HunterLab EasyMatch QC, User Manual

Page: 302 / 366

EasyMatch QC User’s Manual Version 2.1
A-12 Measurement Values
x =
h 280
M
−

 

30
2
if |h
M
- 280|
≤
180
x =
360 - h - 280
M
30
2






if |h
M
- 280| > 180
C =
C C *
2
M
abT abO
+
h =
h h
M
abT abO
+
2
if |h
abT
- h
abO
|
≤
180
180 +
2
h h
= h
abO abT
M
+
if |h
abT
- h
abO
| > 180 and |h
abT
+ h
abO
| < 360
180 -
2
h h
= h
abO abT
M
+
if |h
abT
- h
abO
| > 180 and |h
abT
+ h
abO
|
≥
360
L*
T
, C*
abT
, h
abT
= lightness, chroma, and hue of Test specimen
L*
O
, C*
abO
, h
abO
= lightness, chroma, and hue of Original
dL* = L*
T
- L*
O
dC*
ab
= C*
abT
- C*
abO
sign of dH*
ab
= sign of (h
abT
- h
abO
)
2
ab
2
2
ab ab
* dC * dL * dE = * dH
− −
2 2 2
ab
* db + * da * dL = * dE
+
dEf is used to calculate ISO Grey Scale using the equations below:
1.7
dEf
- 5 Scale Grey ISO
=
if dEf
≤
3.4
( )
( )
2 log
0.85
dEf
log
- 5 = Scale Grey ISO if dEf > 3.4.
ISO Grey Stain
The transference of color from the test specimen to an adjacent specimen is evaluated in a manner very
similar to that of ISO Grey Scale. Again, five standard pairs are used. One half of each standard is
white, and the second half range ranges from white (no staining) to a gray with the chroma value of the