Tintype: Wikipedia

Tintype, also melainotype and ferrotype, is a photograph made by creating a direct positive on a sheet of metal, usually iron or steel that is blackened by painting, laquering or enamelling and is used as a support for a collodion photographic emulsion.

Photographers usually worked outside at fairs, carnivals etc. and as the support of the tintype (there is no actual tin used) is resilient and does not need drying, instant photographs can be produced only a few minutes after taking the photograph.

An ambrotype uses the same process and methods on a sheet of glass that is mounted in a case with a black backing so the underexposed negative image appears as a positive. Tintypes did not need mounting in a case and were not as delicate as photographs that use glass for the support.

The process was identical to the wet plate process, where collodion is employed to produce a photographic emulsion where silver halide crystals (silver bromide, silver chloride and silver iodide) are suspended in the collodion, and are chemically reduced to crystals of metallic silver that vary in density according to the original light values of the original image.

When a photographic negative image on film or plate is very underexposed, it appears as a positive when viewed against a dark background. This is the basis of the process: a very underexposed image is produced on a collodion photographic emulsion on a dark metal backing; thus viewed the image appears as a positive. The fact that an underexposed image is required means that the effective film speed is increased and shorter exposures can be used, which is a great advantage in portraiture.

The process was first described by Adolphe-Alexandre Martin in France in 1853, and patented in the United States on February 19, 1856 by Hamilton Smith, professor at Kenyon College, in Ohio William Kloen also patented the process in the United Kingdom in the same year. It was first called melainotype, and then ferrotype (by a rival manufacturer of the iron plates used); finally came the name tintype. All three names describe both the process and the resulting photograph.[1]

The ambrotype was the first wet-plate collodion process, invented by Frederick Scott Archer in 1851 and introduced in the United States by James Ambrose Cutting in 1854.

While the ambrotype remained very popular in the rest of the world, the tintype process had superseded the ambrotype in the United States by the end of the Civil War. It became 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 had waned in popularity by the end of the 19th century, although a few makers were still around as late as the 1950s and the images are still made as novelties at some European carnivals.

The tintype 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 (hence ferro). The new materials reduced costs considerably; and the image, in gelatin-silver emulsion on the varnished surface, has proven to be very durable. Like that of the ambrotype, the tintype's image is technically negative; but, because of the black background, it appears as a positive. Since the tintype 'film' was the same as the final print, most tintype images appear reversed (left to right) from reality. Some cameras were fitted with mirrors or a 45-degree prism to reverse (and thus correct) the image, while some photographers would photograph the reversed tintype to produce a properly oriented image.

Tintypes are simple and fast to prepare, compared to other early photographic techniques. A photographer could prepare, expose, develop, and varnish a tintype plate in a few minutes, quickly having it ready for a customer. Earlier tintypes were often cased, as were daguerreotypes and ambrotypes; but uncased images in paper sleeves and for albums were popular from the beginning.

Ferrotyping is a finishing treatment applied to glossy photo paper to bring out its reflective properties. Newly developed, still-wet photographic prints and enlargements that have been made on glossy paper are Squeegeed onto a polished metal plate called a ferrotyping plate. When these are later peeled off the plate, they retain a highly reflective gloss.