Photographic Negatives

On Paper

Photogenic drawings

Paper negatives sensitized with silver nitrate and sodium chloride, producing a light-sensitive silver chloride. It was exposed, printed out, and fixed by a salt solution. William Henry Fox Talbot developed this process by 1835.

Calotypes

A paper negative process developed and then patented by Talbot in 1841; they were also called "talbotypes." The paper was sensitized with silver nitrate and then with potassium iodide, and these together produced a light-sensitive silver iodide. Before exposure, the paper was resensitized with silver nitrate and gallic acid. It was developed-out with a silver nitrate and gallic acid solution. Talbot at first fixed his calotypes with a salt solution and later with a solution of bromide of potassium. He later abandoned these in favor of hyposulphate of soda, which Sir John Herschel had discovered in 1819 to have silver-dissolving properties.

"Calotypes" is sometimes used to refer to the salted paper prints made from calotype negatives, but here this term refers only to the negatives themselves. Popular until 1851.

Waxed paper negatives

Paper negatives in which the paper was made translucent by waxing before sensitizing. Popular 1851-1865.

On Glass

Wet collodion negatives

Glass negatives that use a collodion binder made from nitrocellulose (guncotton) dissolved in a mixture of ether and alcohol. The collodion must be coated on the support, exposed, and developed before the collodion has become dry. Therefore, this process required portable darkroom facilities or immediate proximity to a darkroom. Popular 1851-1875.

Dry collodion negatives

Also called "dry plates." Glass negatives using a type of collodion process in which the binder contains an agent, usually tannin, to retain sufficient moisture to allow processing after an extended period of time. They alleviated the need for a portable darkroom. Popular 1850s-1870s.

Gelatin silver dry plate negatives

Also called "dry plates." Glass negatives employing a gelatin binder containing silver. Popular 1880-1920.

On Film

Chromogenic color film negatives

Also called "dye coupler negatives." Film negatives using the chromogenic color process.

Gelatin silver film negatives (stripping)

Film negatives made completely of gelatin, backed by paper that is stripped off after processing. Rolls of stripping film were used in the Kodak No. 1 camera, introduced in 1888. This film was superceded by nitrocellulose base roll film in 1889.

Gelatin silver film negatives (nitrate)

Film negatives with a nitrocellulose base using the gelatin silver process.

Gelatin silver film negatives (acetate)

Also called "safety film." Film negatives with a cellulose acetate base using the gelatin silver process.

Gelatin silver film negatives (polyester)

Also called "safety film." Film negatives with a polyester base using the gelatin silver process.

Text © 1999 The Harry Ransom Humanities Research Center.
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