The wet collodion process originated in 1851, and was widely used for the next forty years. It involves hand-coating a glass plate with a solution of collodion, ethyl alcohol, and ether. It is called a “wet” process because the plate must be exposed and developed before the solution dries. Practitioners of the process have about ten minutes to coat the plate, sensitize it in silver, make the exposure, and develop it.
The collodion process was the first to render a negative image on a transparent surface, which enabled photographers to print duplicates of their images with ease. The immediate nature of the process, however, required photographers to travel with a portable darkroom while shooting outdoors. Additionally, the solutions involved in the wet collodion process give the plates relatively little sensitivity to light, requiring long exposure times.
These images were taken in a studio using a number of flashes to illuminate each subject. The lights were placed as close to the model as possible without appearing in the photograph. In order to render an image with a single burst of the flash, each light had to be undiffused and used at its maximum output. As a result of this dramatic lighting, the subjects take on a ghostly quality. They emerge like apparitions from the darkness around them.
— Zack Taylor, April 2008