StruktAnaly v Druckbd u Pap i - Rotogravure Printability and Structure Analysis of SC-Paper

The project 'Rotogravure Printability and Structure Analysis of SC-Paper' was aimed to explore the causes for print mottle of gravure printed SC paper. The focus was set on the analysis of paper structure and identification of paper properties that cause print mottle. Five main fields of work have been adressed: 1.) Because of the low viscosity of the gravure printing ink and the high ink absorption of SC paper, printing ink penetration has often been mentioned as a main reason for mottle. The main objectives are: a.) Development of a technique to measure local variations of printing ink penetration. b.) Resolving the influence of printing ink penetration on print mottle. 2.) One of the main problems with print mottle is, that multiple interacting paper properties are involved in its occurrence. Often mentioned are for example formation, surface topography or printing ink penetration. The main objectives are: a.) Quantitative determination of the varying influence factors. Which paper properties have major influence, which ones have minor influence? Which parameters do not have any effect at all? b.)Evaluation of measurement methods, in order to identify techniques relevant for mottle analysis and avoid irrelevant ones. 3.) Evaluation of printing dot size and amount of transferred ink and its relation to mottle. Such analysis provides useful information: Is gravure mottle caused by varying amounts of transferred ink or is it caused by differences in the ink preading behavior of the individual printing dots? 4.) Not only the overall surface roughness and compressibility, but also local variations of these properties are generally believed to have an influence on print mottle. The influence of local roughness and compressibility variations on print quality was investigated. 5.) Analysis of industrial paper samples provided by the project partners. Investigation of commercial samples provides practical applicability of the research results.