On the Printing sharpness of News Print Paper and the Measuring Method for Smoothness of It

Abstract

The study was done that by which of Bekk method and Chapman method, the testing methods for smoothness of paper, we could estimate more exactly the printing sharpness of news print paper. Results obtained were as follows. (1) Comparing the sample B which indicated low smoothness in Bekk method but high smoothness in Chapman method with the sample D which indicated high smoothness in Bekk method but low smoothness in Chapman method, it was recognized that the sample B was more exellent in the printing sharpness than the sample D. (2) The sample B had higher compressibility and lower density than the sample D, therefore it was supposed that the difference in the smoothness data between both methods was due to the difference in used pressure. (In Bekk method low pressure is used and in Chapman method high pressure is used.) However, even if we used as high pressure as Chapman method in Bekk method, we could not gain equivalent data to those in Chapman method. Consequantly, it seemed that the difference between data in both methods was not caused by the difference in force to press the specimen, but caused by the difference in the measuring principle of the used methods. (3) Through above mentioned, as to the testing method for smoothness in order to estimate the printing sharpness of news print paper, Chapman method was more suitable than Bekk method, at least on the printing conditions in authors' experiments.