Lithography

A lithography is a planographic print; the surface from which it is printed is flat. It is based on the repulsion between water and grease.

The printmaker draws or paints an image on a special slab of smooth limestone or metal plate. Greasy crayons are used or a greasy ink called “tusche”.
The surface of the stone is treated with a mild mixture of gum arabic and nitric acid. As a result the image will attract greasy ink and the blank areas will attract water. Grease and water do not mix. The printmaker dissolves the ink of the original drawing with turpentine. However, a ghostlike image of the drawing remains on the stone.
The surface of the stone is kept wet during printing. Water collects on the blank areas.
Greasy ink is rolled on with a roller. It is repelled by the wet areas. The ink sticks only where the marks of the drawing were.
A sheet of paper is placed on top of the stone and is covered with a backing sheet and a stiff, slick-surfaced board called a tympan. A scraper bar creates pressure as they pass through the press. When the paper is pulled away from the stone, the image has been printed on it in reverse.