Traditionally, painters use a color wheel whose primary colors are red, yellow and blue. The history of the color wheel is interesting. In the mid-eighteenth century, Isaac Newton’s experiments with prisms resulted in the theory that red, yellow and blue were the primary colors. Color theory no longer supports the concept that all other colors can be mixed from these primaries.
At the time of the impressionists, some innovative theory on color was being developed. Chevreul was establishing a color wheel and Rood had just published a work on the theory of color in 1881. The Impressionists (and Neo-Impressionists) adopted these theories and arranged their palettes according to the chromatic tables furnished by the physicists. Following the theory that light, broken up in a prism, gives off seven colors, they adopted these seven colors on their palettes. They excluded black. Duranty, a prominent writer of the time, felt that this handicapped them. Unlike the "true" Impressionists, Mary Cassatt, Edgar Degas, and Edouard Manet did not exclude black. (By the way, another innovation that changed the way painters painted at that time was the rise of a new guild, the colormen [vendors of color], who manufactured ready-mixed paint available in tubes. That made it possible to paint “au plein aire” [outdoors] and introduced a number of new colors.)
To understand color as an artist, it is useful to understand the concept of “gamut.” A gamut is defined as the full range or compass of something; a range from one extreme to the other. If you look around you, the “gamut” of colors in your environment is all the colors that your eye can easily distinguish. When you take a photograph, because of the print process, the gamut of colors produced in the photo is somewhat reduced. You may have noticed that the gamut of colors captured in a cell phone camera is very much less than those you see. The gamut of colors produced by traditional 4-color printing (used to produce magazines, posters, and the “lithograph prints” that some artists charge a bundle for) is limited by the fact that the printer uses only yellow, magenta, cyan and black in the press. High-end fashion magazines or companies with a particular logo that MUST be a specific color will tell the printer to use a “Pantone” color in addition to the 4-color printing. (“Pantone” colors are precise mixtures of color that produce an exact color when printed.) Modern flat bed inkjet printers are somewhat better at reproducing a wider gamut because they have 6 or 7 inks. Some painters have worked with silkscreen printers because the prints they produce are not limited in the amount of costs, but this is a very costly reproduction process.
I'll continue this discussion in the next post.