Etching is traditionally the process of using strong acid or mordant to cut into a metal surface to create a design in intaglio (the sunken in area that holds the ink) in the metal. In modern manufacturing, other chemicals may be used on other types of material.
Etching examples from UMMA's collection:
Engraving is an intaglio printmaking (the ink goes in the groove) process in which lines are cut into a metal plate in order to hold the ink. In engraving, the plate can be made of copper or zinc. The metal plate is first polished to remove all scratches and imperfections from the surface so that only the intentional lines will be printed.
Engraving examples from UMMA's collection:
Linocut, also known as lino print, lino printing, or linoleum art, is a printmaking technique, a variant of woodcut in which a sheet of linoleum is used for a relief surface (think like a rubber stamp, where the ink goes on the raised surfaces).
Linocut Examples from UMMA's Collection:
Lithography is a planographic printmaking process in which a design is drawn onto a flat stone (or prepared metal plate, usually zinc or aluminum) and affixed by means of a chemical reaction.
First, the design for the lithograph is drawn directly onto a polished slab of limestone using an oil-based lithographic crayon or ink. Once the design is complete, the stone is ready to be processed or etched. A layer of powdered rosin is rubbed onto the stone, followed by a layer of powdered talc.
Gum arabic, or a combination of gum arabic with a mild acid solution, is then brushed onto the stone. The chemical reaction between the solution and the stone fixes the greasy image that is drawn with the oil-based lithographic crayon. At the same time, the solution ensures that the blank areas of the stone will absorb water and repel printing ink.
The original drawing is then wiped away with a solvent, known as lithotine, which leaves a ghost-like trace of the image on the stone.
Lithograph Examples from UMMA's Collection: