The salt print was the dominant paper-based

photographic process A list of photographic processing techniques. Color *Agfacolor **Ap-41 process (pre-1978 Agfa color slides; 1978-1983 was a transition period when Agfa slowly changed their color slide films from AP-41 to E6) *Anthotype *Autochrome Lumière, 1903 ...

for producing positive prints (from negatives) from 1839 until approximately 1860. Saint Michael's Church, Winterbourne

The salted paper technique was created in the mid-1830s by English scientist and inventor

Henry Fox Talbot William Henry Fox Talbot FRS FRSE FRAS (; 11 February 180017 September 1877) was an English scientist, inventor, and photography pioneer who invented the salted paper and calotype processes, precursors to photographic processes of the later ...

. He made what he called "sensitive paper" for "photogenic drawing" by wetting a sheet of writing paper with a weak solution of ordinary table salt (

sodium chloride Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...

), blotting and drying it, then brushing one side with a strong solution of

silver nitrate Silver nitrate is an inorganic compound with chemical formula . It is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It was once called ''lunar caustic' ...

. This produced a tenacious coating of

silver chloride Silver chloride is a chemical compound with the chemical formula Ag Cl. This white crystalline solid is well known for its low solubility in water (this behavior being reminiscent of the chlorides of Tl+ and Pb2+). Upon illumination or heating, ...

an especially light-sensitive chemical condition. The paper darkened where it was exposed to light. When the darkening was judged to be sufficient, the exposure was ended and the result was stabilized by applying a ''strong'' solution of salt, which altered the chemical balance and made the paper only slightly sensitive to additional exposure. In 1839, washing with a solution of

sodium thiosulfate Sodium thiosulfate (sodium thiosulphate) is an inorganic compound with the formula . Typically it is available as the white or colorless pentahydrate, . The solid is an efflorescent (loses water readily) crystalline substance that dissolves well i ...

("hypo") was found to be the most effective way to make the results truly light-fast. The salt print process is often confused with Talbot's slightly later 1841

calotype Calotype or talbotype is an early photographic process introduced in 1841 by William Henry Fox Talbot, using paper coated with silver iodide. Paper texture effects in calotype photography limit the ability of this early process to record low co ...

or "talbotype" process, in part because salt printing was mostly used for making prints from calotype paper negatives rather than live subjects. Calotype paper employed silver iodide instead of silver chloride. Calotype was a ''developing out'' process, not a ''printing out'' process like the salt print. The most important functional difference is that it allowed a much shorter exposure to produce an invisible

latent image {{citations needed, date=November 2015 A latent image is an invisible image produced by the exposure to light of a photosensitive material such as photographic film. When photographic film is developed, the area that was exposed darkens and form ...

which was then chemically developed to visibility. This made calotype paper far more practical for use in a

camera A camera is an Optics, optical instrument that can capture an image. Most cameras can capture 2D images, with some more advanced models being able to capture 3D images. At a basic level, most cameras consist of sealed boxes (the camera body), ...

. Salted paper typically required at least an hour of exposure in the camera to yield a negative showing much more than objects

silhouette A silhouette ( , ) is the image of a person, animal, object or scene represented as a solid shape of a single colour, usually black, with its edges matching the outline of the subject. The interior of a silhouette is featureless, and the silhou ...

d against the sky. Gold toning of the salted paper print was a popular technique to make it much more permanent.

References

Sources

* Taylor, Roger. ''Impressed by Light: British Photographs from Paper Negatives, 1840-1860'' (NY, Metropolitan Museum of Art, 2007)

External links

How to Make a Salt Print
(

Wayback Machine The Wayback Machine is a digital archive of the World Wide Web founded by the Internet Archive, a nonprofit based in San Francisco, California. Created in 1996 and launched to the public in 2001, it allows the user to go "back in time" and see ...

copy)
Salted Paper Printing Process

Salt Prints

* ttp://www.luminous-lint.com/app/contents/the/697/ Luminous Lint{{photography subject Alternative photographic processes Photographic processes dating from the 19th century

References

Sources

See also

External links