Describes a method for the quantitative colorimetric evaluation of small differences between paint films. The CIE 1976 colour difference formula recommended in 1976 by the CIE has proved to be of practical value and is specified for this application. the principle is based on the calculation of differences in colour, lightness, chroma and hue between the paint films of a test specimen and a reference specimen in the CIE 1976 colour space. If the two methods specified are carried out, comparable results are obtained for high gloss paint films.