Application of Neugebauer-Based Models to Ceramic Printing

In the ceramic industry half-tone images are often generated from a small number of separations with the result that inks are printed over each other to achieve the final print. This study investigates whether an n-modified spectral Neugebauer-based model, which has been used quite successfully to predict reflectance for prints on paper substrates, can be used to predict the color of half-tone prints on a ceramic base. A set of 800 binary ink mixtures and 100 single-ink mixtures were used to test the model and it was found that best performance (median CIELAB ∆E of 2.73 units) was possible using a high value of the Yule-Nielsen correction factor (n = 20). A Kubelka-Munk model was developed to predict the reflectance factors of the overlap regions in the prints (where one ink dot lies over another). Color differences using the Kubelka-Munk model ranged from 1.8 to 10.4. However, when the measured overlap reflectance spectra were replaced by the Kubelka-Munk predictions in the Neugebauer model the median color difference increased from 2.73 to 3.40 CIELAB units.