A printing process in which an image is represented on a flat surface that has been treated so that some areas retain ink, others repel it. Originally the flat surface was limestone, but now a variety of metallic or plastic sheets are used. The image may be reverse drawn on the surface or drawn directly on a specially treated paper and then transferred to the surface. The technique has been frequently used for posters. Unlike intaglio printing (e.g. Engraving, woodcutting or etching), lithography does not require cuts into the printed surface, and represents an improvement over such older forms insofar as it allows for a longer run or edition of prints before the image deteriorates.