Colorspaces

A colorspace is a mathematical model that describes how colors can be represented as numerical coordinates. It defines a gamut, the set of colors that can be represented, along with a white point and a set of primaries used to generate colors.

Many colorspaces are device-dependent, meaning their numeric values depend on a particular device. RGB is the dominant example for displays, defined by three primaries and a referenced white point. CMYK is commonly used for printing, with four subtractive primaries. These spaces are suited for producing colors on their respective devices but do not guarantee cross-device consistency.

Device-independent spaces aim to describe color in a way that is not tied to a device. The CIE XYZ space provides a perceptually based reference, while CIELAB and CIELUV are designed to be more perceptually uniform. Perceptual models like CIECAM02 predict appearance under different viewing conditions, enabling more consistent color comparisons across devices and lighting.

Other widely used spaces include HSV and HSL, which map color to hue, saturation, and value or lightness for convenient color selection, but they are not perceptually uniform. Video and image data also use YUV or YCbCr, which separate luminance from chrominance for efficient transmission and processing.

Linear light spaces use linear values to simplify color computations; most computer color spaces are gamma-encoded (nonlinear) to match human perception. Gamma correction, gamma curves, and linearization are standard steps when processing colors.

Color management systems rely on profiles (ICC profiles) to translate colors between spaces and devices, attempting to preserve appearance. Transformations may involve primaries, white points, gamma, and chromatic adaptation to different illuminants, with potential gamut limitations.