The additive color primaries are red, green and blue. Together they make 'white', which varies considerably with the type of illumination and the ratio of the primaries. Light behaves in an additive manner, as do computer monitors and other color displays.
Scanners and digital cameras use red, green and blue sensors to separate images into their component colors.
Additive color describes the color of light. Combined in pairs, the colors created are yellow, cyan and magenta. Combining the three primary colors creates white light.
LAB
Short for CIELAB, this color space is used for color calculations in color management systems. CIELAB has the advantage of being 'perceptually uniform' which makes mathematical calculations more efficient. It is possible to convert and save images in LAB color, and some scanners produce images in LAB color.
CMYK
An abbreviation for Cyan, Magenta, Yellow and blacK, this is the 'process color' system which yields color images on printers and printing presses. CMYK is called 'subtractive' because the colorants (typically ink or dye) act as filters to white light, removing components of white light to create colors.
Subtractive color describes the color of inks. The complementary colors are red, green and blue. Combining the three primary colors creates a brown-black.
Some printing devices, including the , have an extended-gamut color set which includes two cyan colorants and two magenta colorants. These pairs of cyan and magenta colorant sets make possible smoother gradations and larger color gamut for simulating spot colors (Pantone colors, for example). The abbreviation CMYKcm is used.