Lithography
Lithography is an ancient technique used for multiple reproduction of an original. The drawing or painting is done with chalk or ink on stone which is, after a rather complicated chemical procedure, used for printing on paper. Each colour which should appear on the print is applied at a time, one by one on the same printing stone.
When I work, I must plan the layers of colour before printing and anticipate their combinations. In practice this means that I would not use green for example, because green can be created by combining yellow and blue. A precise idea of the final result is therefore essential. All required colour tones may, in most cases, be composed of four or five colours.