These x and y are used because of simplicity of expression in CIE 1931 (see below) and have no inherent advantage. These pairs determine a chromaticity as affine coordinates on a triangle in a 2D-space, which contains all possible chromaticities. This presentation is a projective transformation of the CIE 1931 chromaticity diagram above.

( uвЂІ, vвЂІ), the chromaticity in CIELUV, is a fairly perceptually uniform presentation of the chromaticity as (another than in CIE 1931) planar Euclidean shape.

For example, the white point of an sRGB display is an x, y chromaticity of (0.3127,вЂ‰0.3290), where x and y coordinates are used in the xyY space. Some color spaces separate the three dimensions of color into one luminance dimension and a pair of chromaticity dimensions. The property ' hue' is as used in general color theory and in specific color models such as HSV and HSL color spaces, though it is more perceptually uniform in color models such as Munsell, CIELAB or CIECAM02. Purity is roughly equivalent to the term ' saturation' in the HSV color model. The hue is the angular component, and the purity is the radial component, normalized by the maximum radius for that hue. In color science, the white point of an illuminant or of a display is a neutral reference characterized by a chromaticity all other chromaticities may be defined in relation to this reference using polar coordinates.

Chromatic paint