A computer implemented method, comprising: generating, using a processor, a set of calibration data relating to a plurality of pigments that are present in a collection of coatings defining a paint system, wherein generating includes for each pigment of the paint system: (a) measuring the reflectance of a series of coated samples having different concentrations of the pigment in the coating with a spectrophotometer; (b) calculating multiple sets of K/S data from the reflectance data by using a color matching calculation with Saunderson correction, wherein K1 and/or K2 is allowed to vary by angle, wavelength and concentration; (c) calculating the concentrations of the pigment in the coatings of the series of coated samples; (d) plotting a relationship between the pigment concentration and the calculated K/S data for each combination of K1 and K2 at a given angle and wavelength; (e) linear fitting of the plotted data to identify the set of K/S data which exhibits an optimum R 2 value and the corresponding K1 and K2 values; and determining, using the processor, a coating formulation of a target coating by a color matching calculation including Saunderson correction of spectral reflectance data measured for the target coating making use of the determined optimum K1 and K2 values. generating, using a processor, a set of calibration data relating to a plurality of pigments that are present in a collection of coatings defining a paint system, wherein generating includes for each pigment of the paint system: (a) measuring the reflectance of a series of coated samples having different concentrations of the pigment in the coating with a spectrophotometer; (b) calculating multiple sets of K/S data from the reflectance data by using a color matching calculation with Saunderson correction, wherein K1 and/or K2 is allowed to vary by angle, wavelength and concentration; (c) calculating the concentrations of the pigment in the coatings of the series of coated samples; (d) plotting a relationship between the pigment concentration and the calculated K/S data for each combination of K1 and K2 at a given angle and wavelength; (e) linear fitting of the plotted data to identify the set of K/S data which exhibits an optimum R 2 value and the corresponding K1 and K2 values; and (a) measuring the reflectance of a series of coated samples having different concentrations of the pigment in the coating with a spectrophotometer; (b) calculating multiple sets of K/S data from the reflectance data by using a color matching calculation with Saunderson correction, wherein K1 and/or K2 is allowed to vary by angle, wavelength and concentration; (c) calculating the concentrations of the pigment in the coatings of the series of coated samples; (d) plotting a relationship between the pigment concentration and the calculated K/S data for each combination of K1 and K2 at a given angle and wavelength; (e) linear fitting of the plotted data to identify the set of K/S data which exhibits an optimum R 2 value and the corresponding K1 and K2 values; and determining, using the processor, a coating formulation of a target coating by a color matching calculation including Saunderson correction of spectral reflectance data measured for the target coating making use of the determined optimum K1 and K2 values. <EOS>