(Excerpts from ART HARDWARE: The Definitive Guide to Artists’ Materials, by Steven Saitzyk © 1987)
In an artist-grade paint it is not uncommon to find as many as a hundred and fifty different colors. Approximately one-third of the colors is made using individual pigments in their natural state. Another one-third of the colors is the same pigments chemically or mechanically (grinding) modified to change the color. The remaining one-third is colors produced through mixing two or more pigments together. In lesser grades of oil paint, the color range often consists of only thirty-five to fifty colors, which rely heavily on mixtures of pigments to obtain much of the range.
It is a common misunderstanding among inexperienced painters that most of these colors can be duplicated with the use of a “good red, yellow, and blue.” Although the final one-third of a color line can often be duplicated easily with a palette of colors consisting of one warm and one cool of each of blue, red,· yellow, and violet with some additional help of white and black, the qualities of the other colors cannot be duplicated by mixing. Surface color, or hue, can often be made similar to the other two-thirds of a color line, but depth and brilliance cannot. Secondary (two colors mixed) and tertiary (three colors mixed) colors do not function well as tinting colors, often muddying the appearance of other colors. One example of this is cobalt blue hue, manufactured by some paint companies to simulate the more expensive cobalt blue. While the hue resembles the real thing in surface appearance, it is duller and is opaque, not transparent.
Experienced painters usually try to buy a needed color rather than mix it, and they try to use it in its purest form whenever possible. Consequently, large color lines exist primarily because of the demands of the painter rather than because the manufacturers are looking for something else to sell.