Tintype is a type of photograph made from creating a direct positive on a sheet of Iron that has been blackened by painting. The process dates to the 1700’s where Adolphe-Alexandre Martin described the process in 1853. This process evolved from the ambrotype process. This difference was that ambrotypes were collodion negatives on glass viewed against a black surface, whereas Tintypes where on black sheets of iron. Tintypes had advantages over ambrotypes, like for example they were a lot cheaper to produce and lasted longer as they were a lot more durable.
The Process
Firstly the photo would be taken with a special tintype camera that could have up to 36 different lenses. Each of the iron plates in turn would be exposed, and after exposure the plate would be dropped through a slot into a tank full of the chemicals that would immediately start processing the image. These chemicals would be a high strength solution that would develop and fix an image in one so that the development was quick.