From Wikipedia:
The term Woodburytype refers to both a photomechanical process and the print produced by this process. The process produces continuous tone images in slight relief. A chromated gelatin film is exposed under a photographic negative, which hardens in proportion to the amount of light. Then it is developed in hot water to remove all the unexposed gelatin and dried. This relief is pressed into a sheet of lead in a press with 5000 psi. This is an intaglio plate. It is used as a mold and is filled with pigmented gelatin. The gelatin layer is then pressed onto a paper support.
The term Woodburytype refers to both a photomechanical process and the print produced by this process. The process produces continuous tone images in slight relief. A chromated gelatin film is exposed under a photographic negative, which hardens in proportion to the amount of light. Then it is developed in hot water to remove all the unexposed gelatin and dried. This relief is pressed into a sheet of lead in a press with 5000 psi. This is an intaglio plate. It is used as a mold and is filled with pigmented gelatin. The gelatin layer is then pressed onto a paper support.
The Woodburytype was developed by Walter B. Woodbury in 1864, first used in a publication in 1866 and widely used for fine book illustration from about 1870 to 1900.It was the only commercially successful method for producing illustration material capable of replicating the subtleties and details of a photograph. It is the only mechanical printing method ever invented which produces true middle values and does not make use of a screen or other image deconstruction method.
