Subtractive color

Subtractive color or subtractive color mixing predicts the spectral power distribution of light after it passes through successive layers of partially absorbing media. This idealized model is the essential principle of how dyes and pigments are used in color printing and photography, where the perception of color is elicited after white light passes through microscopic "stacks" of partially absorbing media allowing some wavelengths of light to reach the eye and not others, and also in painting, whether the colors are mixed or applied in successive layers. The subtractive color mixing model predicts the resultant spectral power distribution of light filtered through overlaid partially absorbing materials on a reflecting or transparent surface. Each layer partially absorbs some wavelengths of light from the illumination spectrum while letting others pass through, resulting in a colored appearance. The resultant spectral power distribution is predicted by sequentially taking the product of the spectral power distributions of the incoming light and transmissivity at each filter. The subtractive model also predicts the color resulting from a mixture of paints, or similar medium such as fabric dye, whether applied in layers or mixed together prior to application. In the case of paint mixed before application, incident light interacts with many different pigment particles at various depths inside the paint layer before emerging. Art supply manufactures offer colors that successfully fill the roles of the subtractive primary colors magenta and cyan. For example, the phthalocyanine blues, which became available during the 1930s, and quinacridone magenta, first offered during the 1950s, together with yellow produce more highly-saturated violets and greens than do the traditional red and blue. RYB color model RYB (red, yellow, blue) is the traditional set of primary colors used for mixing pigments. It is used in art and art education, particularly in painting. It predated modern scientific color theory.