MODELING PROPERTIES OF FLAKE FINISHES USING DIRECTIONAL RESOLUTION AND STATISTICAL FLAKE ORIENTATION DISTRIBUTION FUNCTION

The light reflectance of metallic flake finishes can be successfully separated into a flake component and a diffuse component. An empirical model accurately represents the statistical distribution of flake orientation in extreme cases and in areas of transition between the extreme cases. Colorimetric measurements at three angles of observation are both necessary and sufficient to characterize a flake finish to the precision required in normal quality control applications. Filter colorimetry or spectrophotometry can be used to obtain the data from which the model parameters are calculated. The model parameters provide objective qualitative data describing the optical and physical characteristics of flake finishes. The parameters of the empirical model as calculated from colorimetric measurements at the three angles can be correlated with physical properties of flake finishes to facilitate matching of finishes and to provide specific guidance to operators applying finishes as to what might be changed to achieve a better match.