Critical Analysis of Mottling and its Impact on Various Grades of Paper Substrates Printed under Conventional Sheet Fed Offset, Dry Toner & Liquid Toner Based Digital Print Engines

Mottle is one of the print quality factors which highly affect the final print in any printing system. Print mottle is without doubt one of the most important factors regarding visual impression of print quality in any printing system. It is usually the result of uneven ink layer or non-uniform ink absorption across the paper surface and it is more prominently visible in middle tone images or areas of uniform colour such as solids and continuous tone screen images. A mottled picture highly makes the picture smudgy and in most of the cases is not acceptable to the end user. It is required to print photographs with high sharpness and consistently from the very first print to the last print. Mottle pictures can also be observed visually and hence it needs utmost care and attention for enhancing the final print quality. Various types of mottles are generally resulted from the surface characteristics of the substrate, the setting and operation of the printing machines, and the behavior & characteristics of the printing in