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The Nadars, a photographic legend

I. Les Nadar

The Nadars

FR

Collodion glass negatives and the attendant photographic process

Negative of Victor Hugo on his deathbed in his room, Félix and Paul Nadar, May 1885
© Architecture and Cultural Heritage Multimedia Library
The wet-collodion negative process, also known as silver monochrome negative process, was invented in 1851 by Frederick Scott Archer.

Compared to Daguerreotypes, the technique considerably reduced the pose time for picture-taking. In addition, thanks to the glass plate (matrix), it was possible to make multiple identical prints.

The process consisted in coating a glass plate, which had been cleaned and cut to the desired size beforehand, with a printing emulsion composed of cellulose nitrate (powdered cotton), ether and alcohol. After evaporation, the collodionized plate was dipped in a solution of silver nitrate, then transferred to a frame inside a lightproof box. It was then immediately exposed, i.e. while still wet, in the photographic chamber.
After exposure (to light), the latent image obtained was then developed in a pyrogallic acid or ferrous ammonium sulfate solution for a few seconds. The collodion plate was then fixed in sodium thiosulfate. Next it was washed and then dried by the heat of a flame. Finally, it was varnished in order to protect the collodion layer. Printing from a collodion negative plate was done by direct contact with light-sensitive albumen paper.

Practically all of the portraits that Félix Nadar took were done with the wet collodion technique.