Editing Collodion (section)

==Wet-plate collodion photography==
{{Main|Collodion process}}<!-- Linked from elsewhere! -->[[Image:1860 Anonyme Un vétéran et sa femme Ambrotype.jpg|right|thumb|Anonymous "A Veteran with his Wife", ambrotype]]
[[Image:Alice Liddell as Pomona by Julia Margaret Cameron.jpg|right|thumb|[[Julia Margaret Cameron]]'s "[[Alice Liddell]] as a Young Woman" print from wet collodion negative]]

In 1851, [[Frederick Scott Archer]], an Englishman, discovered that collodion could be used as an alternative to [[egg white]] (albumen) on glass photographic plates.<ref>Frederick Scott Archer (March 1851) [https://books.google.com/books?id=VxoFAAAAQAAJ&pg=PA257 "On the use of collodion in photography,"] ''The Chemist'' … , new series, '''2''' (19) :  257–258.</ref> Collodion reduced the exposure time necessary for making an image. This method became known as the 'wet-plate collodion' or 'wet collodion' method. Collodion was relatively grainless and colorless, and allowed for one of the first high-quality duplication processes, also known as [[Negative (photography)|negatives]]. This process also produced two types of [[Positive (photography)|positives]]: the [[ambrotype]] and the [[tintype]] (also known as [[ferrotype]]).

The process required great skill and included the following steps:
* Clean the glass plate (extremely well)
* In the light, pour "salted" ([[iodide]], [[bromide]]) collodion onto the glass plate, tilting it so it reaches each corner. The excess is poured back into the bottle.
* Take the plate into a [[darkroom]] or orange tent (the plate is sensitive only to [[blue]] light) and immerse the plate in a [[silver nitrate]] sensitising  bath (for 3–5 minutes)
* Lift the plate out of the bath, drain and wipe the back, load it into a plate holder and protect from light with a [[Dark slide (photography)|dark slide]].
* Load the plate holder into the camera, withdraw the [[Dark slide (photography)|dark slide]] and expose the plate (can range from less than a second to several minutes)
* Develop the plate (using a [[ferrous sulfate]] based [[photographic developer|developer]])
* Fix the plate (with [[potassium cyanide]] or [[sodium thiosulfate]])

All of this was done in a matter of minutes, and some of the steps in (red) [[safelight]] conditions, which meant that the photographer had to carry the chemicals and a portable darkroom with him wherever he went. After these steps the plate needed rinsing in fresh water. Finally, the plate was dried and varnished using a [[varnish]] made from [[sandarac]], [[ethanol|alcohol]] and [[lavender oil]].

Dark tents to be used outdoors consisted of a small tent that was tied around the photographer's waist. Otherwise a [[wheelbarrow]] or a horse and covered wagon were used.