Study of the Printability of Matt Papers by means of Photoacoustics

摘要

Microphotographs show different structures of the surface coating of tested papers -from the relatively smooth (APCO) to the rough structure of the G-PRINT paper. The ink printed on a bare paper produces a relatively smooth ink layer (increase in the gloss) attached to the substrate by means of an intermediate layer formed by the penetration of ink into the coating structure of the coated paper. The thickness, density and structure of this layer depend on both ink properties and paper finishing. Our study proved that a photoacoustic technique could be very useful for evaluating the optical, geometrical and structural (thermal diffusivity and conductivity) properties of this intermediate ink/paper layer. The evaluation of the real deposited ink on substrates in multicolour printing and the extent of ink trapping are very important for digital workflow in prepress, and for the exact formulation of ICC profiles, especially for presses of non-obvious construction Results presented in this study show that an analysis of the optical, structural and mechanical properties of thin ink layers on different substrates on prints can be very effective using as experimental techniques a combination of: photoacoustics optical spectrophotometry and colorimetry. We shall continue our photoacoustic study of ink/matt-paper interactions using higher modulation frequencies and high er energy light-excitation sources (lasers 632.8nm and 403nm).