Basic equations used in computer color matching, II Tristimulus match, two-constant theory

The calculation of a tristimulus match in an opaque film using two-constant theory and four colorants can proceed in two stages: first, the computation of a rough match, and second, iteration to an exact match. The same formal matrix is used for the rough solution and for the iterative calculations, but it must be recomputed and reinverted once before the iterative stage of the program.