Surface finishes

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 positive is, obviously, the opposite of a negative – that is, it is an image which is not reversed. Positive images are made through a double negative: silver salts react to light producing a negative which, when projected onto photographic paper (more silver salts), produces a positive.

C-type printing involves printing colour paper enlargements from small, colour negatives. This is the most common type of colour printing found in the high street and mini-labs.

Silver salts Silver salts are light sensitive chemical compounds. When exposed to light – either in a camera (in the case of film and negatives) or in the dark room (photographic papers) – the silver salts react by darkening in proportion to the amount of light reflected from the subject. Silver bromide Print Silver bromides…

Different types of photographic paper have varying degrees of susceptibility to fading over time. The main cause of this is exposure to UV (ultra violet) light, although humidity, temperature, pollution and acidity are all contributing factors. Exposure to direct sunlight should be avoided, and UV-resistant glass can be used when framing.