Comparative study of delta e of hybrid modulated and digitally modulated screening on different grades of paper

Abstract

Screening technology has become highly advanced during past few decades. This research emphasizes on the use of hybrid modulated(XMS) and digitally modulated screening (DMS) on different grades of paper for evaluating quality parameter. The purpose of thisresearch is to determine the significant differences that exist in measurable print attribute Delta E at 25%, 50% and 75% tint printed bymulticolor sheet-fed offset printing process using XM and DM screening. The experiment is conducted using FOGRA39/ PSO standard.The master of 44.5×29.5 cm output is prepared by incorporating quality measuring parameters and printed in KCMY color sequenceon different paper types by RYOBI 524HX Sheet fed offset process using XM and DM screening technologies. During test, around 150sheets were printed to achieve target Solid Ink density value (+ 0.05). Once the density values were achieved according to standard SIDvalues, next 50 sheets were printed, measured and evaluated. Delta E is used to determine the color difference perceived by humaneye. The color values are specified in the Lab color space. To achieve quality in printing the grey component must be adjusted so thatchromatic CMY values are matched with achromatic in print (grey balance correction).