Effects of viscosity, pressure and time on the penetration of varnishes and inks into paper

Summary The penetration of varnishes and inks into supercalendered paper under pressure was studied by means of reflectance measurements. The penetration appeared to be proportional to the square root of the ratio of the magnitude and duration of the applied pressure to the viscosity. This relationship is in agreement with the classical physical law for the viscous flow of fluid into a porous medium. It is also concluded that for the systems studied the ink penetrates, under the applied pressure, as a homogeneous body into the paper with no filtration of pigments from the carrying varnish.