photogravure

Photogravure (in French héliogravure) is a process for printing photographs, also sometimes used for reproductive intaglio printmaking. It is a photo-mechanical process whereby a copper plate is grained (adding a pattern to the plate) and then coated with a light-sensitive gelatin tissue which had been exposed to a film positive, and then etched, resulting in a high quality intaglio plate that can reproduce detailed continuous tones of a photograph.
The process was important in 19th-century photography, but by the 20th century was only used by some fine art photographers. By the mid-century it was almost extinct, but has seen a limited revival.

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