-cut in the night as in the day, and the lens should produce as clear an image on the retina. Why does it look so blurred? T h e camera, of course, cuts the night with razor edges, as much as it does the day. I believe the blurring is purely psychological. T h e masses of dark grays are sharply enough separated on the retina by clear edges, but the values of these masses are so alike that the attention finds great difficulty in distinguishing, keeps slipping over the edges, and thus loses them. I may be wrong, and it may be the retina which acts indecisively. B e this as it may, night to the mind is edgeless, and so are the contents of dark shadows. T h e wide-spread fallacy that shadows are brown could never have been so frequently put to practice or so universally accepted by the lay mind had there not been a reason. James, even in this age, when impressionists say, "Shadows are not brown, they are

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bluish," tells us in his psychology that shadows are brown. They are not, nor have they more than a suspicion of blue in their constitution—that is, indoor shadows, in ordinary light. T h e y are brownish when brown light is reflected into them, and bluish when illuminated by the blue sky, and greenish or any color depending upon what colored light is added to them. T h e art student discovers that they are neither brown nor blue and decides they are delicate grays of all varieties; but the gray version chills some enthusiasts, who insistently illustrate their enthusiasm by painting shadows the same color as the lights, and much too saturated. T h e truth that shadows, apart from reflections, are the same color as the lights, but darker and with possibly a tinge of blue, is slowly grasped by the advancing student. But singularly, and consistently with my argument, all those who fail to see shadow color easily discriminate the color of the lights. So obtuse is the eye or mind to differences of color when very dark that the painter can lay fairly large patches of brown, purple, blue, and green side by side in his shadows, and if they are approximately of the same value, they will fuse and blend and appear to be one. T h e general, average warmth or coldness of the blend is, however, keenly felt, and that shows that the color sense is active but lacks discrimination. T h i s one can easily understand; the edges of the patches of the different colors being scarcely visible, the attention, in its confusion, drags the colors more or less through each other and obtains an average tone of warmth or coldness. Of course, the converse of this is equally true. T h e great difficulty in painting light skies and light flesh is to keep the color clear. T h e lighter it is, the more distinguishable and confusing will its small differences seem. What is true of the color of shadows is equally true of the values. When shadows are dark the differences in their values can be many times greater than when they are light and yet pass undetected, and a dark shadow of variegated values will tend to appear evenly valued. T h i s explains why in candlelight differences of values in shadows may be unobserved and pass as the same; why they can be painted the same and appear true. W e now come to a very strange phenomenon of the mind. We

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can look at shadows, into shadows, or through shadows, and w e can eliminate them through inhibition. Each of these acts alters the appearance of the shadow, the physical, objective shadow, of course, remaining the same. A n d each of these acts implies a different mental attitude caused by the kind of interest the attention takes. If we glance rapidly at nature, and if the light is clear and strong and the shadows very dark, w e become conscious of the shadows as such. W e feel them to be entities, things, dark and solid, blocking from view what is below. T h e n something awakens our interest in the shadows. W e n o longer look at them but into them, and see things lying in the darkness, enveloped in a darkness, and are conscious of both the things and the envelopment. O u r interest becomes intense, and we forget the envelopment and see only the dark-valued objects under the envelopment. Finally, if we forget ourselves and become unconscious of the act of looking, we shall even fail to note the dark values of the objects in the shadow and see the o b j e c t s — experience the objects in consciousness as normal, as having color and value like the objects in the light. A single series of experiments will not reveal these phenomena; in fact a willfully and consciously conducted investigation gives no result; we must forget ourselves, clear the consciousness of scientific interest, and then occasionally we shall suddenly realize that we are looking at, or into, or through, or are inhibiting the shadow. Of course, some shadows will more readily invite one form of attention than another. Very black shadows invite attention to look at them. Pale shadows ask to be seen through or to be inhibited. Certain types of mind are apt to assume one attitude more easily than another. T h e crude mind inhibits on every possible occasion. T h e aesthetically cultured plays with shadows, one moment looking at them, the next inhibiting. W e will now study them in detail. THE SHADOW LOOKED-AT T h e Spanish painter Ribera apparently looked at shadows. His figures in bright light sink rapidly into their own shadows — i n t o which we see little, and the whole illuminated portion

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lies almost on the surface of a solid, dark brown or black shadow into which it sinks but a few inches. T h e phenomenon of the shadow-looked-at may have physical existence, but is usually the effect of the attention's either carelessly disregarding what light the shadow may contain, or of the attention's inhibiting the light. This action of the attention will be explained a little further on. Leonardo, Reynolds, and many other artists have left us portraits in which the figure was placed at the edge of an almost black shadow which was looked-at. And all these backgrounds are opaque as night, from which we might conclude that they are atmosphereless. So it seems in the hands of the ignorant painter, but never when the painter has given the characteristic qualities which are apparent to consciousness at the moment when attention presents it with a shadow-looked-at. T o determine what these qualities are it is not necessary to refer to nature or to the sensations effected by looked-at shadows, it is only necessary to recall the fact that a shadow is only looked-at when we see nothing in it. Therefore, to imitate a looked-at-shadow we must paint nothing, which means that no possible definition shall be introduced. And when we have painted nothing and have sunk the foreground a few inches into it so as to connect it into one whole, then we have imitated that idea which consciousness experiences when attention presents it with a shadowlooked-at, and as this shadow-idea appears to be in atmosphere, so will its imitation. T H E WHITE SHADOW

T h e shadow-looked-at is a psychological phenomenon but it has a suggestive parallel in nature. From a well-lit room with light walls look through a doorway into a darkened room. A short strip of floor gradating rapidly for a foot or two from the light into the dark will connect the rooms, but beyond that lies a wall of solid, transparent, opaque, black-gray nothingness. I can not describe otherwise the sensation experienced. It is something like looking into the dark depths of an old swamp. The water itself may be dark; it may not. T h e bottom may be black and only a few inches below the surface; it may be a thousand

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feet down. We know we see a fraction of an inch into the water, perhaps many feet, but all we can say is that something below the surface—possibly the lower side of the surface itself—blocks our view. And so something blocks our view into the dark room whose space may go on forever for all we can see to the contrary. But singularly the black shadow in the dark room appears gray; there seems to be floating through it a fine dust of light sparkle which glitters rapidly. We feel certain of this, but so delicately felt is the phenomenon that the judgment fluctuates. T h e appearance, however, is actually objective, and psychological. T h e shadow beyond the doorway is enclosed as in a frame by the walls of the light room, and the light from these walls, entering the eye, illuminates the fine solid particles of matter existing in the aqueous humor. Although this illumination affects only the liquid in its direct path, yet by reflection within the liquid itself all its particles sparkle a little. Where they lie over the uniform image of the dark room on the retina, they are seen, but where they lie over the illuminated portions of the retina they remain invisible. Looking at the doorway shadow through a tube blackened on the inside—all of the light room being carefully excluded—will cause the scintillation to disappear. Or if the door sill and walls are darkened, the effect of what I choose to name the white shadow is decreased. T o call it "the gray shadow" would not discriminate sufficiently, as so many shadows seem gray, whereas calling it the "white shadow," by its very paradox, attracts attention to the phenomenon and in some degree to its explanation.* I have said that the white shadow is a suggestive physical parallel to the psychological shadow-looked-at. It is the modern version of the shadow-looked-at. T h e old masters did not attempt to imitate the white scintillation. On the contrary, their method in practical painting was to finish these shadows by glazing. Thus they obtained an actual transparency on the canvas which leads the eye slightly below the surface, slightly into the shadow, the * T h e r e is some doubt as to the psychology and physiology of this theory about the white shadow, but it serves to hold together a number of careful observations on the part of the author and can not well be removed from his treatise.

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result being about as true a physical parallel to the psychological phenomenon as has yet been produced. The old masters also unquestionably painted shadows-looked-at when they did not see them. T h e modern painter, in his enthusiasm for what he considers to be technical truth, takes the cue from nature. As the white shadow is the cue given, he imitates that, and as the white shadow from its very nature precludes glazing, he substitutes scumbling, and scumbles light pigment over dark. Or he paints the shadow in a fine staccato, thus introducing actual glitter. T h e white shadow is of the most constant occurrence, but usually is so slightly pronounced as to pass unobserved. The French version of "gray in everything" so prevalent a few years ago, was founded on this phenomenon. But the gray veil is only visible over dark, and these enthusiasts claimed to see it in the lights. T H E SHADOW-LOOKED-INTO

Rembrandt looked into his shadows. But he did not look through them, for to look, to go through, implies leaving behind, and in Rembrandt's paintings, more than in any others, we experience the sensations of being in a shadow. We are aware of both the objects themselves and the envelopment in which they lie, whereas in the shadow-looked-at we are aware only of a shadow which blocks from view objects presumably lying below. If we make a cornucopia of our fist and place the fist in such an illumination that the rim made of the forefinger and thumb are in clear (direct) light, and the hollow in shadow, we shall, just as in the doorway, feel the hollow to be filled almost to the brim with a dark, transparent, colorless, intangible liquid; and if the fist is opened, neither too much nor too little, the receding fingers are seen sinking into the liquid. Only a minimum of the white shadow is evident, but the liquid is positively there. T h e two phenomena we experience when peering into a dark but not black shadow are, first, the sensation of looking through a liquid, and second, the feeling of mystery. The liquid fills the cornucopia of the fist up to the brim, we see the fingers sinking in the liquid into a felt, but indefinable mystery. A series of white pebbles placed in the water at the edge of a dark pool so tbat the

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first is just submerged and the second a little more, and so on until they disappear, causes us to experience the same sensation and feeling. It is not necessary to go into the country to find the pool. In the house there are apt to be red wine in a glass, clear coffee in a cup, and dark, vinegar in a bottle. T o a degree these cause us to experience the same sensation and feeling as the cornucopia, the only difference being that in that case a surface of liquid is not visible. The effect produced by lessening light, as in the cornucopia, or by increasing opacity on account of increasing layers of a clear but colored liquid is the same. A glance at the spoon in the filled coffee cup illustrates that. In both cases the recession is from clearness and brightness into increasing darkness, into an increasingly soft focus, increased color and value blending, and at the end vagueness and obscurity. Vagueness and obscurity appeal to the imagination and cause the foreboding always felt in the presence of the indefinable veiled by darkness. T h e only conclusion I can come to is that this sensation of liquidity in shadows is a matter of association. We fail to detect the association because the shadow so evidently has no surface. In all other respects it is the same. One has had the startling experience of plunging his arms into a dimly lighted forest spring imagining that the absolutely still and non-reflecting surface was only shadow and that the water was below. It is this association that makes us feel that we are seeing through a liquid when looking into shadows. As might be expected, when the shadow is light in value, the sensation experienced is less or not at all. Light shadows do not set the imagination into play. The question of imagination must be touched upon a little more although it is out of place here. We are told of the great imagination Rembrandt displayed in the handling of his shadows. It is true that he had the highest form of constructive imagination, but what we feel in his shadows is something else; it is our own imaginings which we project into them; it is the same form of imagination we continually project into obscurity in nature, and it is a kind which goes little beyond a vague emotional feeling, a feeling of awe in the presence of gloom. What

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Rembrandt did, however, was to obtain the most perfect balance between matter and shadow that we know. W e are ever conscious of the shadow, but under it equally feel the solid matter, whereas in the generality of paintings we either forget the shadow, or the shadow forces the matter out of existence. Elemental values and shadows-looked-into are fundamentally opposed. By elemental values, in this instance, I am referring to those in which light on rounded form sinks gradually into shadow; by shadows-looked-into, those in which light on rounded form turns abruptly and sharply, by a series of jerks, into shadow. A strong light is brought sharply against a somewhat darker value, and this quickly again against another, still darker value, and this, in the same manner, against another, and the operation is over. T h a t is nature's method and it includes the whole essence of the practice. W h e n the light gradates evenly, as in elemental shadows, thus keeping the rotundity of the shape, we find ourselves in the midst of the shadow, still holding the attention on the shape, before we awaken to the fact that we are traversing shadow. But Rembrandt tells us plainly when the shadow has begun, and the attention quickly changes its attitude. T H E SHADOW-LOOKED-THROUGH

T h i s abruptness of change from light to shadow is the secret of shadows-looked-into, whereas the elemental regular gradation from light to shadow is important not merely in elemental values but also in the shadow-looked-through, and we can distinctly say that it is the juncture of the light with the shadow which is the hinge on which the three systems swing. In what I term shadowslooked-through the change from light to shadow is gradual and jarless—although not so gradual as in the pre-Raphaelite values — b u t after the shadow has once well started, it is painted in the same way as the shadow-looked-into. W e can say that the shadowlooked-through is more or less of a middle quality between elemental shadows and shadows-looked-into. In the shadow-lookedthrough, as in elemental values, attention is not sharply attracted to the point where the shadow begins, and so we fail to hold the

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shadow in consciousness and it may degrade into darkness without our being aware of it. This easy grading of the light into shadow, by which the attention is held more closely to the things and their shapes than to the shadow proper, produces a rendering of nature which, although possessing all sufficient value contrasts, yet, when compared with nature or with a shadow-looked-into, or with a shadowlooked-at seems to lack true light. We seem to look through and past the shadows at objects of various degrees of darkness and we feel that the objects are dark only because less light falls on them. This looked-through system is probably the most popular of all value systems today. It does away with the shadowy feeling of shadows—and shadows are rather unpopular—but it retains the necessary value-contrasting power of the shadow and some of its accompanying vividness. It appears to correspond, judging from the general art comments of the layman, to the most usual and normal mental attitude toward shadows. But it must not be confused with the Italian pre-Raphaelites' inhibited values. They eliminate some shadows and exaggerate others, whereas the shadow-looked-through system adheres to the shadow, but joins it into light by a totally different method from that of either Rembrandt or nature or the impressionists. INHIBITED VALUES AND STRUCTURAL VALUES

We hear of shadows falling as the day deepens through twilight into night. We hear also of lights falling on objects and tingeing and illuminating them with life and joy. In the physical world shadows cannot fall. Shadow is merely absence of light; it is nothing. In the mental world, owing to our habit of attributing life to physical phenomena, both shadows and light fall. T o judge from the earliest records of human life man from the very beginning has been annoyed and troubled by these falling shadows. All language attests this. We hear of the shadows of sorrow; the shadows of old age stealing over man; the shadow of death. A man is disgraced and under a cloud. A cloud rises on the horizon of joy; a cloud befogs the reason. We hear of the

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terrors of the black night. And never, in whatever direction we may look, do we hear of shadow betokening joy—only sorrow, depression, evil. Of course, there is a solidly founded reason for this, and as language is entirely built on a psychological base, as words and current phrases are but condensed expressions of mental processes, we need only look to primitive history and to elemental life to find the causes. T h e night holds constant terrors for the savage. In it lurk the wild animals which would prey on him, enemies that would exterminate him, and evil spirits that would cast their spells over him. T o the savage the night is predestined evil. It is the accomplice of destruction, mental and moral as well as physical. It is the accomplice of death. It must be done away with. Shadows in the forest, even in the daytime, are the same. In bright light the enemies and evil forces retire. Light, therefore, is joy. Even to civilized, "reasoning" minds the hiding of enemies in the night and shadows would be sufficient, if continued for ages, to form a strong association between shadows and death or destruction, but not sufficient to connect shadows with moral degeneracy or insanity. In the primitive mind this association, however, is easily accounted for. T o the primitive man the element of chance is non-existent. T h a t the accidental glancing of a spear hurled at a tree should kill a bystander finds no acceptance in primitive logic. T h e man hurling the spear was bewitched by an evil spirit. A man murdering or stealing is in himself not evil; he is possessed of an evil spirit. What we today term moral depravity, insanity, or disease are all effects of the work of evil spirits of one description or another—and for the matter of that so is death—and these evil spirits are far more apt to haunt shadows and the night than the day. So the association between shadow and evil in all its varieties is easily formed. Beyond this psychological cause for the love of light and the dislike of shadow is another, a physiological cause, and for all I know a more potent one. Although excess of sunlight may be destructive to the human system, yet a certain quantity of it is essential. It is a great destroyer of disease and a great life-giver. Those beings who love it will seek it and in the long run survive.

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T h o s e beings w h o prefer shadow will seek that, degenerate, and In the long r u n die out. Therefore, in general, a preference for light and a dislike for shadow is the normal state. A further reason f o r the dislike of shadows is economic. T h e y are a nuisance. T h e y g e t into our field of vision and block from sight that which we are trying to see. T h e r e is n o occupation in which man is engaged w h i c h does not continually demand his ingenuity to eliminate the shadows. Finally, shadows frustrate the satisfaction of the instinct of curiosity. T h i s instinct, which so frequently satisfies itself in the close examination of details of things, requires clear light to function and therefore joins in the general demand for the destruction of shadows. T h i s curiosity is not the predatory hunting instinct, but is a desire to understand for the sake of understandi n g — a l t h o u g h it also seeks to understand for utilitarian purposes. Because there is this fairly universal, instinctive dislike for shadows, the mind gets rid of them and satisfies the instinct. A theory is that that process of mind which is called "the attention" is continually presenting to consciousness fragments of nature in which the shadow has, by virtue of the process, been eliminated or inhibited. W e know that when the attention becomes strongly interested in some one quality, or in an object, it will single that out and become oblivious to the other qualities, relegating them into the background of consciousness. As examples of inhibition there are many anecdotes. In one of them an eastern official asked a European painter to make his portrait and added the particular request not to paint his red fez black on one side, in the usual European style, but red, explaining that it was red all over. T h i s would imply that the official was always so intent on the beautiful red of his fez that his attention never brought to a clear realization the shadow usually attached to it. It would also imply that the painters had failed to make their light and dark pigment surfaces produce stimuli like those produced by nature. It is said of the Indians living in the Arizona desert that the delicate shadows and accompanying colors are invisible to them. Art students' paintings may present startling examples of inhibition.

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where excessive attention to the matter of the draperies or flesh has entirely eliminated shadow. Of all the qualities matter possesses, shadow is the most ephemeral. T u r n the piece of matter this way and that; its extension, shape, hardness, roughness and smoothness remain the same. And of the color and the shadow —although the color will vary somewhat in different strengths of light—it is the color which is far more constant than the shadow. As it is color, and often shape, which is destroyed and distorted by shadow, the attention is everlastingly trying to destroy shadow so as to satisfy various instinctive, economic, and metaphysical demands. Perhaps the most convincing evidences of inhibition of shadows are given by the young student in his first essays at color. With perfect assurance he omits the qualifying action of shadow on color. He may paint the shadow colors in their true, or sufficiently true values, a truth which he arrives at with great labor, but all the same he cannot help himself from inhibiting and keeps on looking through the shadows at the colors, that is, at the local or objective colors, and he paints them in all their strength, whereas the qualifying action of shadow demands a large addition—adulteration with black and possibly a little bluing. Another example is a certain style of pre-Raphaelite * portraiture or painting of the nude, practiced by living painters, in which the shadows are so much eliminated that, were it not for my own early experience, I should feel inclined to doubt the sincerity of these painters when they assure me that that is all the shadow they can possibly see. T h e logical corollary to the inhibition of shadow would be that attention never inhibits light, and this is so true that the only exceptions I can think of are in the rare cases of shadows-lookedat and black objects which appear blacker than they are. These seem to be exceptions only because strong blacks are rare. Strong blacks are so startling that attention fixes on them and fails to see what white they possess. Of course, the attention can inhibit * T h e meaning of this word is the strict one, a n d indicates the school of Italian painters before the time of R a p h a e l . In n o place does the a u t h o r use this as the n a m e of a g r o u p of English painters in the nineteenth century.

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any and everything, but what I mean is that, when attending to light and shadow, it almost invariably inhibits the shadow portion. In other words attention is creative, it desires to see light and it gives light to nature. T h e outcome of all this is that mind much more readily accepts lights than shadows as standing for matter. We came to a similar conclusion in our study of candlelight values. Impressed with the nonentity of shadows, painters have brought into existence school after school—many of them very great—which have tried to do away with shadows altogether. Asia and Egypt have more or less inhibited shadows. How much of this was unconscious, and how much deliberate is often difficult to decide. Taking the record of Chinese painting for the last fifteen hundred years, and leaving out of question pure ornament—which only as a collateral issue deals in shadows—we get a first impression that several attitudes regarding shadows must have been taken. In some of the paintings all shadows are inhibited, the artist depending upon outline and local color to separate the objects from each other; in other paintings shadows in drapery folds and depressions are delicately, or even in rare cases, strongly marked; skies, distances, and mists, however, are almost as full valued as modern European work; and a sea of roaring foreground waves has its quota of light and shadow; even a head may be shadowed at its contour; and through making the delicate value distinctions between the slightly darker foreground and pale distance the Chinese artists obtained as much atmosphere as we do. There does not appear at first glance to be an underlying principle of inhibition and use of shadow. But there is. In Chinese art the integrity of all objects must be preserved and shall not be destroyed by shadows. Therefore (in the foreground) no object ever casts a shadow, for that would encroach on and destroy the unity of the ground or other object on which it falls; this law is rigidly adhered to even if the object itself may, within its own boundaries, be shadowed in its depressions, and naturally would be expected to cast a shadow. From the assumption that objects cannot cast shadows, it should follow that no part of an object can cast shadows upon other parts of itself. This is almost universally adhered to. T h e

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shadows (elemental structural values) on the objects themselves merely lie in the hollows and at the edges and distort nothing. T h i s order of shadow is, as I have remarked above, elemental. T h e mind creating it thinks only of shadow and forgets the light producing it and the direction from which the light comes, and the shadows are no more troubled with physical truth than were the values of T u r n e r . T h e y merely come of themselves, as it were, and cause a desired contrast and relief, and through their flagrant disobedience of the physical laws of light they lose the feeling of shadows and become innocuous. Distances in Chinese painting, however, are often almost full valued, and the objects in them lose character and sink into their own shadows and mists and uncertain focus. T h i s may appear to be a contradiction to the integrity of the objects. It is not. In nature individual shadows in the distance merge into each other, into separate objects and into mist in such an inextricable way that they all combine, form a single object, and it is this one object which constitutes the distance, the integrity of which Chinese art preserves. Of course, when the air is very dry this unification takes place less, but still sufficiently to be a general characteristic of distance. B u t why, it may be asked, should the integrity, the separateness, the individuality of the objects be preserved when actually the aim of art is to u n i f y them? Shadows do unify the foreground when, in a scheme of chiaroscuro, they envelop and cancel the objects, but when the art of the painter fails to obtain chiaroscuro, there is nothing more destructive to unity than the cast shadow; it cuts u p not merely the ground on which the objects stand but everything it touches, and groups of objects which perfectly harmonize in diffused illumination fly to pieces when a direct light brings their shadows into existence. A beautiful outline drawing of a group of figures often becomes ugly when shadows are added. Foreground shadows in sunlit landscapes are frequently ugly; they cut the ground into meaningless patches. W e do not notice this when out of doors because we look at the ground and trees through shadows which we largely inhibit, but when the painter fixes the scene immovably on his canvas, we

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realize the shadow and pronounce it ugly. T h e early Chinese artist said, "Shadows are a great destroyer and must be eliminated," and this attitude his successors have consistently adhered to. T h e Chinese artist is not unconscious of all the shadows he eliminates—though some he may not see—but the interesting part of this matter is that the mind should accept and forgive, as it certainly does, such flagrant misrepresentation of nature. T h e mind is so continually in the habit of inhibiting shadows that the Chinese or any other primitive version of inhibition is easily accepted. Inhibited values in painting find a well developed parallel in mind. Inhibited values were practiced until very recent times in Europe. Holbein gives excellent examples of them in portraiture. H e strikes a marvelous balance between inhibited values on the face of the sitter, and shadow-looked-through on the accessories. It is a perfectly logical combination. T h e face, being the more interesting, attracts attention so forcibly that the shadows are nearly all inhibited; the accessories being less interesting, the shadows are less inhibited. Albrecht Dürer's figures in engravings cast shadows on themselves but never on others. He, however, uses a little shadow on the ground to connect it with the figures and to give them solid earth to stand on. W h a t Dürer understood so well was that as nature presents shape to mind through the combination of light and shadow, and as either of these is impotent when by itself, it follows that shadow as well as light must appear to mind as a creative force; and although shadow can at times lie dormant in combination with light, yet at any moment it may assert itself and produce shape. Therefore, if this shadow can be forced to act in harmony with the shape-producing power of structural line, the resultant shape will appear twice as vivid. Also, although the potential power of shadow may lie dormant, yet it is always felt as a potential power. Dürer never uses shadow otherwise than in absolute agreement with structural intention. Never by a hair's breadth do his shadows stand for envelopment other than that allowed by the structure. And never does he lay a shadow which is not at work producing structure. T h e dormant shadow does not exist for him.

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A shadow must be active. If a shadow is so balanced with light that it neither creates nor distorts, but only lies there, its very inactivity makes a balanced strain which is experienced in the mind as ugly. T h i s is seen every day. T h e buildings on one side of the street cast their shadows on those opposite. T h e y neither create nor distort. W e inhibit them for a while and admire the structural beauty of the building. B u t the very process of inhibition is fatiguing. W e soon wish this non-creative activity were away, and when a passing cloud or the moving sun takes it away, we feel relief from the strain. Or, it may be that the shadows are not so inert. T h e y may seem to cut in half the building on which they fall, and the contest between our inhibitions, backed by reason, and the force of the shadows is so great that we feel strain, and that destroys enjoyment. T h e fact seems to be that when shadows are not allowed to do structural work and are made to lie flat, they will cause distortion, even to the extent of putting black holes into gentle pasture grounds. T h e shadows of tree trunks falling across a sunlit roadway turn into prison bars. Looked-through-shadows, inhibited values, and attentionized values, all being phenomena of the attention functioning in the act of inhibiting shadows and finding light, are compatible with each other in the hands of the knowing artist. Looked-at-shadows and candlelight shadows, however, in which the attention inhibits light instead of shadows, and dwells on these shadows, are diametrically opposed. Looked-into-shadows stand by themselves. T o the student attempting to practice any of these systems, it is needless to say that his first operation is to arrange the illumination in his studio as much as possible to correspond to the particular idea in his mind, and then to copy the idea, making constant reference to nature. OF PAINTING BLACK

It is very rare that the painters of today rival the old masters in the beauty of their blacks. T h e old masters' blacks are rich and deep in color, whereas the modern version is often thin and chalky. It might appear that this difference is frequently caused by the texture of the objects represented: the old masters painted

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velvets and lustrous silks, whereas we paint wool. T h e trouble lies deeper. T h e most difficult problem black presents to the painter is that of black woolen draperies. T h e old masters' method is to put black in the shadows and a fairly black tone in the lights. T h e modern painter, while adhering to the dark shadows, renders the lights gray. For him black obeys the laws of values as absolutely as does white and the other colors. Since these, when strongly illuminated, turn pale, black must also turn pale under strong light. In his view the old master falsifies the values of black in the lights, and even if he obtains beauty of an individual color, loses a naturalness of appearance that is essential to the attainment of tone and atmosphere. T h i s argument, containing as it does a part of the philosophy of modern painting, requires careful examination. T h e first thing to determine is whether we are on the right track when we assume that the beauty of the old masters' blacks lies in the blacks themselves, and not in some relation they bear to the rest of the picture. W h y should not the modern painters' argument that beauty is a question of relation be true? And should not a specific relation clearly indicated in one part of a whole be carried out in all the other parts? T h i s sounds logical. In everything mind can conceive there can only be unity when there is agreement of all parts. But the old masters' deeply painted black takes its place in the tone and atmosphere of the composition. It shows a submission to the unity of all the parts, as is amply attested by hundreds of portraits by Velasquez, Titian, Rembrandt, and Hals. Is the solution that all of these are painted in candlelight values? A glance at these portraits reveals that, although some of them are of the candlelight value type, many are painted in ordinary full-light studio illumination. Yet the blacks are painted black and contradict the argument of the modernists. It is the treatment of the black itself and not the relation between that and other tones which makes the old blacks beautiful. This apparently lands us in contradiction between theory and practice. T h e contradiction is only verbal. If, instead of postulating that the integrity of the proportionate system of values must not be encroached upon, we can postulate that the

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integrity of the relation between sensations must not be encroached upon, then we strike much closer to the truth. Painters assume they are dealing in values; the proportionate system of values is the rule, and with it is the rule of tone. But this is not right. T h e right rule is sensation, and if physically proportionate values produce sensations not corresponding to those produced by nature, then must the values be altered so as to make the same sensations. T h e final court of judgment judges sensations, not mathematical facts. If now we recall, as explained above, the conditions under which black produces its pungent and specific sensation, and if we remember that its shock of nothingness, in which its charm and potency lie, is easily destroyed by white, then can we understand that black drapery, relieved against a shadowed and still darker background will, on passing through the proportionate value machine, come out so gray in the painting, that although the demands of the proportionate values are satisfied, yet the mind is not, and the principle object in painting black—the production of the sensation of nothingness—is destroyed. Black, to remain black, must be painted fairly black all over. This is difficult for the proportionist to understand. H e says that green, yellow, red and blue can be as light as they choose and always remain themselves. Why not black? Green in strong light becomes yellowish green, and in shadow bluish green, but always remains green, and although the sensations produced by the varying degrees of luminosity are slightly different, yet they have the same basis. T h e sensation produced by the shock of black, however, and the sensation of gray have no connection with each other. They fall into different categories. But, says the proportionist, what of that? Have I not given you a gray whose soft and caressing sensation is a more than passable substitute for black? If he had, it would be all right. We should lose the nothingness b u t gain the softness. That, however, does not happen; the proportionate system, as applied to black, sets u p a conflict; it produces an imitation of nature which we recognize is meant to stand for black (not gray), b u t it looks gray in the lights, and the con-

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flict in mind due to the effort to reconcile this sensation of gray with the sensation of nothingness effected by the very black shadows distresses us, and it is this distress which is the feeling we call "ugly." T o put the whole of the above in common-sense language, w e can say that the phenomenon of black is due to the absence of light. It is nothing, but it ceases to be nothing when something is added to it. Color, being something, will remain something if more is added. W h a t also enhances the blackness of black in nature and demands almost pure black in painting is that we unquestionably inhibit the light falling on it, unless indeed this light is so strong that it forces itself on attention. W h y we so habitually inhibit the light floating over black (in nature) can only be explained on the assumption that attention, being attracted by the nothingness, the void, and enjoying the sensation, desires to feel it more strongly and inhibits all contradictions. T h e outcome of all this results in several systems of painting black, which can be classed into the objective, dependent on natural appearances, and the subjective, dependent on demands on mind. A naive subjective elemental system, which at first sight appears to be candlelight, is easily applicable to portraits of black-gowned sitters. W h e n attention is paid only to the head, regardless of its relations to the black garment, and when the shadows are translated as strongly (darkly) as possible, the full gamut of the palette being used on the head so as to obtain vividness, then will it be found that, although ivory black plus a very little white will logically represent the lights of the black drapery, there will be no pigment left on the palette dark enough to paint the shadows of the drapery. In other words the full capital has been used up before the deep shadows are reached. T h e consequence of this is a very black garment whose shadows are almost missing. Off hand, we feel inclined to say that such a system must produce great falseness of appearance, and the reason it does not can only be that the judgment recognizes the dilemma, just as it recognizes Turner's equally bright sun and cloud. W h e n there are several black-gowned figures in the composition, the trick is

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difficult to hide, and mind may resent it on the ground that the intention of the values in the head is not carried out in the draperies. T h e simplest objective way of painting black is to relieve it against a lighter, even if only a trifle lighter, background. T h e n will the black, because its lights as well as its shadows are darker than the background, appear, by force of contrast, as being still darker, and will be unconsciously painted so. If the painting is not unconscious, the lights can very easily be adjusted a little toward the shadows without danger of falseness of appearance. A subjective system which is more general in its applicability is founded on the consolidating power of outline. A closed outline has the power of holding together and consolidating into one unit all that is contained within its enclosure if it is at all encouraged to do so. When these contents are more or less softly painted and somewhat blended, then, on account of delusive blending, they will fuse still more in mind into one whole. For example, if a black woolen dress, painted according to the proportionate system, has a gray chalky side somewhat cut u p by dark shadows and organic structural markings, and if in addition it presents also a black-shaded side, as is not unusual, and if these lights and shadows are softly gradated into each other, and if, finally, the whole is set in a broad, dark, containing outline, then will all the value contents fuse or blend or synthesize in the mind, and the lights will appear darker than they are. T h e application of a system is a matter of adroit juggling. When it so happens, as is often the case with paintings executed according to the proportionate system, that the strongly illuminated gray side of a dress juts abruptly against a darker background, then will the introduction of a broad outline, of a darker value than the background, laid on the dress—not on the background—and blended and modeled into the gray, but sharply separated from the background, act as a containing line, and a synthesis will form between the lights and shadows of the dress. This dark irregular outline appears to the mind as a shadow— unaccounted for save on elemental principles. If it is of the same general value as the shaded side of the dress, it will sink into

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that, lose itself here and there in other shadows, and attract no undue attention. This is particularly so because shadows on silk, to a certain extent, fall on planes which turn or bend toward the background, and as the phenomenon is so often seen we fallaciously accept it as a principle. Possibly this system loses the exact texture of the wool, but its blackness is retained. It must be clearly understood, though, that such a containing outline has to be darker than the background or it will act weakly; and it must, as I have said, cut fairly sharply against the background and melt into and form one unit with the dress. This would imply that when the background is so dark that an outline cannot be still darker, the system cannot be used. T h a t is somewhat the case. T h e dark containing line then must be lighter than the background although darker than the gray light on the dress. In consequence, there results a gray mass whose grayness is not emphasized by the sudden opposition of a very dark background, but which melts gradually into it through the intermediary of this half-value line. This is a distinct gain, for what is so particularly ugly in proportionately painted black is this very shock, this contradiction of ideas between the expected blackness and the assertion that the black is gray. So disturbing to the judgment is this shock that at times such proportionate interpretations actually fly to pieces and the mind can only hold them together through reason. Consistently, however, colored objects under the same condition of light, and painted proportionately, whatever the other objections may be, do not jar but hold together. It is enough to say here that when the illuminating source is diffused, that is, comes from all sides, and at the same time is not very strong, then the shadows take refuge in crevices and corners, and the objects are seen in their true, local colors. R e d is red all over, and white, white, or almost so, and black looks black, as black as night, and can be imitated guilelessly. T h e reader may complain that I have said nothing of painting black velvet. There is no need. Blackness is artificially locked up in its texture; the threads of silk standing on end reflect only from their points and reflect as little white light as possible. And the

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bodies of the threads crowd each other in a shadow, made all the darker by their own blackness. When placed in a strong light it lightens comparatively little. T h e rule for painting it is just to paint it. It has an aesthetic intention in itself and more than half of the work is already done for the painter. T h e very existence of black velvet and the pleasure it gives is a suggestive proof that what we enjoy in black is the black itself.

V Production of Color by Addition H E M O S T I M P O R T A N T objective fact concerning color is the existence of the sun in the heavens, for, as we know, apart from the almost negligible exception of artificial illumination it is the source of all light and color. T h e surface of the sun appears to be in a state of violent molecular excitement, and this excitement is communicated to the ether which permeates all space. On and through the ether the excitement travels to the earth in the shape of waves, as the waves of water started by a stone thrown into a pool travel to the shore. When such a wave or mass of waves—a beam of light the mass is called —reaches the earth, it is white, unless indeed it has encountered some untoward circumstances like dust, or moisture. Whether the beams coming from the sun start as white, or as colored, and only become white on their journey, is another question which need not trouble us. All we have to know is that the sun sends white light to us. This white appears very pure (a fact that has caused psychologists endless worry), but when it is passed through a glass prism or a raindrop it breaks u p into many differently colored lights. When these several lights are gathered together by some simple apparatus, like a concave mirror, they all unite once more into white light. T h e various colors into which the prism separates the white beam arrange themselves in a row as follows: red, orange, yellow, green, blue, violet, and lavender, but none of these colored lights is clearly separated from its neighbor, and at either end the series fades out so gradually that we cannot tell exactly where it stops. Beginning at the red end we see a color somewhat like carmine

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or crimson blending into a vermilion which blends into a reddish orange that turns more and more yellow as we move along. T h e yellow becomes greenish and then green. T h e green grades into blue and that into a violet which sinks into lavender and fades out. T h e spectrum of the glass prism does not present the purples —though some spectrums produced by other instruments d o — but if we mix the two ends of the spectrum of the prism together, or imagine it bent in a circle so that violet overlaps red, the purple is created. It is popularly supposed that such a spectrum (including the purples) contains all the colors, in their pure state, that can exist. This is true, roughly speaking. It would have been considered strictly true a few years ago; now it requires explanation. T h e spectrum colors are not pure; they are mixed with white light which the prism, owing to its inefficiency, has not resolved. Purer and more dazzling colors can be obtained by successive induction as we shall see later. Still, for our purpose and for most practical purposes the statement holds. These various colors, which we experience in mind, are the results of rays of light of different character acting on the retina. When the waves constituting the rays are short, they act in such a manner that the retina telegraphs certain signs to the brain and thence to mind, and we experience the sensation of violet. When the waves are slightly longer, we experience blue, and so on. T h e longest waves produce the reds. When the waves are still longer, they become invisible and act on our sense organs of heat. When they become still longer, we fail to record them because we lack the required sense organs. When the waves are very short and invisible to the eye, they act chemically, producing chemical changes in matter. COLOR RADIATION

T h e white light from the sun falls on the earth and undergoes a transformation. Whatever it touches affects it and turns it into some other light, a colored light usually. It falls on trees; the trees turn it into green and radiate the green in every direction. It falls on tiled roofs, and they change the white into red and

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radiate red as far as the eye can discern them. T h e soil radiates light and dark brown, and the sea blue and green and purple. Sometimes an object will not transform the light but will return it as white. These colored radiations are not so pure as those of the spectrum, and not so strong, and we cannot gather them together and change them back again into white light. Something is lost in the transformation. T h e sun radiates white light onto the tree, and it, in accordance with its physical character, instead of splitting up the light into its elements and radiating them all out again, splits up the light into its elements but radiates only those which make green, keeping the others and transforming them into heat. T h i s is called the production of color by absorption or subtraction. W e say that white light falls on matter and that matter subtracts a certain amount and absorbs it and that it radiates the remainder. T h e study of the production of color by absorption of a part of white light and by radiation of the remainder will occupy us later. A t present we are only interested in the radiations themselves, in colored light, white light, and blackness, but not in how they are produced. T o us, for the moment, all causes of radiation are nonexistent. T o us matter radiates light. T h e mountain, the tree, the pebble, and the blue vault overhead send out their colored rays. Even if the sky may be only a transparency transmitting the light of the sun, yet logically we are in our rights when we class it with the tree as being a material object which radiates light, and this for the very solid reason that all light, after leaving any source whatever, acts in only one manner. Lights, colored or white, obey identical laws no matter what their origin. Therefore we can regard a tree as a miniature sun radiating a small quantity of green light. T h e moon radiates the same light as the sun although it manufactures none itself. T H E NUMBER OF COLORS

Attempts have been made to determine the number of discernible colors. T h e spectrum has often been taken as the field of measurement, the lack of the purples being taken into account.

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It would appear at first sight that the spectrum is an impossible field of study, for only pure colors unadulterated with white exist there. This is not necessarily so. White can be added in exactly measured quantities so that the colors can be made to range from almost pure to such impurity that the color element is scarcely visible. T h e spectrum can also be made very bright and can be lowered to a value scarcely lighter than that of night. In these ways all the possible colors in all their possible combinations can be produced. Besides the spectrum, the colors in nature have been observed, and it has been variously determined that 30,000 are discernible (which means 30,000 different color sensations), and that well over a million are discernible. T h e discrepancy is interesting but absolutely unimportant, for both 30,000 and 1,000,000 sensations are equally beyond the grasp of what may be called "the aesthetic mind." COLOR CONSTANTS AND QUALITIES

Physics sharply defines color by three constants: hue, purity (saturation), and luminosity (brightness or value). These three constants or qualities, physics, as well as the dictionaries, claim are all inclusive and are all we need know of a color to exactly understand which of all the myriad in the universe it is. From the standpoint of physics I make no doubt this is true, but from the standpoint of sensation it is not. Physics measures the length and speed of light waves and recognizes their quantity; to the mind light waves are nonexistent. Mind knows only sensations, and one of the qualifying sensations effected by color is luster. T h e artist therefore, thinking as his sensations lead him to think, qualifies color by four constants: value, purity or saturation, hue, and luster. Luster means scintillation, or glitter, or sparkle, or shimmer, or glimmer, or glow. It is always present in all color in varying quantities, and in physics gets confused with values and with what is called "brightness" or "luminosity."

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T H E ELEMENTAL COLOR SENSATIONS, AND T H E BLENDS

There are six elemental color sensations: * red, green, blue, yellow, white, and black. That is all. T h e sensations of white and of black we have already noticed. T h e elemental colors deYcllow

Yellow Green-Yellow Yellow-Creen

Red

Green

mand closer defining. We are sufficiently accurate if we define red as the color of a drop of human blood—but not when spread over white; yellow as the color of bright yellow flowers which are neither greenish nor orange in hue; blue as the color of the sky overhead after a storm which has cleared the air of all moisture and dust; green as the oxide of chromium, popularly called viridian. Purple and violet, are what are called blends, and do not • T h e s e a r e presented as a b s o l u t e facts of p s y c h o l o g y a n d they m a y not b e entitled to such fixed and d e f i n i t e positions. T h e r e is a general soundness, h o w e v e r , in the a r r a n g e m e n t , a n d the r e a d e r can q u a l i f y this statement as his k n o w l e d g e requires.

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cause us to experience simple, single sensations. In them we feel the presence of both red and blue. In orange we feel red and yellow. In green-yellows and yellow-greens, and in blue-greens and green-blues we find this same dualism. But looking at red, yellow, green, and blue colors convinces us that we are experiencing pure sensations, namely single or uncompounded sensations. Therefore we call them the elemental colors which produce the four elemental color sensations. T h e elemental colors can be found in the spectrum of the sun if we first determine which they are. T h e spectrum gives a myriad of colors, and much confusion has arisen from fallaciously assuming that those prominent in this gaudy assemblage are elemental. T h e spectrum has nothing to do with sensation and never should be mentioned in that connection. T h e elemental colors are those which produce the pure, elemental sensations and must be arrived at by feeling. They can be arrived at in no other way. T h e elemental colors are those in which we can feel, or experience, no trace of any others. T h e practical painter, under the influence of his pigment mixtures, may think that he feels yellow and blue in green. It is certain that almost all greens tend either to blue or to yellow, but it is equally certain that no green can have the two tendencies, and the green lying between the yellowish green and the bluish green is elemental. T o study the four elemental colors and understand their interplay with each other, and with white and black, the easiest and most logical way is to arrange them on a circle as in Figure 1. This arrangement is not arbitrary. It is inevitable, as we shall see, except of course that any color can assume the top if the others take their corresponding positions, or that the circle can be turned upside down, or from right to left. If we study this circle, beginning at yellow, and pass through green and on through blue and red to yellow again, we can in imagination fill in every possible blend. This is shown in Figure 2 in which the minor intermediate blends are left out for convenience. This filling in of the blends in imagination seems simple; we feel and know exactly what each one should be; they are just as inevitable as the conclusion of a proposition in Euclid. We start on our jour-

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ney at yellow and move in the direction of green. T h e r e is no doubt in our minds that a mere trifle of green light added to a yellow light will cause the latter to turn a little greenish. Elemental reason (inference) or feeling tells us so. And an unconscious remembrance of color experiences with nature endorses this. If we add a little more green to the already slightly greened yellow, and then a little more, and more, the yellow will finally turn green as do the yellow leaves of early spring on approaching summer. In the case of the color-circle blends, as green is added, so must yellow be subtracted. T h i s the logic of the blending demands. And when we have arrived at the green, we find it just as natural to proceed to the blue without a break as it is for a foreground of green vegetation to sink into the blue distance. T h e blue melts into the red and then into the yellow as smoothly as the blue sky in the zenith, at the hour of sunset, grades through light violet and crimson into vermilion and orange and gold. All this is easy. T h e only thing left to make our color circle complete is the blends, across the diameters, in Figure 3, from red direct to green and yellow direct to blue. (Here we are always talking of colored light, never of pigment; that will come later.) T h e mind hesitates at a red-green. W e often see green leaves shot with red, and red fabrics shot with green, but these are not blends. A blend is as smooth as the separate colors it is composed of; it is as smooth as white, and it only differs from white in being less elusive. White exposes nothing of its composition, whereas the blend frankly reveals that. Orange differs vastly from yellow and from crimson or vermilion, yet in spite of its individuality we know—a glance reveals it—that orange is made of yellow and red; and purple, of red and blue; and peacock blue, or peacock green, of green and blue; and green-blue or blue-green of blue and green—their names disclose their nature. W h i t e tells us nothing, and yet, mechanically, objectively, it is a blend. T o make these distinctions in the character of the blends intelligible, the following terminology has been adopted in physics and psychology. When colored lights are mixed (physically) and the mixture reveals its constituents, it is called a color-blend. But when the mixture, whether white or colored, fails to reveal its constituents,

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it is called a color-fusion. I will adhere to this terminology for the moment though under certain conditions the color-fusion term contains a fallacy. FUSION AND COMPLEMENTARY COLORS

We may return to our attempt to make the blue-direct-toyellow and the red-direct-to-green blends. Mind somehow does not lend itself to this operation. Yellow-to-blue formulates itself into blends in minds which are in the habit of thinking in terms of pigment, but red-to-green finds no response. We sometimes think we see a blending gradation created by the blue sky gradually sinking into a yellow sunset glow, but when we examine closely, we always find either a sudden transition—produced possibly by an intervening cloud—or we find a gray band between the two colors. T h e fact is that when yellow light is added to blue light, white (gray) light is produced. There is fusion. If a small amount of blue is added to yellow, the yellow appears to become washed out a little—to be somewhat paler. And as the process of adding more blue continues, the pallor increases until all trace of yellow has disappeared. But they are both there. Where have they gone? They have fused into white. Red and green fuse in the same manner. Adding yellowish-green light to yellowish-red does produce a blend of yellow, and this is taken advantage of in some systems of color. T h e hues I have defined will, however, produce fusion. Therefore there are no blends of red and green, or of yellow and blue. Instead there are fusions. Physics considers yellow and blue as being complementary to each other, and red and green the same. This term would imply that white is the whole unit, and red, or green, or blue, or yellow only parts of the unit. Sometimes these complementary colors are spoken of as being opposed to each other, implying that they destroy each other. They do destroy each other's color, but the white (or gray) they produce is brighter than either color, so that they cannot be opposites (in the philosophic sense of the word). I shall try to use the term "complementary" as suggestive of an enhancing force. Nature furnishes us with countless blends, but, to casual ob-

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servation, with few fusions. Every moment we see colors blending into each other, but unless we understand how to find the fusions, we fail to see them. A notable fusion is the one I have alluded to, that of the blue sky melting into the yellow sunset glow—a light gray band separates the two colors where, for a space, they apparently lie on top of each other. Usually, however, the blue blends into the yellow through a series of minor blends —blue, bluish-violet, violet, violet-purple (this, however, as well as the purple, is often lost in a gray), then purple-crimson, crimson, crimson-red, red, red-orange, orange, yellow-orange, and finally yellow. In Figure 4 I have filled in more blends, connecting those situated on the opposite sides of the circle by diameters. T h e position given the blends on the left semicircle is not arbitrary. Violet has its position nearer the blue and more distant from the red in direct relation to the proportion of blue and red it contains. T h e same for the purples and oranges. T h e blends on the right semicircle are arranged and named according to the points where the diameters from the violets, purples, and oranges touch the opposite semicircumference. T h e right half could be determined first and the left made dependent upon that, but as the green and blue blends have no very distinctive names, and as the colors on the left do have, and also as the latter are always considered the more important, they must be taken care of first. T h e question now is, can interior blends be made from the blends situated at the opposite ends of the diameters? We already know that blue and yellow fuse into white, and that red and green do the same, but these colors are elemental. Do the same laws pertain to blends situated at extremities of other diameters? T h e question can be answered equally well by feeling and by logic. T h e yellow I have chosen as being elemental yellow is of a middle quality between red and green, namely a yellow which has neither a red nor a green hue. A n d the green is neither yellow nor blue, and so on. Therefore all these four elemental colors have been placed at equal distances, 90 degrees from each other. Violet is roughly 35 degrees removed from blue and 55 from red. It has more blue in it than red. T h e blue and red are neither

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of them lost, they are there and acting, as consciousness reveals. Green-yellow is 35 degrees from yellow and 55 from green. It has more yellow than green in its composition. When we mix the violet and the green-yellow, the blue in the violet must of necessity fuse with the yellow in the green-yellow, making white, and the same for the red in the violet and the green in the greenyellow—it cannot be otherwise, because the yellow and green and the blue and red, although blended and locked in couplets, have lost none of their character and instantly express it. All of the blends at the extremities of diameters are complementary to each other. An endless series of such complementary blends exists and could be put into the circle. T H E T R U E BLENDS

We know that yellow and red blend into an orange in which both of the elements are experienced. Suppose, however, we mix red-purple and red-orange. One contains blue, and the other yellow, and both contain red. In other words we have here a mixture of three colors, two of which are complementaries, that is, "opposites." They must mix—that is inevitable—but do they fuse or blend? A little logic (inference) and feeling will suggest the answer. Feeling tells us that as they are both so red the red cannot disappear, and the result must be some kind of a red. And logic tells us that yellow and blue fuse into white and therefore the mixture should be white as well as red. This is the case. Redorange consists of a large quantity of red and a little blue. T h e two reds added together make a still brighter red, and the yellow and the blue fuse into white. Therefore the sensation is elementalred, brightened by the addition of the two reds, but washed out a little by the white. Violet and yellow-orange also make red, or something in its neighborhood, depending upon which violet and which yelloworange are used. But this contains less red than that furnished by the red-purple and red-orange because its constituents furnish less, and more white because the constituents contain more blue and yellow. If we mix blue-violet and a very yellow orange, the red will be still less and the white more; mixtures of blue-

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violet and yellow-orange make paler and paler red, and more and more white as they approach the blue and the yellow, until at last, as the violet touches the blue and the orange the yellow, all the red disappears from the mixture and it is only white. T h e same reasoning with the same results can be applied to the upper semicircle, the right hand semicircle, and the lower semicircle. I have defined a blend as a mixture of colored lights which reveals its constituents, and a fusion as a mixture which fails to reveal its constituents. These definitions are not my own. A fusion fails to reveal its constituents, but in the orange and purple mixtures, for example, the red is revealed. And a blend exhibits its constituents, but the yellow and the blue are not visible. Apparently the terms "blend" and "fusion" do not cover all the phenomena of color mixture, and we must add the term "blendfusion" or "fusion-blend." If now we study the color circle, it becomes evident at a glance that pure blends can only take place within each of the four quadrants. A mixture of a color within one quadrant with a color within either of its adjacent quadrants produces a fusionblend as we have seen. A mixture of colors in opposite quadrants produces a whitish fusion with a residue, the white increasing as the mixing colors approach complementary positions, at which point the residue disappears and is entirely substituted by fusion. An illustration will demonstrate this if it is not already evident. Yellow-orange and blue-green present all the elemental colors and, when mixed, the blue and yellow fuse as do the green and red, but unless they are perfectly balanced there will be a residue. This residue cannot be composed of complementary colors. It can, however, be any one of the four elemental colors; or it may be a combination of blue and green, or of green and yellow, or of yellow and red, or of red and blue. But this residue, whether it is an elemental color or a blend, is accompanied by white, and is therefore a fusion-blend. T h e evident conclusion from this is that there are only four groups of true blends: the yellow-togreen, the green-to-blue, the blue-to-red, and the red-to-yellow. I have so far always spoken of colors either as being elemental or as being composed of two elemental colors, or of two blends

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or of one elemental color and one blend—never of three or more. I have also spoken of blends as exhibiting two elemental colors, never more—that is apart from the white they contain, which is also found in the elemental colors. We shall now try to mix three colors. For example, yellow and yellow-orange and red. We instantly get our answer: as the elemental colors of yellow and red are the only constituents, they are the only ones which will be found in the blend. This holds, of course, for the other three quadrants. Let us try mixing three colors in adjacent quadrants. We shall try purple, green, and blue-green. This resolves itself into red, blue, and green. T h e red and green fuse into white leaving a residue of either green or red depending upon which is in excess; and if it is the green that is left over, then that blends into the blue making some sort of a blue-green in which only two elemental colors are experienced; and if it is the red that is in excess, that mixes with the blue into a purple or violet. I need not give more illustrations. T h e reader, by studying the color circle can easily convince himself that it is impossible in any existing color to experience the sensation of more than two elemental colors, because through elimination by fusion their number is always reduced to two plus white and often to one plus white. I am speaking of evenly spread flat colors or of colored lights. Naturally, broken-color presents more, but if we separate out each part from a patch of broken-color, then that part obeys this law of dualism—or of singleness. THE TRUE FUSION BLENDS

I have been assuming all along that the circumference of the color circle represents pure colors, pure being used as meaning freedom from white light. T h e use of the word pure in this sense may appear ambiguous, but when we remember that white light is composed of at least two colors, and that the light of the sun is composed of a large number of colors, then we see that a pure color signifies a color free from a large number of other colors. If, then, the circumference indicates the pure elemental colors and the pure blends, we are at fault in assuming that the fusionblends can be plotted on it; the circle must be so reconstructed,

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or added to, as to illustrate graphically the position assumed by the fusions and fusion-blends. It has therefore been proposed to assume that the center of the circle is white grading into pure colors at its circumference, as in Figure 5. T h i s single addition, it is held, enables us to plot Yellow

Yellow

Red

Red

Creen

Blue

FIG.

7

FIG.

8

all fusions. For example, yellow and blue fuse into white at the center of the diameter connecting them, as in Figure 6. As the center is equidistant from all the colors on the circumference, the white it stands for is also equidistant, that is, partakes equally of all of them. This is true. Yellow and purple blend and fuse into some other color plus white. T o determine what color and how much white, let a chord be drawn from the yellow to the purple (Figure 7), and its center will, by its relative position between the center of the circle and the circumference, indicate the quantity of white. A.

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radius through will show, where it touches the circumference, what the color of the mixture is. This appears very false. Yellow and purple blend from yellow to red, and the fusion, production of white, only takes place from red to purple, namely over the stretch where the blue element becomes active. Besides, what right have we to assume that the center of the chord indicates the color of the mixture? That this chord method is wrong becomes evident when, as in Figure 8, we try to determine the position of the orange produced by yellow and red. It falls at p which indicates the presence of a large quantity of white, whereas experiments show that the white in an orange produced by mixing red and yellow is no more than that already contained in the red and yellow. T h e fact is that the color circle merely enables us in a rough way to indicate graphically certain truths, but by no means all truths. And we can also use it to deduce, or rather predict— provided always that we verify the predictions experimentally. T h e color circle is, however, one of the most valuable concepts that the practical painter can possess, and will, when his "feeling" fails him, or in very difficult problems, come to his assistance as a veritable tool. It is therefore that I am, as much as possible, stringing all the color facts on it. T H E RELATION OF L I G H T WAVES T O SENSATION

We have seen that when light rays of different wave lengths impinge on the retina, they cause it to send such signs to the brain as to cause consciousness to experience colors of different hues. F rom this we might conclude that each different wave length finds a different cone, or group of cones, in the retina sympathizing with and responding to its particular character, namely, that the retina is like a musical instrument in which each note experienced in mind has its corresponding string, and each string its particular corresponding and affecting air wave. T h a t is far from the truth. There are violet rays as physics can prove. When a beam of them impinges on the retina, we experience the sensation of violet. But when certain mixtures of red and blue waves simultaneously affect the retina, we also

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experience the sensation of violet. A combination of red and green rays makes us experience the same white as that produced by a combination of blue and yellow. What this comes to is that when we experience violet, or white, or orange, or any other color, we never can tell by the sensations what it is composed of. T h e retina does not respond to the different light wave lengths as, in our hypothetical case, do the strings in the musical instrument to different frequencies of air waves. Different color theories attempt to explain these facts. Hering * puts forth the claim that, besides black and white, there are four color susceptibilities, or processes, in the retina, red, yellow, green, and blue, and that when, for example, yellow light waves strike the eye, they affect the yellow susceptibility and we experience yellow; red rays in the same manner cause red; but when orange rays strike the eye, they cannot awaken into activity the corresponding process because there is none. Therefore they affect the two nearest processes, namely, the yellow and the red, and the two sensations of yellow and red are experienced simultaneously; this compounded sensation we experience as orange. Violet affects the blue and red processes. Therefore an orange light may be composed of pure orange light rays, or of a mixture of yellow and red, and consciousness is not able to recognize the difference. The spectroscope, however, can instantly tell us the truth. As a matter of fact, according to the theory, all the four processes, as well as the white and the black, are in action all the time with varying stress laid here and there. T h e YoungHelmholtz theory demands only three susceptibilities—red, green, and blue, but singularly calls a yellow-green by the name of green, and is not at all adverse to accepting a slightly orangered as red. It therefore denies yellow as being an elemental color sensation and claims it is caused by the mixture of what it chooses to call green and what it chooses to call red, namely, a redorange and a slightly yellowish green. Certainly, these mix into the fusion-blend of yellow plus white, that is, a pale, washed-out • As has been said on previous pages, the precise reference to or description of these various comments and theories from published works is not given by the author.

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yellow; and the theory excuses the paleness of the yellow on the ground that the yellow in the spectrum is also pale. T h e method of reasoning is interesting and suggests the question, what connection is there between the spectrum of a glass prism and sensation? It might be logical to conclude that there is no such color as purple because the glass prism does not furnish it. Young's retina requires neither a white nor a black mechanism. But both Young and Hering assume the retina to be like a musical instrument with very few strings, which are all in constant action. Their interplay can reduce a multiplicity of wave lengths tc very simple elements, which, affecting the brain and mind, are again enlarged into a multiplicity. We can compare the whole process to writing. There are thousands of words. Writing simplifies this manifold of words into twentysix letters, and mind again multiplies these letter-signs into thousands of ideas. T h e practical upshot of these two color theories, and all the others, is enormous confusion for the theorist but great simplicity for aesthetics and practical painting for the following reason: elemental colors, blends, fusion-blends, and fusions which produce like sensations, no matter what their composition is, always act alike when acting upon other colors whether elemental, blended, or fused. Two purples or oranges quite differently composed will mix in the same manner with a peacockblue whether made of yellow-green and violet or of blue and green; or with light waves corresponding directly to the peacockblue. T h e practical painter therefore is at liberty to forget the theory of the relation of wave length to sensation. A singular claim has been put forward that the green of vegetation, containing as it does (according to the analysis of the spectroscope) much more red and yellow than green pigment matter, responds to the orange rays of the setting sun and appears more orange than do other greens under the same condition. This would appear to upset our facts as stated above. I have tried the experiment of closely matching with oil pigments (on a panel) the color of green leaves, and at sunset of hanging this panel by the side of the natural leaves. They were both influ-

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enced equally. It is hard to understand how the mixture composing the green of vegetable matter should be an exception to a law. (The fallacy of trying to bridge from color to music on a basis of wave lengths is shown in the above few paragraphs: the ear can make approximate distinctions of air wave frequencies, but the eye absolutely none of ether wave lengths.) Experimentally it is possible to verify these reasoned conclusions. Paint a number of pieces of white paper (one to two inches

square) with a variety of colors—including, of course, the four elemental colors which are approximately represented by the pigments called chrome yellow (of neither an orange nor a green hue), crimson lake (suggesting neither orange nor purple), ultramarine blue (genuine), and viridian or oxide of chromium. T h e paint employed should be transparent water colors. If these are not at hand, oil colors, thinned with a drop or two of turpentine, can be used, but the result is not so brilliant. T h e colors must be as smoothly blended, as flat (without gradation), and as transparent as possible. If oil colors are used, the pigment should be smoothed with the thumb and excess of pigment removed so as to leave sufficient to cover the paper entirely, yet not so much as to prevent the light of the white paper from shining through and giving brilliancy. T h e paper must have a texture so balanced between rough and smooth that the colors spread evenly. A dull black cloth or paper spread smoothly on

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a board or table and a few pieces of sheet glass cut into squares, two, three, and four inches, complete the equipment for the experiment. Place two of the colored squares on the black board (Figure 9), which should be in a fairly strong indoor light, and holding a piece of the glass so that one of the squares is seen through it and the other reflected from it, superimpose the two colored lights on the retina and thus form a mixture. A l l the mixtures I have been describing above can be produced in this manner. T h e faintness of the reflected image, however, at times very much weakens the effect. When the scraps of color and the glass and the eye are placed as in Figure 10, the color from the reflecting scrap falling on the glass at a very acute angle is (owing to a law governing light) reflected in much larger quantities, and some of the experiments are performed to advantage in this manner. Each experiment should be tried a second time with the color squares in interchanged positions. T h e difference in values of the two colors is sometimes disturbing, and on occasions one of the squares can be tilted so that it receives and reflects more or less light. Certain experimenters have great difficulty in experiencing these effects, particularly the fusions, because they inhibit them. T h e fusion of red and green may present imperfections if either of the colored papers is spotted because these spots catch the attention, which fastens on them and inhibits all other colors. T u r n i n g the head well to one side and using only one eye—on account of the unwonted position—seems in some way to distract attention from its inveterate habit of fixing on spots, and the true mixture is experienced. A Lambert-Helmholtz apparatus is very easy to construct and manipulate, but the effects produced are often so delicate as to be unsatisfactory. I shall therefore describe a method of mixing through a rapidly repeated and alternating stimulation of the retina by two or more different colors, known as the method of the Maxwell disks. Clearly to understand these disks we must first examine a physiological phenomenon. T h e excitation produced on the retina by light does not subside the instant that

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the light ceases to act, it continues a moment or two, the consequence being that when the eye is rapidly moved from one object to another, the second object is seen through the fading image of the first. We are not ordinarily aware of this; but we all know that when we look rapidly around, we do not get clear images, and that an appreciable space of time elapses after fixating an object before the blur or confusion clears up. This condition is, of course, caused somewhat by improper focal adjustment, but even when the objects looked at are placed in a concave row, so as to be at equal distances from the eye (thus requiring only one focal adjustment), the blurring is evident. Possibly the attention also takes time to adjust itself to the new object, but be this as it may, it is certain that the afterimage, as it is called, takes a third of a second to fade out entirely after the stimulus has ceased to act. This has been determined by elaborately conducted experiments. Therefore it would seem that a stimulus could be broken several times in a second and still appear continuous. This is so. T h e spokes of a rotating wheel look like a solid block. Any marked imperfections of color in a spinning top are drawn into circles. What happens is this. Any color spot on the top will in each successive position it assumes in its rotation stimulate the retina; therefore there is a string of positions, or rather a line of position from which stimulation is effected. But long before the effect of the stimulation has worked off, the spot on the spinning top has come around again and effected fresh stimulation. The application of this principle to color mixture by means of the Maxwell disks will be evident the moment they are described. A Maxwell disk is a circle of paper or cardboard slit along a radius (Figure 11). T h e disk can be combined, or slipped together with another (as in Figures 12 and 13) and, with a screw cap, the combination can be fastened on a rotating machine, worked by hand or machinery (Figure 14). T h e disks are tinted any desired color, and when they are joined with one another, any desired proportion of the colors can be obtained, a proportion easily gauged by either an inner or outer circle acting as a percentage scale (Figure 15). When these disks are rotated at 50

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revolutions per second, an absolutely smooth color is experienced, and it is claimed that this color is the true and exact blend or fusion of the colored lights entering the mixture. When there are several colors in the rotating circle, the principle is the same. T a k e the combination of green-yellow and violet. T h e green-yellow sector is spread into a green-yellow circle, and the violet into a violet circle; therefore at one instant the violet is seen through the vanishing stimulus of the green, and the next instant the green through the violet, and it is claimed that the colors are effectively mixed according to the laws of fusions and blends. Innumerable experiments can be made with this color wheel, illustrating far more vividly the effects of color combination than does the Lambert and Helmholtz method. As the reader probably has no machinery wherewith to produce the rotation, he can easily make some color tops which, although they may be very clumsy, will sufficiently suggest what the more perfect Maxwell disks can effect. Out of thick white pasteboard cut some circles two and a half to three inches in diameter and through their centers force pointed sticks of wood an inch and a half to two inches long. These sticks or stems, which convert the circles into tops, can be made of pieces of old paint brush handles. Paint one of the tops with sectors of the colors to be mixed and spin with the forefinger and thumb. T o mix colors properly into a smooth blend or fusion, the speed of rotation should be at least fifty revolutions per second. This, of course, cannot be attained by our home-made tops; moreover, just as we are succeeding in clearly focusing our attention on the tops they are apt to fall over. But they are valuable to the student. I have purposely avoided mentioning the question of the value of the fusion or blend produced by the mixture of colored lights. We should suppose that the value of a mixture of lights would be equal to the sum of the values of the individual lights composing the mixture. A red light, entering into combination with a green light, furnishes a definite quantity of light of its own, none of which should disappear merely because it fuses

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into combination with the green light. A n d the green should also add its own light to the fusion. T h e matter does not work out altogether so nicely, but we can say that the addition of colored lights is an additive affair: the more colored lights that are reflected onto a surface the brighter the surface becomes. T h e Maxwell method, which mixes colors by a means nature never employs, at times introduces errors, and so to study this matter of addition in a normal way, and, also, to employ the method most frequently used by nature for mixing or adding colors, I have tried the experiment described below. REFLECTIONS, INHIBITION OF REFLECTIONS, AND DELUSIVE BLENDING

T h e only apparatus required is a set of rectangular, white panels of thick pasteboard or thin wood, measuring about nine by twelve inches. T h e s e should be brilliantly colored like the Maxwell disks—and some also should be very pale—particular precautions being taken that the surfaces do not shine. W h e n oil colors are used to effect the tinting, the pigments can be thinned with petroleum spirit, and if the surface of the panels is unsized, the pigment will dry mat. T h e purpose of the experiment is to reflect colored light from one panel onto another, just as natural objects reflect color onto others, and then to study the altered appearance. T o use the panels to their greatest advantage the experiments should be performed close to the window when the light is strong. O n e of the panels is held so as to face the window more or less and to receive the fullest possible light. T h i s light is reflected onto another panel submerged in a half-shadow. W e observe that an unexpectedly large quantity of light is reflected and added to the receiving panel. W h e n the reflecting panel is in sunshine, the light it adds to the receiving panel has almost the power of direct light coming in through the window. O f t e n both panels may be reflector and receiver. But, although added color means increased light, at times it is very difficult to convince ourselves that the added color has increased the brightness, and this because when the reflecting panel is in such a position as to add much light to the re-

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ceiving panel, it is apt to be so close to the receiving panel as to cut off other sources of illumination. For example, a blue panel brought sufficiently close to a yellow panel to reflect blue light onto it will also, by its position, cut off the general light of the room, and the addition of the blue to the yellow, although actually lightening it, will not appear to do so. My reason for insisting so much on the additive effect of mixing colored lights is that the mixture of pigments, and the mixture of the differently colored materials with which we come into daily contact is invariably accompanied by degeneration of color, and generally by the production of a value the average, or below, of its constituents. Association, therefore, forces on us the habit of expecting the combination of colored lights to act in the same way as colored pigments. T h e colors radiated by chrome yellow and ultramarine blue are colored lights, which add together into a gray lighter than either of them; but chrome yellow and ultramarine blue pigments mix together into another pigment which radiates green light of a value, roughly speaking, half way between the chrome yellow and the blue. Pigments and colored materials hold their existence in a totally different world from light: colored pigments have their base in matter; colored lights in the world of force. Each is governed by laws of its own, and we can not reason from one to the other. Mixtures of lights are questions of adding so and so much light, but, as we shall see, the colored lights produced by mixtures of pigments are the results of subtraction. It will be found most instructive, by means of these panels, to throw light onto all manner of objects, both indoor and out. Sometimes the deeply colored panels will be most effective; sometimes the pale. Sunlight has a habit of making colors appear yellower—a red may turn into a yellow-orange. T o obtain truly scientific results, both of the mixing colors should radiate from equally illuminated surfaces; and many other precautions are necessary. But what these panels easily illustrate are the phenomena of blending and fusing, and it requires little experimenting to bring us to a vivid realization that all interiors are flooded with reflections and that the consequent blending

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and fusing must be so great that nothing can appear in its own color. Outdoors the color radiated by the sky dominates everything, and when the sky is blue and the sun shines, the local color, or the object's actual color, is so modified that we almost concur with the bewildered landscape painter who exclaimed, " T h e right way to paint landscape is to paint it any color except what it is!" One thing is certain: whatever strange blends and fusions we may find, we never discover that yellow and black fuse or blend into olive-green as the Maxwell disks inform us. Yellow and black mixed by reflection through means of the panels makes yellow, a yellow which is in shadow or darker. Yellow and black, blended or fused into olive-green by the Maxwell disks, does not give the shadow color of yellow. It is a phenomenon effected by what we may for the moment call the idiosyncrasy of the disks. Black pigment also has the trick of turning yellow pigment into olive-green. T h e Lambert and Helmholtz and the panel methods of mixing colors present certain peculiarities which will trap the inexperienced into making false determinations. T h e peculiarities I allude to are what I call delusive blends, and are caused by expectant attention. T h e experimenter will soon observe that it is often very difficult to determine the color of a fusion produced by reflection from the panels. For example, the gray caused by the reflection of red onto green may at the same instant appear red and green and gray, or may fluctuate rapidly from one to the other. This never happens with the Maxwell disks. T h e reason is this: it is almost impossible to paint the panels so evenly that specks of more saturated color, or other kinds of imperfections, do not appear, and when these catch the attention, the attention, in obedience to the laws of expectant attention, spreads them over the whole surface. We expect to see something. Our minds are charged with the idea of the object. Our efferent (outgoing) mental and nervous mechanism is ready to visualize, that is to reproduce, the image of the object on the retina at the least hint to do so. An old, whitewashed, damp wall often breaks out in

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delicately colored green mould w h i c h apparently spreads everywhere. W h e n , however, we examine the wall closely we find that the green is only in spots softly grading into the white, or rather gray, and that somehow in our imagination we have filled in the rest. If we take a pencil and outline each of these green areas where we guess their probable termination should be, then instantly will all the color fade out of the white, and the colored areas will become distinct and appear more saturated and darker in value. T h e spreading or blending of the green over the whole will have ceased. W h a t happens is this: the spots of green catch the attention because they are the outstanding feature. T h e attention assumes a distinct attitude toward the green spots, and as it wanders easily o u t of them, over their soft edges, it finds itself in a gray spot of almost the same value, and altogether the same texture, and possessing so many similarities to the green that it does not alter its attitude. T h e dependent o u t g o i n g nervous adjustment, c o n t i n u i n g to expect green, meets the weak incoming stimulus of gray, overpowers it, and projects green on the retina. T h i s must be so because, by an effort of will, we can momentarily separate the green spots from the gray, b u t they blend again when the effort is relaxed, showing that the phenomenon is not altogether physiological. In popular language we can say that the attention, having become set for the green, finds it easier to remain so, particularly as the gray is not sufficiently different or strong enough to cause it to assume a new attitude. A n d remaining in this attitude, it inhibits, of course, the gray and expects the green. T h i s phenomenon is rarely seen except in areas of gray or very delicate colors; attention experiences difficulty in ignoring any very strong or sudden stimulus. T h e habit of attention in persisting in its interests, and remaining oblivious to the rest, we are familiar with. W e k n o w that the violinist sometimes concludes his performance by so dclicately shading the terminating note into silence that w e believe we still hear the music after it has ceased. A n d this is obviously owing to the fact that attention is intently concentrated on the musical note, and, inhibiting (being oblivious to)

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all else, and therefore adjusting itself entirely to the note, finds no reason for altering the adjustment. It is aided in this expectancy by the imagination. T h e most frequent delusion in the effect of one colored panel illuminated by another is that experienced when the colors are complementary. Take red and green. We experience red, then green, then gray, then all three together, then a couplet. Our determined will to see gray sometimes assists for a few moments, but presently one of the colors comes popping in. Fixating our eyes may assist, or it may not. It is always obvious that there are two colors. We can not get rid of the fact. But soon we learn that this is because of inequalities in the surface of the receiving panel, and possibly in the reflecting panel, and also to inequality of illumination. T h e fact, however, remains that the general hue of the mixture is gray, and it is the attention which causes all the trouble. T h e attention, true to its character, catches on some miserable little spots or larger areas which have not been entirely fused, and, according to the law of expectant attention, imagines (projects) the color over all. T h e rotating disks, as I have said above, naturally do away with these inequalities. But we can also do away with them to some extent by squinting and throwing the lashes over the eyes. We can still more destroy attention's opportunity to act expectantly by viewing a small selected portion of the mixture—containing the fewest spots—through a small opening cut in a sheet of gray cardboard large enough to block from view all except the chosen portion. Then if the head is tilted and we view with squinted eye, the true hue of the mixture will probably reveal itself. Delusive blending will not affect a blend so much as a fusion, for the simple reason that in a blend both colors are experienced, and the only alteration which delusive blending can effect is to delude us into believing one of the colors to be still more dominant than it is. It will now be understood why I have chosen the term delusive blend to designate the phenomenon I have been describing. It is blending, not fusion which takes place: imaginary blending of color into a gray makes the gray appear colored;

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and when it occurs in the blends, it blends but does not fuse into them. It is also a delusion—not an illusion—because there is no extra mental stimulus, no physical existence which causes the phenomenon. T h e phenomenon is just as much a delusion as the sight of a ghost, and caused much in the same way— natural suggestion is seized upon and exaggerated by the attention and imagination. Delusive blending is of the most common occurrence in nature, but is rarely detected because it seems so natural that it is not questioned. Its detection, however, is of paramount importance to both the theorist and experimenter in color as well as to the practical painter. T h a t its recognition by the scientific experimenter is absolutely demanded is self-evident; his failure to discriminate results in false conclusions. T h a t its discrimination by the painter is equally important is not so evident. We might reason that if a painter experiences a gray as colored and paints it as such, then the spectator of the picture should experience the same color sensation as the painter. T h i s is false reasoning although universally indulged in by the layman and by many painters. T h e sensation a delusive blend causes in consciousness is due to the combined action of attention, expectant attention, and imagination, plus the rest of the usual action of the perceptive machinery, whereas a physical blend causes its sensation without bringing into action the processes of expectant attention and imagination. We should be able to detect the action of expectant attention and imagination when experiencing a delusive blend. A physical blend has an appearance of stability, solidity, which no willful effort to disturb it can affect. A delusive blend can, by the closest attention on the part of the practiced experimenter, be resolved into its constituents: it wears an appearance of delicate shimmer caused by the fluctuation of expectancy. This sounds a little like broken color b u t it is not; the shimmer of broken color is an evenly broken fluctuation, whereas the delusive blend, when it is closely studied, disappears entirely for an instant and gives one the uncomfortable feeling that possibly it is not there at all.

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EXAMPLES OF DELUSIVE BLENDS

One who is not trying experiments and studying nature, as we go along, may be largely misinterpreting my meanings for the reason that to give a recognizable description of sensations as delicately differentiated as color sensations is very difficult and I am relying, not on the usual method of color charts included in the text—which I deem useless—but on the appearances of natural objects to make my meaning clear. T h e color of shadows, as I have pointed out, is very difficult to judge because of the weak light, because of certain tricks of attention, and, as we can now say, because of delusive blending. Moderately dark shadows have, apart from the reflections which influence them, the same color as the lights, being only darker and in certain cases more blue. Still darker shadows, still more impoverished as to light, may sometimes appear washed out in color. T h e greatest discrepancy, in the judgment of deep and often even of light shadows, exists in the different minds of those who see them. Many shadows which are physically not far removed from gray appear strongly colored to some observers, owing to delusive blending, and to others they appear gray, slightly tinged with color. Shadows in foliage are variously judged. Some observers find them greenish gray, but others blend in the few lighter and more strongly colored leaves accidentally lying in the shadows and experience the shadows as being much more saturated in color. Objects against a very bright and highly colored sunset seem to some painters very dark gray tending toward violet or purple on account of contrast combined with deprivation of light. Other painters, however, are overpowered by the general brilliancy, expect to find the shadows highly colored, and paint them so, even making deeply shadowed foliage strong green. T h i s is a case not of expectancy and repetition of some particular color sensation, but of the reproduction of the expectant idea of strong color which has been born into consciousness by the strongly colored sky. T h e most perfect examples of delusive blending are found in

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flesh coloring, particularly of the figure. W e can not turn indiscriminately to the old masters for information, or even to modern masters, because nowhere in the whole province of painting does art deviate more from nature's methods in its efforts to attain effects than in painting the nude. T h e reason for the artificial methods of the artist is largely that the difficulty of attaining an imitation of flesh coloring is so great that every resource at the painter's disposal is called in. For example, the brown shadows of many of the Venetian paintings might lead the layman to suppose that the delicate reds and yellows evident in the lights gathered force in the shadows and appeared brown. T h e truth is nothing of the kind. These same Venetians, for reasons of tone or of color harmony, either caused the prevailing studio color to be brown, which reflected into the flesh and other shadows, or they assumed it to be brown. T h e same is true with the red and crimson shadows. Some painted flesh presents in the lights a meshwork of pale green and red or pale yellow-green and purple which might lead us to numerous wrong conclusions regarding the color structure of flesh. In truth these broken threads and blotches of color are not intended to indicate appearance, but are what is called broken color, and fuse and blend into a brilliant gray which is rosy and golden-yellow and lustrous in color. W e might give dozens of examples of essential differences between the painted and the natural nude, but it is not necessary because we have at our disposal a means whereby we can with certainty determine the almost exact hues of flesh, and having got these we can compare them with our idea of what we presumed them to be, and thus determine how much delusive blending plays a part. In a room filled with white light, that is, a light in which all strong reflections have been neutralized by complementary colored reflections, a nude is posed so that the shadows shall not be very dark, or the lights very bright. A sheet of glass is firmly placed in an upright position between the model and the line of sight of the operator. T h e n , with oil pigment and a sable or other soft brush, samples of the lights and shadows of the nude are carefully imitated on the glass, in the shape of flat, un-

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gradated patches. These colored patches, if accurate, will almost disappear when the eye is held in such a position that the patches partially cover their counterparts in nature. On account of the limited value range, it may be impossible to imitate both lights and shadows without turning the glass so as to receive more or less light from the window. This, however, does not matter because what we are after is not value relations, or indeed relations at all, but independent physical appearances. T h e collection of patches is often astonishing to the young art student. They are all silver grays and appear to be much undercolored, particularly the shadows. On close comparison, however, it will sometimes, not always, be recognized that a certain amount of the apparent rich color in nature, particularly in the shadows, is caused by little specks of stronger color which expectancy has blended into them. If we are allowed to turn to the artist's product for corroboration, and turn to the one who today bears the reputation of being the truest of them all, namely Velasquez, the gray version of flesh is borne out. When, on the other hand, we turn to the earnest endeavors of the art student, and compare the pale tints and shades on the model with his flamboyant version, we are often rewarded by discovering exactly what small spots of stronger color his expectant attention has blended into the grays. Every practiced painter understands the magic effect that a few touches of rose softly graded into gray produce. A woman's breast may be painted with a mixture of yellow ochre plus black plus a very large quantity of white, which will make a silver-gray of pale olive-green or olive-brown hue, and will appear somewhat ghastly; but if a few touches of crimson lake or burnt ochre (diluted with such a quantity of white as to effect the same value as the gray), be touched in here and there, even if the pigment be meaninglessly and irregularly spotted around, then instantly will the whole area become rosy and lifelike, and the individual rose spots will almost disappear. In the same manner do the green and blue veins in flesh blend into their surroundings and produce a greenish or bluish effect like that of the whitewashed wall.

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A very delicately colored dress of almost the same value as the flesh will sometimes blend into the flesh. This at first sight strikes us as singular. We should think that a pale rose or yellow dress lying across the breasts would make the flesh appear to be of the complementary color by induction, the rose inducing a greenish color, and the yellow a bluish color. As a matter of fact, the dress does both. If the edge of the dress, where it is juxtaposed against the flesh, is melted into the flesh by means of an edging of semitransparency or by fraying, then will delusive blending take place; but if the dress is sharply marked by an abrupt change, as by a narrow clear black line, then complementarism takes place. This brings us to one of the most important practical, as well as theoretical, phenomena in color, namely, that a color may at one instant act sympathetically, and the next in opposition. As the phenomenon is as much one of contrast as of blending, I shall continue it in my remarks on color induction. All that need be pointed out now is that the blending is the same phenomenon as that of the whitewashed wall and the green mould. Another phenomenon of blending is that a blue dress accentuates the blue of blue eyes, even if the dress is in no way softened at the edges. It can not be that the blue dress reflects its blue into the eyes because a blue feather on a hat—where it can not throw light below the brim—causes the same effect. It probably is ideal blending. I have remarked that the attention experiences difficulty in ignoring any very strong or sudden stimulus. An example of a moderately strong stimulus being inhibited is seen when a certain kind of dull red grass or weed makes its appearance in a field of dull green grass. T h e red weeds, scattered here and there in softly edged patches, remain separate from the grass, b u t as the eye wanders, the red will suddenly sweep over the field, in a moment to disappear again. INHIBITED FUSIONS

A beach or sandy plane lying in the sun under the blue sky appears gray-blue to some observers, gray-yellow to others, and to still others it appears to fluctuate. T h e sky radiates blue onto

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the sand and the strong sunlight reflected from the sand excites the retina into yellow activity. These should fuse into gray, but in reality they act like the reflected light from colored panels, which should fuse and does not. Irregularities of illumination make us conscious of the two colors, and a fight for dominance sets in. Sometimes the fight is won before the problem even presents itself. For example, inhibition of the more delicate outdoor shadows, and the accompanying blue tone, is habitual with many young painters; and others have—for reasons I do not understand—so reversed themselves that the yellow is inhibited and they paint sunlit landscape in an exaggeratedly blue tone. This is not an unconscious imitation of impressionism, because impressionism credits the sunlit portion of objects with a very full quota of yellow. Some experimenters and painters can artificially overcome this inhibition. Viewing, with tilted head, a small portion of the beach or sandy plane through a hole in a cardboard (as in our previous tests) will probably tell the truth. It is often useless trying to determine why inhibition preferably cuts out one color in a combination. Before me, in the sunlight, lies one of my black reflecting panels. T h e sun causes it to appear slightly yellow. Tilting my head and squinting one eye (the other being closed) shows that I was inhibiting the blue skylight, and that the color, as it reaches my retina, is faintly bluegray. Gray rocks lying in sunlight under a blue sky may radiate bluish or yellowish light, but whatever color they radiate on the retina, the action of this color on the inhibitory process is very uncertain. What is often at the bottom of these phenomena is that we know the local color (the color of the pigmentation) of the object, and expectant attention insists on that color and produces it. An extraordinary phenomenon illustrating this can often be easily observed. A casual glance at a face very near a window when the sky is blue, and no yellow light is entering, will inform us that the flesh is pale in color but normal otherwise, whereas the tests (with which we are already familiar) reveal the fact that almost all yellow in the flesh is fused into gray by the blue skylight, leaving grayish-purples and greens, and

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yellows so attenuated as to make us feel they must be "cold yellows." But after once experiencing the flesh as being bluish and purplish and after holding the corrected version in mind for a while, we may find that it reverts at any instant.

VI Broken Color and Luster

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E H A V E S E E N how colored lights reflected from objects onto other objects not only add together but add into differently colored lights—even the color of the far-away sky is summed into that of the things on earth. W e have seen how colors, alternating in rapid succession as presented to the retina are made to blend and fuse, though we can not recall an example of nature ever making use of the method. W e have seen how, through the action of the attention, colors add together in consciousness. W e have seen how colors, which nature has added together, are again separated by the attention. Now we shall see how fragments of dissimilar colors lying close together seek to add themselves into one unit. Twist a red and green thread together. Close inspection of the strand reveals the red and the green. Weave a cloth of such strands. O r more easily, on a white surface place numerous small dots of alternating red and green pigment very near each other. A t close range all the dots will appear. But if they, or the threads, are viewed from a distance, they begin to flicker, as it were, and a white or light gray film spreads over the surface; and, when they are viewed from a greater distance, the white film predominates, the spots or dots flicker more, and come and go. At a still greater distance the color spots disappear, and an even gray surface spreads over all. T h i s surface seems lustrous, as if it created a little light of its own. T h e explanation of the phenomenon is simple. At close range the dots of green and red form clear images on the retina; farther away the images become very small and, on account of

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the imperfect lens and retina, are blurred, overlap, virtually lie on top of each other, and one color is seen through the other. I n accordance with the laws of fusion explained above, they fuse into white. When the fragments of broken color are not complementary, they mix into blends or fusion-blends, as the case may be. Most significantly however, in contradiction to the Maxwell disks, yellow and black blend into olive-brown, not olivegreen. T h e flickering observed when the broken color is at a certain distance occurs because attention, being distressed by the confusion and indecision, tries to bring the images to a clear focus; for an instant it does so, but the next instant loses the focus again. When physical focal adjustment fails to produce clear vision, the attention comes to its assistance; but the attention fluctuates in its efforts, and this fluctuation, in the present case, produces scintillating color images, which at one instant are clearly experienced as specks of color and the next instant slip out of the hold of attention and fuse into grayNature furnishes countless examples of broken color. A field of thinly growing grass or weeds lying at our feet presents, when the sun is shining, patches of light yellow-brown and darker purplish brown earth, yellowish green and bluish green verdure, positive blue shadows on the gray stones, touches of bright yellow, and orange, and red flowers. But in the distance all these various colors fuse and blend into gray, which, if there is mist, becomes tinged with blue; and through this veil some of the stronger spots, which have not entirely disappeared through fusion and blending, gleam and shimmer, causing the whole mass to appear lustrous. T h e immediate foreground itself, when very closely examined, will be found to consist of a mass of broken color. A clod of dirt, for example, is composed of a mass of pinhead-size and smaller specks of various colors which blend and fuse into brown when the dirt is only a few feet distant. T h i s brown, however, is not very lustrous because its constituents, as a rule, more or less approach the same hue. Broken color to produce its maximum effect must be composed of complementary colors—the nearer complementary they are the more lustrous the

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mixture. It is for this reason that many objects, most in fact, being made up. of patches of color more or less alike, do not (to ordinary perception) present the characteristic shimmer of broken color-fusion. But it is there. T h e green leaves of the trees are yellow-green under the sun's illumination, and bluegreen in the shadows, and when the tree is far enough away these two colors blend and fuse into a green a trifle gray—but because moisture in the air also acts as a gray veil, we fail to appreciate the luster. It is widely recognized that sunshine causes shimmering far more than gray cloud illumination, and some impressionists claim that this is because of the fusion and half fusion of the yellowish lights with the bluish shadows. I believe this claim to be correct but exaggerated. T h e sun causes millions of tiny broken images of itself to be reflected from all matter, and these reflections, every instant shifting, cause a veil of great luster. T h e clear blue sky apparently shows no signs of broken color, but a claim is put forth, in physiological psychology, that the luster or shimmer the unbroken blue sky sometimes presents when brilliant is caused by fluctuations in attention—always taking place but exaggerated by the intensity of the light. Roughness of texture acts as broken color, particularly under sunlight. A rough mortar wall or plastered side of a house or pale-colored, worn bricks, illuminated by the sunlight falling at such an angle that each irregularity casts a shadow colored by the blue sky, presents broken color. And this broken color is of such quality and the luster produced is so great that we often judge the value of such a wall to be higher in the scale of values than the value of the sky from which it may happen to be relieved, whereas in fact the reverse may be pronouncedly the case. This phenomenon, on which is based much of the physical—not psychological—practice of impressionism, is one of the most important in the theory of color, but is apt to be ignored by physicists. They say, as I have pointed out, that color has and can have only three constants or qualities, hue, purity, and brightness or luminosity; the last is something which the painter splits into two qualities, values and luster. This is why painters

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refuse to accept luminosity or brightness as other than a literary term of variable signification to be used with caution. Wundt accepts luster as the fourth quality, although he does not enlarge on it. What is much to the point in this connection is that broken color, although an additive matter, does not really produce more light. It produces luster which our untrained senses mistake for high luminosity (in physical terminology) or high values (in painters' terminology). But the trained artist recognizes that a distant landscape, rich in broken color, although it appears very light to the senses, is in truth (according to the mathematical scale of values) not light at all. Broken color is almost always present except in highly polished things like mirrors, and those reflect images of other things in which the color is broken. Even smooth (unpolished) marble has a fine grain, and so has fine white paper, and this broken texture unquestionably acts as broken color at one distance or another, even if the shimmer it produces is so slight as to be scarcely felt. Because broken color is so universally present in nature and is always producing luster, we accept the luster as being part of the color of the object itself, and fail to recognize the ever-present broken color producing it. W e have seen that broken color blends and fuses into differently colored lights and in doing so produces luster. If broken color merely fused and blended into other colors, although still remaining an interesting psychological phenomenon, it would never have gained for itself the great power it has in the practice of art. As it is, the whole question of beauty of color is more or less dominated by luster. T h e midday sun in a clear sky is our ideal of luster. It shimmers, sparkles, glitters, glares, and flutters, and it pains us to look at it. T h e pain is a necessary accompaniment of high luster and is caused, not by affection of the retinal tracts by the intense light, but by the strain in the ciliary muscles encircling the pupils in their effort to shut out the light. T h e waves dancing on the surface of a pond produce luster. T h e distant ones produce it according to the laws we have laid down. Those too close by to use these means effect it by simply reflecting into the eyes two dissimilar, colored lights. This they

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easily do because their irregular, but polished and reflecting, surfaces lie at every angle, and in their continual change of movement send clearly cut beams in every direction. By chance the two eyes will every moment receive dissimilar images. Consciousness, as is its wont, whenever presented by two dissimilar images, attempts, under the stress of the attention, to unify them, and the irregular, alternating successes and failures to do so produce the effect of fluttering, or shimmer. In ordinary binocular vision of near-by objects two very slightly different images are presented to consciousness, and the attention, without apparent effort, coordinates them into one. But when there are presented to consciousness two very dissimilar images (as by the optical instrument popularly known as a stereoscope), attention, in spite of the evident non-connection of the images, tries to unite them into one. Since, momentarily, it can unite only a fraction of the one with a fraction of the other, there arises in consciousness a sensation of fluttering due to the rapid alternations of success and failure. This fluttering is accompanied by a slightly disagreeable feeling because of the strain of attention. T h e same disagreeable or strained feeling is always produced by luster. It is strong when the luster is strong, and weakens into a slightly exciting and agreeable sensation when the luster is weak. As for the underlying cause of the sensation itself, we may either suppose that it is altogether kinaesthetic, muscular, or that it is the resentment of the thwarted will in its efforts to control. A hundred times shall we find this same disagreeable or agreeable sensation—or feeling, if we admit it to be the thwarted will—in our study of the beautiful. But it must be understood that this painful or disagreeable or exciting feeling forms no part of the phenomenon of luster itself. It is a by-product of the production of luster, but for all that, a by-product which often dictates our liking or dislike of a lustrous effect. A mouth full of salt produces a distressing sensation, whereas a very small quantity accentuates the flavor of food and is agreeable. Jewels present three overlapping lights: that from the interior of the jewels, that from the surface imperfections (the diffuse light which makes the surface visible), and that which is directly

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reflected from the polished surfaces, that is, as from a mirror. In addition the two eyes perceive slightly different images. Attention tries to unite into one all these sensations with the usual result. Polished metals also reflect light directly; and they also radiate the color and imperfections of the surfaces themselves. H e r e we have only two masses of light. Polished and varnished woods radiate light from their own surfaces as well as from the surfaces of varnish, and in addition the varnish surface reflects a little weak, directly falling light. A thickly varnished oil painting or painting under glass presents an image composed of overlapping images from the angle of refraction of the glass through which the painting is seen. T o these is added the vague, directly reflected light from the surface, for no matter where we choose o u r point of observation there is always some direct reflection from a polished surface. In some of these examples the stimuli coming from the objects are in actual movement. In others an effect of movement in the stimulus is caused by actual movement on the part of the observer. May it not possibly be, then, that the physical movement of the stimuli causes the apparent fluctuation and shimmer? It may be so to some extent in the jewels and the dancing waves, but can hardly be so in the case of polished wood because the effect of luster remains even when the observer is in absolute repose. Besides, the effect of luster, which I am trying to describe, is more steady and constant and even than the exaggerated effect of the playing waves, or of the momentary glimpse of the sun. Of course it is true that physical fluttering seems to aid the production of luster, but this may be due to the ideal fusion of the rapid physical fluttering with the still more rapid attentive fluctuation. A very good example of luster is seen when sunlight, only moderately strong, falls on a gray, not white, mortar wall. T h e absence of all color except that of the sunlight and blue skylight makes it easy to study. Without the slightest doubt, it shimmers and faintly glitters and is lustrous. T h e effect at times appears translucent; we seem to feel, or see, the wall through a veil of infinitely fine sparkle; or the sparkle through a veil of

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transparent mist. It is not merely an appearance I am trying to describe, but a sensation, possibly a feeling. Another example is often seen in steel engravings, which largely depend on shimmer to produce their particular beauty of texture. The cleanwiped passages of dark shadows in good etchings depend upon the sparkling of the tiny whites for their life. Luster is produced by the attempt of the attention to hold in conscious vision the specks of white which the retina would let coalesce into the black. (See Figure 16.) T h e quantity or intensity of the luster which accompanies light varies greatly. We say that the dazzling sun glares hideously, that strong sunlight glares and sparkles and glitters, that soft

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sunlight glitters and shimmers, that polished metals glisten and glitter, that pale sunlight breaking through mist shimmers and glimmers, that flesh, indoors under direct window illumination, shimmers and gleams, that strong light reflected into flesh shadows causes them to gleam and glow, that red-hot iron glimmers and glows as do the embers on the hearth. These terms indicate not merely varying degrees of light, but also varying degrees of luster. Experiment endorses this distinction. A piece of cold iron painted the same red as the hot iron and placed in such an illumination as to be of the same value as the hot iron does not glow, even when radiating the same quantity of light. A silk cloth stretched flat and placed so as to reflect no direct light shimmers, whereas a cloth of wool of the same, or even of a higher value, will appear dead. A spoked wheel rotating slowly, makes the eyes try to follow the spokes, and this attempt is distressing

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physically. But if the rotation is more rapid, the eyes cease in their attempt to follow, and there is experienced a fluttering effect alternating with momentary glimpses of the spokes. A t a still higher rate the spokes disappear altogether, and also the fluttering, and these are replaced by delicate shimmering. If we analyze the shimmering, we realize that the sensation we experience is only an accompaniment of light and not the light itself. W e also judge that the volume of light has not increased even if a brilliant something has come into existence—a thing which is not light. A lustrous color casually glanced at appears to be of a considerably lighter value than a less lustrous color of the same value and is continually misjudged by even the most practiced painters. I am not alluding to such obvious phenomena as the sunlit rough mortar wall, but to more intangible problems, such as the painting of the nude. Flesh, even of the finest texture like that of a young woman, when examined under a magnifying glass is found to consist of a meshwork of scales, not so unlike those of the crocodile. Each scale reflects the light of the window, or any other strong light, and these specks of light coalesce into a shimmering mass. T h e mass fuses and blends into the little specks of local color of the flesh, which produce more luster and this causes us to judge the color as lighter than it is. Particularly is the flesh value of "olive-colored" brunettes misjudged. W e speak of their dazzling complexions—which is correct—and experience it lighter than it is. So confusing is this dazzle that often the white draperies brunettes may be wearing seem darker than the skin. A n d there have been whole schools of painters (including portrait painters) who habitually, unconsciously, and often consciously, have painted the flesh too light in an attempt to imitate the effect of luster. W e have no scale in consciousness wherewith to measure the sensations of color and value; we discriminate relative strengths of sensations by means of feeling, and as the feel of the sensation of brightness of values and the feel of the sensation of luster are not so very different, we often, unless carefully trained, confuse them. Mind judges quantities of stimulus by the feel of the

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sensation. It can not do otherwise. T h e only connection mind has with the physical world is through sensation. T h i s truth becomes more evident if we study very strong lights, where glare and the sensation of pain in the ciliary muscles are the invariable accompaniments. And this sensation of pain, being apparently indistinguishable from the sensation caused by the light itself, is confused with it and accepted as standing for the index, or coefficient, of the quantity of the stimulus. We can put this in another way by saying that mind judges quantity of stimulation by vividness of sensation, and the most vivid sensation we are acquainted with is pain. Physicists object to the admission of luster as a color constant or quality on the ground that luster implies broken color, that the skin, for example, is composed of a variety of colors, that it is not simple. And physicists explain that the constant of a color should apply to one simple color and not to a mixture or a variety. T h i s sounds logical, but where is that color? Matter does not furnish it; nor does the spectrum falling on a piece of matter; nor does the clear blue sky, for that too fluctuates, not merely because of the fluctuation of attention, but because, as we know, the specks of matter in the humor of the eye are projected on it. T h e spectrum, viewed directly, glows, shimmers, and glares. T h e r e is no such a thing as a non-varying patch or speck of color. All color has variety. Physicists may also contest the admission of luster as a color constant on the ground that the phenomenon of color sensation is a phenomenon due to the stimulation of the retina by actually existing light waves, whereas luster has no physical parallel in nature and is altogether a psycho-physiological phenomenon. T o that we can reply, "So is white." Besides, the three accepted constants, hue, value, and purity, fail to define color differences, as for example that between red-hot iron and cold iron painted red, and that between silk and wool. At very high levels light apparently does not have to be broken so much as at lower levels in order to produce luster. Light at a high level acts directly on the physiological machinery causing

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physiological disturbances which are sufficient to produce fluctuation of attention without calling upon the aid of broken color— although that also may help. At low levels it is only the broken color which effects the luster, and the greater the quantity of broken color, the greater the luster. Therefore intense light always effects great luster, whereas the luster in medium illumination varies greatly. A phenomenon well known to physics probably has some bearing on that. In normal indoor illumination a colored object will appear more brightly colored if placed in a brighter light, and the color will gradually disappear and be lost in blackness when the object is placed in shadow. This seems consistent. T h e greater the intensity of light falling on an object, the more the object's color-producing powers are awakened into activity. From this we should conclude that the stronger the white light falling on the object is, the stronger (more vivid) the color produced. Pale sunlight should effect more vivid color than indoor light near the window. T h e truth is the reverse. Pale sunlight adds luminosity, that is, raises the value, but washes out the color a little. Stronger sunlight washes it out still more. In fierce, glaring sunlight the luster is very high, and, of course, also the value, but the color is very pale. T h e same phenomenon is observed in raising the luminosity of the spectrum; therefore it has nothing to do with the peculiarities of the action of colored light radiated from matter. T h e phenomenon is contradictory to reason: a beam of white light falls on a patch of vermilion pigment; a part of the beam is absorbed by the vermilion; and those rays which constitute vermilion are sent back, radiated out. T h e stronger the beam of white light, that is, the more rays it contains, the more red rays there are that should be returned. It seems to me the solution is this: the brighter the illuminating light, the brighter is the color produced. But the brighter the illuminating light, the greater also is the quantity of luster produced, and this luster, which apparently lies on top of the color, obscures and pales it. That the luster should appear to lie

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on top of the color, and thus produce the effect of transparency, I have several times mentioned, and that a film of grayness or whiteness should in this manner pale the color lying below is so evident as to require no explanation. Is luster white? And is it the same white we already know? It certainly is not the same white because it fluctuates, trembles, shimmers, and moves. It is a colorless shimmer overlying color and one which, at the same time that it gives movement to that color, pales it. GLOW

When the colors of the spectrum or any natural colors are low in luminosity, the glare and whiteness disappear; the colors become more nearly pure (more saturated); under certain rare conditions they glow. Because the term glow is used variously, it needs more description. Red-hot iron glows; the firefly glows; the sun setting in certain kinds of mists looks like a glowing red orange illuminated from inside. Stained-glass windows glare or glow depending upon the strength of the light passing through them. Rubies and emeralds usually glow, but diamonds usually gleam or glare. Gold, in reflected illumination, glows, but polished steel and lead and tin are more likely to gleam. Clouds, illuminated by a sun that has set, sometimes glow, and a forest pool of brown water will reflect and augment the glow. Glow at first sight appears to be a form of luster, but has marked characteristics of its own. A glowing color looks as if it were illuminated from underneath, as if white were shining through a transparently or translucently colored layer of matter. T h e little boy's scooped-out pumpkin, in which he places a lighted candle on Hallowe'en, glows, and glows because the thin rind is translucent and allows the candlelight to pass diffusely and softly. Red-hot iron, although it appears to be as translucent as the pumpkin or glowworm, is opaque. Sheet gold in soft reflected light is also opaque, but appears illuminated from within. Glowing colors usually have soft edges and are variegated and graduated in value and very frequently consist of several colors softly blending and fusing into each other. Glow is usually colored, although white ground-glass over white light will cause

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a little glow. Glow is often conceived as belonging to the luster series, glare being the top, and glow the bottom, but I am unable to connect them. I have defined luster as the product of broken color and, in cases, of strained attention. It is a white scintillation lying over color and is characterized by its sparkle, by its restlessness. Glow, on the contrary, is characterized by its great quietness, by its restfulness. Therefore, on the principle that opposites belong to the same series, we can include it. T h e fact is that the effect of glow is produced by a variety of physical causes, but the idea of glow is one of association: the dying embers in the fire escape no one; the rich and the poor, the savage and the civilized, see them from earliest childhood, and are strongly impressed. According to the laws of association, any other piece of matter which presents a similar appearance will be said to glow. However this may be, and unimportant as glow may be to physics and psychology, to aesthetics it is all important. Glowing colors constitute one of the most frequently used color themes of the artist. A glowing mass is a mass in which nature has perchance brought together colors in such a manner that they exhibit the unities of soft focus, gradation, and several of the color harmony series, all of which, combined, are sufficient to cause beauty. Because it is beautiful, glow has given inspiration to whole schools of colorists who have carefully studied it and have tried to introduce its effect in their paintings. It offers, as few combinations in nature do offer, an opportunity of producing beauty by simple imitation. THE SENSATION OF BRIGHTNESS

I have referred to the word brightness as being a term too loose in its denotation to be accepted by us even if physics and psychology take it. Accepted science says that brightness is the sensational equivalent of physical light waves, and that the relative strength of the sensation of brightness varies in accordance, though not in proportion, with the relative strength of the light waves. Of course, accepted science makes due allowance for the variability of the pupil, and for photopic and scotopic adjust-

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ment. But, for our purposes, the sensation of brightness will have to be regarded as a compounded sensation caused by the stimulus of light, plus the physiological and attentive effects of luster. Thus defined I can use the term. Nature produces luster in various ways: by broken color, by myriads of tiny high lights (scattered reflections), by larger splashes of light as on metal and jewels, by actual motion as of water, by kinaesthetic eye strain, and so forth. Broken color and the myriads of reflected high lights are the most important, and of these two the reflected lights take precedence. What follows is a more minute study of these lights. T o understand it we shall begin by examining the eye, which is generally accepted as being (in certain illuminations) a very brilliant and lustrous thing. Dark-colored eyes, when shaded under the brow and reflecting no high light, look dull and not so very dark, but when a pin point of white light is reflected from such an eye, suddenly the dullness disappears: the pupil and iris seem to darken and also to gain an appearance of transparency, and at the same time a singular feeling of vividness and light pervades the whole eye socket. Here we have two contradictory phenomena: on the one hand the tiny light darkens the pupil and iris, and on the other hand it induces a feeling of light, spreading it over the whole eye socket. But how? And where does the transparency of the pupil and iris come from? And is it really transparency? An eye in shadow without a high light appears dull, and the pupil lighter than it is, for the same reasons that a background in shadow appears dull. T h e introduction of the high light gives a point from which to measure and to recognize the true depth of the values of the darks. It is merely a matter of contrast. T h e effect of transparency is more complicated. An eye without a high light, when closely examined, will always reveal dim, confused reflections of various objects. These should, according to the laws of reflections, appear to be as far behind the cornea as the objects reflected are in front of it, as is the case with a mirror. But this law holds poorly in our present case because the images are so confused that they fail to form into clear ideas of reflections. W e are only conscious of patches of light which slightly

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suggest that they may be some material objects situated a little distance underneath the surface. T h e fact that the cornea is itself slightly transparent has nothing to do with the matter and need not be brought in, because elemental reason (Helmholtz's inference) can not understand, it only feels and jumps at conclusions. When any surface is presented to it, even if opaque, polished jet, and when the images it reflects are so vague as to fail to convey the idea that they are reflections at all, then will elemental reason conclude that these patches of color come from something below the surface and that the surface is transparent. Possibly the association of nebulous patches seen through the semitransparent waters of dirty pools may assist in producing the idea of transparency. T h e reason we do not feel a mirror to be transparent is because the images it reflects are so clear that we instantly know what is happening. And yet who of us has not at times felt a mirror to be transparent with actual objects below? The eye is always reflecting patches of light of this vague kind of which we are but dimly conscious. When a whitish spot is set in their midst, a most singular phenomenon takes place. The white spot is too small to be distinguishable as a reflection of the window. It does not present the idea of being a reflection, and, as it is not nebulous, it does not appear to lie below the surface. T o the contrary, the white spot frequently appears slightly in front of the eye because, owing to its clear edges, it separates out of the mass which is so softly blended. Separating out, it must of necessity come forward. From this it is easy to see that the suggestion of actual depth of transparency in the eye which has no high light will, by the introduction of a slightly protruding bright spot, be measured by elemental reason as being behind that spot. Further, there is something in mind that is always trying logically to correlate sensations and ideas, and in this present instance it tries to relate the high light and the surface of the eye. It follows that the protruding high light is more or less successfully pushed back to the surface. The nebulous reflections, being already felt to be behind the high light, are sunken still more into the eye which we therefore feel to be, and call, transparent.

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T h e feeling of vividness and light which spreads over the whole eye socket when the high light is added to the dull eye is caused, first, by the sensation of vividness produced by the sudden transition of the attention from a high light to a dark—a phenomenon we have frequently noted—and, second, by ideal blending of this feeling of vividness into the somber and softedged color patches which constitute the socket of the eye. When the high light is very large and covers a fair portion of the eye, the feeling of light, the blackness, and the transparency, may all disappear again. A highly polished black leather shoe or a polished and varnished piece of dark wood will exhibit the same attributes, which will appear and disappear not in accordance with the intensity of the light reflected. T h e phenomena seem somehow dependent upon the shape of the high light, or on its size, or some condition of that kind. A study of the artist's method of painting an eye may help to explain the difficulty, for certainly the artist can obtain transparency, blackness, light, dullness, or anything he chooses, at will. A spot of white as large as a small pinhead, and as round, and set on the pupil or on the darkest part of the iris of a painted eye, will frequently produce all the phenomena I have been describing. Sometimes, however, in addition to those phenomena the painted eye will "stare." And, again, sometimes the white spot will only look like a speck of white pigment. T h e conditions appear to be these: if the painted eye is painted in oil color (for convenience of execution), and if a small, round high light is set on the still wet pigment, it will blend at its edges a little into the dark pigment representing the pupil or iris, and will on some occasions look like pigment and on others like a high light—by chance, as it were. If the small high light is sharp and clear at one edge, and gradates at the opposite edge into the dark ground, it always looks like a high light and never causes the eye to stare. If the high light is very large, particularly when blended at all its edges, it merely looks like a reflection, and the phenomenon of apparent luster is apt not to take place. If now we return to the natural eye (indoors) a series of experiments reveals the fact that the high light, being a reflection

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and miniature copy of the window light, is usually gradated like the window light; and further, the more perfectly and smoothly the high light gradates and melts into the pupil or iris at one edge, and the sharper and more abruptly it terminates at the opposite edge, the more is the luster produced. When one examines all manner of shining and lustrous materials, from polished wooden furniture with its large splashes of high lights, down to jewels, the head of a pin, and even the fractured crystalline surfaces of stones, and studies these objects in all varieties of lights, he can not but convince himself that the more a high light resembles what we may call a comet, with its light concentrated in its small head—striking sharply against darkness— and its tail fading out and melting into darkness, the greater is the luster and effect of brilliancy produced. Naturally, these high lights are rarely shaped just like our idea of a fan-tailed comet because their shapes are dependent on the light and on the surfaces where they lie, but I choose the comet as the simile because that body more accurately imitates a high light than does any other. T h e high lights on fractured stone are often triangles and squares and other geometric figures, but the majority of them so construct themselves as to gradate from a high light edge to a darker edge often melting into the background. T h e same is true for many fractured metals—in fact for most fractured matter, and for the sands that lie by the sea, and for all finely pulverized things. The high lights on blades of grass are often double-tailed comets coming to a maximum of intensity in the middle; and those lying on leaves may be shaped like starfish, but the part of them which is the lightest often comes sharply into contact with darker values, and the tails often fade out softly. T h e high light on a single human hair is a long double-tailed comet, a number of which give the lustrous and brilliant appearance to hair and fur. It may be asked, "Is the appearance of luster dependent on the high light being shaped like a comet; and why?" T h e appearance of luster in the distance is caused by the blending of numerous high lights and by broken color, as has already been explained, and has nothing to do with the present case, but when

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the high lights are large enough to be of discernible shape, it is the comet shape which is of the greatest assistance to their luster-producing power. In fact a shape very different from that of the comet will often fail to produce luster, or at best only a small quantity. But again, "Why?" I shall begin the answer by asking the reader to place before himself a highly polished black leather shoe and some dark polished furniture and some polished metal kitchen pots and other objects which have large high lights. From this group a markedly comet-shaped light should be selected. The eye wanders back and forth over the comet; it follows the fading tail or tails into deepening shadows; it returns and follows the tails toward their head; it follows the crescendo movement of the ever increasing light until suddenly the movement is brought to an abrupt halt. But this movement of eye is merely the expression of the attention, which adjusts itself to the gentle, jarless crescendo. The attention, as is its wont, expects the movement to continue indefinitely, when, suddenly, it is jarred by the abrupt halt and sudden transition from light to dark, and it is this shock which produces the sensation of vividness. It is true that when the attention passes suddenly from any light to any dark, it produces the shock of vividness, but such a shock is far stronger when the attention is misled into believing that the light is going to continue increasing, than when it is passing into dark from a flat, ungradated light which arouses no false expectancy. It is for this reason that flat, ungradated high lights, which nowhere blend into the dark ground, are not nearly so effective as vividness-producing instruments. At times they are so unconnected and unidentified with the ground on which they lie that they separate from the ground altogether, and until our (conscious) reason tells the truth they appear like white, unaccountable specks of something. One of the most lustrous effects of an eye is seen when it is on the shaded side of the face and the cornea on the side away from the nose, and is strongly illuminated by a reflected light. This produces a flat white triangle which apparently contradicts my comet theory, but when the painter paints it he finds that it is a comet with a broad head jutting against the iris, and with a narrowing tail.

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If the comet is the vital element in luster, it would follow that under any and all circumstances the presence of the comet should produce luster, and, so far as my argument demands, there is no reason why the comet should be reflected light. Any piece of opaque material shaped and valued like a comet ought to produce luster when properly incorporated into a responsive background. In fact, there appears no reason why the ground should be polished if only it imitates the nebulous appearance of polish. Perhaps even that is not necessary. Nor does my reasoning limit the size of the comet; it may be barely visible, or it may be miles in length. A rough, gray, plastered surface of a house, for example, consists of a variety of irregular shapes—miniature pits, ditches, ridges, and peaks, all of them roughened again by finer degrees of irregularities. When such a wall is illuminated by sunlight, falling somewhat from one side, many of the peaks receive patches of light of comet shape, their heads relieved sharply against the shadowed depressions into which their tails sink and lose themselves. And as these shadowed depressions, obeying the usual laws of shadows, are. slightly nebulous and display patches of light which mean little or nothing, we have here all the conditions necessary for the production of luster. The fact that the shadowed part of the plaster is not much darker than the lights reduces the production of luster only by degree. A luster of much less intensity is produced than would be if the ground were dark. As a matter of fact, the luster is so great that the vividness which it produces and which mind adds into the value (as we have seen above) causes us considerably to overestimate the value of the wall. When the wall is so far away that we no longer clearly see the comets, then the laws of broken color act, and luster—although of a somewhat different character—is produced. Chalky surfaces like those of pastel, old fresco, modern tempera, and all similar textures when seen closely act as the plaster wall acts at a greater distance. It requires no argument to say that it is entirely a question of distance as to which of the luster laws will act. T h e present consideration is what, for the moment, we may

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call luster on a large scale. A magnificent example of this, and what to practical painters is of the greatest interest, is produced in painting by that system of values which I term shadows-lookedinto. Assume the ordinary case of painting a portrait. T h e forehead is in moderately strong light coming somewhat from one side, with a deep shadow on the temple on the opposite side, and a high light on the forehead in its logical position. T h e light on the forehead, instead of being gradually blended into the deep shadow on the temple, approaches it by a series of brush strokes which successively edge abruptly against each other and get darker toward the shadow. Now each of these strokes obeys the law of the comet only inasmuch as its head hits abruptly against a darker value, for its tail, which disappears under the oncoming comet behind it, actually (in practice) is often a little darker than the head—but singularly, owing to the laws of contrast, the heads will usually seem a little lighter than the tails. This sounds like a very lame comet and it is, but when a whole head painted in this style is placed by the side of a head painted in elemental, gradually blending values it has an appearance as if light were falling on it, whereas the elemental head will only seem to be giving, or receiving, or imitating what we feel to be some kind of an abstraction of light. Of course, it is understood that the high lights on the comet-painted head are also painted in comet fashion, but that this does not give it much advantage over the elemental head can be shown by reenforcing the elemental high lights with comets; and still this does not give it the light of the comet head. As a fact, elemental high lights on flesh are not so very different from comet high lights on flesh, they are a little more blended, but the use of the comet in joining a light with a shadow has no connection whatever with elemental values and it is that which gives the comet-painted head its appearance of vivid illumination. An important fact to be noted is that a high light which does not lie adjacent to a shadow or other dark mass—one which is in the open, so to speak, as frequently happens on the forehead —is often double tailed, many tailed, for the reason that the highest light does not strike against a dark mass, but instead

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melts again into other tails. This is an incomplete comet and owes its potency to the promise of more light, and to nothing else—that is when painted very smoothly, elementally, as was done by the pre-Raphaelites. When painted truly luster-wise, the series of comets, encircling the central and lightest comet head, approach this head as a series of foam-crested waves approach the shore of the sea, each wave becoming higher and higher, and more and more foam-crested, and each crest jutting upon the tail of the wave ahead until the final big splash is reached. T o complete the simile, we should really assume the shore to be approached by waves from all sides, or better to be a rock at sea encircled and engulfed by ever mounting waves. In a comet painted like this the attention is effectively attracted to the crescendo movement because the rise is punctuated by successive setbacks, each setback being higher than the previous one, and thus arousing our expectancy and making us keenly alive to the rising movement. A good example of luster on a stupendous scale is sometimes seen in nature when the sun has set under a cloudless sky over a large plain or sweep of land. Under dry atmospheric conditions when the sun is far enough below the horizon to cast a blue half-shadow on the zenith, this blue half-shadow sometimes approaches and lightens and subtly gradates into the golden light just above the horizon without a flaw. But on close inspection of the gigantic gradation it will often be seen that the large sky expanse is not evenly gradated after all, but is divided into several—three, four, five—zones, as it were, and these zones, which lie in semicircular fashion with the sun as a center, are constructed on the plan of the incoming sea waves, that is cometwise, with their highest lights directed toward the sun. No sooner do we observe this effect than a strange phenomenon becomes evident: the lines marking the zones from each other seem to move and fluctuate, and ever continue to do so. At first sight this phenomenon might be attributed to some physical effect, the light being influenced by an unseen cloud or mist below the horizon. But as the fluctuations are altogether too rapid and yet too constant to be attributed to such causes, the conclusion I

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have come to is that they are non-existent in nature, and are caused by attention's splitting up the sky into comprehensible masses. Be this as it may, the delicately traced succeeding waves of comets are in mind or on the retina and in crescendo fashion crash against the black horizon. But this is not all. T h e earth forms a black comet. T h e value of the earth from the foreground to the distance may not physically differ much, but owing to the contraction and dilation of the pupil it seems to differ very much, and the half-light foreground forms the tail which darkens and darkens as it approaches the blackish head lying on the horizon and defiantly contradicting the sky. T h e black comet is a constant occurrence, in fact frequently the corollary of the white comet, but as light is the active and attractive principle in vision, we less frequently observe the comet phenomenon when it embodies itself in shadow. T h e black comet is the antithesis of the white comet, and the interplay of the two form the base of what is called "chiaroscuro." I t may be asked why the intense brilliancy of the sunset cannot be accounted for by the principles of contrast. It is very evident that contrast plays a considerable part in the sunset effect, but that luster also must enter largely can easily be proved by comparing two painted landscapes, the one constructed according to my description of the sunset, and the other identical save that the blue half-shadow of the zenith, instead of grading into the golden band lying above the horizon, is brought down to the golden band and there fused into it—a not untrue effect. It will be very evident that although there is obviously more contrast in the latter, owing to the greater area of dark in the sky, yet there is less brilliancy. It is a commonplace in the studios that strong value contrasts are not as effective in producing brightness as gradation properly handled. W e have studied the effect of the comet arrangement of high lights on a forehead, and what holds true for the forehead holds true for the whole head and for the whole figure. Great brilliancy is obtained in painting a figure, draped or nude, not by concentrating the light on one small spot and submerging the rest in shadow—as is often held by the young student—but by en-

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veloping it, so to speak, in one single large comet whose highest light lies anywhere—not necessarily on the forehead, or nose, or bald spot on the cranium. In fact it need not lie on the head at all. This highest light must be logically led u p to and must jut sharply against a dark value. T h e tail of such a comet should increase in lightness toward its head, preferably by a series of risings and very slight recessions. A very long comet is beyond the grasp of the attention and the attention attempts to break it up. Therefore, for aesthetic reasons, the attention should be assisted —but five breaks including the head are perhaps the maximum, for more than that are difficult to comprehend. T o this large comet all the others must be subsidiary. And the background also should be enveloped in one comet. Indeed there should be but one comet—many-tailed possibly—enveloping both figure and background. Such a simple scheme, possibly very difficult of execution, can be carried out over a large group of figures, or over a complicated landscape, and is, as I have remarked, of more value than contrast in producing brightness. This is chiaroscuro, of course, but does not imply any excessive darkness. A picture painted in chiaroscuro can be very light, as many of Turner's works demonstrate. There was for a long period, or rather there springs into existence at repeated periods, a heresy that although nature can be very brilliant without the aid of shadow because natural light itself can be brilliant, yet the artist can gain brilliancy only by strong value contrast. This is far from the truth, as this slight sketch may have shown. There is, however, still more evidence at hand and evidence of a nature of particular interest to modern painting. When thick white oil paint is spread smoothly on a panel with a palette knife, it presents its highest possible value. When the paint is spread thickly with a stiff hog's-hair brush in such a manner as to leave fine ridges, and if, when the paint is dry, another coat is applied so that the ridges cross the first layer at an angle, there will be produced a surface, which, though lower in value, somehow presents what, at first sight, appears to be a higher value than the smooth paint. This should be so according to theory: the pits introduce shadows which darken,

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and all the tiny crests of the ridges reflect fragments of the window light or other light falling on them, thus producing luster. What such a staccato surface, as I choose to name it, really amounts to is a concentrated mass of high lights of very small size, as can easily be seen on close inspection. It is like the plaster wall, being only of a finer and more effective character. A sunlit meadow painted on canvas in staccato brush strokes and broken color is the closest imitation to the real meadow that the artist has yet devised. It is a far closer imitation, even when so roughly drawn that not a single blade of grass or weed is represented, than is a faithful, minutely detailed copy painted with a smooth surface. It far more vividly recalls nature. It succeeds somehow —apparently by crudely imitating nature's luster—in producing what we feel to be a much more vivid imitation than does smooth paint. T h e sharp jutting of the light head of the comet against a dark value requires more explaining. A sheet of white paper in ordinary room light is not a particularly brilliant object, but if it is checkered over with very black sharp-edged squares, the white squares will look very bright. This is said to be due to contrast. If all edges are softened and blurred somewhat, the excessive brilliancy of the white, as well as the excessive intensity of the black, disappears. Here we have a case of a comet with only a head, or rather we have the heads of black as well as white comets in sharp conflict producing luster, and when the conflict is softened, or, annulled, by blending the edges of the heads, delusive blending takes place a little, making the black and white squares partake a trifle of each others' qualities. When a figure or a head is painted softly, with all the edges out of focus, even though the background may be much darker, the result is often dull. If, then, the edges of the light color masses, as they come in contact with darker masses, are sharpened, the whole head will gain solidity and light. That it should become more solid is easily understood because soft edges suggest and imitate mist and colored smoke and vapor and not firm flesh, but that sharp edges should cause the physical values of the flesh to lighten is, of course, impossible. Therefore the ap-

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parent gain in light must and can be only a gain in luster (on a large scale), and this luster, added into the actual light, produces the greater brightness which we mistake for a rise in values. T h e so-called "brilliant" sunshine of a dry day when all the shadows are sharp-edged may actually in cases be darker than the duller light of veiled sunlight with its very diffused, soft-edged shadows, but often is judged the reverse. In this case actual proof through physical methods is well-nigh impossible to obtain, and so we have to rely on the artist's experimental determinations which show that the feeling of brightness of painted sunshine is just as dependent on sharp-edged shadows as on staccato pigment. In each of these cases the sharpening of the edges not merely introduces luster (brilliancy) but also clears, so to speak, the adjacent color masses from each other by stopping delusive blending. In a painting of a landscape bluish-green shadows falling on vegetation and blending very softly (over a wide band) into green lights produces the effect of a gray day, but if this joining band is eliminated and the edges of the shadows are sharpened, then will the shadows turn bluer and the lights yellower, luster will make its appearance, and the effect will be that of sunshine, to a certain extent. Fogs, even when not dense, are felt to be dull, and this for the reason not that they are so dark, but that the fog palpably lying on top of and over all and thus taking away and distracting the attention from the edges lying underneath, causes the attention to glide over the edges and to make them seem broader and softer than they are. While studying shadows we noted that they are soft and that lights are harsh. W e can now understand this better. Because the edges in shadows are difficult to discriminate, the attention glides over them and delusive blending takes place and unifies them. Because the edges are evasive, there is none of the shock which any possible comet lying within the shadow might produce. T h e crescendo movement of the comet passes by and through the edge. T o put it physiologically: such weak comets as exist in shadows cannot be very effective, for the edges of the soft darks they impinge upon do not make the crescendo attitude of the attention change abruptly enough to cause a shock. In

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lights, on the other hand, the edges are sharper and more easily discernible and the comets are effective. T h e young painter often understands this with difficulty. W h e n he peers closely into shadows, his attention becomes very active and discriminates edges which normally it slides over. H e reproduces these sharp edges, thereby giving his shadows one of the most salient characteristics of light. These examples of the production of brightness, and all the others I have given, bring us to a curious conclusion which I can state somewhat metaphysically. T h e r e appear to be two antagonistic forces at work in the perception of brightness: the leveling force of delusive blending which pulls the elements of perception together and unifies them into sameness and shadow, and the creative force of luster which repels shadow and gives being to light. These two forces, although at moments quiescent, instantly spring into life and struggle for dominance when offered an opportunity. T h e struggle is always about and over the edges. W h e n the edges are soft, the leveling force attempts to drag all the colors together and tries to dull them and to produce as shadowy a feeling as possible. W h e n the edges are sharp, the creative force seeks a comet and, breaking itself on an edge, creates brilliancy, thus driving the shadow out. When the leveling force dominates a light, the light becomes dull, weak, and sickly. W h e n the creative force dominates a shadow, the shadow becomes harsh and aggressive. T h e importance of these two struggling forces in assisting the construction of the light and shadow of pictures is enormous, and it is the edge which must be most constantly borne in mind. Crude comets, both large and small, will construct themselves, but they will remain impotent unless given life by the creative force of brightness which refuses to act unless its sharp foil is provided; and on the other hand the leveling, dulling force of delusive blending is always acting unless restrained and confined by edges. Each large mass of a picture must be thought out with regard to these two forces; each smaller mass must obey their dictates; and each brush stroke must serve as well. My reasoning that the comet and its foil are the basis of luster,

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on a large as well as on a small scale, seems to cast out luster produced by broken color. Yet the luster of broken color is certainly an important element in brightness, sometimes the most important. I have disregarded it and the luster of the sun which blinds us, and that of moving things, and that caused by dissimilar colors falling on the two retinas, because these all appear to be isolated phenomena which connect themselves with no great principle—or, rather, with no aesthetic principle—and are therefore of less interest to us. But the sway of the crescendo comet and the foil is felt not merely in the art of painting, but in architecture, literature, music, sculpture, dancing, drama, in all the arts, and in all life.

VII Production of Color by Subtraction

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H E N W H I T E L I G H T in a room falls on a highly polished sheet of silver, it is reflected; it bounds back as does a rubber ball thrown on a hard, smooth floor. But, unlike the ball, some of the light does not come back. It enters the silver and is converted into heat. If the sheet of silver is polished, the light rays are reflected back at the same angle at which they strike the surface, and perfect images of the objects from which the rays emanate are formed. If, on the other hand, the surface is finely granulated—which means that it consists of a myriad of tiny facets turned in every direction—then will the facets reflect light diffusely, in all directions. No images of the surrounding objects will be formed, and the surface of the silver will appear dull and white. White paper has a granulated surface and reflects light diffusely, but, unlike silver, is so constituted that it is impossible to give its surface more than the slightest polish. T h e only difference between silver and paper, so far as reflecting characteristics are concerned, is that it is impossible to polish paper as highly as silver, that is, to make the surface lie as smoothly. A sheet of smooth glass or metal held over burning camphor receives a coat of lamp black, and the only difference between it and white paper is in the quantity of light it absorbs and reflects. When white light falls on lamp black, only a little light is reflected. T h e rest is absorbed and converted into heat. When the light falls on white paper, much more is reflected and far less is absorbed. J e t is as black as lamp black and can be polished and will reflect perfectly formed images, but it absorbs so much light

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and leaves so little to be reflected that the images are dark and weak. These examples present the problem of absorption and reflection in its simplest form; the usual condition is more complicated. A petal of a rose receiving white light absorbs a certain portion of it and converts it into heat, b u t instead of returning the remaining white in the form in which it comes, it returns a crimson light. W h a t happens is this: the coloring matter of the rose not merely absorbs a certain portion of the white light but also disturbs the balance of the remainder by subtracting through absorption some of the green light waves and some of the others, leaving crimson and such a general assortment of rays as will through blending and fusion m i x into crimson. How the pigment of the rose performs this subtraction we cannot say more than that it is a physical property of pigment to subtract light rays selectively. A layer of powdered oxide of chromium subtracts from white light such rays as leave a remainder which fuses and blends into a very strong green. A l l pigments subtract some rays and leave such remainders as m i x into this or that colored light. But now the matter becomes more complicated. W e can easily, by means of artists' pigments, imitate the color of green leaves and would naturally conclude that the two greens, when analyzed by the spectroscope would reveal the same composition. T h a t is not so at all. T h e spectrum of the leaves contains more yellow and red than the spectrum of the pigment mixture. H o w it works out that different compositions give the same result we have already observed when studying blends and fusions; it is purely a question of arithmetic. T h e light that is returned, or reflected, is immediately balanced by vision, and by whatever that term includes; we become conscious only of the result of some definite color and never suspect the differing elements of which it is composed. Now comes another fact. None of these colored lights emanating from matter, and produced by partial absorption, are ever pure. It may seem strange that among the huge number of colors which nature and art provide there should not perchance be a single instance in which the remainder, as we have termed it

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(that mixture of light rays not absorbed by the pigment), is a pure color. There is always an excess of white. Our explanation of color absorption requires amplifying and refining. When white light falls on any body whatever, light or dark, smooth or polished, some of that white is directly reflected from the surface. T h e rest of it sinks into the body of the material a little and there is divided into those rays which are absorbed and those which are returned. When the body is white, like chalk, the returned white rays add into the white ones reflected directly from the surface. Unadulterated white reaches the eye and its simplicity seems natural. When the body is pigmented, the returned colored mass must of necessity add into the white surface reflection which makes it impure. Further, even if there were no white surface reflections, the return remainder could only be pure under the single condition that all rays save those of one single color be subtracted and that that single color be returned. A concrete example will explain this. We will examine an elemental color. Chrome yellow is about as free from white as any painting color ever is. A spectrograph shows, however, that it is composed not merely of yellow but also of red, orange, and warm green rays. A part of the red and orange blend with the warm green, producing yellow, but another part fuses into white. Therefore the yellow is augmented by blending but adulterated with white by fusion. If only yellow rays were returned, then there could be no fusion, no adulteration with white, and the returned rays—assuming also the physically impossible condition that there be no surface reflection—-would reach the eye as pure yellow light. Such a yellow although pure, saturated 100 percent, would not be what is called bright. It would, in fact, be rather dull because pure yellow is not vivid—as the spectrum shows—and the vividness of the chrome yellow is caused by the borrowed assistance of oranges and warm greens. Therefore we are forced to the conclusion that a pure yellow radiated by pigment, although pure, would not be vivid or bright. We will now examine a blend. T h e orange light coming from an orange pigment might be composed of the whole sector (on the color circle) running from yellow to red—the orange rays

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being strengthened by the red-yellow blends. These blends, produced within their own sector, would be unaccompanied by fusion, and a vivid, pure orange would result. If there were no surface reflection we should have our ideal hypothetical condition of vividness and purity. The pure color being hypothetical, however, we can disregard it and come down to facts and pigments. When the painter sets his palette with the most vivid colors modern science provides, he has an assortment which is altogether out of gear so far as relative purity goes. It has not pleased nature to create any such standardized series. In consequence, pedantic persons have revolted and, by mixing these unequally saturated pigments with varying proportions of white and black, have reduced them to what they consider to be a series of equal vividness and purity. But nature is unequal everywhere, and each pigment, when used for purposes of imitation, must be tampered with in so many ways that the equalized palette is just as apt to be wrong as the unequal one. Surface reflection must now be further explained. White light falls on a body and a part is directly reflected from the surface; another part sinks below the surface where it is divided into two parts: that which is absorbed and converted into heat, and that which I have called the remainder and which is reflected back and joins into the surface reflection. We have, therefore, two masses of reflected light. T o determine (approximately) how much light is reflected from any surface, it is only necessary to pour water on the surface. All the spaces between the crystals or grains of matter of which the surface is composed are filled in. The various directions of the facets on the crystals and grains are annulled. And when a surface is wet or is polished, there can be no scattered light reflection, all the light being reflected in a regular manner. Such a smooth surface turned so that it reflects only a dark part of the room, appears not to be reflecting at all. But of course a polished surface, like a mirror, no matter at what angle it is held always reflects some light. When this light is very weak we simply fail to notice it; we often inhibit it. But for our present purpose—which is not to measure accurately but only to grasp clearly a physical fact—a surface on which sufficient water

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has been poured can be said to reflect n o surface light (when held at the proper angle). T h e r e f o r e the light and color we see on wet bodies can be considered as being that which is reflected from below the surface, and the difference between the color and value of the dry and wet bodies tells how much and what kind of light comes from surface reflection. W h e n any difficulty is encountered in making the water fill in the interstices and produce a flat, polished surface, the body experimented upon should be immersed in a basin of water, just below the surface. T h e differences in color between dry and wet surfaces are often surprising, and the colors of surfaces of a value about halfway between black and white alter the most. T h e y become much darker and more intense and saturated. Polished surfaces alter very little, and when very highly polished, not at all. T h a t , of course, is self-evident, the polish of water being no greater than their own. Naturally, it is colored bodies with a granulated surface we must study. Of these, very light and pale cloths, for example, darken comparatively little, the color becoming a trifle more saturated and a few shades darker. Light, pale colors to be light and pale must contain much white, and to effect this the light returned from below the surface—the under-surface reflected light in distinction from the upper-surface reflected light —cannot be saturated and cannot depend very much upon the upper-surface light for adulteration. T h e upper-surface light would not be sufficient for the purpose. T h e r e f o r e the light from the under surface must be well adulterated in itself, and eliminating the upper-surface light by wetting does not alter the character of the total result to a great extent. But when a surface is of a color and of a value which is neither light nor dark, it may easily be that the under-surface light is more saturated than we suspect, and that it depends largely for its white upon the upper-surface reflection. In such a case the effect of wetting may be startling. It is this phenomenon that we frequently encountered. A cloth dyed the color of the soft and yet clear blue of the overhead sky may turn so dark on wetting that at first sight it appears almost black. Both the soft whiteness and the clear blueness are gone. A n d if the blue cloth has a soft,

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strong crimson pattern, this pattern will also turn very dark and appear to possess little color. Greens will not darken so much, oranges and yellows even less, and white still less. B u t of course, each particular surface texture controls the change. Black surfaces may also be tested as to their purity by having water poured on them. If black cloth, for example, darkens very much when wet it simply means that the dye or cloth—probably the cloth—is of inferior quality and reflects too much uppersurface light. A n d if water darkens the black cloth only slightly that does not mean that the dye is a deep black, it means merely that the cloth reflects little upper-surface light. For black to be black, the under-surface reflection must be as free from white as possible, and the upper-surface reflection must be annulled. A surface painted with lamp-black varnish and placed so as to reflect another similar surface is very b l a c k — b u t not entirely so. T h e painter who works in water color is merely reversing the order of experimenting: he first sees the under-surface light of the pigments, and then, when the colors are dry, may be disappointed that the upper-surface light pales and loses so much richness and depth. It is notorious that a pastel drawing is ruined when varnished, even if that varnish be only a thin layer of shellac (in alcohol) sprayed on its surface. Pastel drawings, or rather paintings, are so constructed as to depend upon the uppersurface reflection. Oil paintings, on the other h a n d — w i t h some rare exceptions—are planned to be varnished so as to eliminate as much upper-surface diffused light as possible. I have recommended wetting with water to destroy the diffused light, and for experimental purposes that is sufficient, but to obtain the most perfect elimination, the wetting liquid should be a varnish in which the refractive index approaches as closely as possible that of the pigments. A n d the thicker the layer, u p to a certain point, the better. (There is one very important phenomenon and its correlated question which these experiments bring to the fore and which I have passed over: why does p u r i f y i n g a dark color from white and thus revealing it in a greater degree of saturation often produce a color which induces a far weaker sensation in consciousness than the less pure color? W h y are crimson and blue

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more effective when adulterated with white? Why do crimson lake and artificial ultramarine blue lie in such dead and blackish lumps on the palette? And why does the admixture of a touch of white cause them to spring into such intense life? These questions, which are of practical as well as of aesthetic importance, I attempt to answer in dealing with the effect of mixing colors with black and white.) Silk fibrils are more docile than those of wool and lie flat and smooth and in the same direction when woven into cloth. Wool fibrils have refractory ends and excrescences which point in every direction, and weaving does not eliminate them. T h e consequence is that silk cloth is slightly polished and obeys the laws of polished or wet surfaces. It is saturated and rich in color in those planes or folds, which are so inclined as to reflect no direct light, but from the other planes much light is reflected. As these pale, bright planes are alternated with the rich dark planes, they contrast and, being also two varieties of the same, they harmonize and produce what we call beauty. Woolen cloth diffuses much light from every plane no matter how it may be inclined and reflects light neither so strongly nor so regularly as silk. Therefore it has not its saturation or contrast or variety. Cotton reflects less than wool; the fibrils themselves, when examined under a microscope appear chalky, and even if they were smoothed out would not shine. T h e threads in velvet stand straight on end and present on the surface only tiny points from which very little diffused light is reflected. It can lie at any and every inclination and never adulterate its under-surface light except where its surface is so bent on itself as to expose the sides of the threads to direct reflection. T h e under-surface light is very saturated because, owing to the structure of velvet, the light entering its surface is reflected and re-reflected from the fibrils, one to the other, and thus takes up much color before coming out again. This is a case of addition of light. On the other hand, black velvet is one of the most perfect light destroyers in existence. T h e light striking its surface and entering the narrow shafts between the dark threads is lost in a forest of blackness from which it never comes out.

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THE PRODUCTION OF COLOR BY THE MIXTURE OF PIGMENTS

Suppose a reflecting surface is both yellow and blue. Suppose yellow and blue spots, yellow and blue crystals, lie in it side by side. Is the returned light white (gray) as it should be in accordance with the laws of broken color? If the crystals do not overlap and lie more or less evenly alternated with each other they will, if small enough and close enough together, return gray light, but if they overlap each other, the returned light is green. The small crystals are transparent when thin enough, and when they are superimposed they offer to light a surface which it can penetrate only by passing through both yellow and blue. Suppose the white light first strikes a yellow crystal; this absorbs the blue and violet rays, leaving a remainder which would fuse and blend into and be returned as yellow were it not that this yellow light encounters a blue crystal which absorbs much of the red, yellow, and orange rays, leaving the green—that is also absorbed a little but not enough to do serious damage. This green is finally returned. There is, however, also a small amount of fusion of the yellow and blue crystals from their upper surfaces, and this white (gray luster) adds into the general, diffused surface light. Two superimposed thin sheets of yellow and blue glass laid over a white surface produce green. T h e white light passes through the two colors and is reflected back through them again with the same result as that of the crystal mixture except that there is less surface white added in. Red and green crystals or sheets of glass subtract such an assortment of rays that the remainder fuses and blends into a slightly yellowish gray. This result approaches that of light mixtures and seems more to our expectation—but at first sight only. T h e same red and green mixed as pigments produce a much darker gray than when mixed as lights, by Maxwell disks for example. We instantly recognize that something vital has been lost in the pigment mixture. Ultramarine blue and the pigment known as burnt umber (which is the shadow color of orange) mix as lights into a purple. As

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pigments they m i x into a black closely approaching ivory black. Between them, they virtually subtract all the color. T h e yellow-plus-blue pigment mixture phenomenon has been talked of so much that it has come to be deemed extraordinary, but it is more extraordinary than the dark orange-plus-blue mixture only because it is more striking. Another extraordinary phenomenon is that chrome-yellow and ivory-black pigments mix into a decidedly strong olive-green, whereas a mixture of chrome yellow and black, by means of reflection, or broken color, produces dark yellow. Placing a chrome-yellow scrap of paper in a black-walled box and thus obtaining its undoubtable shadow color produces only dark yellow, not a trace of green. T h e Maxwell disks give black plus yellow as an olive-green but not so strong a one as the pigment mixture. T h e underlying reasons for all this are well outside the realm of art and need not concern the painter. H e can even forget why yellow-plus-blue pigment equals green. B u t that they do he must remember. H e must realize that his palette has been constructed by nature for reasons of nature, far from the thoughts of man; he must realize that if the palette is his instrument on which he plays, as the violin and harp are those of the musician, that, unlike these, which are created by mind, his is only a chance affair with the notes acting all askew. B u t he must learn his palette empirically and know it well, and when it troubles him by being contrary, he must devise methods of eliminating the disorder this physically born palette introduces. T h e laws of fusion and all the laws of luster the artist must master until they become his second nature. H e must feel the elemental colors, and the blends, and the complements. THE PRODUCTION OF COLOR BY TRANSMISSION W h e n light falls on so-called "stained glass," a church window, a part is directly reflected back, the rest enters the glass where another part is subtracted and converted into heat, and the remainder, instead of being returned, passes on through the glass and becomes visible, in the present instance, within the church. W h e n the sheet of glass is very thin, comparatively little

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light is absorbed, and the remainder comes out very light and pale in color. W h e n the glass is thicker, the light in its passage loses more color and the remainder is darker and more saturated. Finally there comes a point where all the light is absorbed and there is no remainder. T h e subtraction of light in the thickened layers of glass is what we may call erratic. T h e remainder passed by a thin layer of glass may be slightly orange yellow; a thicker layer of the same glass passes orange; a still thicker layer, red. T h e subtraction of the different color rays takes place unequally at different depths. Also glasses or liquids stained by different coloring matters act differently. For instance, a solution of chloride of chromium in thin layers passes green; in thick layers, red. W h e n a sheet of red-stained glass is laid on white paper, the red is not so strong as when the glass is in the position of a window, first, because outdoor light is stronger than indoor light; second, because a large quantity of light is absorbed by the white paper (reflection as opposed to transmission); and third, that which is returned is passing through the glass twice, namely through the equivalent of a thicker layer. W h e n a sheet of red glass is broken into large granules, a heap of them thick enough not to be seen through present a much darker and duller red than the sheet glass over white paper. T h i s seems logical. T h e remainder is thrown back from a background of dark crystals which reflect less well than white paper. W h e n red glass is laid over black, the effect is very dark and dull because the greatest part of the light is absorbed by the black and is never returned. W h e n orange-red chrome granules are pulverized a little, they turn yellow-orange; when pulverized more, orange-yellow, then yellow, depending upon the degree of fineness of the grains. It would appear that light is reflected only from surfaces. N o surface is sufficiently resilient to send back all the rays impinging on it. Every surface sends back some. M u c h of matter is composed of masses of crystals in more or less close and perfect contact. A l l crystals have surfaces. T h i s means that the under-surface reflection takes place, must take place, from the surfaces of crystals. In glass the crystals have been melted together and most of the surfaces have apparently disappeared. T h e r e f o r e when

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light falls on a sheet of smooth glass, that part of it which passes through into the matter must travel some distance until it strikes the surface of a crystal. But these crystal surfaces, besides being few, are so cleanly welded together that they lose much of their reflecting power and only a little light is returned. T h e greater quantity is passed on deeper and deeper, and if the sheet of glass is a thick slab, the light that has gone into it is lost forever. But if, on the other hand, light falls on a compact mass of crystals which are not fused and welded together, sea coral, or marble, or copper, the light, after passing the first outer surface, soon encounters other effective surfaces and its journey into the matter is not far; it is reflected back. T h e surfaces of the orange-chrome crystals, when the crystals lie in a heap, are fairly well separated from each other by layers of air, or, if ground as oil pigment, by layers of oil. We shall first study the dry powder and assume the crystals to be large but still too small to be seen individually with the naked eye. Light strikes the upper surface of a crystal, passes through and on to the lower surface. There it finds great difficulty in passing because the index of refraction of the layer of air which separates one crystal from the next is so different from that of the crystals themselves. Refraction means, in the present instance, something which hampers light in passing and causes it to be reflected back. Therefore the light which reaches the lower surface of a crystal is mostly reflected back. Some goes on to the crystal below and possibly to the surface of the third layer of crystals, but that probably ends its inward journey. At least we can assume so for the moment. Therefore, we can say that light on its entering and departing journeys passes twice through the upper and lower surfaces of two crystals, namely, through eight surfaces. If crystals of chrome are well ground, they are small. But the light acts on them in identically the same manner as on the larger ones. It passes through eight surfaces in its total journey before reaching the eye. Why then should the large chrome crystals return orange, and the small yellow? The light on its journey through the large crystals has covered a longer distance than

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through the small crystals, and, as we have seen in studying stained glass, the distance traversed affects the color passed or returned. In fact the explanation of the color of powders is exactly the same as that of stained glass. W h e r e the interstices between the crystals are filled with a liquid, the wet powder is darker and more saturated. T h i s we have studied under wet surfaces; b u t it is not all. If the index of refraction of the liquid approaches that of the crystals, light penetrates farther into the substance and is returned richer in color. W h e n the index of refraction of the liquid is the same as that of the crystals (assuming that there are such correspondences) the light passes through layer after layer of the crystals— in fact the mixture is transparent. A suggestive approximation of this is seen w h e n a glass filled with ice cracked so fine as to appear white and opaque is filled in with water. T h e contents of the glass do not become as transparent as water, b u t they go in that direction. These principles of transmission of light are of the greatest possible importance to the practice of painting. A thin layer of water color on white paper acts like a thin sheet of stained glass laid on white. W h e n the water color is thick, the light cannot penetrate to the white sufficiently, and the returned light is darker. Water colors over black produce very dark and weak color, as does colored glass over black. W a t e r colors mixed with body color (a thick paste of Chinese white) cease to obey the laws of transparency, to a considerable extent, and obey the laws of opaque bodies, as does pastel. M i x i n g oil or varnish with oil pigments produces a semitransparent, a translucent, liquid which acts like stained glass; when this is glazed over light surfaces, the returned light is luminous and vivid; over dark surfaces it may darken still more or even almost blacken, although sometimes even then it adds richness, saturation. A glaze of this translucent, or even on occasions almost transparent, liquid will, when applied to a surface of unequal roughness, form transparent layers of varying thickness producing the varying colors of unequal transmission. It is thus that glazes are so fertile in producing

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variety. A part of the richness of some dyed farbics is due to the unequal absorption of the dye by the hollow fibrils, and this produces variety of color which acts like broken color. THE PRODUCTION OF COLOR BY RE REFLECTION

Some funnel-shaped flowers, like the morning-glory, appear to be colored more strongly inside than out, and more at the bottom than at the top. The increase of coloring in cases may be on account of increase in pigmentation, but sometimes the petals are evenly tinted and the effect is the same. Light falls into the flower and is reflected from one side to the other where it is reflected again, and, after several re-reflections, reaches the bottom. On each reflection some of the white light is absorbed, but in exchange color is returned, and this color, on the subsequent reflections, remains intact and is increased by each addition. The consequence is that the color at bottom is far more saturated than at the top. Roses and many flowers as well as innumerable objects owe the vividness of color in their hollows to this phenomenon. It is often seen on the human figure, as on the palm of the half-closed hand, the orifice of the ear, and particularly the division between the closed lips—although in this latter case the re-reflected light may be augmented somewhat by actual pigmentation. This is taken advantage of and exaggerated by painters like Van Dyck and Rubens who introduced deep crimsons, not merely at the points I have enumerated, but in the nostrils, between the fingers, and at every excuse they could find. Silver to most people appears colorless, but looking into a goblet of the metal makes it seem golden. The color is so pale that unless augmented by re-reflection it fails to force itself through the threshold of perception. Re-reflection plays an annoying trick in practical oil painting. The painter sometimes mixes a large quantity of turpentine or petroleum or other essential oil with his pigments to thin them so that he can easily and speedily wash them onto his painting like water color. They darken considerably in a few minutes after being washed on, and still more on drying. Or, to reverse the

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order in the phenomenon, when the petroleum is poured over and stirred into any pigment, particularly the lighter ones, the pigment flashes u p and turns lighter. A moment later it darkens again, but if the puddle of pigment is touched with a brush it once more flashes up. W h a t happens is that the turpentine separates the particles of pigment considerably. Light entering between them falls on a layer below and is reflected and re-reflected. On emerging, it adds into that directly reflected from the surface layer. But the instant the liquid mixture rests a little, the pigment grains settle down, like sediment in a stirred pool. T h e paint darkens somewhat, and when the turpentine dries out entirely, the grains settle into a compact mass and the paint darkens still more and assumes its normal color again. W h e n the liquid is not a very thin varnish, the particles remain better suspended, and though the turpentine dries out in time and the varnish shrinks somewhat, yet enough transparent resinous matter remains to transfix a little of the phenomenon permanently. THE PRODUCTION OF COLOR BY INTERFERENCE

T h e prism and raindrop interfere with white light passing through them, and sort the rays out in methodical order, but the colors thus produced seem like phantoms. W e feel them to be existing only for the moment and to have no solid pigment basis. They are the result of the accidental position of the prism, the slightest movement of which causes them to fly away. But matter interferes with light in other ways. One of the ways is by breaking itself into an infinitely fine state of granules or by laminating its surface into infinitely thin sheets. T h e interiors of sea shells are often delicately colored like a disordered rainbow, b u t these colors, though shifting a little with the movement of the shell and appearing, jewellike, to come from below the surface, exist only because of the interference with light falling on a surface composed of a multitude of thin superimposed sheets of matter which apparently confuse and tangle it in its efforts to pass through and between them. And at whatever angle the shell is held the coloring is produced. T h e r e are many familiar examples of interference: the brilliant and

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metallic-appearing colors of many insects, flies, beetles, and butterflies; of some fish, snakes, and other reptiles; of some birds; part of the coloring of the peacock and hummingbirds; of pearls; the shells just mentioned; anthracite coal; soap bubbles; oil on water; decayed glass. The surfaces of old paintings often split into a multitude of fine cracks which produce interference. A few drops of milk in a glass of water disperse into a myriad of particles which float in the water and cause interference. T h e liquid seen from above—the direction from which the light is presumed to come—is bluish; from below, yellowish; the light in this kind of interference not being split into as many colors as in some others. Each kind works differently and according to its own regulations. This particular form, which is caused by suspended particles and is popularly termed "opalescence," is, however, so widespread that it gains importance, and we must study it more closely. The particles of milk seem to divide a part of the white light falling onto and into the water into blue and yellow. T h e blue is reflected back with a lot of white light; the yellow, with some white light, passes through. A column of wood smoke appears blue when strong light is falling on it, but yellow from the opposite side. This is the same as the milk in water; the yellow passes through, and the blue is reflected back. Opals consist of fine particles of matter suspended in a solid transparent mass. They act somewhat like smoke and milky water, but, obeying the laws of interference to suit themselves, produce a greater variety of color. T h e most conspicuous examples of the opalescent form of interference are seen in nature. When the air is laden with moisture or smoke, or dust in a fine state of division, the light from the sun, transmitted light, appears unusually yellow, and as the sun sinks in the west and traverses greater and greater thicknesses of air, the yellow turns into orange, then red, then purple and violet. Here we have a color series suggestive of some of the series produced by light when passing through thickening layers of colored glass or liquids, but the causes are entirely different. In the case of the dusty air, yellow light is transmitted, and if we could only get above or beyond the layer of air that lies close to

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the earth, we should find that blue light was being reflected back. A column of smoke in sunlight, as we have seen, returns blue b u t transmits yellow, which becomes red when the smoke is dense enough and the light strong enough to pass through, whereas a yellow sheet of glass reflects back the same color it transmits. T h e r e is no connection between the phenomena of transmission and interference except in some cases an accidental, superficial appearance. T h e r e is a certain phenomenon caused by interference which at first sight appears to contradict what I have described. W h e n a gray color of wood smoke is seen over a dark surface, as the dark color of a roof, it appears bluish, b u t higher, above the roof, against a white cloud or light sky, it may appear yellowish or light brownish. T h e r e is no contradiction here. It is merely a question of which is the stronger illumination. T h e weak light from the dark roof behind the smoke passes through the smoke and sends yellow to the eye, but it is so weak that the stronger daylight from the sky falling on the smoke from the opposite side more than counteracts it. W h e n the light from a white cloud is seen through the smoke, this light may be stronger than the ordinary daylight falling on the smoke, and therefore may be the dominant light. T h i s principle can be clearly illustrated with water or oil paint. A neutral, colorless gray of medium value, thinly washed over black, appears bluish; over white, brownish or yellowish. In both cases b l u e is reflected back and yellow passed through, but in the first case the yellow is absorbed by the black and only the blue reaches our eyes, whereas in the second the yellow is also reflected back, from the white ground, and overpowers the blue. Further, every color tends slightly toward blue when glazed over a dark gray, and slightly toward brown when glazed over a light gray. T h e greater the difference in value between the ground and the glaze, the greater the effect produced. O n e practical result of this is that beginners, when working in black and white oil paint, and frequently altering and repainting with thin paint, are often astonished to find brownish, yellowish, and bluish hues scattered here and there.

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It is said that the blue distance in landscape on a misty day is due to interference by the fine, suspended particles of water which lie between the spectator and the distant shadows. It is also said, though with doubtful truth, that the blue of the sky is caused by the interference of the mist and dust in the air, lying like a veil over the blackness of space. Translucent skin lying over the dark blood in the veins produces bluish colors through interference. We could go on indefinitely. T h e colors produced by interference are, by the practical painter, treated exactly as if they were caused by pigmentation. There is, however, one small group of phenomena caused by interference which is of great importance to the practical painter. It is that particular form of interference which takes place every time that any pigment whatever is mixed with any other pigment. THE DILUTION OF COLORS WITH WHITE

T h e tyro in painting soon discovers to his astonishment that the particular color of his pigments is a very uncertain matter. That various colors when mixed with each other should produce other colors seems natural, but that colors mixed with white should change, that orange-red should become pale crimson, and that green should turn bluish, annoys him considerably. That a mixture of yellow and black should make green is incomprehensible. Why should black pigment, which only differs from white pigment in that it reflects 5 percent of the white light falling on it, instead of forty as the white pigment does— and which therefore is merely white of a low intensity—why should this white of low intensity mixed with yellow make a fairly strong yellowish green? T h e whole question is complicated, but the painter must understand it. The universal effect of mixing any pigment, in oil or water color, with white is to produce a paler and more bluish color. T h e more white is admixed, the lighter and bluer the color. These pale mixtures are popularly termed tints, and I shall refer to them as such. We need not now, any more than heretofore, ask how the light is interfered with; all we need realize is that when white particles of matter lie side by side and above and

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under colored particles, they not merely lighten the value of the mass but also reflect back blue light. This blue light fuses and blends—apparently according to the laws of fusion and blending—with the light radiated by the colored particles. Leaving out, for the moment, the question of the lightening effect of the white we find that the added blue interference-light works as follows: it fuses with yellow into pale yellow, fuses and blends with yellow-orange into pale orange, and with orange into pale red; it blends with red into crimson, with crimson into purple, with purple into violet-blue, and with violet into a bluer violet; it adds itself directly to blue; it fuses and blends with the yellowgreens into greener or bluer greens, it blends with green into blue-green, and with blue-green into a still bluer green. This explains why vermilion and white make a pink which strikes us as if it were a crimson, or even bluish crimson. And we can also understand why green mixed with lots of white makes a bluish sky. Very much paled burnt umber, which is approximately the shadow color of orange, seems almost faintly red-purplish. White mixed with black produces a bluish gray, but some black pigments give a stronger blue than others even if in their pure states they look alike. It is a question of the mechanical constitution of the black. For the matter of that, the quantity of blue created by any and all of the colored pigments when mixed with white is a question of the constitution of the white. Zinc white gives more blue than lead white. The question of the lightening effect of white requires explanation. It lightens the light and medium-light pigments in a perfectly logical manner, but largely alters the character of ultramarine blue and some of the very dark pigments. Ultramarine blue, as it lies in a heap on the palette, often looks almost as black and colorless as ivory black. T h e explanation is this: black reflects only 5 percent of the light falling on it, and as this is a small quantity, it produces a weak sensation; the crystals of which ultramarine blue is composed are very strongly but darkly pigmented; when white light falls on them, it passes through and strikes another dark layer, which absorbs the greater part of the light, and little is returned. In consequence a weak

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stimulus, barely stronger than that coming from black, reaches the eye producing a weak sensation. But when a small quantity of white is mixed with the ultramarine blue, the light passing through the superficial crystals soon encounters white crystals which return the blue in large quantities. It is therefore popularly and truly said that the very dark pigments must be mixed with white "to bring out their color." There is something singular about this kind of interference. It presents none of the characteristics of the other kinds: no gaudy iridescence like that in beetles, birds, and snakes; no pale rainbow hues as in the interior of sea shells; no murky effect of translucency as in opals and watered milk; the effect is solid and stable and nothing would lead us to suspect that the color of tints is not their own, did not physics tell us the contrary. But, of course, the color of tints is their own. This is merely their way of producing color, and all the colors of all solidappearing matter are affected by this kind of interference. There is no such a thing on the face of the earth, except possibly in a physical laboratory, as a pure color. They all contain more or less white. Therefore, the painter should regard this form of interference as a constant state. He should look upon things as simply being their own color and imitate that, or rather paint a parallel. But, and this is an important point, if the painter remembers that the pale tints in nature find their correspondence on his palette in a mixture of the stronger, warmer pigments plus white he will save himself considerable time. Beginners mix half a dozen to a dozen pigments in an attempt to match some color in nature, when, as a matter of fact, the admixture of two pigments plus white or plus black or plus both is sufficient to imitate almost any color in nature. One of the reasons for going into this question of interference so elaborately is that an understanding of what we might call "the tricks it plays" may help to avoid a series of pitfalls. Unless the student accompanies this theory with experiments, however, theory will be of little use. It may also be to the point to note here that the colors of a large number of the pigments the color merchant carries in

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his stock can be approximated by the student himself by mixing white or black or both with a very few standard pigments. These experiments in color mixture must be on a smooth white surface. Grained canvas will not do, as the depressions between the threads introduce the shadow element. Thick typewriter paper is excellent, but precautions must be taken to lay one sheet on several others, or on some opaque white surface, to prevent any other color from shining through. (Water-color papers are usually too rough.) The paints can be directly squeezed from the tubes onto the paper and smeared into areas of proper size. The pigments must be laid thickly and opaquely so that the white paper may not show through because that introduces transmitted light, which is another phenomenon. Excess of oil will be sucked out of the paints by the paper, making them mat like pastel. This increases the reflected, white surface light, but the relations between the pure pigments and whitened pigments remain the same. If the pastel appearance disturbs the experimenter, a thin coat of varnish applied to the colors when dry will remedy the defect. When glazes are to be applied, it must be seen to that the under paintings are perfectly dry. White porcelain plates may be used to advantage in some of the experiments; the paints adhere easily and smoothly to the surface, but as a record to be kept they are clumsy. SCUMBLING WHITE OVER COLORED PIGMENTS

Very thinly smearing (scumbling, as painters call it) white over colored pigments produces interference which causes very evident opalescence. Nature frequently employs a parallel method. Mist over landscape is an excellent example. T h e light radiated by the different objects reaches us after passing through a veil of fine particles of matter suspended in the air, and as this veil is white, and therefore lighter than the objects seen through it, the light sent to the eye has a bluish tendency. And the deeper in value the veiled object is, the bluer is the tint produced. When, however, the mist lies over the sun, the sun being lighter than the mist, the effect is reversed and the sun appears yellow,

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orange, or red. In addition to the sensation of blueness and the effect of opalescence, this scumbling method of nature creates an idea of lack of solidity. Objects, particularly the more distant ones, seem like delicately colored smoke. W e might think that this misty effect in nature could easily be reproduced by painting an ordinary gray-day landscape and then, when dry, scumbling it with white or light gray. It can be done, but the result is miserable. T h e blueness, opalescence, the lack of solidity can be roughly imitated; b u t the scumbling fails to lose its identity and looks spotty, irregularly catching in little depressions and by the side of ridges; if the surface on which it is applied is smooth, it slips, leaving open spaces. T h e difficulty is mechanical and can only be overcome by the greatest skill, and then only in particular cases. It is generally used as a makeshift to hide faults committed. Washing lighter colors ovei darker may, however, be evolved into a process very effective for certain purposes. A frequent and fallacious application of scumbling is the following. A n object, a head for example, solidly painted in thick oil paint may, on completion, be found to be too dark and saturated in certain passages, both the light and the dark. T h e proper, scientific way of correcting the light passages is to repaint them solidly. B u t fear of boldly redoing and possibly failing to do better what is almost right, or consciousness of the lack of knowledge of how to join the repainting onto the old, dry paint will often tempt the painter to scumble delicately a little very thin and pale pigment over the too dark passage, thus obtaining what he may feel to be the desired color and value. But the scumbled passage is opalescent, and the difference between the sensations and ideas produced by opaque and opalescent colors is so great as to class them in different categories. A scumbled passage (in an oil painting) by the side of a thickly painted passage looks disagreeable, bodiless, lifeless, colorless, cheap, and m e a n — a t least we brand it by all these adjectives. T h e reason is that opalescence, in both nature and painting, creates the idea of something seen through, from the very fact that the small particles of mist or pigment constituting the

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scumble are actually seen through, or between, and beyond. We are conscious of the two sources of light, one farther away than the other. Solid pigment, or solid matter in nature looked at through clear air causes no feeling of being seen through. It is looked at. Therefore a scumbled passage introduced into a solid passage causes a disagreement of ideas—one part is solid and seen through clear air, the other part is seen through mist. Or elemental perception may deny the effect of mist and conceive it as a dreamy characterization. These two disagreeing ideas enter consciousness, and the ensuing conflict for dominance between them causes a disagreeable feeling. T h e feeling of the lack of body or substance explains itself; and the lifeless and colorless feelings are merely expressions we attach to things which pretend to be real and are not. T h e adjectives, cheap and mean, require explanation. They seem to express a feeling that all that should be given is not. Solid colors have a frank, straightforward appearance. Nothing is hidden, whereas opalescence, the opal itself for example, appears sly, undecided in expression, hiding something. It is a question of association, and, like all questions of association, is uncertain in analysis. Light-valued—white, gray, or color—pigment thinly washed or smeared over too dark shadows naturally lightens them and may produce the desired color. T h e opalescence introduced often aids in creating atmosphere and the idea of shadow, but precautions must be taken not to let any of the shadows appear to be scumbled either more or less than the others. They must all fall in the same category or else there will be a conflict between the shadows themselves. Unlike opalescent lights, opalescent shadows may on occasion be an advantage for the reason that many of the qualities of opalescence are qualities of shadow. In fact the offense of opalescence in lights is in part because of the fact that it is an introduction of shadow qualities into light. Scumbling shadows is at best usually a makeshift to correct faults. The student may have heard about methods of painting shadows thinly and lights thickly. Glazing shadows thinly imitates shadow qualities wonderfully, but glazing proper means flowing thin pigment over a lighter ground which, although producing inter-

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ference introduces almost no opalescence, and gives a silverygolden effect, a glow of warmth. Scumbling means smearing, or, if desired, washing much thinned pigment over a darker ground, and that produces much opalescence and a washed-out, bluish, colorless effect, a cold deadness. Mixing white and colored pigments produces an effect as if of blue light added to the mixture; mixing black and colored pgments produces the effect as if blue pigment were added: the black pigment acts like a dark dull blue. Mixed with black, yellow becomes olive-green, orange becomes olive-yellow, red-orange becomes olive-brown, red becomes purple, purple becomes violet, violet remains violet, blue remains blue, blue-green becomes a bluer blue-green, green becomes a bluer green, and yellow-green becomes green. Of course, all these mixtures—shades as they are popularly termed—are less vivid and are darker than the colors with which the black is mixed because they are the result of mixture by subtraction. The black displaces some color, eliminates it. # I have said that black pigment acts like a dull, dark blue. If ultramarine blue instead of black is mixed with the colors mentioned above, the results in every case are exactly the same except that they are more vivid, more saturated, and more pronounced blue. T o this there is one exception. Red-orange mixed with black makes exactly the same color as when mixed with blue, if there is not a large excess of the black or the blue in the mixture. If the black or blue is excessive, it will naturally show its own color. Even if the black or blue is diluted with white—which in the latter case strongly brings out the blue color—and this diluted black or blue is mixed with red-orange, the browns produced are the same. Blue mixed with orange, according to the laws of subtraction, unites with the yellow element in the orange into dark green, which unites with the red into a darker and duller yellow. If there is any excess of red left over, this unites with the dark yellow and we call the mixture brown. If the yellow left over is in excess of the red, it gives the mixture a more strongly yellow color and we call it yellowish brown or olive• In his notes the author suggests that these mixtures of black will be more comprehensible theoretically if studied in connection with the color circle.

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brown. If the yellow is still more in excess, we get olive-yellow; and when only yellow is in excess, olive-green is produced. In other words the addition of blue to orange by its double mixing into yellow and red makes black (or dark gray), and the relative quantity of red and yellow left over gives this gray its specific qualities of brown or olive-brown or olive-yellow or, when there is no red left over, of olive-green. It is now easy to see that if the blue added to orange is turned into black, then black added directly must act in the same manner, and the bluish role which black assumes when mixed with pigments only adds to the effect under consideration, because its assumed blue is also converted into black. The question as to why black mixed with other pigments acts like blue demands an answer. It seems to set up some kind of interference which produces blue, but this blue, instead of acting according to the laws of addition, as does that produced by admixture of white, acts according to the laws of subtraction. The physical explanation is involved and not convincing, but the painter can simply formulate the two phenomena by remembering that adding white pigment is equivalent to adding light, and the laws of the addition of light become effective; whereas adding black pigment is equivalent to subtracting light, and the laws of the subtraction of light become effective. SCUMBLING AND GLAZING BLACK OVER COLORED PIGMENTS

Scumbling or very thinly smearing black oil paint over white theoretically produces a delicate brownish gray. But the distribution of the pigment must be very thin and very even—the use of the thumb helps. The particles of carbon seem too opaque and do not easily lend themselves to the production of opalescence by means of scumbling or thin washing. Pencil shading on white paper, adroitly thumbed, produces a smoother result than oil paint. Generally black, scumbled or thinly washed with turpentine or petroleum, over white produces a neutral gray much resembling the shadow color of white. Black washed over yellow darkens the yellow but does not turn it green. It produces

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a crude approach to the shadow color of yellow, which is simply dark yellow, that is, a very dull brown, and is neither green nor olive-green. Washed over the other colors, black has the same effect. It darkens them and produces rough imitations of shadow color. These shades are not shadow color, but they are sufficiently close to shadows to endorse the practice some painters have of washing thin black over certain light passages in their paintings (while in the process of construction) to determine what they would look like if they were thrown into shadow. When, however, black is mixed with more oil, or, better, with thick, almost colorless, mastic varnish, and this mixture is glazed over white, the pale brown color of opalescence makes its appearance. Black glazed over yellow possibly gives a truer shadow color than when thinly washed on. T h e same is true for the oranges and yellow-greens. But a thin petroleum wash of black over pink, vermilion, and green, and all the colors in the lower half of the color circle gives the truer shadow. T h e mastic, or even the oil glaze, should never be used during the process of constructing a painting, as their introduction spells ultimate ruin to the picture. A petroleum wash is sufficient to determine the approximate color.

VIII Local Color and Shadow Color

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P A Q U E P A I N T I N G , and glazing for the matter of that, brings us to the question of the beauty of single colors. T h e r e are two opinions: (1) a patch of a single color uncoordinated with, and unrelated to, any other color can have no beauty because beauty demands a relation; (2) a single sensation may effect beauty. It seems to me that, although some colors are apt to be preferred to others, to be more pleasing, yet this latter opinion is wrong in principle. A patch of color, smoothly distributed, produced by glazing, may be selected and the question about its beauty asked. But such a patch, on the face of it, possesses a complicated relation within itself. Suppose, then, that we try to find a relation in an absolutely spotless, ungradated, unvaried, opaque square of the modern "tempera colors." A tempera wash, owing to the structure of its material, presents a surface of small crystals with their facets turned in every direction, and this spreads a veil of luster of unvarying quantity and intensity independent of the accidental varying thickness or thinness of the pigment, unless it has been applied too thinly. T h e luster and the color radiated by the pigment are two different things, and, lying one over the other, cannot help forming a relation. Therefore a tempera wash is not a single color. T h e relation the luster bears to the color is the following. T h e luster is of a very fine texture; the tiny high lights are small and close together and escape the eye as such, consciousness only experiencing the luminous haze. T h e luster is large in quantity, because of the large number of high lights, and catches the attention forcibly and holds it firmly, and the attention—and this is

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the gist of the matter—as the eye wanders over the patch adopts one single unaltering attitude. Through this one attitude it views the unvarying color which, from its invariability, also demands a single attentive attitude. T h e meaning of this is that consciousness, with the minimum of effort to the attention, experiences two distinct sensations which flow so smoothly as (except on willful analysis) to be experienced as one. This is about the simplest form of unity we can imagine, but why merely two pure sensations blending into one should cause the unquestionably evident, even if small, quantity of beauty of a single color does not appear very clear. T o say that the two sensations form a unity is begging the question. Why should such a sensational combination effect beauty? Why should not the taste of lemonade, which is compounded of the sensations of cold, wet, sour, and sweet, effect beauty? As the question is put, I am forced to admit that the sensation of lemonade, or cold fresh milk, and of a patch of tempera color stand on a par, but the difference is that whereas the sensations of the taste of milk and of lemonade never beget any other ideas than the taste of milk and lemonade, the sensation resulting from the visual stimulus of tempera color begets many other ideas than that of itself. We may pass from one drink to another, and from one food to another, but the only ideas that will be created will be the ideas of the drinks and the foods, and animal satisfaction, whereas when we pass from one square of tempera color to another, we are soon astonished by the growing beauty, and this beauty is because of a variety of colors, each one demanding a separate and distinct attentive attitude. T h e different attentive attitudes are all under the dominance of the one unvarying attitude attention assumes toward the luster, which is absolutely alike in all the variety of colors, in all the mixtures, and in all the values. Tempera owes its beauty to the very nature of its matter, which possesses an ever present unity, an unvarying degree of luster. If in one given fraction of the square inch there are eightythree high lights then will there be eighty-three in all other similar fractions. This unity throws a sameness over all the colors, whether the painter intends it or not, and in accordance with the

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laws of attention and harmony binds them into one. W e can say that all degrees of luster being alike, attentive readjustment is eliminated, the work of comprehension is easier, and we grasp the contents of the color combination or picture more readily. O r we can say that, all the colors in the picture being subjugated to the unity of luster, the sense of order in mind is satisfied on experiencing the subjugation of the many to the one. Whereas tempera, and pastel as well, forces luster on the painter, oil paint, being far more docile, allows the painter to introduce as much or as little luster as he likes, and where he likes. But the fineness and absolute evenness of the tempera or pastel shimmer he can not equal. O n the other hand, the oil painter can, with his staccato handling, follow the varying degrees of luster in nature and thus produce a truer imitation. In such a case these varying degrees of luster, truly proportioned according to the dictates of the laws of light, cannot assume the role of a unity any more than truly proportioned values. If luster is to be made a unity, the shadows and lights must have an equal staccato handling. As any excess of luster is inimical to shadow, particularly deep shadows, the method may lend itself poorly to indoor painting, but it revels in modern plein air. In spite of this, certain celebrated portrait painters of today and of recent times, in their desire to "preserve the life and freshness" of the premier coup, paint both shadows and lights equally thickly, with moderately stiff paint and bristle brushes. T h i s easily enables them to produce a fairly equal staccato. T h e effect, although falling short of tempera, has some of its freshness. T h e observer may wonder why the shadows are so opaque. A sketch of one sitting often has much charm because in his necessarily rapid workmanship the painter cannot make the luster distinctions between light and shadow, and his staccato is all alike. Some painters, singularly, seem to believe that the virtue of tempera is that the pigments are mixed with white and that the white "tones" them. T h a t this is not true is seen when they are wet; the upper surface reflection is then eliminated and they appear as saturated as oil paints. If excess of white pigment were the virtue, oil colors would easily be forced to render the same

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account of themselves. T o make oil painting look like tempera requires much "doctoring." An absolutely even opaque pigment surface when smooth and flat makes a unity. Its attainment in a picture is difficult to achieve and accomplished only by skilled artists. Let us examine a plaque of such paint. Any color except black will do. T h e attention adopts one attitude toward the material of the pigment and keeps it while the eye wanders over the surface. T h e attention encounters no variety and unites all the contents of the plaque in one, and this it accomplishes easily because the contents are one. T h e sensation effected is the simplest there can be because it is a single uncompounded one. But will such a simple, single, uncompounded sensation remain effective and unify and dominate other sensations that may be added? W i l l the sensation of evenly applied opaque pigment predominate when a number of sensations effected by a variety of color patches, as demanded by a picture, are added to the single sensation? A unity, to be a unity, must effect such a strong sensation, or stable compound of sensations, or lively idea, that it stays predominant in consciousness over and above any other sensations or ideas which may be present. Sensations are easily driven into the background of consciousness by stronger sensations. Ideas hold only so long as no stronger idea competes. Is the effect or sensation of opacity sufficiently strong to dominate a group of other effects or sensations? If the opacity has in its nature qualities such as to strongly attract attention and hold it, then it will dominate. If not, then attention will turn elsewhere, to greater attraction. Attention is strongly attracted by complicated relations, such as those existing in glow, in luster, and in syncopated and elemental and candlelight values. Each of these aspects induces in mind complicated and pleasurable reactions, whereas an opaque surface seems to be, so far as I have been able to determine, of a very neutral quality. It seems, like white light, or clear water, or the air, entirely tasteless. An extended paint surface, evenly opaque and smooth and flat, acting neutrally as it does, attracts the attention as little as possible and thus allows some other quality easily and forcefully to set

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itself up as the dominating unity. W h e n pigment entirely eliminates itself, the attention turns more forcefully to other qualities. And this is exactly what happens in practical painting. Such a paint surface as we have described looks clear, clean, lucid, and the other qualities in the painting become more apparent. Opacity is a unity that is always stepping out of the way to make room for other unities. THE COLOR OF SHADOWS W e speak of strong light and weak light. According to physics this simply means a large quantity of rays of light or a small quantity. T h e bundles of light coming from the sun are supposed to contain many rays; and the bundles coming from white paper in a room, far fewer rays. T h e question of strong light and weak light is merely a question of quantity and not of- quality —according to physics. T h i s distinction is important because natural appearance does not correspond to theory. All colors appear not merely lighter but yellower when in sunlight than when indoors; and all colors appear more violet at night, outdoors, than in normal daylight. I f physics is right in asserting that the quality of light is the same in bright sunlight as in normal daylight, and that the difference lies in the quantity, then colors in sunlight should be the same as in shadow, being only lighter and easier to see. T h e yellow tendency remains unaccounted for. So does the violet of night illumination. T h e phenomenon, however, is purely physiological. T h e retina works normally in medium light, but when the light falling on it is strong, the visual element which responds to yellow becomes unduly excited and an excess of yellow is registered in consciousness. Weak light, on the contrary, fails to excite the yellow element in due proportion, with the consequence that all the colors tend toward violet. T h i s is roughly stated and requires refining. W e will first more carefully study sunlight and then night light. A yellow object placed in sunlight looks still yellower, but if the sunlight is at all strong, the paling effect of luster counteracts the yellowing, and we often conclude that the color is less yellow

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than when in a light but sunless room. Orange in sunlight moves toward yellow, the extent depending upon the strength of the light. But again very strong light washes it out more or less. Vermilion may become orange, but with violent sunlight it also washes out; crimson becomes vermilion, and washes out; yellowgreen becomes yellowish, and washes out; green becomes yellowgreen, and washes out. These are all cases of addition and blending. Blue shows no tendency toward yellow; it is merely washed out, and if it has much white in its composition, will disappear altogether. T h e washing out of the blue, however, although it can be caused by luster, as in cases of the other colors, is also caused by fusion: the blue and the yellow fuse into white or gray. Violet washes out and may appear more purple or more red depending upon the quantity of blue-yellow fusion that takes place and upon what the remainder is. Purple tends toward crimson, and the blue-greens toward green. This is a confused assortment of color changes, but when white sunlight (I am not speaking of yellow autumn sunlight) falls on objects, the average yellowing is so great that the strongest association has been formed between yellow and sunlight. This is shown when the sudden appearance of a yellow tree in a gray-day landscape deludes us for a moment into believing that the sun is breaking through the clouds. A patch of light yellow sand or clay produces the same delusion, and looking through yellow glass at a gray landscape makes it appear sunny. White houses or white blossoms do not do this and, therefore, we can regard it as a matter of association. Reproducing these color changes in a picture is not, however, sufficient to effect an appearance of sunlight, for that is as dependent upon the shadows as upon the lights. T h e bluish or violet quality of the shadows in sunlight can hardly be caused by their low illumination. It is not low. Shadows in sunlit landscape, although darker than the lights and appearing still darker on account of the contraction of the pupil, are really so light (except in isolated cases) that the law of weak lights appearing violet holds comparatively little. Shadows in sunlight appear bluish

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and violet because they are to a considerable extent illuminated by the blue sky and bluish clouds, and they seem still more blue and violet, so Chevreul claims, because of the effects of color induction: the sunlit yellowish colors surrounding the shadows induce their complement, namely a blue-violet color, in the shadows. The differences between the shadow and the sunilluminated colors are sometimes very great, running from orange to purple-violet, or from yellow-green to blue-green, and when the colors are pale and easily washed out through fusion, they may run from yellow to violet. When night steals over the earth, the first color to begin to disappear is yellow. This disappearance of necessity turns oranges toward red, and the yellow-greens toward green. With less light the reds blacken to a marked degree; that is, with less light the red element of red begins to disappear, leaving only the black and white element. We are astonished to realize how very dark that element is, and how much red depends upon its peculiar, pungent, life-giving qualities. It is because of these that we credit it with a value so much higher than it possesses. At this same level of light the yellow almost entirely leaves the greens, and what remains of the yellow itself is replaced by a faint green. This green seems to spread over all the lights and to a slight extent tones them. In this same light the blue appears to become lighter and to be diluted with white. At still a lower level we see only weak green in the lights and dull violet in the shadows. In the night all is monochromatic, a dull, gloomy, violet-gray color. These changes are not the result of the physical action of light, but of the peculiar structure of the eye which, in weak light, sees too much violet and purple and too little yellow. That in low light the scotopic eye, the rods, does the work, and that the rods see in this way may, for the purposes of practical painting, be accepted as a full explanation. T o paint a moonlight scene we must paint the moon and the lights greenish, and the shadows dull violet and purple, because these are the sensations we experience when looking at moonlight; and the fact that we experience the

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sensations derived from nature through one organ (the scotopic eye) and the sensations derived from the painting through another organ (the photopic eye) must be forgotten. T h e paling of the blue requires a few more words. It is called the "Purkinje Phenomenon." In twilight, blues at first glance appear to become stronger, they stand out from the other colors. As a fact, however, they do not become stronger. They do not become more saturated in color, but, as explained above, they look as if white light had been added to them and that makes them stand out. Certain small blue flowers that nestle in the fields close to the ground will be passed by in daylight because their value is so nearly the same as that of the rest of the vegetation, but in twilight they shine as pale blue stars. T h e young painter in the morning is disconcerted to find that the pale blue sky he painted at twilight is so saturated and heavy. Blue-greens act somewhat like blue, but less clearly: they lighten first, then disappear, but remain longer than the blues. T o sum up all this we may say that yellow retires and is partly replaced by green, and a green veil spreads over the lights; that red retires leaving its blackwhite element visible; that green and blue disappear through the process of being washed out with white, gray, and black; and that violet remains intact but dimmed with black. In the explanation of the colors of the night, I may have attributed the violet tendency too much to the fact that night is seen with the scotopic eye. In medium daylight illuminations indoors there exists some evidence of the same effect, and shadows in daylight are seen with the photopic eye. A vermilion-colored object placed in the middle of a bright room, the light of which is neutral in tone, seems to appear a little bluer or more violet in the shadow than in the light side. We may find it difficult to trust this judgment, but the shaded side of the object in the back (dark part) of the room compared with the light side of the object near the window forces us to realize that in such a large range the shadow is distinctly bluer than the light, and that the light is distinctly yellower than the shadow. Pale, dull yellow, which, however, appears positively yellow near the window, looks almost silvery in deep shadow—the retinal blue or violet fusing

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with the faint yellow into gray. T h e r e are color changes even in a studio, but they are so slight and the effects of tone are so much stronger and so contradict or exaggerate these retinal effects that the practical painter has little interest in them. T h e r e is another phenomenon allied to this. Yellow, orange, and vermilion in strong light seem to gain force or vividness. Strong light seems to favor them, particularly the orange and yellow. W e can attribute this to an accord between the retinalyellow of strong light which adds into the yellow and orange and vermilion. Orange and yellow are less effective in shadow; the yellow leaves of the autumn maple look miserable on a gray day and would never lead us to suspect the brilliancy they exhibit in sunshine. Here we have discord between the tendency of the yellow to be yellow and the tendency of retinal blue to neutralize it. Or, to put this physiologically, the retinal blue of shadow fuses into some of the yellow of the leaves and thus dulls them somewhat—at times very much. O n the other hand, blue and violet are at their best in shadow because of their accord with the blue tendency of the shadow itself. T h i s brings us to a strange question: what is the true color of things? W e know that every color radiated either blends with or fuses into every other color it touches. W e are prepared for this and unconsciously, through flaws in the mixture, often detect and discount the added color, inhibit it, and we thus frequently gain an approximate idea of how the color originally radiated would look if seen in neutral light. But we are not at all prepared to discount additions of what we have termed retinal color, because mind knows nothing about retinal color. Consciousness is incapable of distinguishing between color sensations produced by rays of colored light and color sensations produced by the illogical working of the retina. Consciousness registers flashes of golden light when the eyeball is pressed exactly as it does when lightning flashes. T h e yellow sun and the greenish light of the moon give no clue as to their true nature. W e might reason that the true identity of a color is that color which we experience when the object is illuminated by pure white light of medium strength, a light which does not excite the retina into

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yellow activity.* But at what point is such illumination reached? I may think I have found the point at which white paper is neither yellowed by the retina nor blued by a pale shadow cast on it. But reason tells me this is improbable, that either the light is the merest trifle yellow, or the shadow bluish, and that it is only because the blue or the yellow is not strong enough to cross the threshold of sensation that I fail to experience either of them. Painters say that at this point a thing is seen in its true color, and they call this true color the "local color," that is, that color which is its own. T h e term is ambiguous, but rather than invent new terms when one has already been widely accepted, I shall adhere to it. Adopting the term we can say, for example, that the local, actual, true, real color of a yellow maple leaf in autumn, seen in temperate light, is not a strong yellow; but when sunlight excites the retina into abnormal activity, and the retina produces a large quantity of yellow of its own and blends this into that of the leaves, and the leaves become so brilliant as to appear as shining gold, then that is not the local color at all, but a mixture of the retinal and the local color. Again, the intense, saturated appearance of violets and blues and blue-greens in twilight, being caused by the addition of the retinal-color of low illumination, is not the local color either. T h e local color of white is a white which is neither yellowish nor bluish. When the painter speaks of it, he almost invariably is thinking of pure white pigment, whereas white to the physicist means white light of any and all intensities. T h e local color of black is black, meaning, in a painter's terminology, the black of ivory-black pigment in temperate light. T o the physicist, black is only black when it reflects no light at all; it is the absence of all light activity, that ideal appearance of nothing which probably has never been produced. SHADOW

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Shadow color is more difficult to define than any other. It is the effect of a complicated relation. By this I am not referring to • Retinal yellowing may not be capable of explanation in authentic physiological

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the obvious relation between the shadow and the extraneous color reflected into it, reflected color which fuses and blends into the shadow in just the same manner as into the light; nor have I in mind the physical color and value contrasts between the light and the shadow, such as darkening the shadows by lightening the lights, or bluing or greening the shadows by yellowing or reddening the lights and thus inducing the complementary colors. It is more complicated than that. It is a psychological relation between shadow and light which confuses the judgment, causing it to render wrong decisions. The problem may be stated as follows: elemental mind, the feeling, non-reasoning mind, the basic, ever-acting mind which has to be continually corrected in its judgments by logical reason, that mind accepts lights, the illuminated parts of objects, as the real thing, and denies shadows. This singular trait of elemental mind I have several times alluded to. If we hang a curtain part way across a room, making a shadow-looked-into, and then place ourselves so to be able easily to see and to compare the shadow and the directly illuminated part of the room, we shall note that whereas on the one hand our judgment quickly renders decisions, possibly right and possibly wrong, as to what the various colors in the light are, on the other hand it hesitates at rendering any decision at all regarding the shadow. When we ask ourselves what any particular color in the shadow is, we become conscious that we are looking through a veil at color underneath and become confused as to whether the veil or the object below constitutes the color. And when, with an effort of will, we determine to disregard the veil, we decide that the colors under the shadow are the same as those in the lights, only darker. But what does "darker" mean? Is "darker" the same as "quieter" for a musical note? Is "darker" the same as "weaker"? Physicists tell us that light darkens because the light rays become fewer; there are less of them to the square inch, and therefore the sensation produced is weaker. This seems to be common sense. But what terms, but its empirical justice seems clear and, as a hypothesis at least, it is reasonable in the author's development of theory.

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does weaker light look like when disentangled from the confusing alliance with the shadow? Or, to put the question otherwise, can we not in some way isolate a patch of light and a patch of shadow so that consciousness can experience them side by side unaccompanied by all that which confuses the judgment? If, in a piece of gray cardboard, we cut two holes, we can easily place side by side any patches of light and shadow lying within a reasonable distance of each other. And if we take precautions that these patches are simple and flat, and unconnected with any other patches—which might betray that they are lights or shadows—then we should be able to place them on a par. T h e instant we do this the shadow patch ceases to be a shadow because shadows are only shadows when stronger light surrounds them. Still, this cardboard method isolates two fragments of color, and places them side by side, and we may learn something from comparing them. T h e fragment of shadow, of course, is usually darker than the fragment of light and appears transparent and smoothly flowing, whereas, the light fragment is opaque, and, even when its texture is fairly smooth, is bestrewn here and there with the fine dust of luster. This seems to contradict our theory of shadow which explains that the effects of transparency and smooth flowing are caused by the juxtaposition of light and shade. Possibly the neutral gray cardboard excludes all strong stimuli from the field of vision save that of the single light coming through one of the apertures. That light, therefore, acts strongly and affects the weaker light coming through the other aperture, making it appear like a shadow. We can, however, reverse the values of the light and the shadow by letting one aperture pass light coming from a directly illuminated but dark color, and letting the other pass light coming from a light color lying in a moderate shadow. If the experiment is properly conducted, the result, though delicate, is distinct: the dark color appears solid even if only weakly lustrous, whereas the light color appears nonlustrous and vaporous and slightly shadowy. Without doubt a part of the shadowy effect is caused by expectant attention, but certainly the greater quantity of luster in light than in shadow

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has much to do with it. We conclude that although the effect of shadows is mostly on account of value contrast and psychological causes, yet the actual physical luster plays a part, a conclusion we have come to before. All this brings us no nearer an answer to our question about what is the color of shadow. On an upright sheet of glass, placed on a line between the eye and a colored object with a light and a shaded side, paint a small patch imitating the directly lighted color of the object as closely as possible; and in the same manner, the shadow. Naturally, precautions must be taken that the range of values of nature does not exceed that of the palette. T h e light can be imitated very closely (in oil paint), but the shadow imitation lacks the transparency of the shadow. It is opaque. This is exactly what we are in search of: a piece of shadow color disentangled from its confusing alliances. These two imitations on glass are the best we can get. T h e method has a decided advantage in that the colors surrounding the lights and the shadows are not effaced. They remain visible through the glass, and therefore their effects on the lights and shadows are not destroyed and we can imitate the latter as truly as can be. Having decided on our method, we can now compare any light and shadow we please, provided only that they fall within the range of the palette. We shall find that the lights and shadows on a cloth of "old gold" are light yellow and dark brown. They are the same, being only of a different value. When, however, we look at them painted on the glass, or better, as they appear when transferred to a sheet of white paper, they certainly do not look the same, they seem to cause different sensations. T h e slightly orange color of directly illuminated red lead disagrees still more with its slightly purplish color in shadow. In fact, none of the shadow colors of the different materials, certainly not those of a very much lower value than the lights, entirely agrees with that of the light; and yet, we cannot but acknowledge that they have much in common. They seem first cousins, as it were. But when we are asked if at least the sensation produced by shadow color is not the same as that produced by the directly illuminated color except that it is weaker, we have to say that it is very dif-

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ferent. We might demonstrate physically and mathematically that the light and shadow colors of chrome yellow, even if not of red lead, are the same, but that would be aside from the question, because elemental mind, aesthetics, and practical painting do not work according to physical theory. They acknowledge only sensations and feelings and ideas. Why, then, have I stated so often and so emphatically that the shadow of an object (in medium indoor illumination) is the same as its light, being only darker? A cubical block of wood is bounded by twelve edges all of which are of the same length and remain so in whatever position the cube is placed. We know this because we have seen a cube, we have with our fingers felt a cube, and have judged all the edges to be the same. Turning it in any position whatever has not made us alter our judgment. On what has our judgment been based? We may answer that each of the twelve edges has caused like sensations and therefore they must be alike. Visually this answer is not logical. These twelve edges, owing to perspective, produce on the retina images of different lengths lying in different directions. In consciousness these are different sensations. These different sensations combine with the sensations effected by the two or three (out of the six) visible square planes, and the consolidated combination of sensations creates the idea of a cube. So it has come about that the idea of a cube is the idea of equal lines and equal squares bounding matter or space. And whenever the idea of a cube enters consciousness, the idea of equality of bounding edges rises. It is this idea of equality which is ready at the slightest provocation to step forward and assert itself. When looking at a cube we are conscious only of experiencing equality of length of edges—unless we are willfully looking for the seeming inequality. A circle in perspective turns into an ellipse—experience has taught us this—but coins or plates lying on a table in front of us seem like circles. They are drawn so by children and were by primitive artists. A circle in perspective produces not a true ellipse on the retina but a distorted ellipse, in which the nearer half is larger than the farther. No one ever observes that except

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the draughtsman. All perspective is a case of inhibition of this kind, the actual sensations of the instant being inhibited and the idea being installed in their stead. Of course, we can inhibit the idea at will and focus on the particular sensations, but even then we blunder greatly. When, however, a group of lines without meaning, lines which do not relate themselves into ideas, are presented to us, we experience the separate sensations and can compare them. What holds for line holds equally for color. Single patches of color, separated from each other and without meaning, produce separate sensations which are experienced in consciousness as such; but a group of color patches with meaning causes a mass of sensations which, although the single sensations are possibly experienced as individual, forms itself so quickly into an idea that we instantly inhibit the sensations and are never clearly conscious of anything except the idea. A fragment of light red, tinted slightly orange, and a blackened red, tinted slightly purple, placed fairly close together, but not in contact, produce two distinct sensations; but an earthenware pot exhibiting the two colors, one in its light and the other in its shadow, produces the single sensation and idea of vermilion, and we say the pot is vermilion in its lights and vermilion in its shadows. It is only when we are called upon to analyze them that we say the vermilion shadow differs from the illuminated vermilion in being darker. In truth, neither of them is vermilion. T h e conclusion we come to is that the sensations produced by the color of shadow and the color of light are very different when two colors are isolated, but on account of the superior force of the idea over the sensations the two seem much the same when related to each other. In the world of sensation the color of shadows is very different from the color of lights, but they are much the same when considered in the world of ideas. At times, however, shadows are so different from lights that there appears to be no connection. This brings us to an interesting question: what discrepancy in color between light and shadow will mind combine into one idea? I remember seeing, at the Salon at Paris, a picture by Besnard of two life-size horses on a beach, the effect apparently be-

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ing sunshine. T h e horses were of a deep sky-blue, and they cast vermilion shadows on the gray sand. T h e horses were all right, they were blue horses, and although biology may protest, m i n d can not; but the vermilion shadow on the light gray sand, although well painted otherwise, found no response in the illuminated part of the sand and failed to coalesce with it into the idea of one color. Apparently there are limits. Yet, in strong light — o r better, at the hour of sunset—we see orange lights and violet shadow forming into the idea of one color. For example, the yellow color of a yellow barn illuminated by the orange sunlight blends into yellow-orange; the violet from the east, falling onto the yellow in the shadow, fuses into grayish violet, and the two colors combine into the idea of yellow local color under that particular sunset illumination. T h i s is no more of a stretch of the imagination than that attempted by Besnard, b u t he failed to give the reason for the vermilion shadow, and mind refused to coordinate it and the gray of the sand into one idea. W e might say there is no limit to the disparity between light and shadow sensations which mind will coordinate into one idea. B u t is this statement true? Yellow-orange and violet form into a single idea, b u t are the colors not held together by a flimsy thread? W e can positively say that whereas on the one hand red tinted slightly orange and red shaded slightly blackish-purple form into one idea with the one single attached sensation (vermilion), yet, on the other hand, although the sunset effect of orange and violet form one idea, there are unquestionably two sensations attached to that idea: we are always strongly conscious of both the orange and the violet sensations. Many artists protest and claim that unity is not achieved, that the shadow and the light fly apart. Occasionally we see a picture with a vivid yellow light and an equally vivid blue shadow each slightly broken with other colors. Both sensations hold us strongly and refuse to combine and we fail entirely to understand the meaning of the things portrayed. Suddenly, without warning, the blue and yellow change into yellow-green and reds and purples and what not. T h e single idea of a double illumination of yellow and blue enters consciousness. T h e things gain shape and the picture meaning. But

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there always remains a feeling of conflict between the single idea of unity and the many different colors. This, however, may add to the life of the picture. Attempts have been made to chart those degrees of difference between lights and shadows that will transmute them into one idea. Such a chart must be useless because it is not merely color differences which are antagonistic, b u t value differences as well. T h i s question of value antagonism we have touched on repeatedly. T h e greater the contrast between the light and the shadow, whether the contrast be one of color or one of value, the greater the reluctance of light and shadow to unite into one idea. T h e span of reconcilable differences also depends, I have a strong suspicion, not merely on so-called "perception," but also on the imagination of the spectator. T h e following determinations of the light and shadow differences in temperate illumination are set down here because they are those which every mind unhesitatingly unites into one idea. T h e results were obtained by the sheet of glass method and then were copied on white paper in the shape of two squares laid side by side but not touching. T h i s paper was then laid on a table in such a position that the light of a window cast the shadow of a small, upright piece of black cardboard, placed at the edge of the square representing the light, in such a manner that the square was half in shadow and half in light. This manipulation gave the opportunity of comparing a light both with its real shadow and with a painted imitation of its shadow—as seen in light. T h e real shadow and its imitation, lying side by side, were then viewed through a horizontal slit cut in the gray cardboard, and the painted shadow was only accepted when it agreed both in value and color with the real shadow. T h e object of repeating the sheet of glass results with the cardboard was merely for a check. T h e results, as looked at without the aid of apparatus, are these: a fairly dark shadow falling on one half of a chrome-yellow square, compared with the light (unshaded) half, seems not dark at all, and of much the same color as the light. But the painted (and detached) shadow compared with the light square looks un-

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duly dark and effects in consciousness a totally different sensation from that effected by the true shadow in combination with ihe light. We fail to imagine how they (the painted shadow and the light) could ever unite into one. This, of course, is because real shadows are experienced as lights shining through an intangible liquid—as we have noted before—and this habit of mind, under certain conditions, gives to shadows a lighter appearance than they really have. This we have also noted. But as we are not concerned with the psychology of shadows at present we must disregard this phenomenon and look only for color differences. T h e shadow of yellow is a dull, dark brown—by some minds experienced as olive green. T h e brown, however, is not reddish, and not being greenish must of necessity be yellowish. If we name it olive-yellow we satisfy the demands of physics as well as those of sensation. T h e shadow of orange is a dull, dark brown inclining to red. It is olive-brown and is generally called so. T h e shadow of greenish yellow is olive-green. I have said that in the world of ideas the shadows of colors are much the same as the lights—being only darker—but that in the world of sensation the shadows are a trifle bluer than the lights because of the retinal blue of low illumination. T h e olives do not contradict either claim. They appear the same as the lights when united to them and they assist in creating the idea of light. When separated in the world of sensation, the bluish element, which we shall assume is there, fuses with a little of the yellow of olive into a gray, leaving, however, a large surplus of yellow. T h e effect of the retinal blue begins to show distinctly in the shadow of vermilion, which is dark, dull purple; in the shadow of crimson, which is a stronger purple; and in the shadow of purple, which is dark, dull violet. In the case of vermilion the retinal blue both fuses and blends, and in the case of the crimson and purple it only blends. T h e shadow of violet is dark but not dull violet, particularly when the shadow is very dark, and the shadow of blue inclines toward violet, particularly when it is Very dark. These last two are suggestive of scotopic vision, but are really only low light photopic vision. But the shadow of

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green seems less blue than we should expect, the green, to a considerable extent holding its own. Apparently in deep shadows the blue loses its power and fades out from the greens and violets and also disappears somewhat from the blue itself. T h e matter becomes very confusing when we try to explain it logically, for there is so much concerning color that we do not know. Therefore, all we can do is to remember the facts as they are and call it "low light vision." T h i s is the place to add a little empirical evidence to the theory of the transmutation of sensations into ideas. A light and its adjacent shadow, from the fact that they are light and shadow, cannot escape the laws of color induction and color contrast. Every visible patch of color in light or in shadow is actively operative in influencing all other patches in its neighborhood. It either tries to blend with them according to the laws of delusive blending or makes the difference between them seem larger than it is. A shadow and its light must do one or the other. T h e vermilion color produced by a slightly orange light and a slightly purplish shadow could easily be explained by the theory of delusive blending if we had only to deal with soft-edged shadows. W e might say that the colors easily pass into each other through the soft edges because of the laws of expectant attention, were it not that a vermilion cube, on which the light and shadow are sharply marked by a crisp edge—which precludes b l e n d i n g — presents the same vermilion color as that produced when the shadows are broad-edged and soft. If then, delusive blending is not operative, contrast must be, and the light should appear yellower and the shadow bluer when they are juxtaposed than when they are separated. If this effect of contrast is a fact, as experiment tells us it is, on what other ground can it be that consciousness experiences the same vermilion, in both light and shadow, than that the idea of vermilion is created by the summation of the sensations of orange and purple and predominates so strongly in consciousness that the separate sensations are not experienced as such? Of course because we prove that a thing can be neither A nor B, it does not follow that it must be C. It may be D or E, and I mention this merely as evi-

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dence pointing in the same direction as the fragment of the theory of ideas which I have advanced. T o the experienced painter all this may seem less plausible than to the novice or layman, because he is very little deluded by the ideas of color; he has analyzed them out so many tens of thousands of times that he habitually experiences the several sensations approximately correctly, as they would appear if separated out from their other elements. T h e series of shadow colors is a heterogeneous assortment and the question arises, how shall the practical painter treat them in a picture? Each shadow unites with its respective light into a single idea, such as the idea of yellow-green light or of violet light, but when several of these color ideas are presented to consciousness at the same moment, they stand isolated, they have nothing in common which consolidates them into one single and larger idea. T h e yellows and oranges have somewhat similar shadows and may combine (at a stretch) into one idea, but the shadows of red lead and vermilion and crimson, being bluish, have nothing in common with those of the yellows and oranges; the shadow color of violet light, being so strong, stands by itself; and the greens fall into their own group. If we state this psychologically, we shall understand the reason. Attention assumes a distinct attitude toward each color idea, and when it is called upon to alter its attitude every moment, consciousness feels the strain of the incessant alteration and remains awake to the many. If all colors had only the same shadow or the same light, attention would adopt one attitude toward this sameness, and on such a stable base cause consciousness to experience the variety. At least a small amount of unification, consolidation into one idea, would take place. There are five solutions that are usually practiced, (i) We can make an exact (proportionate) copy of the colors of the lights and shadows which, as in proportionate values, effects unity if there is, by a rare chance, unity in nature. (2) We can much darken all the shadows, as in candlelight illumination. The very darkness of these shadows renders their color difficult to discern and therefore requires less alteration in the attitude of attention

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toward the several shadows and effects some degree of unity. (3) T h e shadows may all be darkened very much, and at the same time one color (such as the brown of the old masters or the violet of modern painting) can be added to them, thus effecting a sameness which requires still less alteration of the attention and effects still more coordination into one color idea. T h i s is color harmony of a simple kind and is one of the methods of the old masters. (4) T o n e and envelopment hardly deal with the question, as they influence the lights as well as the shadows, and lights have nothing to do with the present matter, but I note them both as this classification demands it. (5) T h e shadows can be inhibited, as in primitive art. T h i s achieves unity by destroying the discordant element instead of subjugating it. T o many this seems a childish solution b u t if the shadow problem is solved, the loss of the shadow is so great, and so much skill has to be used to hide the loss, that the accusation of childishness is unjust. THE LOCAL COLOR SYSTEM W e have seen that all colors in strong illumination turn toward yellow and, when still more strongly illuminated, bleach out. W e have seen that colors in shadow turn toward blue and in weaker light toward violet and in still weaker light into violet-black. W e have also found an intermediate point at which colors tend neither toward yellow nor toward violet and exhibit themselves in their true colors which artists name local colors. T h i s local color is only local color when in a flat patch. W h e n the color comes from some body with shape, it necessarily presents several values because of the inequality of the illumination of the different planes. T h e genius of artists, however, has devised a method whereby a rounded body, evenly colored, may be made to appear in almost all its parts in its local color. If some colored object, like a cloak for example, is placed in a room with white walls and white ceiling and a light floor, and if the walls and ceiling are illuminated by the rays of numerous lights, the lights themselves being hidden from view, the result will be an illumination which comes from every direction, and falls on the

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cloak from every direction. T h e shadows mostly disappear; they r u n and hide and are only visible in small deep folds and crevices, and all the rest of the cloak is seen in its local color—if the illumination is neither too strong nor too weak. A group of figures, garbed in different colors, under this illumination suggest some of Rubens's color schemes, which are often spoken of as being "self-luminous." T h e several colors contrast with each other as colors—not as light-and-shade contrasts—and value contrast is mainly between the values of the several local colors. Of course, there are a few dark shadows here and there in crevices, and also considerable areas of light gradating into dark, b u t these latter shadows are all of the shadow-lookedthrough variety. T h e i r presence is not suspected at first glance, and often is never seen by the inexperienced because—and this is the important point—perception sums these elusive, edgeless, partially inhibited shadows and lights into single ideas of local color, and these ideas so dominate consciousness that it experiences nothing else. T h i s summation is assisted by the fact that there are practically no high lights on the colors. T h e source of illumination, being so wide, causes the high lights to spread o u t until they virtually eliminate themselves. Perception, therefore, has only to correlate broad masses of light with shadows. T h e s e two, however, so softly and easily melt into each other that, altogether apart from any difficulty of combining them into one, it is usually impossible, even on analysis, to define clearly which is the shadow and which is the light. T h i s difficulty of distinguishing the shadow from the light we touched on in studying shadows-looked-through, and it is often astonishing how very dark a light may become before it is realized as no longer a light but a shadow. All this, however, is merely a description of appearance and of how several ideas of local color come into existence side by side. It leaves the several ideas in unrelated form to be dealt with. How do these ideas as of red and dull blue-green and black and all the rest, which stand separately in nature, become united into one larger idea? For if they cannot be made to combine, they are useless to us and belong to that great stream of unre-

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lated sensations and ideas which is ever flowing through consciousness. It is true, there are small shadows and we can treat them in any of the ways outlined, but they are so small that they may not have the force demanded of them to effect unity. Or we can "envelope" the whole combination according to modern principles, but this loses a large part of the local color. It happens, by chance and by art, that the appearance I have described has within itself much agreement; it is the closest parallel matter can assume to that kind of inhibited values which was so much in practice with certain of the Chinese and primitive Italian artists for whom the integrity of the objects must not be destroyed. As shadows are the great destroyer, they must be eliminated. Also, as the integrity of the objects depends on their structure as well as on their color and value, and as shadows following structural line assist structure, those shadows lying in crevices must be retained. Before attempting to understand how this combines and achieves unity in the several masses of local color, or rather in the several ideas of local color, we may closely observe a combination of a few draped and nude figures with accessories of furniture, and, on the wall behind them, a piece of tapestry or other colored material. We observe that each piece of drapery stands by itself clad in its own local color; each piece of uniformly colored furniture does the same; the masses of flesh separate clearly into their own local colors; the details, such as the eyes, have no confusing shadows under the brows, and the masses of hair are all themselves. We next observe that the dark shadows lie in the crevices and around corners, and we note that each of them agrees in shape, in perfect conformity, with the shape of the structure it is lying on or adjacent to. And they must do this because the diffuse light coming from every direction destroys all the dark shadows except those lying in the deep depressions, which of necessity are bounded by structural shape. We further observe that, although these structural shadows emphasize the form on which they lie, they in no way exert their force outside of their own little provinces. We observe finally—or it may be our first impression—that although every object stands by itself,

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disconnected from all others, yet all the objects, in some mysterious way, seem strongly connected to all the others. How does this simultaneous disconnection and connection happen? It cannot be by envelopment by either veils of shadow or by some one strongly colored and predominating light, for these are eliminated. T h e r e is no mist present; indeed, the objects are unusually clear and the light is limpid. Nor is there any apparent sameness between the different colors, for, although that does assist, we have in this instance presumed diversity. T h e black is black, black as night, and black all over; the browns and all dark colors are dark and almost suggestive of candlelight illumination; the whites are white, b u t not glaring; the yellows and oranges and light greens are luminous; and all the colors seem saturated to the fullest of their individual capacity. They certainly are very different from each other, b u t they are strongly unified. W e reason that we should find much more unity in a room with single window illumination because there the things all sink into a shadow on one side and at least have that in common, but, in fact, there is less unity than here. Softly diffused light effects unification in different ways. Because the structural shadows agree with the structure, the objects are more easily understood than when there is contradiction. Mind seeks primarily and always to understand shape. Mind or attention or the spirit or whatever it is seeks to know instantly what a thing is, and to know what a thing is implies knowing its shape far more than knowing its color. W e are every instant trying to determine what the things in our immediate proximity are. We may not go far in our determinations, we may only desire to know what is dangerous and what is not, and we may, when we determine that the thing is not inimical to us in one way or another, instantly forget it. But even this small amount of knowledge means some knowledge of its shape. Some of the shadows, however, which lie on matter almost invariably contradict the shape—even if only to a slight extent—and there must take place in mind a reconstruction, which consists in part of inhibiting the shadows, but also in part of making the form

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over to correspond to the idea of the object. Everything that w e have ever seen has left in our minds an idea more or less distinct, and recognition comes down to finding a correspondence between that and the object perceived, or, rather, between the new idea it causes, and the old idea already in mind. B u t as the new idea rarely corresponds exactly to the old, there must ensue a reconstruction, a translation of the new into terms of the old, before we recognize the object. A l l this takes energy. T h e r e f o r e there is always a struggle. W e may not feel it as such because it is ever present, b u t when we are presented with an object whose appearance conforms to its shape, whose shadows agree with and assist in creating its shape, then we are at least saved a part of the work of reconstructing the new idea in terms of the old, and the relief takes the form of that pleasurable feeling w e name the aesthetic. Each object in our g r o u p presents the same conditions and allows the same ease of attention and perception. A l l those processes of mind which are concerned in perception adopt one and the same attitude toward all objects, and through this one attitude unity is achieved to some degree. It is assumed that the diffused illumination is of medium strength, and that implies that the eye is subjected to no physical strain. T h e r e f o r e that source of physical disagreement is not encountered. T h e range of values of the different colors is small, in fact so small that whatever high lights there may be, even on the whites, rise but slightly above the value of white pigment; and the darkest value, that of the black, does not fall much below that of ivory black pigment. T h e pupil expansion, therefore, remains fairly constant, which means only a little work for the iris. O f course, there are the dark organic shadows in the crevices where values fall below the gamut of the palette, but they are small and the pupil seems never to adjust itself to them, rather taking its cue from the large expanse of light. T h e quantity of luster, in diffused light, is small. It is largely eliminated by the diffuse illumination because the myriad of tiny reflections, which constitute the essence of luster, are, like the high lights, broadened out into the general light. T h o s e

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which remain are denied the necessary shadow relief, for that is excluded by diffuse illumination. Also, what there is of luster is more evenly spread over the objects than in any other form of illumination which has the same amount of light. T h e consequence of this is that one attentive adjustment to luster is sufficient to cover the entire field, save that for the small shadow. Therefore the struggle of perception to separate the colors from their luster so as to recognize their true local colors is reduced to a minimum. Mind (elemental mind, the aesthetic mind) always seeks to know the local color in the general color it is experiencing. This I have pointed out frequently. Mind inhibits shadows to get at the local color underneath. Mind reconstructs gaudy lights and shadows—like those in which the setting sun clothes objects—so as to get at the local color. T h e young painter paints objects, both indoors and out, in their local colors, convinced that that is the color falling on the retina. Mind does this for the same reason that it seeks to know form. Nature frequently disguises local color so thoroughly that only conscious reason can discover it. When a color is itself and requires no disentangling from other colors, a mental effort is saved. It will be noted that, among the reasons for diffused lights' producing unity, I have not merely called upon the unifying power of agreement, but have brought in ease of perception, both physical and psychological, as a unifying power. It may be asked, on what grounds can I place ease of perception on the same plane as the active, constructive powers of attention and agreement? Attention effects agreement through holding in the fore, in clear focus in consciousness, one or several qualities which are possessed in common by the disagreeing variety, and this idea of agreement floods consciousness and creates the idea of oneness or peace or order, and the disagreeing qualities, which are in the background, and which attention does not insist upon, are viewed through this unity. Agreement may be effected not merely by introducing one or several predominant qualities which attract attention, but also by taking away the cause of disagreement from the variety. A feeling of peace results, quite the same. Peace is unity, or one of its forms. A body of disagreeing

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m e n may come to agreement under the influence of one idea interjected by one leader, or they may come to agreement when the causes of disagreement are removed. Among the causes which destroy the idea of peace are all kinaesthetic efforts, and the more they are reduced to a minim u m the more is the idea of peace experienced. Thwarted desires of instincts or thwarted demands of elemental mind produce distress, and distress is antithetic to peace. Easy perception assists in creating the idea of peace, of oneness. Diffused illumination forms a unity, or it effects a group of unities. T h e r e are varieties of diffused illumination, and I have described an extreme case. If the floor of the room we are experimenting in is dark instead of light, as I have demanded in my description, more dark structural shadows are introduced and the light is somewhat encroached upon. T h a t introduces more of the structural and less of the local color unity. A certain amount of diffused light may be obtained in a room with one window by veiling the window with gauze and by assisting the dispersion of the light with a few white draperies which act as reflectors. These reflectors are placed not too close to the things that are to be seen in their local colors, but on either side of the window so as to broaden out its light. In such an illumination the objects, when looked at from a position between them and the window, will appear in their local colors, relieved from a background of chiaroscuro more or less dark. T h e old masters, the Venetian School of the period of the Renaissance especially, often introduced into their landscape backgrounds a very beautiful light effect, which is today spoken of as the golden light of the old masters. T h e gold is largely because of the yellowing by time, but the beauty is felt, among other reasons, on account of the local colors. T h e prototype of this effect is seen in nature at those rare moments we call golden summer afternoons and is caused by a particular atmospheric condition. T h e sun may be in the west, an hour or two before setting, but the sky in the east and north and south appears self-luminous and throws soft light into all the shadows. All the colors appear as themselves to a remarkable degree. T h e trees are green all

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over. T h e i r deep shadows follow their structural formation; the high lights are at a minimum; and luster nowhere obtrudes. What is true of the trees is true of the fields and rocks and pathways. Naturally the whole effect is in a brighter value key than the local color of indoor illumination, but the pupil adjusts itself because the range of values between the highest light and the deepest shadow is comparatively small. In copying, or painting a parallel to this effect, it is well to remember that it exists by chance, and that the complete harmony of the artificial indoor arrangement cannot be expected. Sudden contradictions must be expected and eliminated. T H E MAXWELL DISKS AND T H E OLIVES

According to the Maxwell disks, a mixture of yellow and black makes olive-green. Perhaps because of this, there is a more or less widespread fallacy that the shadow color of yellow is olive-green. Certain experimenters hold that mixing a color with black, by means of the disks, produces the same effect as lowering its luminosity, that the result is the true shadow color. T h e y point to the fact that a sector of yellow rotated in front of a trueblack shadow produces the same olive green. Both methods may be wrong. If we mix black and chrome yellow according to the Maxwell method, and in a shadow behind the rotating disks hold a piece of paper colored with chrome yellow, so that its value is the same as that of the disks, the color should be the same. It is not. T h e rotating disks are olive-green, and the shaded yellow is olive-brown. If a black and a white disk are conjoined and rotated and white paper is held in shadow behind them, the paper appears gray and the disk bluish gray. I do not know what the trouble is, or, indeed, that there is any trouble, and I cannot understand why the Maxwell method should be expected to give shadow results any more than does glazing black over colors, or colors over black. T h e fact that the results of rotation are endorsed by other optical methods bears no weight; countless fallacies are endorsed by other fallacies. T h e test of the correctness of the reasoning is not more rea-

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soning of the same sort but an answer to the present question, "does it work?" T h e answer is, "it does not work; sensation says so." I do not understand how the method ever could have been expected to work; it seems very farfetched to expect alternating stimulation to effect the same sensation as continuous and even stimulation. It may be of interest, though, to find out why yellow shadows have sometimes been so misjudged. If we make a mixture of ivory black pigment and chrome yellow, and another of black and orange, and another of black and reddish orange (red lead), we get olive-green, olive-yellow, and olive-brown. This we have seen, and the reasons have been given. When these three olive colors are placed side by side, it is easy enough to distinguish them correctly, but when they are separated and placed in different illuminations in different parts of the room the olive-brown, to say nothing of the olive-yellow, is frequently pronounced to be olive-green. If the olive-green is dulled a little, to imitate the black-yellow mixture of the disks, it is often mistaken for oliveyellow. Moreover, olive-yellow remaining in the same light will, at one moment be judged green, and a few minutes later, brown. If we look at the dulled olive-green for one or two seconds and then at olive-yellow, the latter will seem to be olive-brown; and if we look from olive-brown to olive-yellow, the latter will seem to be olive-green. And finally, if we carry any of the three colors into different parts of the room, steadily looking at it, it will alter under our eyes. These phenomena are caused by contrast. T h e three olives all have a strong yellow base. They differ only in that olive-brown has a slight addition of red, and olive-green (the kind made by the disks) a slight addition of green, the olive-yellow being neutral yellow. T h e predominant sensation caused by the olives is therefore yellow, and the red and the green sensations, being weakly experienced, are, on account of the laws of contrast, very easily displaced by other sensations, and as easily added to the olive-yellow.

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HUE T h e word hue is used by physicists and by painters to indicate the color quality of a color, the color element separated from its white and black elements. For example, the hue of the flower known as the common garden pink is some kind of red, and the hue of the sky is blue, and the hue of the sea is blue-green. So far painters and physicists agree. But painters say the hue of chocolate is brown, whereas physicists say it is red, and when a physicist is asked what particular red, he replies vermilion or some red close to it. H e also says the general hue of the bottoms of swamps and bogs is yellow and yellowish-orange, and explains that the dark brownish appearance is caused by the yellow and yellow-orange appearing in their deep shadow colors, and that yellow and orange in shadow or in light are yellow and orange. H e says that the general hue of the skin of the fair races in Europe is orange and red-orange, and that if it does not seem so, it is because the orange appears in its medium shadow color and is mixed with a lot of white. H e says that the hue of the dark silvery bark of the ash tree is also orange, that is, a very dark shadow color of orange. Painters fail to follow. T o come back to the hue of the garden pink. W h e n painters are asked to state the exact red of the hue, they say it is crimson, but when they try to match it with pigments, they find it is redorange (red lead)and physicists endorse that, even if the sensation experienced is one of crimson, possibly inclining toward purple. Painters deny that the hue of the bark of the ash is orange; they say it is gray because that is the predominant sensation; and painters insist that the hue of the pale under sides of certain leaves is blue-green, and this in opposition to the careful measurements of physics, which prove that it is the shadow color of yellow-green. Evidently the physical world and the aesthetic world are expressing totally different ideas. In physics one thinks in terms of light composition; in aesthetics, in terms of sensation. Sometimes they correspond; usually they do not. It is true that if an exceedingly dark shadow color of orange is mixed with white, the result will be the color of the bark of the ash tree;

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and it is true that the pale bluish green of some vegetation is composed of the shadow color of yellow-green pins a large quantity of white, yet sensation denies this. Which is right, physics or aesthetics? Of course both are right, the painter using the term as defined by the dictionary, and the physicist as defined by himself. I have so far, as much as possible, avoided the word "hue" but will now use it in the physicist's sense. T h e physicist has carefully defined the word and has created a new meaning; psychology has endorsed it. T h e r e is still another and important objection to the use of the word "hue." For example, when the physicist speaks of the hue of a color as being vermilion he does not mean the vermilion coming out of a paint tube; he means that pure (free from white) color in the spectrum which corresponds to vermilion, and as vermilion pigment is well diluted with white, the spectrum correspondence has an astonishingly different appearance. T h e same is true for all the other pigments, even the most brilliant. Relegating the word "hue" entirely to physical usage leaves aesthetics in an awkward position, for it may at moments require such a term. " H u e " or "true hue" can express the physical conception and "seeming hue" can express the painters', the aesthetic, conception. PURITY AND SATURATION

T h e terms "purity" and "saturation" I have used and defined frequently. I shall define them again. A pure color is one free from all other colors. Of course, such a color cannot exist, as we have seen in studying the blends and fusions, but it exists in varying degrees, and physics attempts to measure those degrees. A color is saturated when it is free from white light. But this is not always true. A pure color, as pure as can be, is experienced as being pure or saturated when it is in medium illumination, but when it is very dark, in shadow, although seeming equally pure, it does not look so saturated. For example, chrome yellow in bright indoor light is experienced as being almost pure and very saturated, but when in a deep shadow, although seeming equally pure, does not cause us to experience a sensation of

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saturation. This is for the following reason. Shadow, physically, merely means less light. T h a t is all. As color darkens it radiates fewer rays, and if it is free from white light, the darkening does not add it to them. But as it radiates fewer rays it produces less sensation, that is a weaker sensation; and as saturation is judged by the strength of the sensation, we judge the shadow to be less saturated—and in the sense of actual quantity of color, deep shadows are less saturated than lighter ones. If, however, saturation means filling up to its capacity, even if the capacity is small, then the shadow is as saturated as the light.* T h e word saturation should never be used for physical definitions; purity covers the whole ground. But psychologically or aesthetically it can be used if one always remembers that saturation and purity do not go hand in hand into the deep shadows. It is singular, however, that in spite of the obvious difference between purity and saturation the latter word is, in recent writings on color, often used in place of the former. T h e matter is of such paramount importance to the practical painter that I shall try to make it clearer by an imaginary parallel. W e shall assume that we are up in a balloon and below us is a vast plane of jet black earth. As we look down we see nothing. All is as dark as night. Suppose, now, there should spring from the soil a scanty growth of spears of oats of pure (free from white) elemental green. At the distance we cannot distinguish the spears individually, they blend into the black, and the effect produced is a very dark shadow color of green. T h i s green color is pure, no white being present, but we cannot say that it is saturated; we experience none of the abundance, none of the fullness and richness of saturation, all we experience is a faint sensation of black tinted slightly green, and we pronounce the sensation a meager one. Let more spears spring from the soil. They lessen the quantity of black space and increase the volume of green, and the black-green blend becomes lighter in value and produces a more * Purity as the word is used by the author is synonymous with chroma. It stands for contrast of a color with a neutral (mixture of all colors) at the same value. Saturation stands for that inherent quality of a color which is its strength; that is, its strength of hue. Chroma (purity) has been defined by Morton C. Bradley, Jr., as the product of brightness and saturation ("Systems of Color Classification," Technical Studies, VI [1938], »45).

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saturated feeling but loses none of its purity. As more spears are added, the darkness becomes less and the saturation is increased, but the purity remains the same. With still more spears, the retina becomes more excited and begins to send yellow signs to consciousness. With more green, the retina becomes further excited and adds the white veil of luster and we experience the effect of sunlight. But the instant luster begins to make its appearance, the purity begins to decline and the saturation to diminish again. If we have a right to draw conclusions from this hypothetical example—and I think we have because if we substitute green ray of light for green spear, and blackness for black soil, we conform entirely to physical fact—then it will be seen that the words purity and saturation cannot be used synonymously, for doing so confuses and even denies certain psychological truths. Having now defined the meaning of the words we can take up the practical application. Very dark shadows are not saturated in color, they are almost entirely black and must be painted so when it is desired to imitate the truth of nature. We know that the laws of harmony contradict physical truth and admit more saturated shadows than nature, but there is a limit to which this contradiction can be carried and beyond which the difference between our idea of nature and the demands of harmony becomes too conflicting. This is especially so when the picture essays to be realistic. The greatest fault usually committed is to oversaturate the shadows at the expense of the rest. T h e objection is this: the shadows are usually the base, the unity through which attention views variety, namely the lights; if this base is too saturated, there is experienced a feeling of saturation over the whole picture. This feeling easily becomes transmuted into one of heaviness. T o oversaturate the lights is not so bad, because they are the variety and, being different from each other, do not insist on repeating the same color, and also because their excessive saturation is somewhat contradicted by the feeling of general grayness created by the gray shadow.

IX Color Constants—Induction and Contrast

E H A V E observed how physicists and psychologists agree that there are three color constants, three qualities or characteristics which are always to be found in every color. T h e y are hue, value, and purity; and the claim is, that given the hue, and the value, and the purity in figures of percentage one can accurately tell the precise color. Without doubt this is so—within a very narrow value range—but if a painter turns to a book on physics for data on the formula, or on putting the formula to practical account, he will soon realize that the complications are so great as to render the system useless to him. Besides, the system takes no account of scotopic, twilight and night, vision, or of the variability of the pupil, or of vision at high (sunlight) levels, and even more it totally ignores luster and transparency. W e can make a sweeping assertion that the whole mass of quantitative color measurements—and with that, color spheres, cylinders, and cones—although of great use in physics, has little to do with painting or aesthetics. A l l these color measurements, so often introduced into textbooks on color, deal more with ether waves of light than with sensations. There is much complaint that color names have never been reduced to a logical simplicity. By some it is thought that mind resents being trammeled by mathematical expression, by numbers and letters, particularly when seeking to express the emotions. T h i s can hardly be so; musical tones are not designated by names but by letters, and everyone who knows anything of music seems to enjoy expressing himself in these letters. T h e difficulty lies deeper. T h e eye as we have seen, is an incomparably more

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complex organ than the ear, the same stimulus effecting different sensations under different physiological and psychological conditions—and when we come to study induction of color, we shall learn how colors change into other colors while we are looking at them—so that actually, unaided by physical instruments, we know little of the specific stimulus which effects the particular sensation. Therefore, in describing colors we are apt to give them the names of flowers or fruits or metals or minerals or other widely known things whose color they happen to resemble; and we qualify the name by adjectives and the adjectives by adverbs and thus, in a very loose way, describe the sensation we experience—although possibly erring considerably as to the nature of the stimulus. It is a pity that the hue-value-purity system is not applicable to practical painting because it contains so much that is valuable in such a compact form. A sketch of the theory may be useful. A beam of light may be packed solid with rays, or there may be large spaces between the rays. A beam may be likened to rain, in which the drops represent the separate rays. If the rain is what is called a light sprinkle, the drops are far apart; if the rain pours, the drops are closer together. If the rays of light are widely separated, the empty spaces between them do not stimulate the corresponding parts (cones) of the retina, which therefore send no signs to consciousness and there is experienced a dark, weak sensation. If the rays are farther apart, the sensation becomes darker and weaker; and when the rays are still more separated, they fail to excite sufficient activity to pass the threshold of sensation, but are still capable of exciting the rods, namely of effecting scotopic vision—that is, if time has been given the retina to bring the rods to the fore. On the other hand, as the rays increase in number they affect more cones and the sensation becomes lighter and stronger. It will be noted in this explanation that there is supposed to be no difference in the strength of the individual rays, only in the quantity. Rays never become feeble or weak; they are absorbed, get lost. It is entirely a question of quantity of stimulation and not of quality. T h e red rays in chocolate color are the

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same, and of the same strength, as in vermilion, but there are fewer of them, and, as they fall on the retina, less red sensation is experienced, and the black, the nothingness, predominates. When vermilion pigment is mixed with black pigment, some of the vermilion particles are displaced by black, that is, they are shoved farther apart, and the beam of light coming from the mixture contains fewer rays, but the rays themselves are unaltered in character. T h e reason the sun looks terribly bright is that the beam is so closely packed with rays; the beam coming from white paper in shadow radiates exactly the same kind of rays but not so many. This conception of the nature of light— which for all we know may be wrong even though it works— gives us a physical conception of values: namely, more and less of rays. In the study of blends and fusions we noted that it is impossible for any pure color to be otherwise than one of the four elemental colors or a blend of two elemental colors which are not complementary. All other mixtures leave a residue of white. Therefore all the possible hues are found on one or another single spot on the circumference of the color-circle. This gives us the physical conception of hue. The particular red color we perceive when looking at vermilion pigment, however, is not the pure hue because the pigment is adulterated with white—the composition of the white is of no account. It may be made of a fusion of some of the red with green, or it may be a fusion of blue and yellow, or it may be compared in many ways as we have already seen, but when it is separated out from the red, then the red is seen in its true hue, and it, the disentangled mass of white, becomes the impurity. We can make a pigment parallel of this which may be instructive. We will set our palette with chrome yellow, crimson, ultramarine blue, oxide of chromium, black, and white. We will imagine the four colors to be pure and the white as light as the sun and the black as black as night. Then, to imitate any color in existence, we (1) mix the two elemental colors required to produce the hue, if an elemental color is not the hue; then (2) we add a sufficiency of white to equal that of the impurity; then (3)

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we shove the rays apart to the required distance by the addition of black. That is all. Unfortunately the yellow works wrongly, mixing into green with the black, but this can be rectified by adding some violet to the black. This parallel, as I call it, is not merely theoretical but is practical and an excellent method, though crude, for impressing on the student the theory of the nature of color. I speak of it as being crude because it leaves out the element of luster, or rather, unwittingly, counts the luster in with the impurity. But, as I have said at the beginning, the hue-value-purity system is not complete in itself. T H E THRESHOLD OF COLOR SENSATION

A small boy, attempting to push a cart, may not succeed in moving it; he may not be able to produce even a quiver in the cart, but a few pounds more pressure will move it. It is the same in vision. Because we cannot see a color, it does not follow that the color is not there, it is merely too faint to pass what psychology terms the threshold of color sensation. A blue spot on a white cloth may be invisible because the blue rays are scattered too far apart, but when a few more rays are added, the spot becomes visible. What is interesting about this is that the threshold of color sensation is more easily passed at higher value levels than at lower levels. Very much more delicate changes in color are visible in the light values of a painting than in the dark values. Painters experience great difficulties in keeping pale skies and the lights of fair flesh "clean," whereas dark ultramarine blue and an equal-valued brown can be set side by side, as in a painted shadow, and often pass detection. The same is true for differences in values, which may be many times greater in shadows than in lights. The reason seems to be, as I have already suggested, that at low values the eye has difficulty in seeing, it makes uncertain distinctions; at highervalue levels it sees better. This is a common-sense explanation and I am afraid slides over many facts, but as these facts are of interest only in physics and psychology I shall let the explanation stand. When colored light is of a very low value, it effects a color-

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less sensation. In low light things are dimly seen and are gray. This is true for photopic as well as scotopic vision and means that, although in the early dawn the green tree and the red housetop send green and red rays of light to the eye, these green and red rays affect the retina in a similar manner, namely, in such a way as to cause it to produce in consciousness sensations of light of different values, but no sensations of color. We find an analogy to this in the other sense organs. Slightly impure water may cause a sensation of taste; we know we taste something, but what we cannot tell, and it is not until the stimulus is strengthened sufficiently to pass the threshold, that we know it is wine or sugar or salt. In other words, we can distinguish a sensation before we can tell what specific sensation it is. Artists sometimes paint the night in colors as saturated as their dark values permit. That may be art, the substitution of the idea of strong color for the idea of grayness—but the sensations achieved by these strong colors are not the same as those achieved by colorless, or almost colorless, grays, and a picture of the night painted in such a manner cannot be a parallel to the night of nature. This may be, however, too sweeping an assertion. A picture which looks "overcolored" when placed in an ordinary indoor light will, when placed in a shadow, lose its excess of color—as we have just seen—and will appear truthfully colored. This accounts for the fact that so many great Italian altarpieces, which looked truthful in color in the dark churches for which they were painted, look in the strong light of the galleries where they now hang, vivid and crude. It also accounts for the distress of the purchaser of a picture which looked well-balanced in the artist's studio, but which on a particular wall space in his own home looked "all wrong"— either too pale or too rich in color. All this drives us to a curious conclusion. T h e trio of color constants, hue, value, and purity, apart from its impracticability, is merely relative, having to do with the relations among value and hue and purity as these vary in every varying strength of light. When luster is added to the trio—and luster disappears rapidly as the value lowers—the relations among the four

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constants become still more variable. Certain color relations undoubtedly are a matter of physics, but color sensation is mostly a matter of psychology and aesthetics—itself a branch of psychology—and physics can tell us little. A very extraordinary phenomenon relating to the threshold of color sensation is the following. When, under the influence of music, perception distinguishes colors otherwise invisible, when smaller quantities pass the threshold, then the value range also is expanded, and the colors, most singularly, seem more beautiful. T h e phenomenon gives a basis for the legitimacy of a combination of color, acting, and music, as in grand opera. COLOR AND VIVIDNESS

We have noted that the sensation of vividness is produced by a sudden transition from one sensation to another. It is, however, also produced by continuous stimulation if the stimulation is sufficiently strong. Close proximity to a fire produces the sensation of the vivid, and the sensation becomes more and more vivid each second without closer approach to the fire, that is, without subjection to any transition from one sensation to another. A fragment of ice held in the hand produces a vivid sensation which increases as the stimulus continues. A large area of vermilion or yellow or pea-green or blue, when gazed at steadily, acts powerfully on the physiological system, even when there is no transition from one sensation to another. In the case of colors the element of pain does not seem to enter— unless indeed the colors are very light and intense—and they do not grow stronger as we continue to look at them; but certainly fatigue sets in, that is, exhaustion of some kind, and they slowly become duller. T h e sense of smell acts in the same way. The very beautiful town of Ferrara smells terribly. One notices the smell at a distance of some miles. It increases on approach. Then suddenly it disappears, not because the smell, the stimulus disappears but because exhaustion of the olfactory nervous system amounts to a paralysis, and the smell (the particular smell) is no longer distinguished. In all these cases it is the large

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volume of stimulation which effects vividness, not the transition from one sensation to another. We suddenly look at a large patch of vermilion and experience a strong sensation of vividness. T h a t is caused by the sudden transition. But as we continue to look, the vividness continues. T h a t is caused by the large volume of stimulus. We suddenly close our eyes and shield the retina from all light by placing a black cloth over the lids and experience a strong sensation of vividness—that is also caused by the sudden transition—but as we continue to pay attention, the vividness rapidly disappears because the retina receives no further stimulation. Everyone knows that different colors produce different degrees of vividness, and the popular belief is that the lighter and more saturated the colors are, the more powerfully they act. Vermilion, chrome orange, and chrome yellow pigments best fulfill these demands, in the popular judgment, and are therefore said to be particularly vivid. T h e popular reasoning, however, is ill-founded. If we assume the value of ivory black to be zero, and white paper to be 100, then will chrome yellow be about 75 to 80, and vermilion certainly not more than 35. Also, chrome yellow is much more saturated in yellow rays than vermilion is in red, or rather in red-orange and red. This undoubtedly gives the advantage greatly to the yellow pigment, as regards both lightness and saturation. But no one will for an instant deny that a patch of vermilion is far more vivid than a patch of chrome yellow. T h e fact seems to be that different rays of light, in themselves, produce different quantities of vividness, and although each person may vary in his decision as to what red or orange it is that acts the most powerfully, yet we can roughly say that for most it is what we call vermilion. This agrees with popular judgment but not for the popular reason. We can now account for a phenomenon which frequently causes the young painter embarrassment. Vermilion is not a light color—some estimates give it a value of 25 instead of the 35 I have given it—but owing to its vividness it seems very much lighter than it is. This is not difficult to understand. Consciousness or the judgment, or whatever it is, does not re-

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sort to physical instruments to measure values; it measures by the strength of the sensation, and as the sensation achieved by vermilion is very strong, the judgment credits it with a lighter value than it has. W e have seen a similar action on the part of the judgment when comparing luster and values. Why it is that the colors vary in degree of vividness is probably a purely physiological question. It has something to do with physical light waves and retinal activity and is not at all a matter of association, as is sometimes claimed; but that the colors do vary in vividness is a fact of the utmost importance in color composition. T H E PRODUCTION OF COLOR BY INDUCTION

T h e strangest, the most common, and the least observed of all the color phenomena is color induction. W e look at the soft blue distance and observe that the white sunlit houses all seem pale gold; we make a copy of the landscape and discover that the houses, altogether apart from being pale gold, are not even white; they are pale blue. W e note the faintly yellowgreen sky on which the blurred crimson and purplish sunset clouds are scattered, but when we copy, we find that pale gray must be substituted for the yellow-green. T h e white trunk of a birch tree standing in a field of fresh green grass, as seen against the sunlight, seems strong, light violet. We search for the source of the violet and find none. W e may reason that the violet is retinal and is the shadow color of the brilliant sunlit grass. But the value of the birch trunk is so light—being only a few shades darker than the grass—that we hesitate to attribute it to any of the phenomena effected by the darkening of color. If we look through a tube of white pasteboard and exclude the grass, the red element vanishes from the violet, leaving the blue, which we then recognize as being radiated by the sky. But where does the red element in the violet come from? On a sheet of white paper measuring about one foot square, paint a patch of chrome yellow two to three inches square and put a small black speck at its middle. Place the paper on a table in a clear, strong, indoor light. Stare at the black speck for twenty

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to thirty seconds moving the eyes as little as possible. Then, abruptly, stare steadily at some previously selected spot on a moderately shaded part of the white or gray ceiling. In a moment an exquisite blue patch makes its appearance and lasts for several seconds slowly fading out. This induced patch of color appearing on the ceiling has been called a spectral color, meaning a color like a ghost. T h e experiment can be tried with green, blue, red, yellow and all the blends; indeed with every imaginable color, and they all induce their respective spectral colors. If the ghosts are not visible on the dark part of the ceiling, they are in the light part. Dull colors induce dull spectral colors, strong colors induce strong spectral colors, and each color induces a spectral color which is its opposite, both in value and hue. They all induce their complements. T h e spectral color of yellow is blue, that of green is red, that of blue is yellow, and that of red is green, and the same is true for the blends—they can all be found on the color circle. T h e experiment can be varied by looking from the color blotch to a sheet of clean white paper lying on the table instead of at the ceiling. And if the white paper is too light, it can be tilted so as to be in shadow. Nor is it necessary that the color patch shall be in strong light, but the lighter and the more vivid the inducing color is, the more vivid is the induced spectral color. These spectral or induced colors—also called contrast colors for reasons that will presently appear—can be explained by the Young-Helmholtz theory combined with Hering's theory of four color susceptibilities, and this corresponds well with painters' practice. T h e reader who has tried the experiments I have suggested may or may not have observed that after some seconds of staring at the colored patch—particularly if it is vivid—the patch seems to darken and then to lighten and then to darken again as if in waves. There seems to be a struggle between some force, attention possibly, which tries to hold the color in its full strength and another force or factor which depresses and would sink the color into nothingness. This depressing factor is supposed to be no more or less than exhaus-

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tion of the retinal processes, fatigue. Direct experiment on the dismembered retina shows this to be not unlikely, and also shows that recovery from the exhaustion is very rapid. The outcome of this fatigue is simple. We stare at a color patch, green for example. T h e corresponding processes in the retina become exhausted, but all the other processes which are not involved remain fresh and ready for full action. We then stare at white, which means calling into activity the full set of processes. The green processes, however, being tired, respond weakly, and the consequence is that the field is left to the others, namely, to white light minus green. If, now, we study our color circle, we shall see that white light minus green means fusion of the yellow and the blue into white, and fusionblending of all the rest into white plus red. There will result a red diluted with white. The explanation for all the other spectral colors is the same and can easily be worked out with the aid of the color circle. Also all spectral colors are the complements of the inducing color plus white for the very simple reason that they can not be anything else. The induced color lying on the retina, so to speak, is the complement plus white; but as it appears projected on a white wall or sheet of paper, it is the mixture of itself and the color of the wall, and even if the latter is unmodified by reflections, its value (degree of quantity of light) modifies the image in one way or another. Also, the presence of an excess of white in the spectral color, over that in the inducing color, prevents it from being the true complement of the inducing color. Therefore spectral images cannot be relied on as being exact complements. Many interesting experiments, however, can be tried, among them all those concerned with blending and fusing which we have gone through by other methods. The blue spectral image of yellow projected on red blends into purple, and projected on a very pale yellow fuses into gray. T o produce the fusions, the color on which the image is projected must not be strong or else it will overpower the image; and we realize, to our astonish-

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ment, that these ghosts are not nearly so strong as their strange appearance forces us to expect. T h e most pleasing experiment of all is the projection on black of the yellow spectral image of blue; it does not make olive-green, it makes dark yellow. There may appear to be a slight conflict between the above explanation of spectral colors and that of the Maxwell disks. T h e phenomenon of intermittent stimulation producing continuous sensation results from the fact that the image on the retina lingers a fraction of a second after the stimulation ceases, and this is taken advantage of by the rapidity of the rotation of the disks, whereas in successive contrast—meaning that a contrasting color follows another—the fractional moment that the residual image remains on the retina, after the cessation of stimulation, is so short that it escapes notice, particularly as that moment is taken up in moving the eyes—an act which is most destructive to every kind of image—and the residual image has departed long before the spectral image makes its appearance. Therefore, the two phenomena virtually have nothing to do with each other. So far we have had plain sailing; the difficulty now begins. There are two kinds of spectral colors produced by two forms of induction, or, to use more common terms, there are two kinds of contrast: successive contrast, which we have just been studying, and simultaneous contrast, which we shall now take up. Entirely cover half-a-dozen pasteboard panels with thin, oil color washes of light grayish yellow, grayish orange, and so on, and when they are dry, with a loaded brush paint a stroke of identical neutral gray at the middle of each. Each gray stroke appears as the complement of the color it is set on, and this whether we look directly at it or at some spot to its side. And it remains firm and does not vanish when the eyes move, as do the spectral colors of successive contrast. T h e experiment is an excellent one for purposes of class illustration, and anyone not knowing of induction is apt at first sight to believe that there is some trick in it. If the panel is strongly colored, the gray stroke is apt not to respond. In that case, however, a sheet of very thin white tissue paper laid over the whole panel will

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soften the color and the gray stroke will assume the complementary color. A rough texture, like that offered by some pasteboard, induces color more easily than a smooth texture. It is not true, however, as is sometimes stated, that a very saturated color does not effect simultaneous contrast. If we lay a piece of vermilion paper, with a black spot in the middle, on a large sheet of very pale gray paper, and fixate the black spot, to keep the eye from wandering and from projecting the spectral green on the gray, there will instantly be observed a green tint over the gray, which tint is strongest close to the red and fades out as it retires from the red. T h e effect is not easy to observe, Green

Orange

Red

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but it is there; and it seems to me that the reason it sometimes escapes observation is that the vivid red, from the very fact of its being so vivid and pungent, forces itself upon the attention, and the attention, whether it will or not, holds the strong color in the foreground of consciousness, and the very delicate spectral green is relegated to the background and is often inhibited. It must always be remembered that induced color, from the nature of its construction, is weak (much diluted with white), its seeming strength coming from the exaggeration caused by astonishment at the specter, and also from the smoothness of its texture. O n the other hand, although these induced colors seem stronger than they are, yet, as the experimenter must have experienced, the slightest shifting of the eye destroys t h e m — i n fact, we are in the midst of them every moment without observ-

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ing them—and it is only by especially arranged experiments that we can experience them. It happens, now, that we have at hand empirical proof that vivid colors effect simultaneous contrast to a marked degTee. On a large square of vivid green, place a somewhat smaller square of vivid red, and on that a smaller square of green. Also, on a large square of vivid orange, place a somewhat smaller square of vivid red, and on that a smaller square of orange. (See Figures 17 and 18.) Then look at the reds in the two combinations, taking pains to fixate them so as to avoid the effects of successive contrast. T h e red in the first combination is intense; the red in the second combination is dull. This can only be for the reason that the red and the green in the first combination complement each other, that is, they add their induced colors to each other; and in the second combination the induced color of orange, namely green-blue, fuses with and washes out the red and blues it, and the induced color of red, namely green, fuses with and washes out the red from the orange—and thus they mutually suffer. This enhancing in the first case, and detracting in the second, is a permanent quality which is instantly perceived and does not vary according to the manner of looking at the combination. I believe that simultaneous contrast and successive contrast are variations of the same, although by some it is held that the former is psychological and that the latter is physiological. It is certain, however, that there are marked differences between them. The effects of simultaneous contrast are instantaneous and lasting. T w o colors set alongside each other modify each other so instantly that we accept the modified forms as the truth, as the local color. And not merely do two colors modify each other, but each patch of color lying on the retina modifies every other patch. This is easily observed in a room where the introduction of a new color alters all the others. It is still more easily observed in dress, particularly in women's garments where, apart from colors "going well or badly together" (harmony), colors are said to "kill" each other, or to make others appear as shades or tints which they are not. Pale green clothes make delicate flesh look rosy, and purple makes it look greenish

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and "sallow." W h e n all the furnishings of a room are too much alike in color, they may look "dirty," but the introduction of some strong complementary color "clears them u p " and they become "bright" again. It would be a waste of space to enumerate more examples; the reader can easily devise experiments for himself, the easiest always being to contrast two identically colored objects with two differently colored objects, and then to compare them. T o explain all this by a somewhat questionable theory, the retina may be likened to a rubber bag or cushion filled with air or water. If it is touched on one part, not only is that part affected and sunk in but all the other parts are affected in an opposite manner—they swell out. A n d swelling out, being the opposite to sinking in, represents the opposite, that is the complementary color. Each added touch to the cushion adds a depression and also a sympathetic swelling out that is felt in all parts, and the action is instantaneous. T h i s would correspond to simultaneous contrast. And the parallel to successive contrast would be found when the pressure is so great or so long as to produce a depression so deep or fixed that it takes the rubber several seconds to recover after relief from the pressure; and the process of recovering, swelling out again, being the opposite to the sinking in, represents the opposite color. For example, the recovery, reaction, from a blue force pressing in is a yellow expanding force, and this represents the slowly disappearing spectral image. According to this, vision always implies the presence of simultaneous contrast, even when the eye and the surroundings are at absolute rest; and when there is sudden relief, successive contrast is effected. T h e retina is not a rubber bag, or even a mass of quivering, elastic jelly, and my simile may appear ridiculous and farfetched. It correctly corresponds, however, to those large and simple facts which the practical painter must grasp. Besides, the unity of the retina is an established fact, and we cannot speak of one part of the retina as being affected independently of all the other parts. This manner of speaking is often adopted, possibly for the sake of brevity and possibly through lack of understanding. (I

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adopted it in describing the experiments on successive contrast for the purpose of gradually approaching the problem, but it may be misleading.) W e are now ready to explain, as well as we can without a reliable theory, the examples of induction we cited at the beginning of this section. T h e pale yellow of the houses in the blue distance is the complementary color of the blue and is caused by simultaneous contrast. T h e yellow-green of the sky is the complement of the purple and crimson of the clouds and is induced on a light gray background by means of simultaneous contrast. T h e violet birch trunk is distinctly a case of successive contrast, as well as simultaneous. T h e green shade in the black walls is caused, probably, by both simultaneous and successive contrast. In the first and second of these we found that, in making painted parallels, the pale blue pigment representing the distance and the soft crimson and purple pigment representing the clouds were sufficient to induce the required amount of yellow in the first case and the required amount of yellow-green in the second, and the induced color required no strengthening. But if we attempt to obtain the violet of the birch by this method (and the induced sky color with it), we shall fail. T h e very vivid, sunlit, yellow-green grass simultaneously induces violet on the white (gray) birch; and when the eye is shifted from the grass to the birch, and when the retina is relieved from the pressure of the yellow-green, the violet spectral color of successive contrast effected by the yellow-green also makes its appearance on the birch and augments the color already there. But colors induced by sunlight, both simultaneously and successively, are far stronger than those induced by pigments in the weak light of a room. Therefore the colors induced by pigments, to effect anything like the same forceful sensations as those induced by sunlight, require much strengthening. T h i s brings us up against a problem somewhat similar to that of proportionate values. Some will say that such exaggeration is illegitimate, that it is contrary to the physical facts. Although the proportionist can advance his argument of physical truth in the case of values because there is such a physical thing as values

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—more rays and less rays—in the case of induction his argument of physical truth is utterly meaningless because the matter is entirely within the eyeball and in consciousness and finds no correspondence in nature. T h e attentionist makes a denial of reinforcement. He says that we center our attention on objects and closely follow their forms; our eyes do not jump rapidly from spot to spot and thus project and cover the objects with meaningless ghosts of color which can only contradict and distort the true and characteristic color of the objects—and often the shapes as well. T h e impressionist answers that we scatter our attention everywhere and retain the unity of large relations. We are indifferent as to exactitude of details, and if the spectral colors distort both the characteristic color and the exact shape, the distortion is equal everywhere. And the spectral colors, being the complementary, opposite, by their very opposition add life and it is that for which we search. Both are right. T h e ultra-modern says, we wake up in the morning, our retinas are fresh and active and supersensitive. From our beds we gaze upon the bright sky. We gaze and gaze. T h e sky is the source of all light and life. It is life itself! Then we drop our eyes and look into the shadow of the room. It dances with specters of the most vivid green, such green as the spectrum itself does not afford. And suddenly the specters turn into an intense crimson and purple and then back again. We gaze upon the sun, for two or three seconds only, and then we look upon the black ground and it jumps hysterically, madly, with wild ghosts of every color. And so shall we portray light, for light is life and it is that which we are after. T h e effects of successive contrast are most marked when the values are light and the colors vivid, and the reader should by this time (if he has tried all the experiments I have described and suggested) be able to predict and find them. T h e finding, however, is not easy. A brilliant red and yellow sunset sky should cast a blue-green spectral veil over the dark fields and trees, but, as a matter of fact, purple may predominate because of the lowered value of the light. A strong green spectral color projected on a red object fuses into some of the red, and we

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believe that the grayed red is the color of the object and that the spectral color is not there. In landscape, color radiated by the sky and reflections from objects may contradict spectral color; and above all, rapid movement of the eyes shatters these spectral colors so much that we never suspect their presence. T h e theory that when the eyes move, objects are seen through departing spectral as well as residual images is interesting and is stressed by the impressionists, and that there is such a thing as colors glanced at rapidly and seen through the departing ghosts of others can be proved by the following experiment. Place a green, a gray, and a red panel, in that order, on easels or chairs three or four feet apart. Look at the green panel for a second, then, in the same manner, at the gray and red panels, and then back again to the gray and the green. At the first slow sweep of the eye the gray appears slightly reddish in color; at the second sweep slightly greenish. T h e effects are most evident, of course, when the panels are close together in strong light and the movement of the eye is slow, but it will be noted that, no matter how strong the light on the panels or how long they are looked at, the spectral colors are never evident on the spaces between— they are seen only when the eyes are momentarily at rest. Movement obliterates them. And it will also be noted that even a quick glance at the gTeen or the red is sufficient to induce a faint spectral color through which the gray is seen. T h e experiment can be varied by standing up a dozen or any number of colored panels alternated with gray panels and running the eye from left to right, and then right to left. T h e gray panels, on the second eye sweep, assume the opposite color from that which they assumed on the first sweep. A spectacular version of the experiment can be arranged. Lay together, one on top of the other, six strongly colored panels, alternated with five gray panels, and stand the pack upright on a table in such a manner that the panels, one after the other, can be tilted and thrown forward on the table, thus exposing the next panel to view. If, then, on each gray panel, as it comes to view, we write (at the top) the words red or blue-green or orange or whatever the tint may be, or better, if we merely initial them as R or Bl.G or O,

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and so on, it will be observed that, on lifting the panels back to their first positions, that is, on reversing the order of the sequences of color, the naming or initialing on the gray panels is exactly the opposite of what the color is. W h a t strikes the casual spectator as so strange in these panel experiments is that the colors experienced depend upon whether the eye is run from right to left or left to right, and he may wonder if there is anything like it in nature. T o infer from the above carefully guarded experiments that the haphazard arrangements of nature will effect the same results may seem to be stretching a point, but, as a matter of fact, objects outdoors as well as indoors, particularly the latter, besides exhibiting simultaneous contrast (which, as we have seen, is ever present) exhibit a continuous fluttering, so to speak, a rising and falling flow of enhancing and diminishing and changing color, and the only reason I have brought in the experiments is to show the student what he is to look for in nature, and how to look for it. T h e easiest experiment to begin with, after the panels are familiar, is performed in a room. W e select a gray object, a moderately strong-colored object, and a still more strongly colored object. T h e latter two should be more or less of the same color. O n looking from the gray to the medium strong color and then to the strong color, one judges these two latter colors to appear as they should; but when one looks back again, the medium strong color will appear to have faded out so much that, unless the experiment has been frequently tried it causes astonishment. W i t h this experiment as a start the student can easily devise others for himself, and after a number of them his aesthetic attitude will begin to alter, and he will become conscious of the continually fluctuating appearance an interior always presents, and of how much this fluctuation depends upon the path over which his eyes move. W h a t is true of interiors is true of outdoor nature, but there the phenomenon is often more difficult to observe. These principles can be applied to practical painting. Let our problem be to make a portrait according to the method of procedure so often resorted to t o d a y — w e are uncertain at the

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outset just what the colors of the garments and background are to be; we shall feel our way. Our model is a woman with pale skin and black hair and she is dressed in old lace and cream-colored silk and is posed against a medium-valued bluishgray background. W e copy the whole combination on a white canvas with thin semitransparent pigment. T h e light canvas shines through the pigment with the usual warming and harmonious result. We paint it over again opaquely and as truthfully as possible. T h e result is not pleasing. T h e simultaneous, as well as the successive, color contrasts, mutually induced in the background and in the dress—which escaped our notice in life because there the yellow induced in the dress added a golden effect, and the blue induced in the background merely made it appear bluer—in the opaquely painted copy seem aggressive. T h e cream-colored silk is a crude, hard, yellowish color and the background a little too blue. We decide to eliminate the excess of yellow from the dress and to make it harmonize with the background, and we paint regardless of the appearance of nature. But now we find that the face, which had appeared a little, but not much, too yellow at the end of the second painting—because then it contrasted with the still stronger yellow in the dress—now has become impossibly yellow; it is like that of some light-colored Africans. We repaint the face (eliminating some yellow) so as to make it harmonize with the dress, and are satisfied. T h e portrait is hung in a brown, oak-paneled room with brown accessories. T h e cream-colored dress and the flesh look bluish and the whole picture is top light in value, particularly the shadows. We reason that all this is on account of its assuming, to a slight extent, the complementary color of the dark brown oak walls, becoming light blue a trifle greenish. W e bring the painting back to the studio and note that its walls are very light; this, by contrast, made the painting appear darker and made us paint lighter than we thought. W e hang the painting in the next room on the white-washed wall and it seems dark enough in the shadows as well as in its general value, nor is it much too blue, and we realize that frescos in white halls must be painted light in value because the induced color

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of white is black and darkens all that is contrasted with it. But, still, we are not pleased with the slightly bluish tint of the dress and face, a tint we brought about by trying to harmonize them with the gray-blue background which was causing them to appear too yellow. On the other hand, we are afraid we may lose what we have if we repaint it. Therefore, we introduce a large quantity of strong, light blue flowers at the bottom of the portrait and also some not far from the face, and the induced color of the blue, being yellow, rectifies the bluish tendency of the rest of the picture—even to "killing" much of the blue in the background. And so we learn that any generally wrong color tendency in a picture may be eliminated, or even reversed on occasions, by introducing a saturated mass or masses of that same color. We can try this out on our theoretic rubber cushion. We slightly press down one spot. That stands for weak blue. A corresponding spot, or rather area, arises. That stands for weak yellow. We slightly press down another spot and another and still more spots, but do not approach too close to the edges of the cushion. The whole central portion becomes depressed, and that stands for the generally bluish tint of the picture; and the surface of the whole outer area of the cushion rises, and that stands for the induced yellow color affecting what lies outside of the picture. Then we press hard on one spot of the slightly depressed blue area standing for the picture. T h e spot we press on hard goes in deeply, a deep spot for strong blue, but the rest of the depressed portion rises somewhat, and that stands for induced yellow. From this it would appear that it was not at all necessary, when we discovered that our bluish gray background was inducing too much yellow in the dress and face, to eliminate that yellow; we could have introduced some vivid yellow flowers or draperies and they would have induced sufficient blue to fuse with and neutralize the excess of yellow. But it is too late. Our sitter refuses any accessories in her portrait and insists that the dress shall "look just as it is" when the portrait is hung on her brown oak paneling. We start a fresh canvas and place her in front of a piece of brown cloth of

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the same color as the panels and let a moderate light fall on it, just as it fell on the panels. It seems a good combination, but when we make a copy the result is dull. It is harmonious enough, nothing jars, and the induced color of the brown background—namely, a slightly greenish-blue—fuses into the yellow and light pale browns of the dress and flesh without paling them to an objectionable degree, but somehow all the colors look dull and muddy. W e turn to our color circle and find that the background and dress and flesh and hair are approximately of the same hue; they differ only in value and in purity; and also, according to the circle, we find that the various colors do not enhance each other, they detract. W e recognize that we are painting a monochrome and in consequence the question of value contrast must be important. We mix much black into the brown background, which not merely lightens the dress and face through value contrast but shoves the orange rays in the brown so far apart that their number is greatly reduced and their detracting power is greatly lessened. T h e result is excellent, but the shadows on the dress and face have become paled by the contrast and we glaze them down to darker values. Then let the problem be to paint a landscape. We select a narrow river winding through a plain past a hamlet of white houses with red tiled roofs, the river disappearing in the misty distance, which melts into the sky, and the sun fitfully trying to break through soft clouds. We make a copy of the scene, piling on the paint thickly. T h e copy is crude, and, in particular, lacks the diffused grayness that we feel in all we see. We repaint, dragging gray and blue in broken threads into all the colors. T h e result seems true, but as we do not include the immediate foreground—which is less enveloped in gray than the rest—we lose the advantage which the contrast of its strong green with the grayed and blued green of the middle distance would have given us, and the picture is dull and monotonous. We try to enliven it by touches of brighter color, but they destroy the truthful gray tone which envelops all the objects. W e also observe that the addition of even a small touch of stronger color inclines all the others in the opposite direction. We feel that

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the picture is suffering from an excess of simultaneous contrast, so to speak; all the colors are so blue-grayed and softened and lacking in positiveness that the play of simultaneous induction is too easily discernible, and we experience an uncomfortable feeling of lack of solidity. It is true, of course, that a slightly misty gray day does produce a feeling of lack of solidity of matter, but there is a l i m i t — w h i c h we have overstepped. O u r rubber cushion tells us that the pressure of all the various colors differs so slightly and that the depression they cause is so much the same that the smallest addition or subtraction causes a comparatively large sinking or rising. W e try an experiment. W e very much lighten and brighten, with vermilion and orange and white, some of the roofs and sides of those houses which are situated well to one side of the picture. A l t h o u g h the brightened areas are small, the effect of the successive and of the simultaneously induced color, particularly of the latter, is so great as fundamentally to alter all the rest of the delicately balanced colors. T h e y all become more positive and cease fluttering and assert that they represent definite shadow, whereas, on the other hand the orange-roofed houses seem bathed in sunlight—although we cannot explain how they alone should be touched with its rays. T h e bright spots they awkwardly make seem too much to the right, yet their influence is as much felt at the extreme left of the picture as in their immediate vicinity. A n d the shadow, which spreads everywhere, is not dark. Singularly, the addition of these small lights has lightened the whole landscape, and we remember the explanation of how the lightening of the eye socket by the addition of the high light is caused by ideal blending. However, we do not like the awkwardness of the placing of the high lights. W e could transfer them more toward the middle of the picture, but decide to try another means. W e restore the gray to the houses and paint a bright yellow and red rift in the gray clouds near their middle. T h e effect is identically the same as that produced by the bright houses. But the vivid color is too strong; it requires explanation; we cannot understand how such strong orange should make its appearance in the sky without affect-

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ing some other objects in the picture. We therefore dilute the orange with white to one half its strength, that is, we eliminate one half of the orange rays by shoving them farther apart. T h e sky now seems logical, but its shadow-producing effect on the ground below is weakened. We therefore introduce a reflection of the rift on the river and spread it over such an area that the number of orange rays in the sky and on the water equal those that were presented by the too saturated rift. Now the effect on the gray ground and clouds is the same again as that produced by the too strongly colored rift, and the whole color construction seems more logical. W e learn from this that when a color is so strong that it jars, it can be diluted and spread over a larger area and its inducing power remains the same. Of course, the dilution with white introduces the element of increased value contrast, and spreading the color over a larger area lessens its dramatic power; therefore we cannot say that the effect is entirely the same. In portraiture we often run into this problem. A head, painted in such an illumination as eliminates shadow—or when the shadows are too much inhibited—may, unless very skillfully painted, suffer from excess of simultaneous and detracting contrast. A strong light (if an excuse can be found) introduced somewhere, preferably on the forehead, throws the lower part of the face into shadow. This lower part, however, now appears more luminous than it did before the addition of the forehead high light (ideal blending), and, also, its color having been given one definite tendency, all destructive induction and muddy appearance is done away with. Or we need not touch the head; the large high light can be introduced on the chest— or lower down—and the result is the same. When the strong color which is introduced to effect the enhancing contrast appears too crude, though desirable in other respects, it may be preferable, instead of lightening it with white and increasing its area, to darken it with black and increase its area. T h e two methods are the same so far as color induction is concerned, and if the student has any difficulty in understanding why, he has merely to call to mind the fact that

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chocolate and vermilion are equally the complementary colors of bluish green, but that it takes a larger area of chocolate than of vermilion to neutralize (fuse into) a given area of bluish green because its rays are farther apart. And as for a color diluted with white, which introduces a large quantity and variety of rays, it need merely be remembered that these rays are all innocuous because they are locked in pairs which, until broken, have no color-inducing power. VALUE AND COLOR CONTRAST AND RELIEF

It is a commonplace that pictures with strong contrasts of light and shadow produce an appearance of strong relief, relief meaning the condition of separating out from, of projecting from, the surrounding mass. We all know that if, in a portrait, very dark shadows are placed by the side of the nose, and just under the nose, and under the eyebrows and between the lips, and under the lower lip, and on the neck just below the chin, the nose and brow and lips and chin will appear to come forward, that is, to take their places in front of the rest of the head to a slight extent, and we are illusioned into believing that there exists actual projection. Or, if the whole shaded side of the face is made very dark and juxtaposed against a lighter background, relief is also produced. Or relief may be effected when the background is somewhat darker than the general mass of the shaded side of the face if there is painted on this side, at its line of contact with the background, a narrow light strip. Or the shaded side of the face, with the exception of the very dark shadow by the side of the nose, may be fairly light, and the whole contour of the head may be fairly light, and may be posed against a light background, if only on the background, in immediate juxtaposition to the head, there is painted a very dark band, a dark halo, blending into the background, but jutting sharply against the head. T h e relief obtained by such means as these may be so great that we are actually (for a few moments) deluded into believing that we are seeing a rounded and real object. What is the cause of this phenomenon, the phenomenon be-

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ing that of a flat surface appearing to be raised, of appearing to project in places? O f f h a n d it appears simple enough: the values in nature have a considerably larger range than those of the palette, and w h e n we paint a shadow the color of almost black pigment and its juxtaposed light fairly bright, although we may still fall short of the value range of nature, yet we make an approach to it, we make a fairly successful attempt at imitation. T h i s contains a part of the truth but not all. T r u t h to nature in terms of value cannot consist in equaling nature's range, b u t does consist in disposing the different values logically. In the methods I have described, however, logical disposition is not at all necessary, the black halo, for example, being most illogical. T h e fact of its surrounding a lighter mass with nothing further to explain it, is sufficient to produce strong relief. More than this, we can get strong relief by using structural values and these flagrantly disobey the laws of light. It is, of course, true that w h e n structural shadows are light in value, as they often are, they produce no more relief than proportionate values, b u t w h e n the light and shade are such that there is much sharp juxtaposition of black or almost black against almost white, the relief is great. Most singularly of all, heavy dark outlines, such as used in Egyptian and still more primitive art produce relief. Some early frescoes and mosaics, even if all their values, save a minim u m of structural values, are inhibited, present as real qualities as any modern, realistic, full-valued work. But when the outlines are pale, realism goes. It is plain to see from all this that relief is not a question of values, although they assist; it is a question of something else, and that something else is the strong and sharp opposition of a light against a dark, independently of whether that dark is a dark value in nature or an "abstraction," as an outline. T h i s is vividness. T h e vivid, as we have seen, effects in consciousness the idea of great vitality, of life, and when consciousness becomes flooded with the idea of life, all other ideas entering it are seen, or rather experienced, through this predominating idea and are given attributes of life and of material which they do not actually possess. It may seem strange that a group of out-

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lines filled in with flat tints should more vividly effect relief than a logical, proportionately valued rendering, but there is no such thing as appearance; nature has numerous qualities but never the one of appearance. Appearance is a fiction of the mind. It is the result of reason juggling with sensations; and it should not be difficult to understand that reason juggling in one manner with a group of sensations, X , and effecting an idea, A, should, by juggling in another manner with a group of sensations, Y, also effect the same idea, A. For example, if reason juggles with the sensations, or rather ideas, of 3 and 4 in a multiplicative manner it effects the idea of 12, but if it juggles with the ideas of 5 and 7 in an additive manner it also effects the idea of 12. I do not believe that this accounts for the whole phenomenon of relief. T h e dictionary defines contrast as "opposition or unlikeness of associated things or qualities, especially as shown by comparison." Turning this into other words and completing the definition, we can say: when associated things or qualities are compared and the comparison shows unlikeness or opposition, what we call contrast is produced; but when the result shows sameness, what we call agreement or harmony is produced. For example, the comparison of water at the freezing point and water at 130 degrees Fahrenheit results in unlikeness; we say one is cold and the other is hot, and not only are they unlike each other, they are opposed. What is not evident in the illustration, or in the definition, is the idea of opposition. Why does that which is unlike oppose? Why does light oppose darkness? Why does noise oppose silence? Why does 2 oppose 3? In fact, does 2 oppose 3? They are unlike, that is true, but does this unlikeness entail any opposition? Is the term opposition not used in a literary manner? Is it not used in a metaphorical sense? If it is true that 2 opposes 3, then we "get a feeling" that everything opposes everything else that is not exactly like itself. What does opposition mean? We shall return to our definition of contrast and analyze it. Comparison, which is the same as discrimination or judgment, is a process of mind, of attention, of the spirit, or, according to

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the materialists, is a physiological adjustment which performs the act of weighing or measuring one quantity or quality against another. And consciousness which may itself be the discrimination or judgment for all we know becomes, or is, aware of the result of the judgment. But the judgment does not, and cannot, and here is the point, compare actual things or qualities; it knows nothing of things or qualities; it only knows of sensations indirectly effected in consciousness through means of the sense organs as affected by the instrumentality of physical stimuli. T h e judgment also knows ideas, which are derived from reason acting on sensations and effecting an interaction of these with each other; but for the moment we will disregard ideas and will try to discover if the comparison of unlike, that is of dissimilar sensations, results in consciousness's experiencing opposition, or what we may call the feeling of opposition. Let us try some experiments. On a sheet of gray paper we lay a black and a strong green square. We compare them. They certainly are unlike. But are they opposed? W e taste sugar, then quinine. They are unlike, but this time we get a vague idea that they are the opposite of each other, that bitter and sweet are somehow opposed. W e compare a white square with a black square and possibly experience a feeling of opposition, possibly not. W e try to compare the sensation of sugar and the sensation of green, but are baffled, confused; there is something which prevents comparison—the idea of comparing them is meaningless, they do not fall within the range of comparison, they are things apart, they belong to different worlds. W e compare a bright electric light with the black night sky. They are unlike, so unlike that they seem to belong to different worlds, and yet, although they produce sensations widely separated in character, we can compare them, and we find that they are unequal quantities of light; and also we experience the element of opposition we have been searching for, and this element of opposition takes the form of a feeling of separation. T h e light and the night, particularly if the light is seen directly against the black sky,

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distinctly and forcefully separate from each other even if they are merely different qualities of the same. We try again to compare sugar and green. They also separate but there is no quality that makes us feel that they have separated out from each other; we cannot conceive that they ever were together; they belong to totally different categories; the judgment refuses to compare them. We try to compare sensations from the category of touch with those from the category of sight and fail in the effort. Touch, however, gives us the sensation of roughness, and so does sound, and judgment can compare the two. Deep musical notes and deep saturated colors have sufficient in common to allow comparison. But if we listen attentively to a deep note and restrain ourselves from lapsing into the world of dreams, into the world of associations, and if we look at the deep color in the same attitude, we recognize that the simple unadorned sensations have nothing in common. A cold, steel-blue color and vinegar effect non-comparable sensations, but we have built up similar associations around each of the two sensations, and these two groups, forming into two ideas, have sufficient in common to permit comparison. Whenever we compare sensations effected by different sense organs, and we do constantly, the comparison is crude; it is between like qualities of the sensations, not between their differences, the differences being so far apart, so separated, that the judgment does not even recognize them. We can compare the sensation effected by swallowing cool Munich beer with the sensation effected by an absolutely smoothly gradated area of color on the basis of smooth flowing, but all the other qualities are so far apart, the opposition, the unlikeness, is so great, that we laugh when asked to compare them. In other words, Munich beer and a smoothly gradated pigment surface have a little likeness but no unlikeness; for qualities which are so far apart as not to permit comparison fall outside of the pale of judgment and are therefore non-existent in the world of like and unlike. Therefore we can say that comparison, judgment, can only function within one category at one time, and as the

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group of categories we are treating of at present is given by the various sense organs, we can say that comparison of sensations can only be made among those that are given by one of the sense organs. This, now, gives us one of the limits of comparison. But there are others. We observed in the comparison between the electric light and the night, although they are within one category, that the difference between the two sensations was so great that we felt a distinct "separating out." This separating out, this break in continuity, this contrast, was so strong that the two sensations might almost have belonged to two different categories. T h e sound of a humming bee on a summer day and the din of hammering iron, although both belong to the category of sound, separate out to such an extent that it is just as difficult to reconcile them as it would be to reconcile the bee's hum and the icy blast of a winter's day. T h e fact seems to be that when sensations are very strong they tend to, and on occasions do, separate out of the category to which they belong. This gives us the basis of sensational opposition of value and color. T h e brilliant electric light and the black night do not hold together, they try to fly apart, and are only prevented from actually separating by reason. When the electric light is dimmed slightly, it still struggles somewhat to separate. And when it is still dimmer, the opposition is still more decreased. And when we come to our black and white squares, the opposition is lessened to such an extent that we scarcely feel it, or rather we do feel it, but we are so habituated to it that we regard it as normal and merely feel a slight strain which blends in with, and forms part of, their vividness. When the black square is grayed the opposition lessens, and it lessens more and more as the square approaches white, but is always there until all unlikeness has been eliminated. T h e meaning of this is that opposition is always present in greater or less quantities, and absolute agreement can only exist when all unlikeness is eliminated. It may now be asked, granting that great contrasts fly apart, why is it that they do so, why do they not contain themselves

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within their own sphere? T h e question takes us deep into the nature and the history of man. In the beginning, the sense organs were not so clearly differentiated as they are today. There may still be some confusion; when the organs are at all strained they work uncertainly, and in addition the element of pain begins to enter. Now, whether the sensation of pain arises from the sense organ itself, or whether it comes from other organs and acts as a protective warning telling us to cease straining, is of no account, for pain always blends into, and becomes confused with, the particular sensation we are experiencing. T h e pain resulting from a terribly loud noise may not come from the organ of the ear at all; it may not be the sound that causes the pain; it may be that the excess of stimuli calls upon the pain organs for the purpose of giving warning that if the organ of hearing continues to be subjected to the stimuli, it will be damaged. Excess of light falling on the retina calls upon the ciliary muscles to contract the iris, and excessive contraction causes the pain. T h e pain of excessive pressure may not be felt in the organs of touch. But consciousness and judgment experience the specific sensations effected by the sense organs and the accompanying pain as being the same. Now, as it happens that the different qualities of pain indirectly achieved by the different sense organs are not so very different from each other; and as they are always present to a slight extent in their weaker, less active, state, in which weak state they act as an excitement, it follows that the sensations proper, those from the organs of sight, hearing, and touch, are not so individual as we assume them to be, and may on occasions separate out from their proper categories and may fallaciously be compared by the judgment. This very sketchy explanation goes further than we require for our present purpose, but since the confusion of sensations transmitted as stimuli by the sense organs is the basis of what literature calls simile and metaphor, and since simile and metaphor, in the hands of great poets, are quite sound, I have extended the explanation. We have seen, some pages back, that light and dark values sharply contrasted effect vividness and relief, and we have

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noted the reasons for the phenomenon. If to those reasons we add that of strong contrasts separating out or flying apart, we shall understand what is otherwise inexplicable that a black outline surrounding an object causes that object to come forward and the background to retire. If the black outline is painted so as to appear to be a part of—that is, melted into the figure—it will come forward with the figure; if it is painted so as to be a part of the background it will retire with the background. Apparently lines in themselves, either dark on a light ground (as on this printed page or in Figure 19) or light on dark (as in Figure 20), tend to come forward, and the more positive they are the more they come forward. Pale gray lines lie closer to the white ground than dark lines, as is shown in Figure 21, and the same is true for the light lines on a dark ground, as in Figure 22. T h i s is the principle which is employed in producing the effect of distance in outline drawings. A n d all of this results from the decision of the judgment to separate out a strong contrast from its surroundings, and as obviously a line cannot move sideways, or up, or down or off the paper or picture or other object it may be lying on, it must move forward or backward. It is impossible for it to move backward, that is inward, without producing the effect of making a hole. It must move forward. But when we come to pictures, which attempt to produce the effect of depressions, of sinking in, as well as of rising, the line is at liberty to take its choice and move forward or backward. T h i s it does at the slightest hint. W e shall now study the matter of color contrast. Can we compare strong green and black? W e certainly can compare vivid green and vivid blue. T h e y seem each to be what is called a color; the two colors are different yet they have a great deal in common. T h e y certainly fall into the same category but exhibit unlikeness and some opposition. T h e result of the comparison of vivid green and vivid blue-green tells us that they fall into the same category more certainly than the blue and the green, that they have much more in common, and much less opposition. But for the comparison of vivid green and vivid red the

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category must be broadened. T h e y have less in common and they strongly separate out from and oppose each other. Vivid green and black seem to have nothing in common, yet, we frequently (unconsciously) compare them, for they are both given to consciousness and judgment by the visual sense organ. T h e difficulty in comparing black and color seems to lie in the comparison of the sensation of experiencing nothing and the sensation of experiencing something. T h e sensations naturally belong to different categories. It is also difficult to compare white and color. We can compare green and black on a value basis, and we can compare any color we choose with black, but the actual color contrast in each case seems to be the same; the color opposition and the color agreement appear to be the same,

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and what we really judge is the relation of the value of the color to the value of the black. We say that chrome yellow and black form a strong contrast, that they are strongly opposed, whereas ultramarine blue and black do not contrast strongly. This feeling of greater or less opposition is because of value, the color element neither opposing nor agreeing. But that in contrasting colors it is not the value element that agrees or opposes may be seen by contrasting vermilion pigment with viridian—diluted with white to the value of the vermilion. If now we try to forget all theory and turn to our color circle and think only of our sensations, we shall note, after sufficient experimentation, that our sensations tell us that the greatest contrast, the greatest separating out, the greatest opposition occurs between colors situated at the extremities of the diameters. For example, orange and blue-green cause the feeling of separating out very strongly, a feeling enhanced by the fact that the orange, through induction, makes the blue-green appear more blue-green, and vice versa. We note that these are complementary colors, and now understand why complementary colors are spoken of as being both complementary and opposed. (According to proper scientific usage, however, the term "complementary color" means such a subtraction from white light as, united with the remainder, produces white.) But bluegreen contrasted with greenish-blue does not create the feeling of opposition, it creates the feeling of agreement, and, because of induction, which in this case produces detraction of color, they appear still more like each other. In popular terms, they do not set each other off. We shall also find that some of the contrasts are pleasing to look at and that others are displeasing. T o avoid confusion I shall distinguish again between color induction and color and value contrast. Color induction is a physiological process which creates a color sensation not warranted by the stimulus falling on the retina. Color induction does not include the idea of opposition. Contrast, although it includes the process of induction, is caused in its essence by a physiological straining of the organ of the eye. If this strain

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did not exist, the element of opposition would fade out of the contrast. But the feeling of straining, of opposition, could exist without induction. Contrast, without doubt, is partly psychological. T h e retina is not its entire creator; it is partly created in mind. Induction, although some of its phenomena may be psychological, is mostly physiological. Color induction and color contrast function side by side, but it is to be noted that when the contrast is strong, the induction seems to disappear, it is overpowered, inhibited. When the contrast is weak the induction asserts itself to such an extent, that unless skillfully handled, it will "muddy" all the colors, cause weakness, and destroy the color scheme of a picture. As we have seen, the use of sharp value or color contrasts or outlines will reduce the apparent induction. On the other hand, a picture painted in strong contrasts and in such a manner as to exclude induction appears over-assertive, aggressive, and brutal. Charm lies in induction, force in contrast. THE WHITE EDGE

When we look from a dark interior out of the window at the bright sky, the edges of the window casement in contact (so to speak) with the sky appear darker than the rest of the casement, and the sky where it juts against the casement, appears to be separated from the rest of the sky by a narrow brilliant line. This undoubtedly is caused by simultaneous induction, the black casement and the light sky inducing their opposite values in each other. But what the theory of induction does not explain is that this super-blackness and whiteness, particularly the latter, should take the form of a narrow line. T h a t induction should lighten the sky in direct proportion to its nearness to the dark casement is easily understood, and that it does this is clearly evident; but that, in addition, it should effect what is unquestionably a bright line seems to require explanation. I have none to offer except the vague one that it may be some kind of physiological conflict in the retina caused by strain or shock at the juncture of two strong stimuli. I do not believe that it is a matter of the action of attention or judgment—

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though it may b e — b u t the application of the white edge to practical painting is so farreaching as even to cause distinction among schools of painting. Hals was a master of the white edge and indulged in it freely. H e would outline his sitters' black hats, where they were silhouetted against light backgrounds, with a still lighter line cutting sharply against the hat and rapidly gradating into the background. H e w o u l d use it at other strongly contrasting junctures. R e m b r a n d t seems hardly to have resorted to it, the light edging which sometimes appears at the contours of his figures in reality being the edge of a patch of light falling on the background, and being part of his chiaroscuro. Michael A n g e l o employed it at times. O n e can distinguish between the faint white edge produced by the contrasts in the picture itself and that which has been added by the artist for the purpose of augmentation. T h e white edge probably is always produced by sharp, sudden contrast, but w h e n the value contrast is small, the white edge effected is too weak to pass the threshold of sensation; therefore, its artificial addition merely accomplishes that which would take place were the contrasts stronger. Stronger contrasts mean greater approach to reality, to life, and because of the laws of association we connect this offspring of strong contrasts, namely the white edge, with the strong contrasts themselves and imagine them to be there. T h e white edge, skillfully introduced where, under conditions of great contrast it might actually exist, accomplishes great vividness and life. T h e white edge also produces luster on a large scale, and it produces relief. It separates a foreground from a background to an astonishing degree. But it does not make the foreground come forward; it sends the background back, eliminates confusion between them, and achieves clarity. T h e white edge and the black outline are sister and brother, but either can be present without the other. T h e white edge does not destroy unity, it does not cut the picture into parts, because if its intention is logically carried throughout the picture, it creates a feeling of unified reality.

COLOR

CONSTANTS—INDUCTION

AND CONTRAST

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OF PAINTING YELLOW

Some painters experience difficulty, when working in oil colors, in keeping yellow "clean," particularly when it is strong. T h e premier coup painting goes all right, but when the picture is painted over several times the yellows grow "muddy." T h e r e are several reasons for this. T h e shadow color of yellow, in ordinary indoor and gray outdoor illumination, is dark yellow—the same color as the light—and on account of the laws of color induction, the light and the shadow do not contrast favorably. In fact, they detract from each other. Red and green do not suffer so much, the shadow color of red being purple, and that of green being bluish-green. T h i s detraction places yellow at a disadvantage as compared with blue and green. Nor is it in painting alone that the yellow suffers. It suffers in nature as well. Our strongest association with yellow is brightness of all descriptions, and when we experience the usual consequence of disappointed expectancy, the judgment pronounces the stimulus to be ugly. When the painter lays bright yellow and its shadow on a light canvas the light of the canvas shines through more or less, causing these colors to appear light, airy, and so on. But when, by repainting, the transparency is lost, "heaviness" of color sets in; and when a third coat of paint is added, in addition to the opacity, the ridges of the underpaintings force through the upper, and an appearance of confusion of intention, muddiness, is created. There are several solutions. (1) T h e yellows can be painted transparently. Frequently this is impossible, for such transparencies may not harmonize with other passages. (2) T h e ridges of the under brush strokes, particularly in the shadows, can be scraped down before the next coat of paint is applied. Here again, if the rest of the picture is not treated in the same manner, a conflict of intentions may set in. (3) W h e n yellow inclines toward green, its shadow is greenish of course; and when it inclines toward orange its shadow is slightly orange. T h e slightly orange yellow with its shadow is more beautiful than the greenish combination. T h i s s