Lithography is a planographic process in which the design is drawn or painted with greasy chalk or ink on the printing surface, traditionally stone. The drawing is then fixed on the stone by applying a solution of water-soluble resin and acid. The surface is moistened and, as grease and water do not combine, the drawn areas repel the water and the untouched parts absorb it. A greasy ink is then applied over the surface with a roller. The wet parts reject the ink while the greasy parts attract it. Paper is then placed over the surface of the stone, and both are passed through a press.
Lithography is a printing process based on the antipathy of grease and water. The printing elements used are limestone and aluminum or zinc plates, grained to varying degrees of roughness. The image can be produced by photochemical and transfer processes, or be drawn using lithographic crayons and pencils, tusche, chalk, and various grease, lacquer, or synthetic materials. The stone is then washed with a solution, thus chemically producing water-receptive non-printing areas and grease-receptive image areas. The drawing grease is cleaned from the printing surface. A roller bearing greasy printing ink is then rolled over the surface, with the ink adhering only to drawn grease-receptive image areas. Finally, paper is laid on top of the stone or plate, which is passed through a lithography press for transfer. Lithography is often described as a surface or planographic printing process in order to distinguish it from the relief and intaglio processes.
In a transfer lithograph, the design is drawn on paper and then transferred to the printing surface. The drawing is made with lithographic chalk or ink on prepared transfer paper. The paper is dampened and laid face down on the printing surface. Both are passed through the press and gradually the paper soaks off, leaving the greasy drawing adhered to the printing surface.