A Hybrid Model Approach for Achieving the Highest Level of Matching Between the “Print and Original” in the Sheet-Fed Offset Process

Abstract

This study was designed to explore an optimized hybrid system through dual measurement approach of contrast measurement method and CIE L*a*b* measurement method to arrive a logical interface for achieving the highest matching between the print and original in sheet fed offset printing process. The work was started with the detailed study of contrast measurement, CIE L*a*b* measurement method, visual and computational intelligence based assessment and control. The master was designed in such a way that value of density and other values can be measured easily in effective way. X-Rite eXact instrument is used for capturing the readings, the 10 standard observers were selected initially by manual method and finally by using on line Fransworth-Munsell 100 Hue Colour Vision Test and visual assessments and judgement were done on X-Rite’s Macbeth Lighting Booth and their visual assessments are recorded, analyzed and represented. All the parameters like Paper, Ink, Measuring Conditions and Measuring Instruments etc. were maintained in compliance with ISO specifications. After the analysis of data, the study reached to the following main conclusion i.e. It is observed that almost in all the cases, preference of the Standard Observers are for Delta E Value leading to the higher contrast value instead of Minimum Delta E with less contrast value. Therefore the dual approach of “Hybrid System” will help us to arrive at the most convincing, measurable and perceptually acceptable print result which will be the highest (closest) match to the original by clubbing the best of “CIE Lab, Contrast Method and Standard Observers Visual Perception” as there are positives and negatives in all these three when one approaches individually. The objective of this paper was to develop a dual measurement approach of CIE Lab & Contrast to arrive at a logical inference for the highest level of matching between the original and print in the sheet fed offset printing.