What printing technique uses a stone or metal plate with a greasy substance?

Lithography is a printing technique in which an image is drawn with a greasy substance on a smooth stone or metal plate.

The process depends on the repulsion between oil and water. In traditional lithography, the artist draws with oil, fat, or wax on limestone. The surface is then treated so that the unmarked areas attract water, while the greasy image remains water-repellent and ready to accept oily ink. When the plate is pressed against paper, the ink transfers the drawn image.

German author and actor Alois Senefelder invented lithography in 1796. He originally sought an inexpensive way to reproduce theatrical texts and musical scores, but the method soon became important for maps, illustrations, posters, and fine-art prints. Because the printing surface is flat, lithography is classified as a planographic technique.

A common mix-up is confusing lithography with etching. Etching uses acid to bite lines into a metal plate, while lithography uses chemical differences between greasy and water-loving areas on a flat surface. Modern offset printing is a later development based on the same basic principle.