First-order goniospectrophotometric spectral modeling of isotropic and anisotropic colorant mixtures

Color modeling of translucent and opaque media commonly uses two-constant Kubelka-Munk (KM) turbid media theory. KM theory is designed for isotropic color systems that rely on absorption and scatter to produce an overall reflected color. KM theory has previously been considered inadequate to use with interference pigments (IPs) due to their specular reflected, angle-dependent color and anisotropic behavior. If, however, an IP's reflected color is considered to contribute to the background reflectance and not as a colorant in a mixture with a conventional colorant, KM theory can be used. KM theory was successfully implemented to predict the goniospectrophotometric, normalized spectral reflectance of conventional colorants and IP mixtures.