Methods for the Calculation of Contrast

An expression for the luminance factor of glass-covered surfaces, such as those used for the Bruel & Kjaer reflectance standard, is formulated, and the parameters of the expression are determined, so that a close reproduction of the measured data of the standards is obtained. A compact method is based on the expression, which is well-suited for computer calculations of contrast conditions. Other practical problems of such calculations are considered also, and advice on practicable methods is given.