lithography

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A printing process in which the image to be printed is rendered on a flat surface, as on sheet zinc or aluminum, and treated to retain ink while the nonimage areas are treated to repel ink.

Century Dictionary and Cyclopedia

1. n. The art of making a picture, design, or writing upon stone in such a manner that ink-impressions can be taken from the work, and of producing such impressions by a process analogous to ordinary printing. Lithography was invented by Aloys Senefelder of Munich, about 1796. A special kind of stone is used, called lithographic stone. (See lithographic.) The design may be put upon the stone by direct drawing, by transfer from paper or from another stone, by engraving, or by-transfer from a photograph. In the first process the stone is prepared by grinding to give it a grained or slightly roughened surface, on which the design is drawn with a lithographic crayon precisely as it is to appear in print, but reversed; or the surface is smoothed, and the design is made with pen or brush in lithographic ink. When the drawing is finished, the stone is etched with dilute nitric acid, and then flooded with a solution of gum arabic in water, or it is flooded with nitric-acid and gum-arabic solutions combined. The acid decomposes the soap of the crayon or ink, and leaves the marked surface of the stone in a chemical condition that fits it to absorb fatty inks. The gum-water, on the other hand, covers with an adherent film all those parts of the surface of the stone which have been left untouched by the crayon or ink. The stone is then passed on to the printer, who “washes out” the picture with turpentine, after which the image appears faintly defined in white. To print from it, an inking-roller is now passed over the stone. The wet gummed surface resists the ink and remains clean, while the design takes up the ink and readily gives it back to paper under pressure in the press. The second or autographic process is by transfer. The design, picture, map, or writing is made on prepared paper with the proper ink, dampened, laid face downward on a heated stone and pulled through the press, when the ink leaves the paper and adheres to the stone. The after-treatment is the same as in the first process. Transfers are also made from stone to stone in like manner, to save from wear the original drawing on the first stone. The third process is allied to copperplate engraving. A smooth stone is prepared with gum-water, its face is colored with lampblack or other pigment, and the picture is scratched through the gum with a steel needle. When it is finished the stone is oiled, and the oil is absorbed wherever the surface of the stone has been laid bare by the needle. The incised design is thus made fit to take up fatty inks, which are resisted by the gummed surface so long as it is kept damp. The fourth process is that of transferring a photograph to the stone, and is called photolithography (which see). These four processes are modified and combined in a great variety of ways, yet in all, with the exception of photolithography, the method is essentially that invented by Senefelder.

Wiktionary

1. n. The process of printing a lithograph on a hard, flat surface; originally the printing surface was a flat piece of stone that was etched with acid to form a surface that would selectively transfer ink to the paper; the stone has now been replaced, in general, with a metal plate.

GNU Webster's 1913

1. n. The art or process of putting designs or writing, with a greasy material, on stone, and of producing printed impressions therefrom. The process depends, in the main, upon the antipathy between grease and water, which prevents a printing ink containing oil from adhering to wetted parts of the stone not covered by the design. See Lithographic limestone, under lithographic.
2. n. a printing process for reproducing images, using any flat surface, such as a metal plate, in a manner similar to lithography{1}.
3. n. The process of producing patterns on semiconductor crystals by exposing photosensitive coatings on a matrix, such as silicon, to light patterns in the form desired for the circuit, and subsequently treating (e.g., chemically) the patterns thus formed in such a way as to create integrated semiconductor circuits with the desired properties. This is the principle method (1990's) to create the high-density integrated circuits used in the digital computers on which you are reading this.

WordNet 3.0

1. n. a method of planographic printing from a metal or stone surface
2. n. the act of making a lithographic print