HunterLab EasyMatch QC, Руководство пользователя

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EasyMatch QC User’s Manual Version 2.1
Measurement Values A-27
Tint GANZ Difference is also available, and is defined as follows:
dTint GANZ = (Tint GANZ)
sample
- (Tint GANZ)
standard.
A few caveats regarding measurement of tint:
•
The application of this equation is restricted to samples that are called “white” commercially, that
are similar in color and fluorescence, and that are measured on the same instrument at the same time.
Under these conditions, their use should give relative, but not absolute, evaluations of tint that are
adequate for commercial use.
•
The more positive the value of tint, the greater is the indicated greenish tint of the sample. The more
negative the value of tint, the greater is its reddish tint. Lines of equal tint are approximately parallel
to the line of dominant wavelength 466 nm. For perfect white, tint = 0.
•
Equal differences in tint do not always represent equal perceptual differences in tint.
•
This equation should only be used for samples having tint values between -3 and +3.
USP 10-mm and USP 20-mm (ColorQuest II Sphere, ColorQuest XE,
ColorQuest XT, UltraScan PRO, UltraScan XE, and UltraScan VIS only)
USP (United States Pharmacopeia Color) is a visual liquid color index used in the pharmaceutical
industry. It consists of three primary color standard solutions (cobaltous chloride, ferric chloride, and
cupric sulfate) that are combined with water to produce fifteen reference USP liquid color standards
labeled A-T.
A HunterLab spectrophotometer standardized in a transmission mode may be used to instrumentally
determine the closest USP standard to any sample solution read. Samples should be measured using a
10-mm or 20-mm path length transmission cell, choosing the matching version of the USP index for
display. The USP standard value (or “Water” if the sample is closest to water white) is then reported.
Refer to U.S. Pharmacopeia Monograph 631, “Color and Achromicity,” for more information.
Whiteness Indices
Whiteness is associated with a region or volume in color space in which objects are recognized as white.
Degree of whiteness is measured by the degree of departure of the object from a perfect white.