Acid-free

Also known as heliogravure, photogravure is arguably the finest photomechanical means of reproducing a photograph in large editions. Copper plates are acid-etched directly from an original silver print; the etched areas then hold differing amounts of ink in order to correspond to the tones of the original print. If prints remain untrimmed, the impression of…

Digital colour coupler Colour coupler prints, or chromogene prints, are very similar to standard C-type prints, but the silver salts ‘couple’ with coloured dyes, rather than being replaced by them. The end result is very similar to standard C-type prints. Colour coupler prints have the benefit of using the same extremely light-sensitive silver salts as…

Selenium gelatin photogram: see photogram and selenium toning. Selenium toned gelatin print: See silver gelatin print and selenium toning. Selenium toned photogram: see photogram and selenium toning. Selenium toning: A type of toning using the metal selenium to replace silver salts. Used both for the aesthetic benefits of a slightly warmer tone and greatly improved archival properties

A sheet of transparent film coated with silver salts which react when exposed to light (usually in a camera). In black and white negatives, one layer of salts reacts to white light (the full spectrum of light). The result is a reversal of normal vision: the shadows are light, the highlights dark. In colour negatives…

Resin-based paper Plastic-based paper type. The most common paper type for printing colour images as it gives greater gloss potential than fibre-based papers (e.g. supergloss on Fujiflex). R-type paper R-type papers work in the opposite way to traditional papers. A transparency (positive) is projected onto reversal paper which thus develops a positive image.

The autochrome is an early color photography process, patented the 17th December 1903 by Auguste and Louis Lumière. Before the commercialization, they diffused the autochrome technique to some favored photographers, like Sergey Prokudin-Gorsky. The commercialization started in 1907 and the technique was used between 1907 and about 1932. A lot of photos of the First World…