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.

1.1 This test method covers the automatic determination of color of a wide variety of petroleum products such as undyed motor and aviation gasoline, aviation turbine fuels, naphthas, kerosine, pharmaceutical white oils, diesel fuel oils, heating oils, and lubricating oils by the automatic tristimulus method. This test method correlates to Test Method D156 and Test Method D1500 as calculated by the instrumentation.

1.2 This test method reports results in terms of Test Method D156 or Test Method D1500.

1.3 This test method has a one-to-one correlation for the entire range of Test Method D1500 ASTM Color and for the range from 0 to +30 for Test Method D156 Saybolt color.

1.4 This test method does not apply to solid samples, petroleum products containing dye, and petroleum products having extreme fluorescence.

1.5 This test method does not apply to cloudy samples. Such samples shall be filtered so they are clear before measuring.

1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.7 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 and health practices and determine the applicability of regulatory limitations prior to use.