Color Spaces, Part 1.
by eduardoangel – June 24th, 2009
By Eduardo Angel
A color space is an abstract mathematical model describing the way colors can be represented with numbers. For example, Adobe RGB and sRGB are two different absolute color spaces, both based on the RGB model. Although several specific color spaces are based on the RGB model, there is no such thing as the RGB color space.
RGB uses additive color mixing, because it describes what kind of light needs to be emitted to produce a given color. RGB stores individual values for red, green and blue. A particular RGB color space is defined by the three chromaticities of the red, green, and blue additive primaries, and can produce any chromaticity that is the triangle defined by those primary colors. The complete specification of an RGB color space also requires a white point chromaticity and a gamma correction curve.
CMYK uses subtractive color mixing used in the printing process, because it describes what kind of inks need to be applied so the light reflected from the substrate and through the inks produces a given color.
Color space conversion is the translation of the representation of a color from one basis to another with the goal to make the translated image look as similar as possible to the original.
Working color spaces, like Adobe RGB, are device-independent and define the set of colors available to work with when editing images in applications like Photoshop.
A device color space simply describes the range of colors, or gamut, that a camera can see, a printer can print, or a monitor can display. We will talk about which color space to use and when in the next post.