Lithography, discovered in 1796, was an early printing method that involved applying oil or wax to limestone plates. Offset lithography, found in 1875, is a modern technique where images are transferred from a plate to a rubber blanket and then to paper. Letterpress, used since the 15th century, imprints inked type onto paper by pressing them together. Laser printing and photocopies, a modern invention, provide a fast and inexpensive way to reproduce paper documents using digital technology.