First conceived in England by William Henry Fox Talbot in 1834, photogenic drawing is the first photographic process capable of producing negative images on paper.
The inventor did not publicize his experiments until the Daguerreotype was introduced in January 1839.
The paper is sensitized using a two-step process: water and table salt (sodium chloride) are applied, followed by a brushed-on coating of silver nitrate. The resulting silver chloride is not particularly sensitive, which means that the process requires relatively lengthy exposure times. As a result, the first photogenic drawings were obtained through direct contact with flat objects (plants, fabrics, drawings or manuscripts, etc.), following the principle of a photogram. Later on, Talbot experimented with using the same sensitized paper in camera obscura to capture still life images and architectural silhouettes, including some of his own home at Lacock Abbey.
The negative image was formed by printing out in direct light. It was then stabilized in an alkaline halide solution (chloride, bromide, or iodide) before the remaining sensitized salts were washed off the paper with water. The lilac, brown, and yellow shades generated by sodium chloride, potassium bromide, and potassium iodide respectively tend to darken over time, making the image relatively unstable when stored in darkness and even more fragile when exposed to light.
More stable photogenic drawings were obtained after the introduction of sodium thiosulfate (known originally as hyposulfite of soda) to 'fix' the images. This did not occur until around 1840, however, when the process became obsolete and was gradually replaced by the calotype, a faster and much more effective way to capture images.
At the time, photogenic drawings were printed by contact on salted papers in a printing-frame. The image of a photogenic drawing, which may be matte or semi-matte depending on the paper used, is formed in the fibers of the paper itself. Sometimes, the paper is coated with a translucent oil- or wax-based product to improve the print resolution.
Visual glossary of photographic techniques
© ARCP / Mairie de Paris, 2014