1.1 This practice covers the instrumental requirements, standardization procedures, material standards, and parameters needed to make precise instrumental measurements of the colors of gonioapparent materials. This practice is designed to encompass gonioapparent materials; such as, automotive coatings, paints, plastics, and inks. 1.2 This practice addresses measurement of materials containing metal flake and pigments. The measurement of materials containing metal flakes requires three angles of measurement to characterize the colors of the specimen. The optical characteristics of materials containing pearlescent and interference materials are not covered by this practice. Note 1 -Data taken by utilizing this practice are for gonio-appearance quality control purposes. This procedure may not necessarily supply appropriate data for spatial-appearance or pigment identification. 1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 1.4 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.