Difference between revisions of "Wet-collodion"
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| − | '''Wet-Collodion''' is a negative-positive [[:Category:Photographic processes|photographic process]] using potassium iodide dissolved with ''collodion'' - a solution of gun-cotton in ether. Gun-cotton is made by treating cotton wool with nitric acid, producing nitro-cellulose | + | The '''Wet-Collodion''' process is a negative-positive [[:Category:Photographic processes|photographic process]] using potassium iodide dissolved with ''collodion'' - a solution of gun-cotton in ether. Gun-cotton is made by treating cotton wool (almost pure cellulose) with nitric acid, producing nitro-cellulose. Nitro-cellulose was later used as a flexible film base; in the wet collodion process it does the job that gelatine does in modern film; it contains the light-sensitive material, in a layer permeable to chemical solutions. |
| − | The potassium iodide/collodion solution is spread onto glass plates, where the ether evaporates. Before the ether completely evaporates, the plates are sensitized in a bath of silver nitrate solution. Plates had to be exposed whilst still wet, so the plate preparation had to be done immediately before use | + | The potassium iodide/collodion solution is spread onto glass plates, where the ether evaporates. Before the ether completely evaporates, the plates are sensitized in a bath of silver nitrate solution. Plates had to be exposed whilst still wet, so the plate preparation had to be done immediately before use (once dry, the collodion would not be permeable to the developing solution<ref name=NMM></ref>). This meant that outside the studio, photographers had to carry a small tent with a supply of plates, sensitization bath and bottles of the solutions. However, the process was popular in part because the plates were considerably more sensitive than other existing media, allowing shorter exposure times, which in particular made portrait photography more convenient.<ref name=NMM>[http://www.nationalmediamuseum.org.uk/ National Media Museum] Information Sheet [http://www.nationalmediamuseum.org.uk/~/media/Files/NMeM/PDF/Collections/Photography/PhotographsOnGlass.ashx ''Photographs on Glass''].</ref> |
The process was invented in 1850, and published in 1851 by [[Frederick Scott Archer]], although a Frenchman, Gustave Le Gray may have discovered the process at around the same time. | The process was invented in 1850, and published in 1851 by [[Frederick Scott Archer]], although a Frenchman, Gustave Le Gray may have discovered the process at around the same time. | ||
| − | + | ===Notes=== | |
| − | + | <references /> | |
| − | == | ||
| + | ===Links=== | ||
* [http://www.cwreenactors.com/phorum/ Wet Plate Collodion Forum] | * [http://www.cwreenactors.com/phorum/ Wet Plate Collodion Forum] | ||
| − | * [http://en.wikipedia.org/wiki/Collodion_process Wikipedia] | + | * [http://en.wikipedia.org/wiki/Collodion_process ''Collodion Process'' on Wikipedia] |
| + | * [http://unblinkingeye.com/Articles/WPC/wpc.html ''Getting Started in Wetplate Collodion Photography''] by Joseph Smigiel on [http://unblinkingeye.com/ Unblinking Eye]. | ||
* [http://www.mhs.ox.ac.uk/cameras/item8.htm Lewis Carroll's wet-collodion outfit] and a [http://www.mhs.ox.ac.uk/cameras/index.htm?item7 portable sensitizing tank for collodion plates] in the catalogue of an exhibition ''Cameras: the Technology of Photography'' at [http://www.mhs.ox.ac.uk/ Museum of the History of Science, Oxford] 20 May - 13 September 1997. | * [http://www.mhs.ox.ac.uk/cameras/item8.htm Lewis Carroll's wet-collodion outfit] and a [http://www.mhs.ox.ac.uk/cameras/index.htm?item7 portable sensitizing tank for collodion plates] in the catalogue of an exhibition ''Cameras: the Technology of Photography'' at [http://www.mhs.ox.ac.uk/ Museum of the History of Science, Oxford] 20 May - 13 September 1997. | ||
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| + | [[Category: Photographic processes]] | ||
Revision as of 02:54, 6 May 2011
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| wet-plate camera with brass lens made by Charles Louis Chevalier image by Roman Art (Image rights) |
The Wet-Collodion process is a negative-positive photographic process using potassium iodide dissolved with collodion - a solution of gun-cotton in ether. Gun-cotton is made by treating cotton wool (almost pure cellulose) with nitric acid, producing nitro-cellulose. Nitro-cellulose was later used as a flexible film base; in the wet collodion process it does the job that gelatine does in modern film; it contains the light-sensitive material, in a layer permeable to chemical solutions.
The potassium iodide/collodion solution is spread onto glass plates, where the ether evaporates. Before the ether completely evaporates, the plates are sensitized in a bath of silver nitrate solution. Plates had to be exposed whilst still wet, so the plate preparation had to be done immediately before use (once dry, the collodion would not be permeable to the developing solution[1]). This meant that outside the studio, photographers had to carry a small tent with a supply of plates, sensitization bath and bottles of the solutions. However, the process was popular in part because the plates were considerably more sensitive than other existing media, allowing shorter exposure times, which in particular made portrait photography more convenient.[1]
The process was invented in 1850, and published in 1851 by Frederick Scott Archer, although a Frenchman, Gustave Le Gray may have discovered the process at around the same time.
Notes
- ↑ 1.0 1.1 National Media Museum Information Sheet Photographs on Glass.
Links
- Wet Plate Collodion Forum
- Collodion Process on Wikipedia
- Getting Started in Wetplate Collodion Photography by Joseph Smigiel on Unblinking Eye.
- Lewis Carroll's wet-collodion outfit and a portable sensitizing tank for collodion plates in the catalogue of an exhibition Cameras: the Technology of Photography at Museum of the History of Science, Oxford 20 May - 13 September 1997.
