THE VAN DYKE BROWN

This method of photographic printing was formulated by Dr W. W. V. Nichol in 1889. The process is named after the seventeenth century artist Anthony Van Dyke whose paintings, with their rich brown tone possess a character similar to those resulting from this photographic printing technique. The prints are made from enlarged negatives which are then contact printed onto a hand prepared sensitive emulsion coated on art paper and exposed for times in excess of many minutes to high intensity ultra-violet light, usually sunlight. Chemically, the process relies on the light sensitive properties of certain silver and iron salts. After exposure, the chemicals from the areas which have not received any light wash out in water. The result is a red-brown image created by the light passing through the clear areas of the negative and exposing the emulsion. Finally, to make the picture permanent and to intensify the rich brown tone it is bathed in the dilute fixer solution.

THE CYANOTYPE

Sir John Herschel discovered the cyanotype process in the early 1840’s. Herschel coated paper with a solution of ferric ammoniun citrate and potassium ferricyanide. He exposed this paper in sunlight in contact with a negative and washed it in water the resulting image being a blue positve image. The process was not used widely as it only showed the subject in blue, but some photographers found it convenient for making proofs from negatives. Anna Atkins 1843, used this process to produce photograms of algae for her botanical studies and produced; Photographs of British Algae: Cyanotype Impressions. Engineers and draghtsmen adapted this process for the blueprint copying of their plans and drawings. Today it is more widely used in the production of photographic art.

William Crawford, The Keepers of Light, Morgan and Morgan, Dobbs Ferry, New York,1979.

THE ARGYROTYPE

The Argyrotype is another contact printing process using sunlight for exposure to create the image. This process uses silver in the photosensitive emulsion that is applied to surfaces for example Art paper. The final result is a dark black/brown toned image.

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