Lithography

This article is about a printing method. For rock types, seeLithology.For the microfabrication process, seemicrolithography.

Lithography(fromAncient Greekλίθος(líthos)'stone' andγράφω(gráphō)'to write')is aplanographicmethod ofprintingoriginally based on theimmiscibilityof oil and water.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 actorAlois Senefelderand was initially used mostly formusical scoresand maps.Lithography can be used to print text or images onto paper or other suitable material.Alithographis something printed by lithography, but this term is only used forfine art printsand some other, mostly older, types of printed matter, not for those made by modern commercial lithography.

A lithograph ofCharles Marion Russell'sThe Custer Fight(1903), with the range of tones fading toward the edges

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 flatlimestoneplate. The stone was then treated with a mixture ofweak acidandgum arabic( "etch" ) that made the parts of the stone's surface that were not protected by the grease morehydrophilic(water attracting). For printing, the stone was first moistened. The water only adhered 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 blankpapersheet, producing a printed page. This traditional technique is still used forfine artprintmaking.

In modern commercial lithography, the image is transferred or created as a patternedpolymercoating applied to a flexible plastic or metal plate.The printing plates, whether stone or metal, can be created by aphotographicprocess, a method that may be referred to as "photolithography" (although the term usually refers to a vaguely similarmicroelectronics manufacturing process).Offset printingor "offset lithography" is an elaboration of lithography in which the ink is transferred from the plate to the paper by means of arubberplate or cylinder, rather than by direct contact of the two. This technique keeps the paper dry and allows high speed fully automated 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 fromintaglio printing(gravure), wherein a plate isengraved,etched,orstippledto score cavities to contain the printing ink; andwoodblock printingorletterpress printing,wherein ink is applied to the raised surfaces of letters or images.

The principle of lithography

Lithography uses simple chemical processes to create an image. For instance, the positive part of an image is a water-repelling ( "hydrophobic") substance, while the negative image would be water-retaining (" hydrophilic "). Thus, when the plate is introduced to a compatible printing ink and water mixture, the ink will adhere to the positive image and the water will clean the negative image. This allows a flat print plate to be used, enabling much longer and more detailed print runs than the older physical methods of printing (e.g., intaglio printing, letterpress printing).

Lithography was invented byAlois Senefelderin theKingdom of Bavariain 1796. In the early days of lithography, a smooth piece of limestone was used (hence the name "lithography": "lithos" (λιθος) is theAncient Greekword for "stone" ). After the oil-based image was put on the surface, a solution of gum arabic in water was applied, the gum sticking only to the non-oily surface. During printing, water adhered to the gum arabic surfaces and was repelled by the oily parts, while the oily ink used for printing did the opposite.

Lithography on limestone

Lithography stone andmirror imageprint of a map of Munich

Lithography works because of the mutualrepulsion of oil and water.The image is drawn on the surface of the print plate with a fat or oil-based medium (hydrophobic) such as awax crayon,which may be pigmented to make the drawing visible. A wide range of oil-based media is available, but the durability of the image on the stone depends on thelipidcontent of the material being used, and its ability to withstand water and acid. After the drawing of the image, anaqueous solutionofgum arabic,weakly acidified withnitric acid(HNO
₃) is applied to the stone. The function of this solution is to create a hydrophilic layer ofcalcium nitratesalt,Ca(NO
₃)
₂,and gum arabic on all non-image surfaces.The gum solution penetrates into the pores of the stone, completely surrounding the original image with a hydrophilic layer that will not accept the printing ink. Using lithographicturpentine,the printer then removes any excess of the greasy drawing material, but a hydrophobic molecular film of it remains tightly bonded to the surface of the stone, rejecting the gum arabic and water, but ready to accept the oily ink.

When printing, the stone is kept wet with water. The water is naturally attracted to the layer of gum and salt created by the acid wash.Printing inkbased ondrying oilssuch aslinseed oilandvarnishloaded withpigmentis then rolled over the surface. The water repels the greasy ink but the hydrophobic areas left by the original drawing material accept it. When the hydrophobic image is loaded with ink, the stone and paper are run through a press that applies even pressure over the surface, transferring the ink to the paper and off the stone.

This very early colour lithograph from 1835 uses large washes of orange and cyan with black ink providing the details.

Senefelder had experimented during the early 19th century with multicolor lithography; in his 1819 book, he predicted that the process would eventually be perfected and used to reproduce paintings.Multi-color printing was introduced by a new process developed byGodefroy Engelmann(France) in 1837 known aschromolithography.A separate stone was used for each color, and a print went through the press separately for each stone. The main challenge was to keep the images aligned (in register). This method lent itself to images consisting of large areas of flat color, and resulted in the characteristic poster designs of this period.

A lithographer at work, 1880

"Lithography, or printing from soft stone, largely took the place of engraving in the production of English commercial maps after about 1852. It was a quick, cheap process and had been used to print British army maps during thePeninsular War.Most of the commercial maps of the second half of the 19th century were lithographed and unattractive, though accurate enough. "

Modern lithographic process

Main article:Offset printing

1902 Polish lithograph map of the western parts of theRussian Empire.Original size 33 cm × 24 cm (13.0 in × 9.4 in).

High-volume lithography is used to produce posters, maps, books, newspapers, and packaging—just about any smooth, mass-produced item with print and graphics on it. Most books, indeed all types of high-volume text, are printed using offset lithography.

For offset lithography, which depends on photographic processes, flexiblealuminum,polyester,mylaror paper printing plates are used instead of stone tablets. Modern printing plates have a brushed or roughened texture and are covered with a photosensitiveemulsion.Aphotographic negativeof the desired image is placed in contact with the emulsion and the plate is exposed toultraviolet light.After development, the emulsion shows a reverse of the negative image, which is thus a duplicate of the original (positive) image. The image on the plate emulsion can also be created by direct laser imaging in a CTP (computer-to-plate) device known as a platesetter. The positive image is the emulsion that remains after imaging. Non-image portions of the emulsion have traditionally been removed by a chemical process, though in recent times, plates have become available that do not require such processing.

Lithography press for printing maps in Munich

Lithography machine inBibliotheca Alexandrina

The plate is affixed to a cylinder on a printing press. Dampening rollers apply water, which covers the blank portions of the plate but is repelled by the emulsion of the image area. Hydrophobic ink, which is repelled by the water and only adheres to the emulsion of the image area, is then applied by the inking rollers.

If this image were transferred directly to paper, it would create a mirror-type image and the paper would become too wet. Instead, the plate rolls against a cylinder covered with a rubberblanket,which squeezes away the water, picks up the ink and transfers it to the paper with uniform pressure. The paper passes between the blanket cylinder and a counter-pressure or impression cylinder and the image is transferred to the paper. Because the image is first transferred, oroffsetto the rubber blanket cylinder, this reproduction method is known asoffset lithographyoroffset printing.

Many innovations and technical refinements have been made in printing processes and presses over the years, including the development ofpresseswith multiple units (each containing one printing plate) that can print multi-color images in one pass on both sides of the sheet, and presses that accommodate continuous rolls (webs) of paper, known as web presses. Another innovation was the continuous dampening system first introduced by Dahlgren, instead of the old method (conventional dampening) which is still used on older presses, using rollers covered with molleton (cloth) that absorbs the water. This increased control of the water flow to the plate and allowed for better ink and water balance. Recent dampening systems include a "delta effect or vario", which slows the roller in contact with the plate, thus creating a sweeping movement over the ink image to clean impurities known as "hickies".

Archive of lithographic stones in Munich

This press is also called an ink pyramid because the ink is transferred through several layers of rollers with different purposes. Fast lithographic 'web' printing presses are commonly used in newspaper production.

The advent ofdesktop publishingmade it possible for type and images to be modified easily on personal computers for eventual printing by desktop or commercial presses. The development of digitalimagesettersenabled print shops to produce negatives for platemaking directly from digital input, skipping the intermediate step of photographing an actual page layout. The development of the digitalplatesetterduring the late 20th century eliminated film negatives altogether by exposing printing plates directly from digital input, a process known as computer-to-plate printing.

Lithography as an artistic medium

Further information:List of printmakers

During the early years of the 19th century, lithography had only a limited effect onprintmaking,mainly because technical difficulties remained to be overcome. Germany was the main center of production in this period.Godefroy Engelmann,who moved his press fromMulhouseto Paris in 1816, largely succeeded in resolving the technical problems, and during the 1820s lithography was adopted by artists such asDelacroixandGéricault.After early experiments such asSpecimens of Polyautography(1803),which had experimental works by a number of British artists includingBenjamin West,Henry Fuseli,James Barry,Thomas Barker of Bath,Thomas Stothard,Henry Richard Greville,Richard Cooper,Henry Singleton,andWilliam Henry Pyne,London also became a center, and some of Géricault's prints were in fact produced there.Goyain Bordeaux produced his last series of prints by lithography—The Bulls of Bordeauxof 1828. By the mid-century the initial enthusiasm had somewhat diminished in both countries, although the use of lithography was increasingly favored for commercial applications, which included the prints ofDaumier,published in newspapers.Rodolphe BresdinandJean-François Milletalso continued to practice the medium in France, andAdolph Menzelin Germany. In 1862 the publisher Cadart tried to initiate a portfolio of lithographs by various artists, which was not successful but included several prints byManet.The revival began during the 1870s, especially in France with artists such asOdilon Redon,Henri Fantin-LatourandDegasproducing much of their work in this manner. The need for strictly limitededitionsto maintain the price had now been realized, and the medium became more accepted.

In the 1890s, color lithography gained success in part by the emergence ofJules Chéret,known as thefather of the modern poster,whose work went on to inspire a new generation of poster designers and painters, most notablyToulouse-Lautrec,and former student of Chéret,Georges de Feure.By 1900 the medium in both color and monotone was an accepted part of printmaking.

During the 20th century, a group of artists, includingBraque,Calder,Chagall,Dufy,Léger,Matisse,Miró,andPicasso,rediscovered the largely undeveloped artform of lithography thanks to theMourlot Studios,also known asAtelier Mourlot,a Parisian printshop founded in 1852 by the Mourlot family. The Atelier Mourlot originally specialized in the printing of wallpaper; but it was transformed when the founder's grandson,Fernand Mourlot,invited a number of 20th-century artists to explore the complexities of fine art printing. Mourlot encouraged the painters to work directly on lithographic stones in order to create original artworks that could then be executed under the direction of master printers in small editions. The combination of modern artist and master printer resulted in lithographs that were used as posters to promote the artists' work.

Grant Wood,George Bellows,Alphonse Mucha,Max Kahn,Pablo Picasso,Eleanor Coen,Jasper Johns,David Hockney,Susan Dorothea White,andRobert Rauschenbergare a few of the artists who have produced most of their prints in the medium.M. C. Escheris considered a master of lithography, and many of his prints were created using this process. More than other printmaking techniques,printmakersin lithography still largely depend on access to goodprinters,and the development of the medium has been greatly influenced by when and where these have been established.An American scene for lithography was founded byRobert Blackburnin New York City.

As a special form of lithography, the serilith orseriolithographprocess is sometimes used. Seriliths are mixed-media original prints created in a process in which an artist uses the lithograph andserigraph(screen printing). Fine art prints of this type are published by artists and publishers worldwide, and are widely accepted and collected. The separations for both processes are hand-drawn by the artist. The serilith technique is used primarily to create fine art limited print editions.

See also

• Block printing
• Color printing
• Flexography
• German inventors and discoverers
• History of graphic design
• Lineography
• List of art techniques
• Proton beam writing,lithography using MeV ions
• Photochrom
• Photogravure
• Photolithography
• Theodore Regensteiner,inventor of the four-color lithographic press
• Rotogravure
• Stencil lithography
• Stereolithography
• Typography

External links

• About Lithography
• Twyman, Michael.Early Lithographed Books.Pinner, Middlesex:Private Libraries Association,1990
• Museum of Modern Art information on printing techniques and examples of prints
• The Invention of Lithography,Aloys Senefelder, (Eng. trans. 1911) (a searchable facsimile at the University of Georgia Libraries;DjVuandlayered PDFformat)
• Theo De Smedt's website, author of"What's lithography"
• Extensive information on Honoré Daumier and his life and work, including his entire output of lithographs
• Digital work catalog to 4000 lithographs and 1000 wood engravings
• Detailed examination of the processes involved in the creation of a typical scholarly lithographic illustration in the 19th century
• Nederlands Steendrukmuseum
• Delacroix'sFaustlithographs at the Davison Art Center, Wesleyan University
• A brief historic overview of Lithography.University of Delaware Library. Includes citations for 19th century books using early lithographic illustrations.
• Philadelphia on Stone: The First Fifty Years of Commercial Lithography in Philadelphia.Library Company of Philadelphia. Provides an historic overview of the commercial trade in Philadelphia and links to a biographical dictionary of over 500 Philadelphia lithographers and catalog of more than 1300 lithographs documenting Philadelphia.
• Prints & People: A Social History of Printed Pictures,an exhibition catalog from The Metropolitan Museum of Art (fully available online as PDF), which contains material on lithography
• Czech author oflithography