HunterLab EasyMatch QC, User Manual

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EasyMatch QC User’s Manual Version 2.1
A-26 Measurement Values
CIE Tint and ASTM E313 Tint are calculated using the same equation, given below, but are available
for different illuminant/observer combinations, as described below. Refer to CIE Publication 15.2 ,
“Colorimetry,” for more information on CIE Tint. Refer to ASTM E313, “Standard Practice for
Calculating Yellowness and Whiteness Indices from Instrumentally Measured Color Coordinates,” for
more information on ASTM E313 Tint.
CIE Tint y) - (y 650 - x) - (x T E313 Tint
n n x
= =
where x and y are the chromaticity coordinates of the specimen and x
n
and y
n
are the chromaticity
coordinates for the CIE standard illuminant and source used. These values are provided in the table
below based on the illuminant and observer used. The T
x
coefficient is also given in the table. CIE Tint
is available for the D65/10°, D65/2°, and C/2° illuminant/observer combinations. ASTM E313 Tint is
available for illuminants C, D50, and D65 and the 2° and 10° standard observers. A blank cell is
received when any other illuminant/observer combination is in use.
Value C/2° D50/2° D65/2° C/10° D50/10° D65/10°
T
x
1000 1000 1000 900 900 900
x
n
0.3101 0.3457 0.3127 0.3104 0.3477 0.3138
y
n
0.3161 0.3585 0.3290 0.3191 0.3595 0.3310
Tint CIE Difference and Tint E313 Difference are also available, and are defined as follows:
dTint CIE = (Tint CIE)
sample
- (Tint CIE)
standard,
dTint E313 = (Tint E313)
sample
- (Tint E313)
standard.
Tint GANZ = mx + ny + k
where
( )
m =
-cos
BW
= - 937.588
α
( )
n =
sin
BW
= 826.697
α
k = - mx - ny = 21.352
x and y are the CIE chromaticity coordinates.
α
is the angle, in chromaticity space, between the x chromaticity axis and the line that joins the
chromaticity coordinates measured for the lowest and highest whiteness steps of the 4-step
cotton white scale. Its value depends on the exact illumination conditions of the instrument.
Note: Only the ColorQuest XE, LabScan XE, UltraScan XE, UltraScan PRO, and UltraScan VIS
instruments with the UV control option installed may correctly calculate Ganz Tint.