Summary

After many attempts to improve the print quality with newspapers by investigating better materials (see IFRA Special Reports 1.5, 1.7, 3.6, 3.10 and 3.15) this time we approached this field in a very pragmatic way. We asked six ink manufacturers and five newsprint manufacturers to send us samples of their standard products as well as their improved grades. Then we asked the researchers at the Technical University Chemnitz-Zwickau (TUCZ/IPT) to set-up a matrix scheme according to which the interaction of both materials, newsink and newsprint, had to be investigated in labora- tory testing, in laboratory printing and in production printing in the field. The findings indicate that with newsinks the viscosity and the composition of the binding agent have an important influence on the absorption and rub-off behaviour, while with newsprint a high degree of surface roughness more than a high percentage of filler (recycled newsprint) content seems to reduce set-off and rub-off for a better print quality. A follow-up project will try to clarify the influence of both components more in depth by using model inks with known composition. We hope that already this intermediate report will serve our members in getting a better understanding of the interaction of ink and paper.