4.1 Determination of the color of petroleum products is used mainly for manufacturing control purposes and is an important quality characteristic, since 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.

1.1 This test method covers the visual determination of the color of a wide variety of petroleum products, such as lubricating oils, heating oils, diesel fuel oils, and petroleum waxes.

Note 1: Test Method D156 is applicable to refined products that have an ASTM color lighter than 0.5.

Note 2: The color of some dyed products may extend outside color range defined by the glass reference standards employed in the testing procedure. Furthermore, samples used to determine the precision and bias did not include dyed products.

Note 3: It is up to the user to determine the suitability of this test method for their dyed products.

1.2 This test method reports results specific to the test method and recorded as “ASTM Color.”

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.