CHARACTERISING SURFACE COATINGS

摘要

Surface coating films containing metallic flake pigment are characterized by (a) illuminating the film with a parallel beam of light which is inclined at a given angle to the film normal and (b) measuring the intensity of light reflected from a point on the film at a plurality of azimuthal viewing positions located in a circle which lies in a plane parallel to the film and through the center of which passes the film normal at the point. Apparatus suitable for carrying out the measurements is described. The invention enables the frequency distribution of the orientations of the metallic flake in the film to be determined.