A tintype or ferrotype is a positive image printed on an iron plate. Like an ambrotype, it’s a variation of the wet collodion process. The process was first described by Adolphe Alexandre Martin in 1853.
A sheet of iron was coated with dark brown or black varnish, followed by a coating of collodion. The plate was exposed in the camera and developed immediately while the collodion was still wet. The result was a negative image but because of the used dark varnish the image appears as a positive image.
The tintype process was actually an early form of instant photography. The images could be made quickly and cheaply and the process was very popular until the 1930s. Tintypes are therefore not rare, but stereo tintypes are much less common. The developed image was most of the time coated with a protective varnish instead of a protective glass plate to keep the costs low.
The two stereo tintypes in this post have a size of 8,5x17cm. They show two rather uninteresting images of street views. Most remarkable is that both tintypes were acquired in two mahogany camera plate holders.
- Lavédrine, Betrand. Photographs of the Past – Process and Preservation, 2009, p.34