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.
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Study of an oak leaf by Sir John Herschel (1792-1871), 26th February, 1839, from his hypo fixing experiments.
Apart from the examples of lace this negative photogenic drawing is Herschel's only contact image of a real object, rather than an engraving or other form of illustration.
The mark on the leaf seems to be a large J.
Apart from the examples of lace this negative photogenic drawing is Herschel's only contact image of a real object, rather than an engraving or other form of illustration.
The mark on the leaf seems to be a large J.
Contact image of heather, Erica mutabilis, made on stiff paper by W. H. Fox Talbot (1800-1877), dated March 1839.
Study of lace, by Sir John Herschel (1791-1871), 1839.
View of the telescope at Slough, by Sir John Herschel (1792-1871), 1839.
At the time that this was taken, Sir William Herschel's 40-foot telescope was already a famous astronomical symbol, although it was being demolished - hence the absence of the telescope's tube.
The only camera images Sir John Herschel is know to have taken are of his father's telescope; they also include the first photograph to be taken on glass (now in the Science Museum, London).
At the time that this was taken, Sir William Herschel's 40-foot telescope was already a famous astronomical symbol, although it was being demolished - hence the absence of the telescope's tube.
The only camera images Sir John Herschel is know to have taken are of his father's telescope; they also include the first photograph to be taken on glass (now in the Science Museum, London).
Negative image of an engraving of a lady by Sir John Herschel (1792-1871), 5th August, 1839, fixed with hypo.