Pore Volumes and Their Relations to Standard Surface Parameters and Print Quality, 1996 International Printing & Graphic Arts Conference Proceedings

O. Lovhaugen, E. L. Berli, F. Bjerke

The Norwegian pulp and Paper Research Institute

Surface height histograms have been acquired using a confocal laser scanning microscope (CLSM), Leica model TCS4D. The equivalent surface pore and a set of average pore volumes have been calculated. These pore volume parameters have been compared to standard surface roughness parameters like the Parker Print Surface and Bendtsen using statistical methods described in (1). Likewise the results from visual assessments of prints (2) have been correlated to these parameters. The paper gives a presentation of methods to obtain the surface height histograms and the definition used for the pore volume parameters. Results will be discussed using data from full scale printing trials on newsprint and uncoated liner. There is a better correspondence between the airflow measurements and the pore volume parameters for liner than for newsprint. This is to be expected, as the more open structure of the newsprint would result in higher air leakage through the fiber web and is not connected to the surface roughness. Also the stiffer newprint fibres give a more elastic web with a greater difference between the surface roughness for compressed and uncompressed newsprint.