Dissertation Defenses

Doctoral Dissertation Announcement

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Candidate: Yu Ju Wu

Degree of: Doctor of Philosophy

Department: Paper Engineering, Chemical Engineering, and Imaging

Title: The Effect of Substrates Properties on Print Attributes for Gravure Printing: From Proof to Press

Committee:
Dr. Alexandra Pekarovicova, Chair
Dr. Paul Dan Fleming
Dr. Veronika Lovell

Date: Thursday, May 22, 2008 2:00 p.m. – 5:00 p.m.
Parkview Campus, Room B-211

Abstract:
Gravure is the major printing process used for publication printing. In gravure printing processes, color proofing is for the purpose of checking the color to ensure that it is as desired. There is no doubt that paper properties have significant effects on the image reproduction for either printing or proofing processes. In order to achieve uniformity of printing and obtain good color reproduction performance, it is important that the all paper properties are well defined and controlled. This study investigates the correlations between paper properties and print quality/color reproduction for gravure publication printing and ink jet printing used in digital proofing stages. In the first stage, the influence of coating compositions on light weight coated (LWC) paper properties and the impact of the paper properties on printing properties was investigated. In the second stage, the effect of paper properties on the color reproduction was examined, as well as color reproduction capability with inkjet proofing systems was evaluated in terms of proof-press color matching and spot color reproduction. It was found that LWC paper sample with a rougher surface and relatively large pore size/porosity tends to decrease print gloss and increase print mottle permanence. For the inkjet digital proofing process, paper with low roughness, high formation index, low porosity or air permeability, high brightness or whiteness, and high paper gloss properties exhibits a high gamut volume. By using the linearization and color matching functions build-in in the RIPs software, the chroma of the inkjet printer can be reduced to better match the printing press. The usage of third party RIP software also results in better spot color reproduction, due to special match features built into the software by the manufacturers. As color matches improve, inaccuracies due to a mismatch of paper color between the proofer and press become significant. In order to improve the appearance of a color match, paper white stimulation must be well understood and compensated for in the color matching processes.