Sir John Herschel's photographic experiments contain 9 photogenic drawings and experimental papers by the inventor of the process, W. H. Fox Talbot (1800-1877; who generally signed himself H. F. Talbot). They are mostly in two small packets (26 and 27) marked 'not fixed' and 'Fixed with salt &c.', in what looks like Talbot's own handwriting. Another one (79213) was found among Herschel's miscellaneous specimens in packet 34. The latter is a photomicrograph (a microscopically enlarged image) marked in Talbot's handwriting 'Lace in the Solar Microscope'. Although undated, Herschel acknowledged receipt of some 'very pretty specimens of Magnified Lace' in a letter to Talbot of September 10, 1839. The solar microscope used sunlight to project an enlarged and very bright image, thus providing the first viable application of photography to microscopy.
The other Talbots are earlier, contemporary with Herschel's first phase of experiments in the early months of 1839. They are mostly very dark, typical of the early experiments with salt (sodium chloride) fixing, or (as the packet implies) not fixed at all. They are also typical of Talbot in being cut (and sometimes torn) to various unusual and untidy shapes. Those bearing discernible images are contact copies of botanical specimens. Two (in fact a single photograph cut into two unevenly shaped pieces, one quite small) show a piece of fern. Another piece of fern is visible at one corner of an oddly shaped paper (26223), the blotchy marks over the rest of which carry hints of what may be vestigial images of plants and flowers. Very indistinct vestigial images may also exist on the three very dark and seemingly blank papers (52921, 65957, 98504); being in the packet marked 'not fixed' they presumably had images which continued to darken and more or less disappeared quite quickly.
A contact image of a spray of heather (49660), very dark and on unusually stiff (and rectangular) paper, is inscribed 'H.F.T. March 1839 Erica mutabilis'. Talbot's use of the scientific name not only betrays his serious interest in botany, but suggests that, like other photographic pioneers (see 11887), he already saw his invention as supplying the means for a programme of recording botanical specimens by directly contact copying them. That may, indeed, be why he tried this experiment on a piece of stiff card. Images exist in other Talbot collections of this same piece of heather.
Another small piece inscribed '4 states of Bromide of Silver' (33743) is a test sheet divided into four squares, which show slightly different colouring or intensity. It evidently illustrates some chemical question Talbot and Herschel had been discussing, probably the unexpectedly inverse proportionality of the sensitivity of bromides: the weaker solutions darken more than the stronger ones. Schultze was of the opinion that the two contact copies of lace in the collection (26027 and 30855) were also by Talbot, but they seem in fact to be Herschel's. An empty packet (95930) among the prepared but unexposed papers is marked by Herschel as having contained samples of Talbot's 'Iodized Paper', prepared for his newly-invented calotype process (in 1840/41). The Museum also has, from a different source, two calotypes (salted paper prints) by Talbot taken in Oxford and dated 1842 (31601 and 37304).
The presence of Talbot specimens among Herschel's experiments is not incidental. Herschel was the man to whom Talbot wrote on January 25, 1839, the day he first announced his invention of photogenic drawing to the public; so it was in direct response to this that Herschel commenced his own experiments on January 29. Talbot read a fuller paper on his invention to the Royal Society on January 31; and the following day (February 1, 1839), on his way home presumably, he visited Herschel to compare specimens and discuss their respective experiments. The visit is mentioned in the draft letter which survives as four pieces of scrap paper (31059, 34848, 55175, 75495). Herschel's Talbot specimens thus illustrate a genuine collaboration between scientific colleagues. Herschel of course made a number of advances which significantly improved, and enhanced the viability, of Talbot's process, notably the application of the fixative hypo.