Characteristics Of The Klett Color Index; Measurement Methods And References - Macherey-Nagel NANOCOLOR UV/VIS II Manual

Color measurements
If the sample is out of range, this will be indicated in the measurement result (see Figure 57).
5.6.9

Characteristics of the Klett color index

The Klett color index is one of the oldest photometric color indexes of all. It is measured with
an American Klett-Summerson photometer. The construction of these photometers has
remained practically unchanged since 1939. These photometers operate with simple glass
filters. In contrast to the first European photometers, the measured value is not the
transmittance or absorbance, but rather a value on an arbitrary logarithmic scale from 1 to
1000, the Klett scale. This scale follows the Lambert Beer Law and is therefore proportional
to the concentration. Due to the properties of colored glasses, the filters originally used in the
Klett colorimeter have a relatively large transmission range; for instance, the filter KS-42
allows the transmission of light in the range of 400 to 450 nm. The original Klett index is
thus an integral measurement value over a range of about 50 nm.
Klett photometers are still used today in bioanalysis for monitoring the growth of cell
cultures. However, it is not the absorption that is measured, but rather, the stray light.
Since the measurement of stray light depends on the geometry of the measuring
device, the Klett index determined by the NANOCOLOR
cannot be used for monitoring cell cultures!
5.6.10

Measurement methods and references

For each color determination, the tristimulus values and chromaticity coordinates are
calculated as specified by International Commission on Illumination CIE, Publication CIE
15:2004, 3rd Edition. The following color indexes are calculated directly from X, Y, Z or
x, y, z data:
XYZ, xyz, L*a*b* and L*u*v* according to CIE 15:2004, 3rd Edition.
Hunter-Lab according to HunterLab Application Note "Hunter Lab Color Scale," August-1-15,
1996 Vol. 8, No. 9
Gardner color index according to DIN EN ISO 4630-2
Yellowness index according to ASTM E 313-05 und ASTM D1925 (outdated)
RGB, CMYK, YUV, HSB, HSL according to www.brucelindbloom.com
ASTM color index according to ISO 2049
Saybolt color index according to ASTM D156, D6045
Hazen/APHA/Pt-Co color index according to ASTM D 5386-05
The following color indexes are calculated from absorbances at certain wavelengths:
NANOCOLOR
Figure 57: Ph. Eur. color measurement out of range
® UV
/ II and NANOCOLOR
VIS
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spectrophotometer software
®
VIS II V 1.1 / 10.2017
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