A Glossary of Photographic Terms
Bromoil Print - A method of producing an image in greasy ink on gelatine sensitised by potassium dichromate.
Carbon Prints - A non silver, permanent photographic print which was popular from around 1870 up to 1910. This was produced by exposing a sheet of paper coated with gelatin, carbon black and potassium dichromate against a negative, the gelatin hardening in proportion to the amount of light passing through the negative. The print is dense, glossy black or deep rich brown tonality, often with slight relief contours thickest in the dark areas
Carte de Visite - A stiff piece of card measuring about 4.5 x 4.5 inches, the size of a formal visiting card of the 1860s, with an attached photograph, usually a full-length studio portrait, of nearly the same size. Sometimes the subject matter was a tourist attraction or a work of art. Cartes-de-visite were most popular during the 1860s and were sometime collected in albums.
Collodion Positives - A unique positive photographic process used primarily in the 1850s, a collodian negative on glass, the image produced is whitish in tone but when placed over a black opaque surface appears as a positive; often hand-coloured portraits.
Daguerrotypes - Introduced in 1839 and in general use until around 1860. These are direct-image photographs on silver-coated copper which produce a distinctive mirror-like surface; commonly in a case.
Gum Prints - A photograph printed on paper that has been coated with an emulsion of gum Arabic, potassium bichromate, and pigment. The emulsion hardens in relation to the amount of light it receives, and the emulsion is then washed away. Introduced in 1894, popular into the 1920s, and occasionally used today.
Platinum Prints - Developed in 1872, platinum-coated papers were commercially available until 1937, when the cost of platinum made the process prohibitively expensive. For a short while the platinum was replaced with the less costly palladium. The process is based on the light sensitivity of paper that has been treated with iron salts and a platinum compound and then developed in a potassium oxalate. Platinum prints were popular because of their permanency and their wide range of soft grey tones.
Silver Gelatin Print - Introduced in 1872 this is a photograph printed on paper that has been coated with gelatin containing light-sensitive halides. Gelatin silver prints are the standard black and white prints still in use today.
Stereographs - A cardboard mount holding two photographs of the same subject, each from a slightly different point of view. When viewed with binocular vision, a stereoscopic effects of three-dimensional depth of fields is achieved
Woodbury type Prints - A print process patented by W.B Woodbury in 1865.
Central Library Photographic Collections