Table of Contents
Advertisement
Standard Operations
5.5.9 Determine the Saybolt color number (ASTM D 156)
5.5.10 AOCS Cc 13 e (Lovibond
5.5.11 Determine the Yellowness-Index (ASTM D 1925)
5.5.12 Hess-Ives color number
52
evaluated in multiples of 0.5 (0.5 1.0 1.5 etc.).The LICO 500
displays the results in multiples of 0.1. For samples whose color
value is higher than 8,***is displayed.
Note:
Because of the intensive color of the ASTM D 1500 color value, it is
calculated only for 11 mm round or 10 mm square cuvettes/sample cells.
No calculation is carried out for the 50 mm path length.
The Saybolt color scale is used to evaluate refined oil products
such as petrol and kerosene, as well as for petroleum waxes and
pharmaceutical white oils.
The Saybolt color properties are comparable to those of the Hazen
scale (APHA). The Saybolt color scale starts at color number +30
(lightest color, equivalent to approximately 8 to 10 Hazen) and ends
at -16 (strongest color, equivalent to approximately 350 Hazen).
Note:
The measurements can be carried out with 10 mm,11 mm or 50 mm
cuvette/sample cell path lengths. A longer path length increases the
degree of accuracy associated with the measurements (50 mm
recommended).
®
) scale
The calculation of the Lovibond color values in the LICO 500 is
derived from the AOCS Cc 13e or BS 684 -1.14 method and is
based on the 5 1 /2 inch or 1 inch yellow/red values of the
AF900/AF960 instruments. On the printout the 1" values are
identified with 1.
The Yellowness Index is calculated and displayed in accordance
with ASTM D 1925 for illuminant C and a 2 ° standard observer.
This color value can be measured by using 10 mm,11mm or 50 mm
cuvettes/sample cells.
The Yellowness Index is calculated as follows:
Y i = 100 * ( 1.277* X 1.059 * Z ) / Y
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 that represent the red, green and blue
fractions of the sample transmission spectrum at 3 wavelengths. It
is defined in DGK 8 method no.F 050.2 and is calculated and
displayed by the LICO 500 in accordance with this method. The
Hess-Ives color number is calculated from:
H - I = ((R + G + B) * 6) / Pathlength
where R,G and B are the color components for the red (640 nm),
green (560 nm)and blue (464 nm)fractions. For R,G and B:
R = 43,45 * E
G = 162,38 * E
640
560
Advertisement
Table of Contents
