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The 'albumen print', invented in 1850 by Louis Désiré Blanquart-Evrard, was the first commercially exploitable method of producing a print on a paper base from a negative. It used the albumen found in egg whites to bind the photographic chemicals to the paper and became the dominant form of photographic positives from 1855 to the turn of the century, with a peak in the 1860-90 period. During the mid-1800s, the carte de visite was one of the most popular forms of this type of printing process.
The process is as follows:
# A piece of paper is coated with an emulsion of egg white (albumen) and table salt (sodium chloride), then dried. The albumen seals the paper and creates a slightly glossy surface.
# The paper is then dipped in a solution of silver nitrate and water which renders the surface light-sensitive.
# The paper is then dried in total darkness.
# The dried, prepared paper is placed in a frame in direct contact under a negative, often a glass negative with collodion emulsion, and exposed to light until the image achieves the desired level of darkness. Direct sunlight is preferable, as the paper is most sensitive to ultraviolet light.
# A bath of sodium thiosulfate fixes the print’s exposure, preventing further darkening.
# Optional gold or selenium toning improves the photograph’s tone and stabilises against fading.
Since the image emerges as a direct result of exposure to light, without the aid of a developing solution, an albumen print may be said to be a ''printed'' rather than a developed photograph.

Contents

How does it work?

References

How does it work?

The table salt (sodium chloride) in the albumen emulsion forms silver chloride when in contact with silver nitrate. Silver chloride is unstable when exposed to light, which makes it decompose into silver and chlorine. The silver is oxidized into silver oxide during the development process and the remaining silver chloride is washed out during fixing. The black parts of the image are formed by silver oxide.
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★ Collodion process

References

★ Marshall, F.A.S. ''Photography: the importance of its applications in preserving pictorial records. Containing a practical description of the Talbotype process'' (London: Hering & Remington; Peterborough, T Chadwell & J Clarke, 1855).

★ Stanford University - Albumen Photographs: history, science and preservation

★ Alternative Photography - Make Albumen Paper