Definition of dating
It was perhaps the most acutely hazardous of all the several highly toxic chemicals originally used in this and many other early photographic processes.
They were often later transferred into the precut openings provided in book-like photograph albums.The tintype photograph saw more uses and captured a wider variety of settings and subjects than any other photographic type.It was introduced while the daguerreotype was still popular, though its primary competition would have been the ambrotype.The glass was either of a dark color or provided with a black backing so that, as with a tintype, the underexposed negative image in the emulsion appeared as a positive.Tintypes were sturdy and did not require mounting in a protective hard case like ambrotypes and daguerreotypes.The tintype saw the Civil War come and go, documenting the individual soldier and horrific battle scenes.
It captured scenes from the Wild West, as it was easy to produce by itinerant photographers working out of covered wagons.
Chemical treatment then reduced the crystals to microscopic particles of metallic silver in proportion to the intensity and duration of their exposure to light, resulting in a visible image.
The later and more convenient dry process was similar but used a gelatin emulsion which could be applied to the plate long before use and exposed in the camera dry.
Sometimes the camera was fitted with a mirror or right-angle prism so that the end result would be right-reading.
The process was first described by Adolphe-Alexandre Martin in France in 1853.
In both processes, a very underexposed negative image was produced in the emulsion.