Details:
Summary:
The purpose of 7-ink CMYKRGB printing, with FM screening, is to extend the color gamut beyond what can be achieved in the conventional 4-ink process. Due to the addition and proportionality failure of inks, the characterization of the 7-ink printing process is more complex than the characterization of 4-ink printing process. The approach carried out in this study lowers the complexity of the characterization problems by subdividing the 7 inks into 6 subsets of 4-ink grouping. Each subset comprises 3 chromatic inks and black ink. The masking-type (2nd) and the Neugebauer-type (Cellular Neugebauer) algorithms, based on the use of colorimetric transformations from ink to color, were derived to model the 6 subsets of 4-ink grouping. The results showed that the 2nd model performed better than the Cellular Neugebauer model. Additionally, the separate test target is required for the characterization of neutral and near-neutral colors to further improve the accuracy of predictions for the models derived. It was also found that the highly saturated colors having less gray contents provide the severe test to the derived models' performance.