The intent of this practice is to precisely specify procedures for instrumental color difference measurement of colored parts or colored materials incorporated in the manufacture of vehicles. The recommended practice provides a consistent engineering practice for determination of color difference, for numerical communication of color difference, and for determination of acceptance or rejection compared to numerical tolerances. The practice is intended to be used as a specification and means of communication for color part acceptance in a buyer-seller agreement. The practice applies to parts and materials used in vehicles manufacture which are intended to be acceptable color matches to a specified color standard. This practice is intended for use with parts or materials which are opaque or nearly so and does not apply to transparent materials. Materials covered by this practice include topcoat paint finishes, interior soft trim, and exterior hard trim, and exterior film.