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Herschel's Hunts

Herschel's Hunts

Packet 28 among Sir John Herschel's photographic experiments, marked 'Hunts Positive Photogc paper & drawings', contains 6 exposed specimens, 9 unexposed prepared papers, and a small printed sheet of instructions, sent to Herschel by Robert Hunt. They illustrate his own photographic process, invented in 1839, which is a direct-positive bleaching process, silver nitrate based but re-sensitised with potassium iodide. It is similar to the process invented about the same time by the French pioneer Bayard. Hunt placed it on the market, to a limited degree, issuing the leaflet and selling the papers and chemicals at his own chemist's shop in Devonport, near Plymouth. The speed with which the primitive photogenic drawing processes were superseded by Talbot's calotype (patented in 1841) allowed little time for processes such as Hunt's to become established or commercially successful. Herschel however was very impressed by Hunt's process, mentioned it in one of his own published papers, and sponsored Hunt's first scientific paper on photography, published in 1840. Several of the samples preserved with Herschel's own photographic experiments bear out Herschel's judgement, and are among the finest surviving examples of photogenic drawing preceding the calotype or Herschel's cyanotype.

Robert Hunt (1807-1887) had for some years been a talented young man in search of a career. He established a chemist's shop (a pharmacy) in Devonport about 1837, and moved to a more academic post in Falmouth in 1840 (and in 1845 to London). In this small window of time the invention of photography transformed his fortunes and provided a focus for his interests in chemistry and light. His invention and his ability as a chemical experimenter brought him, via Herschel, to the greater attention of the scientific world; but his abiding role as an authority on the new science derived particularly from his famous book "A Popular Treatise on the Art of Photography", published in 1841. It was the earliest true textbook of photography, and its revised and extended editions of 1851 onwards were the standard work for a generation. Although his own process had no future, the new processes that rapidly transformed photography at this period owed much of their wide dissemination to the impact of Hunt's book. Herschel figures very prominently in it, his experiments and scientifc conclusions being cited throughout, and a whole chapter being devoted to the processes he invented (cyanotype, chrysotype, etc.).

The Oxford specimens of Hunt's early work illustrate (as annotated on the backs) the several sensitising and processing chemicals he was trying, though they are not mentioned on his printed leaflet. They also represent the uses of photography typically envisaged by early experimenters: copying delicately translucent items such as leaves, copying engravings, and preserving camera obscura images. The leaflet gives brief instructions for both 'taking Views with the Camera Obscura' (an early use of the word 'take' in its new photographic meaning) and making 'Surface Drawings' (contact copies). Little of Hunt's own photographic work survives, and even the printed leaflet in this collection may be unique. Outside Talbot's early work with the camera, Hunt's single surviving 1839 camera image is one of the very few surviving from so early a date. The camera image was (as Hunt's own inscription indicates) one of a pair, but there is no record of the other coming with the collection to the Museum. Although extremely faint and lacking detail, it clearly shows part of a row or street of shops, the centre of attention being a three-storey building with a double-fronted shop at ground level. It is reasonable to assume that this is a photograph of Hunt's own home and chemist's shop in Devonport.

The quality of crisp detail and pleasing colouring of which Hunt's process was capable is better illustrated by the three contact images of leaves. The yellow and greenish colours result from the iodides used, and are particularly appropriate to leaf specimens. Hunt's paper was formed by treating with silver nitrate, exposing it until black, and re-sensitising it with potassium iodide as a bleaching agent. The specimen was placed on the blackened paper and exposed to sunlight, and a direct-positive image appeared by bleaching. The image was fixed (according to Hunt's instructions) by washing in warm water. Various other treatments and chemicals are mentioned in Hunt's annotations to the actual specimens, presumably ongoing experimental variations. It would be assumed that Herschel tried the process using the prepared papers Hunt sent him, but no specimens that can be interpreted in this way have been noticed among Herschel's experiments; the 6 examples of Hunt's process are all annotated in Hunt's own handwriting. The fixing and bleaching properties and the yellow colour associated with potassium iodide and related compounds are represented among Herschel's experiments as early as February 1839, before he heard of Hunt's process (for example 31428); though a series of further tests with potassium iodide as a fixative in June (for example 46015) may possibly have been inspired by Hunt's use of it.

Hunt gave no name to his process, but it is noteworthy that he used the term 'photographic', following Herschel and in preference to Talbot's 'photogenic' (see narrative to 91957). The following is a transcription of Hunt's printed instruction leaflet.

'Directions for using the Photographic Drawing Paper, And for taking Views with the Camera Obscura.

Having fitted the paper to the Camera, place it on a piece of very clean glass, or porcelain, and lay on the Fixing Fluid with a soft brush, over both sides. Replace the paper immediately -- the dark surface facing the glass, and direct the Camera towards the object to be delineated.

The time necessary for the best effect, depending on the intensity of light, varies from thirty minutes to an hour. Bright sunshine on the object to be drawn, not only quickens the process, but produces the most beautiful Picture.

For Surface Drawings.

Carefully place the objects to be copied, on the glass of a Photographic frame; then lay over them the paper prepared as above directed, and expose to the sunshine until the uncovered parts are bleached. If leaves are to be copied, they should be freshly gathered, and their smooth surfaces placed in contact with the dark sides of the paper.

To render the drawings absolutely permanent, soak them some time in soft water, (warm is preferable) and carefully dry them in the dark.

The Photographic Papers must be carefully excluded from light and moisture, and the Fluid also kept in the dark, until the time of using.

W. Richards, Printer (Telegraph-Office), Devonport.'

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