Art Business News' guide to photographic processes

Art Business News, Oct, 2003 by Susan Seiling, Laura Meyers

Photograms/Photogenic Drawings

William Henry Fox Talbot's first photographic experiments in the 1830s did not involve a camera. He made salt prints by placing lace, leaves and other objects on fight-sensitive paper and exposing the paper to the sun. Where the object blocks the light, the paper remains white.

Photogravures

Photographers and book publishers used photogravures to reproduce photographs in the 1890s to 1920s. Photogravures are often composed of a series of lines and can frequently be found in illustrated books from the early 1900s.

Photogravures are essentially handmade printing plates that allow the consistent reproduction of a photograph. The process for making a photogravure is highly complex and involves transferring a photograph onto a hand-etched copper plate. The plate is then coated with ink and pressed onto paper. The result is an image that can be reproduced over and over again.

Polaroids

Polaroid prints are made in-camera and don't require chemical processing beyond letting the print process itself in the minutes following the exposure. Polaroid prints can range from tiny stickers to large prints made with a 4-by-5, 8-by-10 or 20-by-24 camera. They are one-of-a-kind photographs that cannot be easily reproduced (unlike prints from negatives or transparencies). The physical appearance of Polaroid prints can vary depending on the camera that was used to create them. They are most easily identified by the "Polaroid" name stamped on the back of the print.

Salted Paper Prints

Salted paper prints were the first type of paper print used in photography. To make a salted paper print, a piece of paper is soaked in a salt solution and then dried. The dry paper is brushed with a silver nitrate solution and dried again. Light is then projected through a negative onto the paper, and after the paper is washed and fixed, a photographic print remains.

It can be difficult to distinguish a salted paper print from an albumen print, and usually the difference is discerned by the date--prints made before the 1850s are usually salted paper prints; those made after the 1850s are generally albumen prints.

Tintype (Ferrotype)

Tintypes, invented in 1856 by Hamilton Smith, begin as thin sheets of iron covered with a layer of black paint (no tin is used). This serves as the base for the same iodized collodion coating and silver nitrate bath used in the ambrotype process. It is underexposed, developed in iron sulfate and fixed in cyanide. It's difficult to distinguish tintypes from ambrotypes because they are often displayed in the same types of cases.

Albumen Prints

If you're looking at an old black-and-white print with a yellow tone that was made after 1850, it may be an albumen print. Many were gold toned, and all albumen prints yellow with age. This early photographic process involved coating paper with a mixture of egg whites and light-sensitive metals. A photographic negative is then contact printed on the paper, creating a photographic print. Albumen prints gained popularity during the 1850s, when manufacturers made pre-coated albumen paper.