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
Color by coordinates, which in 1931 were also named in global agreement with internationally agreed color names like mentioned above (red, orange, etc.) by the International Commission on Illumination. The RGB color space for instance is a color space corresponding to human trichromacy and to the three cone cell types that respond to three bands of light: long wavelengths, peaking near 564–580 nm ("red"); medium-wavelength, peaking near 534–545 nm ("green"); and short-wavelength light, near 420–440 nm ("blue"). There may also be more than three color dimensions in other color spaces, such as in the CMYK color model, wherein one of the