4.1 The major objective of the visual Pt-Co method of color measurement is to rate specific materials for yellowness. The yellowness is frequently the result of the undesirable tendency of liquid hydrocarbons to absorb blue light due to contamination in processing, storage, or shipping.

1.1 This test method covers a procedure for the visual measurement of the color of near clear liquids. It is applicable only to materials in which the color-producing bodies present have light absorption characteristics nearly identical with those of the Platinum-Cobalt (Pt-Co) color standards used.

1.2 This test method has been found applicable to the color measurement of clear, liquid samples, free of haze, with nominal Pt-Co color values between 0 and 100. It is applicable to nonfluorescent liquids with light absorption characteristics similar to those of the Pt-Co color standard solutions. Test Methods D1209, D1686, and D5386 deal with the visual and instrumental measurement of near-clear liquids.

1.3 In determining the conformance of the test results using this method to applicable specifications, results shall be rounded in accordance with the rounding off methods of Practice E29.

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

1.5 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.

1.6 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.