The Three Primary Colors
The three spectrum colors yellow, red, and blue are equidistant from one another on the color wheel. To help you visualize and recall their positions, keep in mind that they can be connected by an imaginary equilateral triangle within the circle (Figure 3-2). These three colors are the basic building blocks of color for the artist; they are called "primaries" because you must have them to start with. You cannot make spectrum yellow, spectrum red, and spectrum blue by mixing any other pigments.
Theoretically, all other colors—up to sixteen million or more—arc mixable given just these three spectrum hues. In practice, however, the chemical limitations of the
- Fig. J-2- Notice that the three primaries are connected by an equilateral triangle within the circle.
Fig. 3-3. Cyan, yellow, and magenta: the three primary colors of printing.
Fig. 3-3. Cyan, yellow, and magenta: the three primary colors of printing.
To complicate color even more, the three primary colors of light (the so-called additive colors) are green, red, and blue. Perception expert Carolyn Bloomer explains:
"Additive colors apply to computer and video images and to theatrical lighting. The screen of a color TV or computer monitor is made up of tiny dots of light (called phosphors) grouped in red/green/ blue sets (known as pixels). The phosphors emit colored light when excited by electrons; the amount of light emitted depends on the number of electrons striking it.
Varying the red, green, and blue combinations of phosphor excitement within the pixels can produce a full range of colors. You can see the pixels on a TV or computer screen by looking at it through a strong magnifying glass."
Bloomer, The Principles of Visual Perception pigments themselves undermine this theory, illustrating, incidentally, one of the ways that actual practice diverges from theory. As you will see below, artists' colors are not necessarily true spectrum colors. Trace chemicals, especially in the red and blue pigments, reflect light rays other than single, pure wavelengths, causing problems in mixtures with other pigments. Therefore, artists must supplement the three primaries by buying additional pigments whose chemical structures do yield clear hues in mixture.
At this point, I will digress for a moment to make note of an argument that has been going on for many years: whether there exist three primary pigments for painters that work as well as the primary inks, dyes, and chemicals used in printing and dyeing. Those primaries are cyan, a deep greenish blue, yellow, and magenta, a brilliant purplish pink, and they reflect the pure spectrum wavelengths without distortion (Figure 3-3). Cyan, yellow, and magenta are aligned with the physiology of human color perception and, in printing, yield all colors from just those three. Life for the painter would be much simpler with readily available, fade-proof, reliable, nontoxic true spectrum primary pigments, especially in oil paints, watercolors, and acrylics, from which all colors could be derived.
So far, it hasn't happened. True, you will find many art materials catalogues listing "Spectrum Cyan," "Spectrum Magenta," and "Spectrum Yellow." I've tried these pigments, and in every case, have returned to the traditional palette of colors I list for you in chapter 4. Later on, you may want to try these spectrum colors if you are curious, and you may find pigments that give better results than I was able to achieve.
I have no doubt that chemists will eventually suc-cecd in formulating true red, yellow, and blue pigment primaries. For now, however, our only true pigment primary is among the yellow pigments. Because of limitations in red pigments, the artist needs two reds to start; among our blue pigments, there is no ideal primary blue.
Fig. 3-5. The six tertiary colors.
Fig. 3-4. The three secondary colors are connected by an upside-down equilateral triangle. Together, the primary colors and the secondary colors form a six-sided star.
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