II
COLOR
We are all born color-blind. The most perfect eyes in the world cannot see one-quarter of the colors which are known to exist in nature. Those of us who are fortunate, it is true, are able to differentiate with reasonable exactness the three primary colors which go to make up our limited human color-scale—but what about the tones which certainly exist above the ultra-violet band and below the infra-red?
For convenience, the full color-scale of nature may be divided into four octaves, of which less than one-quarter is taken up by the prismatic scale of the rainbow, which includes all the colors visible to the human eye. Immediately below the line of infra-red, at the point where the human vision ceases to record color-impressions, there begins a series of vibrations which we can only feel as warmth; and still lower down the scale is another series which the human ear records in the form of sound. Yet we know of a certainty that these vibrations are also potential color-waves, that each note of music carries its own special color-note, whose quality and beauty, alas! may never be known to man, owing to the limited range of his vision.
However, no one can with certainty affirm that this may not be one of the joys that await future generations. Nothing is beyond the range of possibility. Already, by means of the fluoroscope, we are able to extend our vision somewhat, and peer over a little into the realm of the ultra-violet. And, if it is held that a wise providence, at the beginnings of things, limited our sensory nerves to the record of such impressions as were essential to the physical existence of the primal creature, thereby confining our later æsthetic activities to the exploitation of a given range of sensations, a certain regret is nevertheless permissible when one thinks of the bewildering color-feast that might await us in a Wagner overture or a Beethoven sonata. What a fascinating problem it would be, for instance, to work out the color probabilities of some great masterpiece of music, and fling them glowing upon the translucent page of a vast cathedral window. If the time ever comes when man is able, by means of some miraculous transformer, to gaze upon music-color, it is safe to venture the prediction that it will be found to be harmonious and beautiful in proportion to the harmony and beauty of the music upon which it is based.
This is guesswork, of course, but it rests upon a strong basis of probability. Our actual knowledge of the subject is at present limited to mathematics. The velocity of the impulses has been noted and the number of the vibrations has been counted. We know those of sound to be comparatively slow, there being but 4,000 vibrations to the inch in the highest treble note of the piano. Above this on the ascending scale comes a long series of vibrations of which we know little or nothing; and it is not until we reach 36,000 vibrations to the inch that we come again within the range of human sensory consciousness. This number represents the rate of vibrations in the red note of our prismatic scale. The rate of vibration increases throughout the scale until with the ultra-violet it reaches 61,000 to the inch. Here we step out once more into the unknown.
Yet color has no actual existence. It is only by courtesy that we can use the word. Nature is a monochrome save when there are living eyes to see it. The trees are not really green, nor are the flowers red and yellow and blue. Each object simply reflects rays of light which vibrate at a given rate of speed; and these rays, smiting upon the sensitive retina of the eye, produce the impressions which we know as color. Were it not for the retina there would be no color; and when the sensory nerves of the retina are partially paralyzed or deficient, as in the case of the color-blind, nature appears to the eye in her true monochromatic garb.
The human eye resembles closely the photographic camera, both in structure and in its manner of functioning. At the front in both is placed the lens, with its diaphragm to control the quantity of light which enters the recording chamber, this function being performed in the human eye by the elastic iris, which contracts and expands automatically as the light waxes or wanes. At the back of the camera is the sensitized plate, and at the back of the eye is the infinitely more sensitive retina, overlaid by the optic nerve, with its millions upon millions of minute tentacles, reaching out to seize upon every fleeting color and form that passes before the lens. These little transparent filaments (so infinitely minute that the point of the finest needle is like a fence-post in comparison) are divided into two distinct varieties, known respectively as rods and cones. The rods are straight and pointed like needles, and the cones are somewhat blunt at the extremity.
We are told that the number of these nerve filaments reaches the astonishing total of about 137,000,000, of which only 7,000,000 are cones; but it is with this comparatively insignificant number of 7,000,000 cones that we artists have particularly to do. It is the function of the cones to record color, while the needles take care of the light.
If each of us had only received the 7,000,000 cones which are his just due, all would be well. Unfortunately, this is not the case. Nature abhors a duplicate, and no two human beings are similarly endowed in this respect. To the favored few she has given an unfair share of the precious cones, and others she has deprived of their birthright. The fortunate ones are the great colorists of the world, while those bereft are the color-blind.
Now we, as artists, could afford to ignore all this scientific side of the color question, were it not for the fact that it makes clear certain things which it is well for us to know. In the first place, it shows us the futility of any serious attempt to cultivate the sense of color. We are born with a certain given number of color-cones, and with just that allotment we must be content to go through life, for there is no known way of increasing their number, or of augmenting their efficiency. This efficiency may be decreased, however, either by a sudden shock, by paralysis, or by abuse of tobacco. In partial compensation for the depression is born of the knowledge of this ruthless law, is the further knowledge that the artistic personality of a painter must be chiefly credited to the working of this same law—for our sense of color is primarily due to the varying number of color-cones with which each of us is endowed. It is in color, more than in any other artistic attribute, that the temperamental quality of a painter’s product shows itself most clearly.
In more than the strictly scientific sense heretofore noted, color is very closely allied to music. Both are sensuous and passional, playing directly upon the emotions and producing their effects by some mysterious appeal to the subconscious, whose ways have as yet eluded us. Both, in their highest expression, come nearer to the perfect ideal of beauty as felt and understood by humanity than any other form of art. Finally, both are stimulating and mentally suggestive, while attempting no direct intellectual expression; and this is the test of the highest form of art—that it should stimulate the imagination and suggest more than it expresses. This emotional attribute of color is keenly felt even in a work of art as devoid of any intellectual appeal, as a Turkish rug or a Japanese ceramic; but when color is used purposely to enhance and offset some poetic mood of nature, as in a Venetian sunset by Gedney Bunce, or a spring morning by Corot, its poignant charm is overpowering and irresistible. It is hardly necessary to say, however, that it requires the intuitive genius of the master to accomplish this result with certainty.
Those of us who are gifted only with the average, normal color-sense, cannot hope to rise to similar heights; but we can nevertheless learn something from the great ones—if not how to climb the heights, at least how to avoid the pitfalls. Where the color-sense is not infallible, for instance, it is safe to avoid the brilliant tones, to deal in a gamut of quiet and delicate hues. I have a friend who, though color-blind, is a clever and successful painter. His pictures sell well, and I doubt if one of his patrons has ever guessed that he must label the red and the green on his palette in order to tell them apart. Discovering his misfortune only after several years of study, he determined to see if by limiting his palette to the scale of yellows, blues, and grays in which his sight was normal, adding only a little touch of red or green here and there to heighten the effect, he might not still produce creditable pictures. He was, fortunately, a good draughtsman, with a fine sense of the picturesque in his arrangement of mass and values. For his specialty he wisely chose town-scapes and 
From a photograph, copyright 1906, by Braun, Clement & Co.
Anton Mauve—"A Flock of Sheep"
street-scenes, thus eliminating altogether the dangerous problems of the greens; and his success (for he has taken many medals and received many honors) shows at least how much may be accomplished by pure intelligence in the avoidance of insurmountable obstacles and difficulties.
Another useful point that we may learn is the emotional effect of the different colors. The warm colors, the yellow, red, and orange, are always exciting, stimulating, sometimes irritating, and in the end fatiguing. Red, as is well known, always enrages a bull; and in a lesser degree it affects other animals and birds in the same way. A red skirt floating in the wind is the best protection to the poultry-yard, for the chicken-hawk will never approach it. With man the stimulating effect of this color appears to be pleasantly exciting rather than disagreeable when taken in moderation; but did a wrathful deity desire to punish mankind with a specially hideous form of torture, I could imagine nothing more dreadful than that he should change all the green in the world into screaming scarlet. Imagine a bright vermilion world under a brilliant sun, and tell me how long it would be before all the inhabitants would be raving maniacs.
The cool colors—blue, green, mauve, violet, and all the delicate intervening grays—are, on the contrary, restful colors in the emotional sense; and the wisdom of the choice of these tones for the landscape scheme of the world is hardly open to question. Moreover, it is well known to all expert household decorators that these tones are always the most satisfactory for the walls and all large spaces in interior decoration; and that the powerful notes of red, yellow, and orange should come in only as a spot here and there to enliven the effect. If we carry the same idea into the domain of purely pictorial art, we shall see how the restful beauty of a gray-green landscape by Corot is enhanced by the tiny red bonnet of his peasant woman.
While it is, alas! only too true that any personal and individual progress in the domain of color is debarred by physical law, it is nevertheless a fact that in the broad and world-wide sense, most of the progress made in art in the past two centuries has been made in the domain of color. For one thing, we have in the meantime moved out of doors. From the quiet, subdued, and restful light of the studio, we have stepped out into the gay and palpitating sunlight; and in so doing we have had to meet and conquer many new and fascinating problems, problems whose fundamental color-scheme is the reverse of the one which had for a thousand years engrossed the attention of the older artists. In the quiet north light of the studio, illumined only by the sky, the lights were cool and the shadows warm; in the open air, on the contrary, the lights are warm and the shadows cool, for out here in the open the gay yellow sunlight is the source of illumination, while the shadows catch only the cool reflections of the sky. At the present time it is hard to conceive how difficult it was for the first landscape painters to make this simple change in their point of view, how tenacious the old tradition of the studio proved to be, and how very slowly it was abandoned to make room for the simple truths of out-of-door nature. Even after the new law had been fully recognized and accepted, the methods of the older masters were adhered to. So great and true a colorist as Corot, even, continued to "rub in" his shadows in the warm browns of the sixteenth century painters. Of course, this "rub in" was later painted over with the violet and pearl-gray tones of out-door nature, but the brown underlay has begun to "strike through" in many of his pictures, and it may in the end seriously impair some of them. It was not until the "luminarists" came along with their gay and militant iconoclasm that the old tradition was wholly cast aside, and the pearly stream of out-door color at last flowed pure and free and undefiled. And if it happens (as it very well may) that we shall also cast aside the luminarists' patchwork system of prismatic spots and splashes, we shall nevertheless be eternally their debtors in that they freed us from the fetters that bound us to the old system of in-door painting, and gave us a fresh palette of pearl and opal and lapis-lazuli, in place of the old snuff-colored affair of our fathers. Thanks to them, it is not possible for the worst of our modern landscapists to use such distressing color as is to be found in the best of the Hobbemas and Cuyps and Ruysdaels of the sixteenth century.
What developments in the direction of color the future may hold in store for us, it is of course difficult to say. One thing, however, is sure; the mathematics which govern the laws of color will be worked out and tabulated, as have those relating to music; so that it will be possible and easy for any one, either expert or layman, to produce a harmony in color by the simple application of the prescribed formula. But beyond this the mathematicians' contributions to art will have little value. Its direct benefits will be found to be negative rather than positive. While it may prevent the perpetration of jarring discords, it will hardly make possible the creation of masterpieces; for here again the personal equation comes into play. Lacking the note of personality, no real art is possible. A musician of my acquaintance, having discovered that when the law of mathematics was applied to a sonata by Beethoven, the theme worked out faultlessly to a seemingly inevitable conclusion, decided that the process could be reversed, and that a given theme, if correctly figured out, would undoubtedly produce a musical number of faultless beauty. He put his theory into practice and made a sonata according to this system. His production was impeccable—and absolutely worthless. When will the world learn that art can not be manufactured?