Fig. 1. Actual spectrum and mixed spectrum of offset printing ink predicted by K-M theoretical model

Fig. 2. Relationship between transmission value and spectral reflectance under different models

Fig. 3. Comparison of K/S data with different concentration for Blue1 primary ink. (a) Real K/S; (b) K/S by piecewise linear interpolation; (c) K/S by traditional normalization method

Fig. 4. Comparison of K/S data with different concentration for 550 nm Magenta ink

Fig. 5. Three gradient spectrum curves of Red2 primary ink. (a) Real spectra; (b) deduced spectra by piecewise linear interpolation; (c) deduced spectra by traditional normalization method

Fig. 6. Determination of m values for 2-, 3- and 4-primary ink blends respectively

Fig. 7. Comparison of predicted spectra by two methods and actual sample spectra. (a) Sample 1; (b) sample 2; (c) sample 3;(d) sample 4; (e) sample 5; (f) sample 6; (g) sample 7; (h) sample 8; (i) sample 9