Fine unsigned Woodburytype Portrait Photograph, by Lock and Whitfield, (Sir Samuel White, 1821-1893, Traveller)]

showing him head and shoulders, in slight profile, looking to his right, with a heavy beard, in an oval, 4½" x 3¾", in mount 10½" x 8", no place, no date, circa 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. It is thought to produce the finest photographic images. 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.