A New Process in 1850: Wet Collodion

The inconvenience of the negative on not very transparent paper, gave rise quickly to the search for a better basis: the use of glass was attractive, but how was one to make the sensitive emulsion stick to it?

In 1846, a French chemist, Louis Ménard, dissolved some cotton powder or guncotton – discovered that same year by a chemist from Basel, Christian Friedrich Schönbein – in a mixture of alcohol and ether: he obtained a viscous liquid, which hardened and became transparent as it dried, this was collodion, used for various purposes, including in the medical field.

Photographer Gustave Le Gray, author of a Practical Treatise On Photography on paper and on glass published in 1850, evokes the use of collodion on glass in the appendix of a page. Its method is not very easy, but seems to produce excellent results.

In March 1851, the English sculptor and calotypist, Frederick Scott Archer, perfected the so-called wet collodion method: the plate had to be prepared just before being exposed, at the risk of losing its sensitivity, and then developed straight after taking the photograph. So the photographer had to be equipped with a portable laboratory whenever he went out! The very beautiful quality of the negatives obtained with this process assured the general introduction of this method from the 1860s at the expense of the “daguerreotype” and calotype systems.


Image development
“The glass is removed from its frame, held by a wedge between thumb and forefinger, and a precipitating glass is used to quickly pour into it – in order to wet the entire surface in one go – the developer liquid, usually an aqueous solution of iron sulphate with added pyrogalic or acetic acid. – This is a very important operation: it is carried out over a basin or a sink stone. – When the developer liquid is poured over the ice, the ice is kept in a horizontal position so that the solution is evenly distributed over its entire surface (…). The image is gradually revealed. Only it is negative, i.e. the whites of the model stand out in black on the glass, and vice versa”. (Gaston Tissandier, Les merveilles de la photographie, Paris, 1874).