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CHAPTER 2
– Measurement functions
The thematic separation between densito-
metric and colorimetric functions is displayed
by a dotted line within the measurement
function window. CIE stands for the interna-
tional color institute Commission Internatio-
nale de l’Eclairage which publishes the stan-
dards for colorimetry.
The most popular color system in the printing
industry is the CIE L*a*b* color space. Every
color is precisely described by three values:
The L*-value stands for the luminance and can
have values between 0 (a theoretical, abso-
lute Black) and 100 (a theoretical, ideal White).
The a*-value describes the color value on the
Green/Red-axis (- a*: Green, + a*: Red) and the
b*-value the color value on the Blue/Yellow-
axis (- b*: Blue, + b*: Yellow).
Colorimetric L*a*b*-measurement on a blue
sample. The blue color has a low luminance
of L = 47.21 and a low portion of Red.
2.2 Additional functions of SpectroDens Advanced
CIE L*a*b*
The previously described measurement functions all were based on densitometry.
Thanks to the spectral performance of SpectroDens it is possible to calculate and dis-
play colorimetric values as well. Measurements in
colorimetry
modes have the advan-
tage of an absolute description of color based on characteristic values.
L* = 0
L* = 100
C*
h*
h* = 0
h* = 180
L* = 50
