A color produced through the addition of light of various colors. In theory, every color can be produced by mixing the primary colors of the visible light spectrum: red, green and blue (RGB), as the color vision of the human eye works through red-, green- and blue- sensitive sensory cells. RGB is the usual additive color system and is used predominantly for television screens, computer monitors and scanners. Combining two of the primary colors in equal parts produces the secondary colors cyan, magenta and yellow, which in turn form the basic colors of the subtractive color system (CMYK).