Shades of blue pigment blue, is the tone of blue that is achieved by mixing process (printer's) cyan and process (printer's) magenta in equal proportions. It is displayed at right. The purpose of the CMYK color system is to provide the maximum possible gamut of color reproducible in printing by the use of only three primaries. The color indicated is only approximate as the colors of printing inks may vary. The color defined as "blue" in the NCS or Natural Color System is an azure-like color shown at right (NCS 2060-B). The Natural Color System is a color system based on the four
Secondary color secondary CMY colors (with secondary colors in boldface) are: Ideally, combining three perfect primary colors in equal amounts would produce black, but this is impossible to achieve in practice. Therefore a "key" pigment, usually black, is added to printing to produce dark shades more efficiently. This combination is referred to as CMYK, where K stands for Key. Before the discovery of CMY, at least as far back as Goethe, the best primary colors were thought to be red, yellow, and blue. Mixing these pigments in equal amounts produces orange, green, and purple: That is, the primary and secondary RYB colors