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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:
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Lightness variable L*:
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Chromaticity coordinate a* and b*:
where
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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:
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A color space in which equal distances on the coordinate diagram correspond to equal perceived color differences.
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