ASTM D6045 Color of Petroleum Products by the Automatic Tristimulus Method
4. Summary of Test Method
4.1 The sample is poured into the glass sample container, and the container is placed into the light path of the automatic instrument. A transmittance measurement is performed in order to determine the CIE tristimulus values (under CIE Standard Illuminant C and the CIE 1931 Standard Observer) of the sample in question. These are then converted instrumentally by the appropriate algorithm to Saybolt color or ASTM color values.
4.2 The color of the sample is reported in either Test Method D156 or Test Method D1500 values, as appropriate.
5. Significance and Use
5.1 Determination of the color of petroleum products is used mainly for manufacturing control purposes and is an important quality characteristic because color is readily observed by the user of the product. In some cases the color may serve as an indication of the degree of refinement of the material. When the color range of a particular product is known, a variation outside the established range may indicate possible contamination with another product. However, color is not always a reliable guide to product quality and should not be used indiscriminately in product specifications.
