Lithography is a method for printing using a stone (lithographic limestone) or a metal plate with a completely smooth surface. Invented in 1796 by Bavarian author Alois Senefelder as a low-cost method of publishing theatrical works, lithography can be used to print text or artwork onto paper or another suitable material.Lithography originally used an image drawn in wax or other oily substance applied to a lithographic stone as the medium to transfer ink to the printed sheet. In modern times, the image is often made of polymer applied to a flexible aluminum plate. The flat surface of the plate or stone is slightly roughened, or etched, and divided into hydrophilic regions that accept a film of water and thereby repel the greasy ink, and hydrophobic regions that repel water and accept ink because the surface tension is higher on the greasier image area which remains dry. The image may be printed directly from the stone or plate (in which case it is reversed from the original image) or may be offset by transfer to a flexible sheet, usually rubber, for transfer to the printed article printed directly from the stone or plate (in which case it is reversed from the original image) .