photogenic drawing

In 1834, Henry Talbot so named the first photographic process on paper. He immersed Whatman's writing paper in dilute salt solution, then after drying brushed it with concentrated silver nitrate solution, precipitating silver chloride within the surface fibres. This sensitized paper darkened in sunlight within a few minutes due to the formation of finely divided metallic silver, so could easily provide photograms of botanical specimens and textiles. Treatment with strong solutions of salt, or potassium iodide, partially fixed the images. This low-sensitivity material required hour-long camera exposures, but yielded Talbot's first negatives in 1835.

— Mike Ware

Bibliography

• Schaaf, L. J., Out of the Shadows (1992)