Color Systems

There are at least three color systems worthy of more than a few passing comments: Chevreul's System, Munsell's system, and Rood's system. Chevreul was drawn into a study of color soon after his appointment to the royal tapestry workshops in Paris. The Gobelin weavers, from about 1660, had been trying to emulate Renaissance and Baroque realism in considerable detail. This required a full range of colors in every possible variation of value and intensity, light to dark, strong to weak. The opposite had been the case during the fourteenth and fifteenth centuries in France and Flanders, and earlier still. In the tapestries at that time, as few as 8 to 10 warps [the lengthwise yarns] were used to the inch as supports for the interlacing wefts of little more than 6 to 8 strong hues. By the time Chevreul was called upon the scene, as many as 25 to 40 warps were being used to the inch and literally hundreds of hues for realistic/naturalistic renderings.

Chevreul's duty as dye chemist was threefold: to find ways of dyeing yarns in an unprecedented variety of colors and "tones" of colors; to dye them with dyes that were reasonably fast [nonfading]; and to find a way of classifying them. His duty turned out to be four fold: He soon discovered that, in a given patch of fabric woven of two or more colored yarns, or in neighboring areas of contrasting colors, something appeared to happen that went beyond the dyes he had been hired to solve. Colors seemed to be influencing one another in a way that involved perception itself. Something, as yet unexplained, was happening in the eyes of the beholder. Chevreul's discoveries would certainly be of great value to the Impressionists 30 years later, and especially in the early 1880s, to Seurat and other Neo-Impressionists whose way of placing colors side by side in small points [pointillism] owed much to Chevreul and even more to Ogden Rood. Their divided colors were treated very much as flecks of color in woven materials.

Chevreul set himself the task of finding out what colors do to one another in the very seeing of them. He hit upon very simple empirical experiments. He would stare at areas of different colors--one at a time--and the strange glow each one left when removed from view. These afterglows were described as the psychological opposites or complementaries of each of the stimulus colors. These afterimages, he reckoned, caused all colors in color schemes [and especially in small areas] to affect one another, caused one another to appear lighter or darker, stronger or weaker, or to shift in hue, each toward the other's complementary; hence Chevreul's law of simultaneous contrast. Only in the case of true complementaries in full intensity and in juxtaposition does there appear to be no mutual change of hue; instead, a mutual intensification. Chevreul contrived a color circle of twelve complementaries [clockwise from the top]: green/red, yellow-green/violet-red, yellow/violet, orange-yellow/blue-violet, orange/blue, red-orange/green-blue.

Like most color theorists, Chevreul went on to become expert and adviser to artists in matters pertaining to harmony. His principles of harmony were of two main types: [1] Harmonies of Analogous Colors, that is, harmony of slight variations of the same hue [monochromatic colors] and harmony of neighboring hues [say, orange-red and red], equalized in terms of value and strength; and [2] Harmonies of Contrast, which includes harmony of two contrasting hues, equalized as to value, harmony of two neighboring hues modified in tones of different heights or values, and harmony of complementary hues [again, in tones of different values, if desired]. Then Chevreul explained how these could be applied to painting, to clothes and interiors, to the planting of flowers for lively effects, and so forth.

Albert H. Munsell [1858-1918], born in Boston, studied painting in Europe in the heyday of Impressionism, and seems not to have been the least bit aware of the fact! Nevertheless, his interest in color and color systems commenced early. His Atlas of the Munsell Color System was published in 1915, some time after he had begun work on a three-dimensional model of color. It has proved to be the best standard method of specifying the color of surfaces, and therefore of great value to paint chemists and manufacturers. Several hundred rectangles of colors are arranged according to three dimensions or attributes of color: hue [dominant wavelength or chromatic identity--red, green, yellow, and so forth], value [lightness/darkness factor], and chroma [relative strength, purity, or saturation].

The three dimensional representation of the system is a very attractive form called the Munsell tree. In this ingenious construction, the value of a color is indicated by its position on the vertical axis or trunk of the tree, this being an achromatic scale that ranges from black at the bottom through gradations of gray to white at the top. Five basic hues [red, yellow, green, blue, purple] and five intermediate hues [yellow-red, green-yellow, blue-green, purple-blue, red-purple] take their places around the trunk according to their natural order-yellow "leafing out" near the top and purple-blue near the bottom. Each hue asserts itself horizontally from its position on the trunk, and, as it does so, it expresses, in a regular stepwise manner, increments of chroma from dull to bright. For example, a manufacturer of dyes in Chicago could respond accurately to an order for 50 grams of turquoise should both he and his client in Atlanta make use of their Munsell charts. The order may read like this: "50 grams of 7.5 BG 5/6."

Munsell's complementaries are as follows: red/blue-green, yellow-red [or orange]/blue, yellow/purple-blue [or violet], green-yellow/purple, green/red-purple [or crimson]. Although his system, embodied in the Munsell tree, does acknowledge the natural order of colors and gives us attractive and memorable images and models, it ends up being too pat, too left-brain, for most artists. We can be thankful for the terms hue, value, and chroma, and for more sober names for colors, but the rest is good mainly for the very purpose it appears to have found over the years: the standardization of colors.

Ogden N. Rood, the American color scientist, was most admired as a teacher and experimentalist. Rood also studied painting in Germany and continued to paint throughout his life.

As an artist, Rood knew the works of Turner and John Ruskin. Like the Impressionists, he considered Turner to be the painter-colorist most worthy of careful study. As a scientist, he was acutely aware of the theories of Newton, Young, Goethe, Chevreul, von Helmholtz, and Maxwell. Moreover, he had at his disposal the most recent optical instruments for studying the additive and subtractive properties of colored lights, colors and their complementaries, reflected or transmitted colors [pigment colors], the effect of various lights on pigments, retinal blending, and the like. His technique of flicker photometry for comparing the brightness of colors was considered an important contribution to the science of color. He was able to explain a number of misconceptions about a color and color vision, and among other things, he proposed a different alignment of complementary hues from those of Chevreul, Charles Blanc, and David Sutter. Rood's books were known by Seurat. Evidence of this fact was found among Seurat's personal papers: his copy of Rood's contrast-diagram of 1879. [William Innes Homer, Seurat and the Science of Painting [Cambridge, M A: The MIT Press, 1964; paperback, 1978] pp. 20-48, see also Ogden N. Rood, Modern Chromatics Students' Text-Book of Color with Applications to Art and Industry. Preface, introduction and commentary notes by Faber Birren [New York: Van Nostrand Reinhold, 1973].

Of special importance was Rood's recognition of the natural order of colors--it will be noted that yellow ,the lightest of all colors in its pure and natural state, is placed at the top of his color circles. So keen was his sensitivity to color in both the laboratory and the studio, his respect for certain artists, and what one may refer to as the experimental approach, that he would seem destined to be the color theorist for all colorists since the 1870s, for all artists interested not just in "optical painting," but in color as energy. Modern Chromatics, written for both physicists and artists, came to be known as "the Impressionist's Bible," although Rood doesn't seem to have known about Impressionist painting until after 1879. Ironically, when he did discover it, he didn't like it! He is reported to have said: "If that is all I have done for art, I wish I had never written that book."

Rood's psychological wheel and wheel of the natural order of color combined was given an added function for colorists by H. Barrett Carpenter through his discovery of the principle of Discord. [Again, it was probably Rood's despised Impressionists who hit upon discord and made the most dazzling use of it.]

Color is happily doomed to straddle the fence between art and science. This can be exciting. It is when the question of color harmony arises that Rood, like Chevreul and Munsell, is not very helpful, scientifically or artistically. He [and they] recommend pairs and triads and other "acceptable," "pleasing" combinations of colors [blue and green together are "bad"], most of which are of little more than academic interest to artists and designers of the twentieth century.

Chevreul, Rood, and Munsell, however much they differed on details, seemed to be in agreement on one point: Artists require color theory. I would add, on behalf of many artists, that this is true, but would insist that color theory need not aspire to be an exact science so much as it needs to be clear, sensible, and practical, and especially that it not try to "program" artists in matters pertaining to esthetics, style, and expression.

If, at the moment, the reader is not certain what there is to be gained of a practical nature from these and other systems, he or she may wish to refer to them for some understanding of the physics of color [especially if there is a desire to work with luminous color or colored light--neon and the like], which , along with the psychology of color, underlies its use. The following excerpts from a beautifully illustrated article on color, which appeared in Life Magazine on July 3, 1944, is recommended: Color begins with light. The sensation of color is aroused in the human mind by the way in which the eyes and the brain centers of sight respond to the waves of light which bear the world in on our perceiving consciousness. The perception of color is, therefore, a highly personal experience. It is influenced by association and aesthetic preference, by fatigue, by sharpness of vision and by color blindness. Yet for all human eyes, the perception of color is linked firmly to physical reality and depends first of all on the nature of light.

The waves of visible light are a narrow band in the known spectrum of radiant energy. This spectrum moves from the invisible, miles-long waves of radio through infra-red waves of heat across the visible wave lengths of color the invisible ultra-short ultraviolet waves and on out to the infinitely short waves of cosmic rays. Within the visible spectrum, light waves themselves vary from 700 millimicrons [billionth of a meter] to 400 millimicrons in length. When a beam of white light is dispersed by a prism and separated into its component wave lengths . . . . it is seen at once that each of these wave lengths stimulates a different color response in the human eye.

The colors that compose into visible white light are shown in greater detail in a spectrogram of solar light [in one of the technical illustrations accompanying this article]. The major colors which the eye can discriminate in this gamut are red, yellow, green, blue and violet. White is the total addition of color. It is perceived when a surface reflects all colors equally. Black is the total subtraction of all color. It is perceived when a surface absorbs all colors equally. White and black are exceptions in nature. The rule is the partial absorption and hence subtraction of a band of color from the spectrum and the reflection or transmission of the rest. The mixture of the reflected or transmitted spectrum colors is the color of an object.

All colors, even the pure colors of the spectrum, can be produced by mixture. There is one class of colors, called primaries, which perform this operation most efficiently. Despite widespread misconceptions to the contrary, the primary colors of light are red, green and blue. These three colors are related directly to three response factors in the mechanism of human vision about which nothing is known except that they resolve mixtures of wave lengths into mixtures of cloors. They can be produced by mixture only when they are themselves components of the mixing colors. When added in pairs or altogether in equal or unequal strengths they produce all of the possible colors, including the mixtures of red and blue [the purples], which do not appear in the spectrum, and white. In fact, for all practical purposes in color mixture, white light may be defined as a mixture of red, green and blue. [Perhaps the most helpful and interesting book on matters of a "technical" nature having to do with light, color, and color perception is Harold Kuepper's The Basic Law of Color [Woodbury, NY: Barron's Educational Series, Inc., 1981.]

Most artists and designers are likely to feel that there is little need of a technical understanding of colored light and the peculiarities of additive and subtractive mixing. They are likely to be more involved with paint and the peculiarities of paint, or pigment, mixing. Instead of working with colored lights, prime colors, they work with what is called reflected or transmitted colors. Such colors, except in very special circumstances, never begin to approach the energy of colored lights. For instance, no paint mixture can ever "add up" to white, least of all white light [natural or artificial]. On the contrary, each component will subtract some color from the others--the more colors stirred together, the more they will cancel one another toward a murky gray. All pigment mixtures are subtractive, partially or totally. Other factors are involved also, including the nature and quality of what is referred to as the vehicle, the binding agent [oils, waxes, gums, water, acrylics, and so forth], and the nature and quality of the pigments [from dye colors to various oxides and other metal compounds, to minerals and clays], emerging in the form of oil paints, watercolors, acrylic paints, crayons of many types, pastels, colored pencils, inks, and the like. Most artist still create within the limitations of these familiar pigment colors, as musicians compose within the range of the sound spectrum and the capabilities of traditional instruments--unless choosing to be composers of electronic or computer music, wherein other kinds of limitations may also appear. The two groups of artists who sought to escape the limitations of pigment colors were the Impressionists and the Neo-Impressionists [once referred to as the Chromo-luminists, Seurat and his friends], as mentioned earlier. They did so by placing carefully chosen and adjusted colors on the canvas in small strokes, scumbles, dabs, commas, in such a way as to force paint colors to behave, as much as possible, like light colors and, thereby, act upon the color receptors in the eye as light does.

Whereas the Impressionists seem content with partial fusion in the eye of the viewer, the Neo-Impressionists, through intensive study of color physics, color psychology, the theories of Chevreul and Rood, Delacroix's way with color, and much experimentation, sought a method and technique that they hoped would guarantee almost total fusion at a proper distance. If their aim was color as luminosity; and, even if their goal was never quite realized, they did produce some very lively, eye-filling paintings. Their message to us is that we should never cease to question and explore whatever it is that makes colors vibrant at least--whether it be the result of certain combinations of hues, the way they are combined, or the way they are applied, whether in small patches or broadly, thickly or thinly, in diaphanous layers, and so on.

Whether in the interest of luminosity or of color [hue], as such, of color as intensity [degree of vibrancy], artists still rely primarily on colors given off from pigments and surfaces [and pigments are really surfaces]. The material quality of these substances [rough, smooth, soft, hard, transparent, translucent, opaque, wet, dry], the intensity, hue and direction of the light playing upon them or through them, the way they take the light [the way fabrics take light, as opposed to the way a baked enamel surface or a wet pebble or a dry pebble takes light]--all of these affect colors greatly. Yet to say that the artist is concerned with color, as though it were a physical fact, is putting matters too vaguely: He or she is concerned with affect as well as effect, there being a difference between color as physical fact [something out of a tube] and color as perceived fact [what one actually perceives there in the design]. For artists, this is merely the beginning, because color is the most enigmatic element in art, always revealing itself to the observer in a state o mutual action or interaction--meaning that we almost never see a color alone in the same light, or without an environment. Place any color, successively, in two or more different lights [warm or cool, strong or weak, direct or indirect] and/or against any background, and observe what happens to it. [It makes one understand why artists of any earlier generation valued a studio with a "good north light."] [pp. 86-90]