HunterLab EasyMatch QC, User Manual

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EasyMatch QC User’s Manual Version 2.1
A-36 Measurement Values
Spectral Data Types
% Strength
Selecting % Strength as a difference data type for display in the Spectral Data Table results in the
display of % Strength values for samples as compared to a standard. % Strength is calculated separately
for each wavelength displayed, as follows:
100 *
K/S
K/S
Strength %
standard
sample
=
for reflectance
100 *
Absorbance
Absorbance
Strength %
standard
sample
=
for transmittance.
K/S and Absorbance are described below.
Absorbance (ColorQuest II Sphere, ColorQuest XE, ColorQuest XT,
UltraScan XE, UltraScan PRO, and UltraScan VIS only)
Selecting Absorbance as the spectral data type when configuring a Spectral Data Table for an instrument
standardized in Total or Regular Transmittance results in the display of absorbance values. Absorbance
values are calculated for each wavelength.
Absorbance = -log
10
T
where T = transmittance.
In the Color Data Table configuration, a wavelength range appropriate for your instrument should be
chosen. Do not choose wavelengths above or below the range of your instrument or the results of these
calculations may be in error.
K/S
Selecting K/S as the spectral data type when configuring the Spectral Data Table results in the display of
K/S values. These values are valid only for measurements made in a reflectance mode. Therefore, they
are displayed only when the standardization mode is reflectance.
K/S values for the product standard and sample are calculated for each wavelength. The points of
minimum and maximum reflectance of the product standard and sample may be viewed on the Spectral
Plot.
[ ]
[ ]
K
S
=
1 - 0.01 R
R
2
2 0 01 .
where R = reflectance. Calculating K/S is only appropriate for samples whose minimum % reflectance
(at any wavelength) is at least 10%. If the minimum % reflectance is less than 10%, you should dilute
the sample before measurement of K/S.