Glossary of Photographic Terms
Albumen prints were made by taking a thin piece of paper and floating it in a bath of egg white and salt, and then coating it with silver nitrate. This light-sensitive paper could then be placed in contact with a glass plate negative and exposed to light to make a positive print. These thin paper prints then were typically trimmed and glued to a card mount for support.
The ambrotype process was introduced in the mid 19th century and resulted in the creation of a positive image on a sheet of glass. The glass plate was coated with collodion and dipped in a solution of silver nitrate. The plate was then placed in the camera and exposed. After the plate was developed and fixed, the back of the plate was blackened resulting in a positive appearing image. Like the daguerreotype, ambrotypes were usually placed in protective cases.
Larger than the carte-de-visite photographic format, the cabinet card was about 4 ¼ by 6 ½ inches and featured space for the photographer's name and studio location to be printed on the front. The cabinet card consisted of a paper print (usually albumen) mounted on a thick card support. These gained popularity in the 1870s and eventually eclipsed the carte-de-visite format in popularity.
Introduced to the United States from Europe in the late 1850s, the carte-de-visite (CDV) image got its name from the fact that it was roughly the same size as a formal calling card (about 2 ¼ inches by 4 ¼ inches). The carte-de-visite format became wildly popular in the United States in the 1850s and 1860s. The CDV consisted of a photograph (often an albumen paper print) glued to a square-cornered card only slightly larger than the print. The cards often carried the photographer's name embossed on the front or printed on the back of the card.
Collodion is a solution of nitrocellulose in acetone or ether that was used as an alternative to albumen to coat glass photographic plates. Commonly used in the production of ambrotypes and tintypes in the 19th century.
Named after its French inventor Louis Daguerre, the daguerreotype was introduced in 1839 and represented the first practical photographic process. To make a daguerreotype, a thin copper plate was coated with silver and then highly polished. This plate was then sensitized to light with iodine fumes. Once exposed in the camera, the latent image was developed with mercury vapor and then fixed and rinsed. This resulted in a positive image, which due to its fragile nature, had to be placed in a sealed case with a glass cover. Each daguerreotype was a one-of-a-kind image. Daguerreotypes have to be held at a certain angle to be viewed due to the mirror-like reflective surface.
A process was developed in the mid 19th century for producing photographs on thin sheets of iron. These images are commonly called tintypes, although they are more accurately called ferrotypes. The iron sheet was japanned or blackened, and then coated with liquid collodion and sensitized. After exposure, the plate was developed, fixed, and rinsed. After drying, the plate was varnished to protect the image. The resulting image was positive appearing.