Shades of green color standard is displayed at right. It is the color called green, low green or medium green in many of the older eight-bit computer palettes. Another name for this color is "green W3C". This is the X11/HTML color "dark green". The color defined as "green" in the CMYK color system used in printing, also known as "pigment green", is the tone of green that is achieved by mixing process (printer's) cyan and process (printer's) yellow 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
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