A method for measuring the color strength of a colored batch, the method comprising: a) coating onto a substrate a portion of a first colored batch comprising one or more pigments dispersed in either or both of a carrier and binder, the first colored batch optionally including one or more effect pigments, to form a coated test film; b) optionally hardening the test film; c) illuminating the test film and measuring the intensity of light reflected or absorbed by the test film at a plurality of combinations of illumination angle and measurement angle, and at one or more wavelengths; d) calculating a plurality of color strengths for the test film at such plurality of combinations of illumination angle and measurement angle, and at such one or more wavelengths; and e) determining a composite color strength for the test film by applying non-uniform weighting factors to such plurality of color strengths, wherein the color strength CS is defined using Formula IV shown below for a given measuring geometry: CS = 100 x K B λ imax S B λ imax / K T λ imax S T λ imax wherein CS is the color strength, K B λ imax S B λ imax indicates the wavelength λ imax for which the ratio of absorption K and scattering S is minimal for the test batch color, and K T λ imax S T λ imax indicates the wavelength λ imax for which the ratio of absorption K and scattering S is minimal for the target color; wherein the composite color strength is defined using Formula VI below: CS = ∑ g = 1 G W g ∗ CS g wherein W g are non-uniform weighting factors at G different angles, wherein at least one of the weighting factors W g is not the same as the other weighting factors, CS g are color strength values at G different angles, and CS is the composite color strength, and wherein the term "weighting factors" means coefficients applied to a series of measurements or calculations to assign different contributions by each measurement or calculation to an overall measurement or calculation and wherein the chosen weighting factors may all be positive values, a mixture of positive values and zero values, a mixture of positive values and negative values, or a mixture of positive, zero and negative values, wherein a "zero value" means that the associated measurement is excluded, wherein for a given set of non-uniform weighting factors, their sum is 1, and wherein the individual weighting factors may in some instances be greater than 1 or less than -1. a) coating onto a substrate a portion of a first colored batch comprising one or more pigments dispersed in either or both of a carrier and binder, the first colored batch optionally including one or more effect pigments, to form a coated test film; b) optionally hardening the test film; c) illuminating the test film and measuring the intensity of light reflected or absorbed by the test film at a plurality of combinations of illumination angle and measurement angle, and at one or more wavelengths; d) calculating a plurality of color strengths for the test film at such plurality of combinations of illumination angle and measurement angle, and at such one or more wavelengths; and e) determining a composite color strength for the test film by applying non-uniform weighting factors to such plurality of color strengths, wherein the color strength CS is defined using Formula IV shown below for a given measuring geometry: CS = 100 x K B λ imax S B λ imax / K T λ imax S T λ imax wherein CS is the color strength, K B λ imax S B λ imax indicates the wavelength λ imax for which the ratio of absorption K and scattering S is minimal for the test batch color, and K T λ imax S T λ imax indicates the wavelength λ imax for which the ratio of absorption K and scattering S is minimal for the target color; wherein the composite color strength is defined using Formula VI below: CS = ∑ g = 1 G W g ∗ CS g wherein W g are non-uniform weighting factors at G different angles, wherein at least one of the weighting factors W g is not the same as the other weighting factors, CS g are color strength values at G different angles, and CS is the composite color strength, and W g are non-uniform weighting factors at G different angles, wherein at least one of the weighting factors W g is not the same as the other weighting factors, CS g are color strength values at G different angles, and CS is the composite color strength, and wherein the term "weighting factors" means coefficients applied to a series of measurements or calculations to assign different contributions by each measurement or calculation to an overall measurement or calculation and wherein the chosen weighting factors may all be positive values, a mixture of positive values and zero values, a mixture of positive values and negative values, or a mixture of positive, zero and negative values, wherein a "zero value" means that the associated measurement is excluded, wherein for a given set of non-uniform weighting factors, their sum is 1, and wherein the individual weighting factors may in some instances be greater than 1 or less than -1.