Modification to the JPC79 Colour–difference Formula

Abstract

The JPC79 colour–difference formula has represented a substantial improvement over earlier formulae and is being applied successfully in industrial shade passing. Modifications are described which overcome certain problems and, to some extent, simplify the formula. With available experimental data, the modified version performed even better than the original formula. Perceptibility data are fitted better by increasing the JPC79 lightness weighting by a factor of two. The new formula, designated CMC (: c), has the best overall performance of any formula so far published.