Regardless of whether one works in the pigment, paint or automotive industry, those who deal with interference pigments cannot avoid contending with their physical and optical properties. Unfortunately, that is frequently forgotten and ignored due to a lack of knowledge of, and experience with, that particular type of pigment. Visual and instrumental characterization of a pigment's optical properties are equally important, since the color that results will vary with the angle at which light is incident on it. Together with the viewing angle, that angle yields a precise representation of the interferences involved.