ASTM D6045 Color of Petroleum Products by the Automatic Tristimulus Method
1. Scope
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.
NOTE 1 - With the appropriate sample handling, this test method would apply to petroleum waxes, but they were not used in the round robin, and the precision of this test method with regard to waxes is unknown.
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 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.
2. Referenced Documents
2.1 ASTM Standards:
D156 Test Method for Saybolt Color of Petroleum Products (Saybolt Chronometer Method)
D938 Test Method for Congealing Point of Petroleum Waxes, Including Petrolatum
D1193 Specifications for Reagent Water
D1500 Test Method for ASTM Color of Petroleum Products (ASTM Color Scale)
D2500 Test Method for Cloud Point of Petroleum Products
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
E 284 Terminology of Appearance
E 308 Practice for Computing the Colors of Objects by Using the CIE System
2.2 Institute of Petroleum Standard:
IP 17 Determination of Colour - Lovibond Tintometer
3. Terminology
3.1 Definitions:
3.1.1 ASTM color - the name of an empirical scale of expressing of the color of a petroleum liquid darker than Saybolt color based on a scale of 0.5 (lightest) to 8.0 Dil (darkest) and determined by Test Method D1500.
3.1.2 CIE - the abbreviation for the French title of the International Commission on Illumination, or Commission Internationale de l'Eclairage.
3.1.3 CIE Standard Illuminant C - Colorimetric illuminant, representing daylight with a correlated color temperature of 6774 K, defined by the CIE in terms of a relative spectral power distribution.
3.1.4 CIE 1931 standard observer - ideal colorimetric observer with color matching functions x(l), y(l), z(l) corresponding to a field of view subtending a 2°angle on the retina; commonly called the "2°Standard Observer".
3.1.5 saybolt color - the name of an empirical scale for expressing of the color of a clear petroleum liquid based on a scale of -16 (darkest) to +30 (lightest) and determined by Test Method D156.
3.1.6 Tristimulus Values - The amounts of three specified stimuli required to match a color.
3.1.6.1 Discussion - In the CIE system, they are assigned the symbols X, Y, and Z.
