Comparative Analysis of Delta E Values of Hybrid Screening and Digitally Modulated Screening on Gloss Coated Paperin Offset Printing Process

Abstract

This research is an experimental study. The purpose of this research was to determine the significant differences that exist in measurable print attributes (Delta E at 25%, 50% and 75% tint) of XM vs. DM screening of multicolour offset printing process. The experiment was conducted using FOGRA 39/ PSO standard. Theplates/master of 44.5×29.5 cm output were prepared by incorporating quality measuring parameters and printed in KCMY colour sequence on coated paper on ‘RYOBI 524HX (Sheet fed Offset) by using XM and DM screening technologies. During test, around 150 sheets were printed to achieve target Solid Ink Density value (+ 0.5). Once the density values were achieved according to standard SID values, another 50 sheets were printed for spectrophotometer analysis.Delta E is used to determine the colour difference perceived by human eye. The colour values arespecified in the Lab colour space. To achieve quality in printing the grey component must be adjusted so that chromatic CMY values are matched with achromatic in print (grey balance correction).