Primary color

Primary colors are sets of colors that can be combined to make a useful range of colors. For human applications, three primary colors are typically used, since human color vision is usually trichromatic.

For additive combination of colors, as in overlapping projected lights or in electronic visual displays, the primary colors normally used are red, green, and blue. For a subtractive combination of colors, as in mixing of pigments or dyes for printing, the colors magenta, yellow, and cyan are normally used. However, red, yellow, and blue are commonly used as primaries when painting or drawing. See RGB color model, CMYK color model, and RYB color model for more on these popular sets of primary colors.

In an additive system, choices of sets of primary colors are nearly arbitrary, subject to weak constraints from the spectral sensitivities of each of the human cone photoreceptors. An early color photographic process, autochrome, typically used orange, green, and violet primaries. However, unless negative amounts of a color are allowed, the gamut will be restricted to the color triangle defined by the choice of primaries.