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A tintype, also known as a melainotype or ferrotype, is a photograph made by creating a direct positive on a thin sheet of iron coated with a dark lacquer or enamel and used as the support for the photographic emulsion. Tintypes enjoyed their widest use during the 1860s and 1870s, but lesser use of the medium persisted into the early 20th century and it has been revived as a novelty in the 21st.
Tintype portraits were at first usually made in a formal photographic studio, like daguerreotypes and other early types of photographs, but later they were most commonly made by photographers working in booths or the open air at fairs and carnivals, as well as by itinerant sidewalk photographers. Because the lacquered iron support (there is no actual tin used) was resilient and did not need drying, a tintype could be developed and fixed and handed to the customer only a few minutes after the picture had been taken.
The tintype's immediate predecessor, the ambrotype, was the same process using a sheet of glass as the support. 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.
There are two historic tintype processes: wet and dry. In the wet process, a collodion emulsion containing suspended silver halide crystals had to be formed on the plate just before it was exposed in the camera while still wet. 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.
In both processes, a very underexposed negative image was produced in the emulsion. Its densest areas, corresponding to the lightest parts of the subject, appeared gray by reflected light. The areas with the least amount of silver, corresponding to the darkest areas of the subject, were essentially transparent and appeared black when seen against the dark background provided by the lacquer. The image as a whole therefore appeared to be a dull-toned positive. This ability to employ underexposed images allowed shorter exposure times to be used, a great advantage in portraiture.
To obtain as light-toned an image as possible, potassium cyanide, a very dangerous and powerful deadly poison, was normally employed as the photographic fixer. It was perhaps the most acutely hazardous of the several highly toxic chemicals originally used in this and many other early photographic processes.
One unusual piece of tintype equipment was a twelve-lensed camera that could make a dozen 3⁄4-by-1-inch (19 mm × 25 mm) "gem" portraits with one exposure. Portrait sizes ranged from gem-size to 11 in × 14 in (280 mm × 360 mm). From about 1865 to 1910 the most popular size, called "Bon-ton", ranged from 2 3⁄8 in × 3 1⁄2 in (60 mm × 89 mm) to 4 in × 5 3⁄4 in (100 mm × 150 mm).
Each tintype is usually a camera original, so the image is usually a mirror image, reversed left to right from reality. 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 1856 it was patented by Hamilton Smith in the United States and by William Kloen in the United Kingdom. It was first called melainotype, then ferrotype by a rival manufacturer of the iron plates used, then finally tintype.
The ambrotype was the first use of the wet-plate collodion process as a positive image. Such collodion glass positives had been invented by Frederick Scott Archer in 1851 and the name Ambrotype was introduced in the United States by James Ambrose Cutting in 1854 when he patented a variation of Archer's original process.
The tintype was essentially a variant of the ambrotype, replacing the latter's glass plate with a thin sheet of japanned iron (hence ferro). Ambrotypes often exhibit some flaking of their black back coating, cracking or detachment of the image-bearing emulsion layer, or other deterioration, but the image layer on a tintype has proven to be typically very durable.
Compared to their most important predecessor, the daguerreotype, tintypes were not only very inexpensive, they were also relatively easy and quick to make. A photographer could prepare, expose, develop and varnish a tintype plate and have it ready for the customer in a few minutes. Although early tintypes were sometimes mounted in protective ornamental cases, like daguerreotypes and ambrotypes, uncased tintypes in simple paper mats were popular from the beginning. They were often later transferred into the precut openings provided in book-like photograph albums.
One or more hardy, lightweight, thin tintypes could be carried conveniently in a jacket pocket. They became very popular in the United States during the American Civil War. Although prints on paper soon displaced them as the most common type of photograph, the tintype process continued to enjoy considerable use throughout the 19th century and beyond, especially for casual portraiture by novelty and street photographers.
Ferrotyping is a finishing treatment applied to glossy photographic paper to bring out its reflective properties. Newly processed, still-wet photographic prints and enlargements that have been made on glossy-type paper are squeegeed onto a polished metal plate called a ferrotyping plate. When they dry and split off due to slight shrinkage, they retain a highly reflective gloss.
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