Print mottle modelling relevant to human perception

Abstract

In this research, a critical study of the print mottle indices related to human perception is presented. A particular aim is to try to model mottling indices and human perception based on various illumination conditions. The study is made using different paper grades printed by offset printing. The mottling index measurement is based on image analysis methods. Each mottle printed sample is observed by 20 customers and 20 printers. Finally, a relationship between mottling and human perception is found, by which a model formula for mottling perception in the region of illumination is derived. The results show that the mottling perception is differentiated from one group of observers to another group, based on their experiences. It is found that in normal situation, the printer group perceives the effect of mottle better than the perception of customer. But, vice versa, when the illumination changes, the customer effect becomes dominant. Significant of the statistical result of experiment is 0.05.