Filter
Top Products
65
Standard programs
5.5.7.5 Determination of the AOCS Cc 13 e (Lovibond
®
) scale
The calculation of the Lovibond color values is derived from the
methods AOCS Cc 13e or BS 684 -1.14 and based on the
yellow/red values (5 1/2 inch or 1 inch) of the AF900/AF960
instruments. On the printout, the 1" values are identified by a 1.
5.5.7.6 Determination of the Yellowness Index (ASTM D 1925)
The Yellowness Index is calculated and displayed according to
ASTM D 1925 for standard illuminant C and a 2° standard
observer. This color value can be measured in 10 mm, 11 mm or
50 mm cuvettes.
The Yellowness Index is calculated as follows:
Y i = 100 × ( 1.277 × X 1.059 × Z ) / Y
5.5.7.7 Determination of the Hess-Ives color number
The Hess-Ives color number is used in the cosmetics industry to
evaluate the color of fat derivatives. It combines in one number
the weighted color intensities, which represent the red, green and
blue parts of the transmittance spectrum of the sample at
3 wavelengths. It is defined in DGK 8 method no. F 050.2 and
calculated and displayed in accordance with this method. The
Hess-Ives color number is calculated from:
H - I = ((R + G + B) ×6) / path length
R, G and B are the color components for the red (640 nm), green
(560 nm) and blue (464 nm) parts. For R,G and B:
R = 43.45 × E
640
G = 162.38 × E
560
B = 22.89 × (E
460
+ E
470
) / 2
5.5.7.8 Determination of the ADMI color number
The ADMI color number is used to measure the color of water
and wastewater having color characteristics significantly different
from platinum-cobalt standards, as well as to those similar in hue
to the standards.
The American Dye Manufacturers Institute (ADMI) has adopted
the Platinum-Cobalt standard of the American Public Health
Association (APHA) as the standard for color value. Although this
standard is yellow, the ADMI method works for all hues.
The measurements can be taken using 10 mm, 11 mm or 50 mm
cuvettes. A longer path length increases the measurement
accuracy (50 mm path length is recommended).
Turbid samples must be filtered prior to analysis.