Abstract:
A lithographic fountain solution concentrate is disclosed, the essential components of which comprises an aqueous mixture of: (a) from about 0. 1 to 1. 5 percent by weight of a water soluble film forming hydrophilic gum; (b) from about 0. 75 to about 8. 5 percent by weight of Polyvinyl Pyrrolidone; (c) from about 5. 0 to about 30. 0 percent by weight of a water soluble acid etchant; (d) from about 20. 0 to about 50. 0 percent by weight of a water soluble or water miscible glycol; and (e) from about 0. 01 to about 1. 25 percent by weight of a phosphate/phosphoric acid buffer system. The concentrate is adapted for further dilution by water to yield a fountain solution which when used in the printing process offers decreased scumming and blinding of printing plates while at the same time permitting a reduction in the amount of water applied to the plate. Improved print quality, reduced tendency to wet the paper, faster ink drying and improved ink/water balance is thereby achieved.