Abstract: A cylindrical filter for use in a lithographic printing press recirculation system of the type that circulates fountain solution from a printing press pan, where it is applied to the printing press plate by means of a roller system, through the filter positioned in a reservoir or sump and then back to the roller system. The filter is generally cylindrical in shape and includes a hollow core extending along the central longitudinal axis of the filter, an inner surface surrounding the hollow core, an outer surface and porous filtering medium disposed between the inner surface and outer surface. The hollow core extends from a first closed end of the filter to an opposite second open end, which is removably coupled to a hose which channels the fountain solution from the printing press pan. The filtering medium comprises a graded density whereby the density at the outer surface of the filter is greater than the density at the inner surface of the filter.

Abstract: A non-aqueous fountain solution composition for use with offset printing systems prepared by dry blending 2-25% by weight of a film forming agent, 2.5-50% by weight of an acid, 2.5-50% by weight of an acid salt combination, 0.5-1.5% by weight of a biocide, 0-10% by weight of a sequestrant, 0-25% by weight of a corrosion inhibitor, 0-10% by weight of a humectant, and 0-5% by weight of an anti-foaming agent.