A two-dimensional plot, most often the CIE 1931 x, y diagram or the CIE 1976 u', v' diagram, in which pure spectral colors form the curved horseshoe edge and all mixtures fall inside. The blackbody line, along which white light sources are rated, runs through the middle. Designers use it to see where a source's white point sits, how tightly fixtures are binned and what range of colors an RGB system can mix.
Plot all six samples on the chromaticity diagram, I bet the odd one is sitting way above the blackbody line.
Also heard as
- CIE diagram
- CIE 1931 diagram
- horseshoe
Related terms
Chromaticity
Where a light's color sits on a color map once brightness is set aside, given as coordinates such as x, y or u', v'.
Planckian locus
The line of whites on a chromaticity diagram that a perfect blackbody passes through as it heats up.
MacAdam ellipse
A small oval around a target color on a chromaticity chart, inside which color shifts go unnoticed by most viewers.
Duv
How far a white light's color sits above or below the blackbody line, giving it a green or pink tint.