Photogenic drawings were invented by William Henry Fox Talbot (1800-1877), a gentleman scientist whose interests included optics, chemistry, botany and art. Talbot had experimented with contact printing from as early as 1834, but it was not until Arago's announcement of Daguerre's discovery that he made public his results. Just as Talbot had picked up where Thomas Wegwood (1771-1805) had left off some thirty years earlier, so Sir John Herschel (1792-1871) continued the work of Talbot, exploring a wide range of materials and processes, most notably those involving fixing in 'hypo'.
Photogenic drawings were prepared by soaking a piece of good quality drawing paper in a weak solution of common salt, allowing this paper to dry, brushing it with a solution of silver nitrate, and then further washing it in a strong solution of common salt. Exposure was usually made by contact printing for as long as it took an image to appear. This image would then be fixed: Talbot used a strong solution of common salt for this or, occasionally, potassium iodide; Herschel's hypo fixer (sodium thiosulphate) dissolved away any remaining silver nitrate more efficiently and subsequently became the standard for all silver processes.
