The Influence of Paper on Physical-Chemical Characteristic Change of Fountain Solution

Paper with its properties and the way of producing in the process of offset printing changes properties of fountain solution. This is especially in respect with newspaper paper, where for the reasons of alkaline paper production process and its composition and structure, pH value in the printing process significantly changes. Except pH value, electrical conductivity and surface tension changes, as well other physical-chemical parameters. Investigations in this paper covered physical-chemical measurements of fountain solution in dependence on the quantity of newspaper printing paper, as well interacting time of the paper to the fountain solution. The results show that the addition of paper to the solution raises all physical chemical parameters. The wetting process is carried out in a mild acid media, in a pH range 4.4 to 4.9. Increasing pH value above 6 could cause a permanent damage of boemite Al2O3 structure that forms nonprinting elements, and that could cause changes in nonprinting elements structure and change their hydrophility. The increase of surface tension and contact angle of the fountain solution could cause significant changes in physical-chemical properties. These changes are evident in disturbing the emulgation ratio and the ink-water ratio. The investigations we made are of significance in the field of graphic reproduction. The possibility of damaging the printing plate surfaces which do not accept ink in the printing process could cause disturbance of ink-water balance and prints of poor quality. With defining the influence time of the paper on the fountain solution, as well as with other characteristics of the fountain solution the limits of optimal quality reproduction were determined.