CMYK uses four subtractive colors: cyan, magenta, yellow, and black. Colors are partially or entirely masked on white background. White is natural paper color, black results from full ink combination
RGB red is the brightest possible red on computer monitors. CMYK pigment red is achieved by mixing magenta and yellow in equal proportions. Munsell system specifies colors based on hue, value, and chroma. NCS system uses psychological primary colors based on opponent process theory
Gamut refers to the colors that can be accurately represented by devices. Term originated from medieval Latin "gamma ut" meaning lowest G scale tone. Shakespeare's use attributed to Thomas Morley
Blue can differ in hue, chroma, or lightness. X11 blue is the brightest possible blue on computer screens. CMYK pigment blue is achieved by mixing cyan and magenta. Pantone blue is defined in Textile Paper eXtended color list
Magenta was created in 1859 by Verguin as an aniline dye named fuchsine. The color was renamed in 1860 to honor the Battle of Magenta. A similar color called roseine was created in 1860 by Nicholson and Maule
Photoshop offers three color modes: RGB, CMYK, and Grayscale. Online publishing uses RGB, print uses CMYK. RGB uses 8-bit per channel with values from 0 to 255