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Standard programs
The CIE L*a*b* values depend on the path length and are always
related to the type of cuvette/sample cell used.
1. Press US Pharmacopoeia.
2. Insert the test cuvette.
3. The result of the color calculation is displayed.
The L*a*b* value shows the color difference of the measured
sample relative to the next USP color standard, which is
displayed above the color difference values (in this case color
standard B).
The E* value shows the three-dimensional color difference of
the measured sample relative to the USP color standard B.
The touch-sensitive area around the color standard is active.
4. Press the area around the color standard (in this case B).
The color axis a*, b* and the loci of the sample (+) is
displayed as well as the USP color standards. The color
matching result is displayed graphically.
5. Press the Send Data symbol to print the graphic or Return to
exit the window.
5.5.7.3 Color determination according to the Chinese Pharmacopoeia (CP)
The Chinese grade scheme for pharmaceutical solutions is split
into five color scales: yellow-green (YG1 - YG10); yellow (Y1 -
Y10); orange-yellow (OY1 - OY10); orange-red (OR1 - OR10);
brown-red (BR1 - BR10). The Chinese Pharmacopoeia
resembles the color scales of the European Pharmacopoeia
(EP), with yellow, red and blue primary solutions. The yellow
solutions, however, differ from the European Pharmacopoeia in
the proportion of solution and color designation.
5.5.7.4 Determination of the Klett color value
The Klett color number is used in the cosmetics industry to
evaluate surfactants and detergents. The Klett color value is
usually measured in 40 mm cuvettes/sample cells with a
Summerson photometer using a blue filter (no. 42).
The measuring range starts at Klett color number 0 and ends at
Klett color number 1000.
You can measure the Klett color value with all cuvette types (10,
11 and 50 mm). The 50 mm cuvette, however, offers the highest
accuracy. For Klett, however, the measurement result is always
calculated with 40 mm and blue filter no. 42.