This paper describes the measurement of the refractive index and the absorption coefficient of optical materials, e.g., metals and semiconductors, by a new method which we call absorption digital refractometry. This method rests on the simplification in Fresnel’s equations for reflection and the existence of high-resolution digital voltmeters. Unlike the classical methods which are optomechanical absorption digital refractometry is an optoelectronic method for determining the refractive index and absorption coefficient. We begin the paper by briefly discussing Ketteler’s equations. This is followed by describing the polarizing behavior of optical materials in terms of their Mueller reflection matrices.