Monday 4 October 2010

Lithographic Printing

Lithography
Lithography is a chemical process that uses flat print plates, which allow for much longer runs than the previous approach. A major point in the evolution in the development of graphic design, it gave designers a way to create multi-coloured printed images that held all manner of cropped, embedded and bordered images, as well as free running type.


Lithography is a method for printing using a stone or a metal plate with a completely smooth surface. Lithography can be used to print onto paper or other suitable materials.

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.

Examples of lithography printing:
  • Posters
  • Maps
  • Packaging
  • Newspapers
  • Smooth, mass produced items

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