Datacolor 45IR User Guide, 5.2014, Version 1.0 (4230-0402M)
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CIE L*C*h*
ab
The
CIE L*C*h* ab
display is closely related to the CIE L*a*b* display. Instead of Cartesian coordinates, polar
coordinates are used and presented. The value C* stands for Chroma and the angular value h* for hue.
L*C*h* values are very popular, because they
describe colors simply. The further the color is
located from the center of the color circle, the
more saturated and vivid it appears.
Metamerism Index
Metamerism is the visual phenomenon that two colors match under certain light conditions and differ under
different light conditions.
Colorimetry offers the possibility to detect this effect by measuring the color distance between the two color
samples under two exactly defined light sources. The result of this operation is the
Metamerism Index
.
For the determination of the
Metamerism Index
there are two
measurements to be made.
A reference measurement, which refers to illuminant condition D65.
A sample measurement on the sample patch.
As a result the color distances in ∆E*
ab
for illuminant conditions A, C and D50 are shown.
Identical color impression under light condition I:
Color deviation under light condition 2 caused by metamerism
