Print mottle is a common print defect, so the evaluation of this print parameter is vital in print quality assessment. The aim of this research is print mottle estimation, i.e. solid-tone surface uniformity assessment of different billboard materials, printed using ink jet technology. A GLCM image processing method was used as a tool for print mottle determination, as it proved to be good surface roughness as well as print mottle estimator. The main idea was to apply GLCM image processing method on ink jet printed samples that possess print mottle defects, and to test if this method can produce reliable estimations of this negative print effects. After obtaining quantitative results of print mottle level for each sample, all of them, according to appropriate color, were subsequently visually compared, in order to gain qualitative information about its solid-tone uniformity and establish which substrate material is superior in terms of solid-tone surface uniformity, as well as to verify previously obtained quantitative results and conclusions.
Key words: print mottle, solid-tone uniformity, GLCM, ink jet printing