Some Applications of the Davidson and Hemmendinger Colorant Mixture Computer to Paints and Plastics

Test on colour formulation and correction of spectral matches to light‐coloured paints have given good results, but extension to the matching of deeper colours requires a closer consideration of the suitability of the function used and the exact interpretation of the computer indications. For gloss paints, a modified function, including the Saunderson correction for internal surface reflection, has been found suitable and with this function the computer can be satisfactorily applied to paints of medium depth, provided that they contain a substantial proportion of white base. At least sixty colours of BS 2660 “Colours for Building and Decorative Paints” could be matched satisfactorily by this means. Tests on a range of coloured plastic mouldings varying from nearly transparent to opaque gave satisfactory results only where opacity was high. Results are also reported on the colour matching of textiles.