Type of planographic or surface printing used as an art process and in commercial printing, where the term is synonymous with offset printing; it is also used in the manufacture of integrated circuits. Lithography was invented c.1796 by Aloys Senefelder, and the Bavarian limestone he used is still considered the best material for art printing. Lithography is based on the antipathy of oil and water.

A drawing is made in reverse on the ground (flat) surface of the stone with a crayon or ink that contains soap or grease. The image produced on the stone will accept printing ink and reject water. Once the grease in the ink has penetrated the stone, the drawing is washed off and the stone kept moist. It is then inked with a roller and printed on a lithographic press. As a process, lithography is probably the most unrestricted, allowing a wide range of tones and effects. Several hundred fine prints can be taken from a stone.

The medium was employed by many 19th-cent. artists, including GOYA, DELACROIX, DAUMIER, DEGAS, WHISTLER, and TOULOUSE-LAUTREC. Among American artists noted for their lithographs are A.B. DAVIES, George BELLOWS, and CURRIER & IVES. The medium remains popular with contemporary artists.

Photolithography is frequently used in the commercial reproduction of art works. With the process, a photographic negative is exposed to light over a gelatin-covered paper, and those portions of the gelatin that are exposed become insoluble. The soluble portions are washed away, and the pattern to be printed is transferred to a stone or metal plate. In color lithography or color photolithography, a stone or plate is required for each color used.

The term photolithography is also applied to a process used in integrated circuit manufacture. Light is shined through the non-opaque portions of a pattern, or photomask, onto a piece of specially coated silicon or other semiconductor material. The portions of the coating that were exposed to light harden, and the unhardened coating is removed, as by an acid bath. The uncovered silicon is altered to produce one layer of the integrated circuit. Advances in this technique have replaced visible and ultraviolet light frequencies with electron and X-ray beams, which permit smaller feature sizes in the patterns.

History of Lithography:
Like most print media, graphic arts were dependent on the invention of the printing press. This allowed for the mass production of all shapes and sizes of posters as well. The technique that is used to print posters, is called lithography. This is printing by placing ink on a series of metal or stone ("lithos") carvings which are really reliefs of color regions on the poster.

The Art of Lithography was invented by Alois Senefelder in 1798 in Austria. By1848 the process had been refined to the point that it was possible to print 10,000 sheers per hour. The First person to produce posters in mass through Lithography was Jules Ch ret (1836-1933). He worked in Paris, where his very first poster was entitled Orph e aux Enfants(1958). In 1889 Ch ret was awarded the Legion of Honor for creating a "new branch of art."