CIE 1960 color space
The CIE 1960 color space ("CIE 1960 UCS", variously expanded Uniform Color Space, Uniform Color Scale, Uniform Chromaticity Scale, Uniform Chromaticity Space) is another name for the (u, v) chromaticity space devised by David MacAdam.[1]
The CIE 1960 UCS does not define a
Today, the CIE 1960 UCS is mostly used to calculate
Background
Judd determined that a more uniform
(Note: What we have called "G" and "B" here are not the G and B of the CIE 1931 color space and in fact are "colors" that do not exist at all.)
Judd was the first to employ this type of transformation, and many others were to follow. Converting this RGB space to chromaticities one finds[4][clarification needed The following formulae do not agree with u=R/(R+G+B) and v=G/(R+G+B)]
MacAdam simplified Judd's UCS for computational purposes:
The Colorimetry committee of the CIE considered MacAdam's proposal at its 14th Session in Brussels for use in situations where more perceptual uniformity was desired than the (x,y) chromaticity space,[5] and officially adopted it as the standard UCS the next year.[6]
Relation to CIE XYZ
U, V, and W can be found from X, Y, and Z using:
Going the other way:
We then find the chromaticity variables as:
We can also convert from u and v to x and y:
Relation to CIE 1976 UCS
References
- .
- ISBN 0-306-42195-X.
- .
An important application of this coordinate system is its use in finding from any series of colors the one most resembling a neighboring color of the same brilliance, for example, the finding of the nearest color temperature for a neighboring non-Planckian stimulus. The method is to draw the shortest line from the point representing the non-Planckian stimulus to the Planckian locus.
- JOSA. 34 (11): 633–688. (recommended reading)
- JOSA. 50 (1): 89–90.
The use of the following chromaticity diagram is provisionally recommended whenever a diagram yielding color spacing perceptually more nearly uniform than the (xy) diagram is desired. The chromaticity diagram is produced by plotting 4X/(X + 15Y + 3Z) as abscissa and 6Y/(X + 15Y + 3Z) as ordinate, in which X, Y, and Z are the tristimulus values corresponding to the 1931 CIE Standard Observer and Coordinate System.
- ^ "Official Recommendations". Publication No. 004: Proceedings of the CIE Session 1959 in Bruxelles. 14th Session. Vol. A. Brussels: International Commission on Illumination. 1960. p. 36.
External links
- Free Windows utility to generate chromaticity diagrams. Delphi source included.