Lithography is a printmaking process which uses a press to transfer an image that was created initially on a stone or metal plate on to paper.
The basic principle of lithography is the mutual repulsion of oil and water.
The artist draws on a stone or plate with a greasy wax crayon or pencil. If the lithograph is to be one colour, only one drawing is made. However, if it is to be mulitple colours, each colour generally requires a seperate stone or plate.
A craftsman printer then takes over. The printer chemically treats the surface to stabilize the image. The non-image area of the surface is waterproofed and kept wet to prevent the ink from adhering to these areas. The black original drawing materials are then removed with a solvent, which leaves the greasy image barely visible on the stone. When rolled up the printing inks, which are also greasy, will adhere to the drawn image area.
At the press, the printer prints a series of ‘trial proofs’: the same image with different colour and paper combinations. When the artist is satisfied the lithographs are editioned. Once the edition has been printed, the stone or plate is destroyed or erased, ensuring that no more impressions can be printed.