CIE Chromaticity Diagrams

CIE chromaticity diagrams graphically present color and luminance information on specific electronic displays. The chromaticity coordinates for a display can be obtained by direct measurement using a colorimeter or from the display manufacturer. The white created by a display can be obtained either from the manufacturer or by driving each primary to its maximum and measuring the resulting "white" with a colorimeter.

The horseshoe shaped line is termed the "spectrum locus." All pure spectral, visible wavelengths lie on this line. The line which closes the horseshoe shape is termed the "purple line." All pure purples lie on this line. All colors that can be humanly perceived lie within this shape. A color plotted closer to the center is more desaturated, that is, contains more "white." All colors that can be created by mixing two colors lie along a line between those colors.

Any color can be defined by its Tristimulus values (X, Y, Z) or chromaticity coordinates (x, y, z). "White" lies at or near the middle of the enclosed figure. Mathematical formulae are used to convert between x,y,z values and XYZ.