Chromaticity diagram
From The Glossary of Digital Photography
A diagram of chromaticity derived from the CIE 1931 XYZ color space developed by the CIE in 1931. This color space is the standard reference for defining colors. The diagram is based on measurements of human metameric color matching. Taking into account the way that human vision works, it causes the graphing of the color space to be a three-dimensional figure. The chromaticity diagram consists of the plot of hue and saturation at a constant and maximum intensity. It is a veritable slice through the three-dimensional color space. See also chromaticity; color space
