Tintype or Ferrotype:
The ferrotype, also called the tintype or melainotype, is a photographic process developed in the United States in the 19th century. It was invented by Prof. Hamilton Smith of the Kenyon College, Ohio in 1856.

Basically the process falls under the category “wet plate processes”, where the photographic emulsion is contained in liquid collodion.

It superseded the ambrotype by the end of the Civil War and went on to become the most common photographic process until the introduction of modern gelatin based processes, and the invention of the reloadable amateur camera by the Kodak company. Ferrotypes waned in popularity by the end of the 19th century, although a few makers were still around as late as the 1950s and on some carnivals in Europe these images are still made as novelty. Lately experimental photographers have rediscovered this art.

The ferrotype was a minor improvement to the ambrotype, replacing the glass plate of the original process with a thin piece of black enameled, or japanned, iron (thus "ferro"). The new materials reduced the cost of the productions considerably, and the image, on gelatin-silver emulsion on the varnished surface, has proven to be very durable. Like the ambrotype, the image is technically negative, but, due to the black background, appears as a positive. Since the ferrotype 'film' was the same as the final print, most ferrotype images appear reversed (left-to-right) from reality. Some cameras were fitted with mirrors or a 45-degree prism to reverse and correct the image, while some photographers would photograph the reversed ferrotype to produce a properly oriented image.

Ferrotypes were simple and fast to prepare. A photographer could prepare, shoot, develop and varnish a ferrotype plate in a few minutes, having it ready for a customer quickly. The earlier ferrotypes were often cased, like daguerreotypes and ambrotypes, but uncased images in paper sleeves and for albums were popular from the beginning.