Many color systems have been developed throughout history, including those developed by Tobias Mayer (1758), Johann Goethe (1810), and M.E Chevreul (1864). (For more information about the history of color systems.
The color wheel taught to most people today is the twelve hue color circle developed by Johannes Itten. This color wheel is based on a triadic mixture of pigments with red, yellow, and blue as the primary triad. All hues are formed from mixtures of equal or unequal amounts of primaries. Equal mixtures of two primaries result in the secondary hues and form the triad of green, orange, and violet. In this color wheel, six intermediate hues are created by equal mixtures of primary and secondary colors and form two more triads. (Intermediate colors vary greatly because of the infinite number of unequal primary and secondary mixtures). When mixing pigments, color mixture is described as subtractive. When white light (or sunlight) hits a surface most of the light energy is absorbed. We perceive only the color that is reflected from the surface. In this situation, the part of the spectrum that is absorbed is "subtracted" from white light.
In theory, equal mixtures of subtractive primaries should result in black, however, when mixing red, blue, and yellow primaries together, the resulting mixture is more likely to be gray, brown, or greenish. The Itten color wheel works well as a chart, but is flawed as a practical guide for the actual mixtures of pigments. The primaries used in this color wheel are somewhat inaccurate. Moreover, pigments in paint vary greatly in opacity and undertones, and it is difficult to create pure secondary and tertiary hues from primary mixtures. Mixed colors tend to become dull, therefore, if you want intense or saturated color, purchasing pure tube colors is best.
ITTEN'S TWELVE HUE SUBTRACTIVE COLOR WHEEL
Additive color mixtures pertain to the properties of light and were first explained by Isaac Newton. We form all colors of light by adding combinations of colors from the spectrum. When all the separate color wavelengths of light are mixed together, the result is white light. Likewise, if white light is separated into distinct wavelengths of color using a prism or water particles in the air, for example, the result is a spectrum or rainbow of colors.
The primary colors of light are red, green, and blue (RGB), and are used to create the colors on your television screen (or computer monitor). For more information about color used in television and video, click here. Or go to: (http://home.att.net/~RTRUSCIO/COLORTV.htm)
Equal mixtures of additive primaries result in white light. When blue and green light are blended they form "cyan", the complement of Red. When red and blue light are blended, they form "magenta", the complement of Green. When green and red light are blended, they form "yellow", the complement of Blue.
Commercial printers use inks based on a color wheel comprised of Cyan, Magenta, and Yellow as the primaries. This subtractive color wheel accurately matches printing colors to the corresponding (complementary color) dyes used in color film negatives. The foundation of modern color photography (go to: http://home.att.net/~RTRUSCIO/PHOTOG.htm) is based on this set of primaries and secondaries. In color films, such as Kodacolor, the dyes used in the film negatives are complementary to the colors printed on the paper positive. (The orange cast of a color negative is used to correct deficiences in the color dyes which do not filter light uniformly). The complementary colors of cyan, magenta, and yellow are red, green, and blue (RGB). The primary and secondary colors in the CMY subtractive color wheel and the RGB additive color wheel are the same.
CMYK inks are referred to by printers as "process" colors (the "K" stands for black). An additional printing of black is usually done over CMY, because equal combinations of CMY inks do not produce pure black (because of variations in pigments and transparencies) and can be costly when used in abundance. Printmakers in the fine arts also use process Cyan (turquoise), process Magenta (rose), and process Yellow as primaries, because these three particular primaries create a full range of fairly pure secondary and intermediate colors.
Although the CMY secondaries are red, green and, blue, these color mixtures in pigment do not have the same intensity as their additive counterparts. Pigments tend to become dull when mixed, especially as the proportions of the primaries become more equal. Transparent inks, however, allow light to be reflected from the paper's surface through the inks, creating more luminosity than opaque color.
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