HunterLab EasyMatch QC, Руководство пользователя

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EasyMatch QC User’s Manual Version 2.1
Measurement Values A-9
K
L
:K
C
:K
H
ratio. This ratio is generally 1:1:1 for coatings, 1.3:1:1 for plastics, and 2:1:1 for
textiles.
DIN99
The German standards institute (DIN) developed the DIN99 standard as a new color difference formula
that globally models color space using logarithms of the CIELAB coordinates rather than the linear and
hyperbolic functions of CMC and CIE94. This new formula is easy to use and has equivalent
performance to CMC or CIE94. It also eliminates the reference-color based distortion of CIELAB. It is
calculated as follows:
Redness e = cos(16°)a* + sin(16°)b*
Yellowness f = -0.7[-sin(16°)a* + cos(16°)b*]
Chroma G = (e
2
+ f
2
)
0.5
Hue angle h
ef
= arctan(f/e)
Chroma C DIN99 =
( ) ( )
E CH
k 0.045k
0.045G 1 log
+
e
Hue angle h DIN99 =
Π
180
h
ef
Redness a DIN99 = C DIN99 cos h
ef
Yellowness b DIN99 = C DIN99 sin h
ef
Lightness L DIN99 = 105.509 [log
e
(1 + 0.0158 L*)] k
E
( ) ( ) ( )
2 2 2
DIN99 db DIN99 da DIN99 dL DIN99 dE
+ + =
dC DIN99 = C DIN99
sample
- C DIN99
standard
dH DIN99 =
( )
( )
standard sample standard sample standard sample
standard sample sample standard
DIN99 b * DIN99 b DIN99 a * DIN99 a DIN99 C * DIN99 C * 0.5
DIN99 b * DIN99 a - DIN99 b * DIN99 a
+ +
.
where
k
E
= k
CH
= 1 by default.
CIELAB2000
The CIELAB2000 Color Difference Equation is a ellipsoidal color difference scale similar to CMC, and
is described below.
dE* 2000 is the total color difference.