Precise Color Communication

The L*a*b* color space (also referred to as the CIELAB space) is one of the uniform color spaces defined by the CIE in 1976. The values of L*, a*, and b* are calculated according to the formulas below:

Lightness variable L*:


Chromaticity coordinate a* and b*:


where
X, Y, Z:
Tristimulus values XYZ (for 2 Standard Observer) or (for 10 Standard Observer) of the specimen

Xn, Yn, Zn:
Tristimulus values XYZ (for 2 Standard Observer) or (for 10 Standard Observer) of a perfect reflecting diffuser

If X/Xn, Y/Yn, or Z/Zn is less than 0.008856, the above equations are changed as described below:




A color space in which equal distances on the coordinate diagram correspond to equal perceived color differences.
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