Introducing a new method for generating test targets to evaluate printing mottle

Abstract

Printing mottle is one of the most important print quality factors. It is defined as measure of the appearance of unintended, periodic macroscopic fluctuations of lightness (macroscopic means: between ‘spots’ at distances > 1 mm). Mottle is caused by several phenomena. The non-uniformity absorption of ink, which may be because of the paper roughness or ink quality, may cause various degree of printing mottle. Print quality assessments are usually based on comparing test samples and references as a ruler of different quality samples. Therefore, it is important to prepare appropriate rulers for different quality metrics. There are methods like adding moisture to paper before printing to simulate printing mottle.The present study introduces a new method for generating test targets to evaluate printing mottle. In this method, a set of noise patterns like Hermit and Value noises were used. By changing parameters like frequency and amplitude, we achieved different levels of printing mottle.The experimental results show that with the proposed method, it is possible to generate different levels of mottle, which can be used to generate test targets and mottle rulers.