What is wet plate collodion photography? Here is a little definition from Wikipedia,
The collodion process is an early photographic process, invented by Frederick Scott Archer. It was introduced in the 1850s and by the end of that decade it had almost entirely replaced the first practical photographic process, the daguerreotype. During the 1880s the collodion process, in turn, was largely replaced by gelatin dry plates—glass plates with a photographic emulsion of silver halides suspended in gelatin. The dry gelatin emulsion was not only more convenient but could be made much more sensitive, greatly reducing exposure times."Collodion process" is usually taken to be synonymous with the "collodion wet plate process", a very inconvenient form which required the photographic material to be coated, sensitized, exposed and developed within the span of about fifteen minutes, necessitating a portable darkroom for use in the field. Although collodion was normally used in this wet form, the material could also be used in humid ("preserved") or dry form, but at the cost of greatly increased exposure time, making these forms unsuitable for the usual work of most professional photographers—portraiture. Their use was therefore confined to landscape photography and other special applications where minutes-long exposure times were tolerable.Collodion processes were capable of recording microscopically fine detail, so their use for some special purposes continued long after the advent of the gelatin dry plate. The collodion process is said to have been invented, almost simultaneously, by Fredrick Scott Archer and Gustave Le Gray in about 1850. During the subsequent decades of its popularity, many photographers and experimenters refined or varied the process.