Lithography

Part of a series on the
History of printing
Techniques Woodblock printing 200 Movable type 1040 Intaglio (printmaking) 1430 Printing press c. 1440 Etching c. 1515 Mezzotint 1642 Relief printing 1690 Aquatint 1772 Lithography 1796 Chromolithography 1837 Rotary press 1843 Hectograph 1860 Offset printing 1875 Hot metal typesetting 1884 Mimeograph 1885 Daisy wheel printing 1889 Photostat and rectigraph 1907 Screen printing 1911 Spirit duplicator 1923 Dot matrix printing 1925 Xerography 1938 Spark printing 1940 Phototypesetting 1949 Inkjet printing 1950 Dye-sublimation 1957 Laser printing 1969 Thermal printing c. 1972 Solid ink printing 1972 Thermal-transfer printing 1981 3D printing 1986 Digital printing 1991
v t e

Lithography (from Ancient Greek λίθος (líthos) 'stone' and γράφω (gráphō) 'to write')^[1] is a planographic method of printing originally based on the immiscibility of oil and water.^[2] The printing is from a stone (lithographic limestone) or a metal plate with a smooth surface. It was invented in 1796 by the German author and actor Alois Senefelder and was initially used mostly for musical scores and maps.^[3][4] Lithography can be used to print text or images onto paper or other suitable material.^[5] A lithograph is something printed by lithography, but this term is only used for fine art prints and some other, mostly older, types of printed matter, not for those made by modern commercial lithography.

Originally, the image to be printed was drawn with a greasy substance, such as oil, fat, or wax onto the surface of a smooth and flat limestone plate. The stone was then treated with a mixture of weak acid and gum arabic ("etch") that made the parts of the stone's surface that were not protected by the grease more hydrophilic (water attracting). For printing, the stone was first moistened. The water adhered only to the gum-treated parts, making them even more oil-repellant. An oil-based ink was then applied, and would stick only to the original drawing. The ink would finally be transferred to a blank sheet of paper, producing a printed page. This traditional technique is still used for fine art printmaking.^[6]

In modern commercial lithography, the image is transferred or created as a patterned polymer coating applied to a flexible plastic or metal plate.^[7] The printing plates, made of stone or metal, can be created by a photographic process, a method that may be referred to as "photolithography" (although the term usually refers to a vaguely similar microelectronics manufacturing process).^[8][9] Offset printing or "offset lithography" is an elaboration of lithography in which the ink is transferred from the plate to the paper indirectly by means of a rubber plate or cylinder, rather than by direct contact. This technique keeps the paper dry and allows fully automated high-speed operation. It has mostly replaced traditional lithography for medium- and high-volume printing: since the 1960s, most books and magazines, especially when illustrated in colour, are printed with offset lithography from photographically created metal plates.

As a printing technology, lithography is different from intaglio printing (gravure), wherein a plate is engraved, etched, or stippled to score cavities to contain the printing ink; and woodblock printing or letterpress printing, wherein ink is applied to the raised surfaces of letters or images.