It's More than Just Black and White
For a continuation of our ongoing series regarding the different types of photography I thought today we'd take a look at three more well-known processes.
Gelatin Silver Print: As the dominant photographic mode from its inception in the 1880's through the middle part of the 19th century, the silver gelatin print remains a mainstay in the black and white photography world. The image is printed on paper coated with an emulsion of gelatin and silver salts. Variations of types of paper and silver salt can effect the end product.
- Silver chloride- used for contact printing, produces a generally neutral black
- Silver bromide- used for enlargements, produces a bluish black or cool tone
- Chloro-bromide- may be used for either, produces a warm, brownish black tone
Stanko Abadzic: A Day When Everything Goes Wrong, 2000/2008 (gelatin silver print)
Platinum and palladium print: Unlike the gelatin silver print, this process uses no emulsion and lies on the paper surface itself. This results in a matte surface with a deposit of platinum/palladium absorbed slightly onto the paper and produces delicate rich tones and a range of grays that are unachievable in silver prints. Palladium was introduced as a replacement for platinum paper during the advent of World War I when the price of platinum became too expensive.
Tom Hawkins: Salt Harvest #5: Bonaire, 1999 (platinum print)
Sepia and Selenium toned gelatin silver print: Toning is a common process used to change the color of black and white photographs using a chemical process carried out on silver-based prints by replacing the metallic silver in the emulsion with a silver compound. Toning can increase the range of visible shades in a print without reducing the contrast and can improve the chemical stability of the print, increasing its potential longevity. Sepia prints use silver sulfide resulting in a warmer tone, whereas selenium prints use silver selenide to produce a red-brown or purple-brown tone, depending on the strength of the solution.
Josef Hoflehner: Water Walk, 2007 (selenium toned gelatin silver print)