GELATIN SILVER CHLORIDE PRINT
After the introduction of gelatin dry plate negative emulsions during the 1870s, a series of ready to use photosensitive papers went on sale. They received an emulsion coating for developing the underlying picture that was more sensitive than the ones used during the previous period where pictures were obtained by darkening through exposure to light. Offering greater ease of use and new applications, their introduction marks the opening of the modern photography era.
This gelatin silver chloride paper was produced for the first time in Vienna, in 1881, by photochemists Eder and Pizzighelli. Given its lower sensitivity than that of silver bromide emulsions, it offers the advantage that it can be developed under gaslight without fogging, hence it was referred to as "gaslight paper". The shades of a chemically developed print that are naturally black can be changed by using different kinds of developers or by toning. The most popular toning from 1910 onwards is sepia toning, giving a brownish tone and a greater stability to the print.
The emulsions factory applied to a baryte base. The papers are used by contact with the negative as their low sensitivity does not allow enlargement. The size of the print is therefore the same as the negative, glass plate or medium or large size sheet film. The advantage of this process comes from the exceedingly file half-tone results and the excellent resolution that comes from this. The most widely used papers were sold under the Kodak Velox® (very often used for post card prints) or Gevaert Ridax® trade names. This kind of technology is often linked to quality production for professional applications in portrait studios or amateur use linked to expanding tourism in the early twentieth century. Although it progressively went out of use as small format cameras became the norm and contact printing became obsolete for amateurs, it was still seen in industrial photography until the 1950s.
Visual glossary of photographic processes
© ARCP / Mairie de Paris, 2015