Frederick Scott Archer
Collodion
From 1848 Archer began experimenting with glass as a negative support. A light-sensitive coating of albumen (egg which on glass had been used by others with some success but the solution was difficult to spread smoothly and was extremely delicate. Archer experimented instead with collodion. This was made from guncotton. a powerful explosive invented in 1846. It is produced by soaking ordinary cotton in nitric and sulphuric acid. This substance was then dissolved in a mixture of alcohol, ether and potassium iodide to produce the syrupy collodion that could be poured onto glass. This plate was then sensitized in a bath of silver nitrate solution and exposed in the camera while still wet.
The Wet Collodion Plate was the preferred photographic process from its introduction in the early 1850s until the advent of the mass produced Dry Gelatin Plate in the late 1870s and early 1880s.