color matching blends of precolored fiber using three different methods was studied. best color-matching accuracy was obtained using a two-constant kubelka-munk (km) procedure first-formula color differences averaged 1.6 cielab units and were found to be within the experimental error of 1.6 cielab units useful approximations were obtained using the methods proposed by friele (1952) and by stearns (1944). first-formula color matches averaged 2.4 cielab units for the stearns and 2.7 cielab units for the friele methods. the methods are mathematically compared and the merits of each are discussed. where possible, interpretation of the empirical parameters each method employs is attempted. it is pointed out that absorption and scattering constants calculated for fibers using the km formalism are not true km absorption and scattering constants. it is demonstrated that too literal an interpretation of these constants leads to apparent anomalies. it is shown that the fiber km scattering constants which are normally considered unchanged as dye is applied cannot be considered unchanged if these same fibers are subsequently to be used in blends with other colored fibers