Offset Lithography
This is a method of printing from a metal or stone surface on which the printing areas are made ink-receptive. Rather than pressing inked images onto paper using plates with raised or etched plates, an image is transferred to the paper using oil-based inks, chemically-treated plates made from photographic negatives, and an offset cylinder. The first lithographic offset printing press was created in England around 1875 and was designed for printing on metal. The offset cylinder was covered with specially treated cardboard that transferred the printed image from the litho stone to the surface of the metal. About five years later, the cardboard covering of the offset cylinder was changed to rubber, which is still the most commonly used material.