Archives West Finding Aid

The photographs present within this collection represent a spectrum of photographic processes prevalent circa 1800s-1970s: daguerreotypes, cyanotypes, ambrotypes, tintypes, albumen prints, silver gelatin prints, and color prints.

Daguerreotypes were introduced in 1839 and are considered to be the "first fully successful and practicable photographic process" (Ritzenthaler and Vogt-O'Connor, 29). They are laterally reversed, direct positive images, printed on finely polished, silver-coated copper plates.

Cyanotypes, also called "blueprints," were introduced in the late 1840s, although they did not become popular until the 1880s. These photographs were produced by coating paper in a light-sensitive solution, exposing the paper to a negative once it was dry, and then washing it with water (33).

Ambrotypes and tintypes were introduced in the 1850s as cheaper alternatives to daguerreotypes. Ambrotypes were very similar to daguerreotypes as they were direct positive images, although they were usually not laterally reversed. These images were printed on glass. Tintypes were laterally reversed, direct positive images printed on thin sheet iron (36).

Albumen prints were introduced in the late 1840s and became the "dominant printing process of the nineteenth century" (38). These photographs were produced through the utilization of negatives and albumen emulsion paper. As this paper is rather thin, prints were usually mounted on cards of various sizes.

Silver gelatin prints were introduced in the 1870s and have dominated the market since about 1910. These photographs were printed on one of two basic types of paper: developing-out paper (which required chemical developers), or printing-out paper (which required light exposure) (46).

Color prints were produced using a variety of different chemicals and materials which have been available since 1941. However, it is difficult to differentiate between them unless the prints are labeled (55).

Reference: Ritzenthaler, Mary Lynn, and Diane Vogt-O'Connor. Photographs: Archival care and management. Chicago: Society of American Archivists, 2008.