Hannavy_RT72353_C000v1.indd

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1252


For practical photography’s fi rst four decades, the
picture-maker was also manufacturer and chemist, seek-
ing to produce photographs using homespun chemistry
which by its lack of consistency, introduced an almost
infi nite range of variables. Yet in so doing, the great
photographers of the mid-Victorian era overcame ma-
jor diffi culties, and applied their limited technical and
chemical understanding to the production some of the
medium’s most beautiful and enduring images.
In seconding the motion “That a Society now be
established to be called ‘The Photographic Society’” at
the Photograph Society of London’s inaugural meeting
on 20th January 1853, Robert Hunt accurately sum-
marized the importance of a forum for the exchange of
scientifi c knowledge in the development of photography.
His comments were reproduced in the fi rst issue of the
Journal of the Photographic Society:


Mr Hunt, in seconding the motion, dwelt at some length
on the importance and even the necessity of a Society to
ensure the future progress of photography. He considered
such an Association of practical men would be the best
and most effi cient mode of publishing and comparing
the results of their numerous mutual trials, and pave the
way for new discoveries. However rapid and satisfactory
may have been the improvements in this science, much
yet remained to be done. Reference was made to several
phenomena, hitherto unexplained and still obscure, at-
tendant on the results of photographic operations; for
instance, it is known that the prepared paper is not acted
upon by the yellow rays, while these rays do act upon
glass prepared with collodion.
Hunt’s account, while correctly identifying that
the science of photography was, as yet, in its infancy,
underlined that lack of understanding by incorrectly
suggesting that the wet collodion plate had some sen-
sitivity to yellow. Yellow sensitivity would, in fact, not
be achieved until the early years of the 20th century
when the introduction of dye sensitizers fi nally made
a truly panchromatic emulsion possible. What Hunt
was probably observing was limited green sensitivity
manifesting itself as fogging under an imperfect yellow
glass in the darkroom.
If the experiments of Thomas Wedgwood between
1795 and 1802 are taken as a starting point, photogra-
phy, at the time Hunt was writing, was already more
than half a century old—yet an understanding of the
underpinning science was only in the very earliest stage
of emergence. Wedgwood’s inability to fi x his pioneer-
ing images is often cited as an early example of poor
photographic research—given that the ability of a range
of chemicals to arrest the darkening effect of sunlight on
silver salts had been identifi ed by Carl Wilhelm Scheele
and others much earlier. So, from photography’s earliest
days, an organized dissemination of relevant scientifi c
knowledge would have been benefi cial.


Robert Hunt was, himself, one of the leading fi gures
in the advancement of the science of photography. His
Popular Treatise on the Art of Photography had fi rst
been published in 1841, and he had completed work
on the third edition of his Manual of Photography, fi rst
published in 1851, by the time of the Photographic
Society’s inaugural meeting.
The early years of photography were punctuated by
a number of radically different approaches—indepen-
dent inventors pursuing their shared goal by seeking to
exploit fundamentally different chemistries.
Wedgwood and Davy opened the century with their
experiments—reported in June 1802 in the Journal of the
Royal Institution and later recounted by Henry Snelling
in his groundbreaking 1849 book, The History and Prac-
tice of the Art of Photography (New York: G.P.Putnam,
reprinted New York: Morgan & Morgan 1970).
A piece of paper, or other convenient material, was placed
upon a frame and sponged over with a solution of nitrate
of silver; it was then placed behind a painting on glass and
the light traversing the painting produced a kind of copy
upon the prepared paper, those parts in which the rays
were least intercepted being of the darkest hues. Here,
however, terminated the experiment; for although both
Mr. Wedgwood and Sir Humphrey Davey (sic!) experi-
mented carefully, for the purpose of endeavoring to fi x
the drawings thus obtained, yet the object could not be
accomplished, and the whole ended in failure.
While that report mentions that Wedgwood and Davy
experimented with several different materials on which
to brush their chemistry, only paper is specifi cally cited.
Their other experimental surfaces included leather, and
they noted that
White paper, or white leather, moistened with solution of
nitrate of silver, undergoes no change when kept in a dark
place; but, on being exposed to the day light, it speedily
changes colour, and, after passing through different shades
of grey and brown, becomes at length nearly black ...
and indeed their experiments proved markedly more ef-
fective with leather than with paper, due in part to chemi-
cals contained within the tanned leather about which they
knew nothing at the time. It would be a further thirty
years before William Henry Fox Talbot demonstrated
the practical application of their ideas, by recognizing
the initial production of a ‘negative proof’ from which
a ‘positive proof’ could be made by contact.
In 1816, Joseph Nicéphore Niépce, experimenting
with silver chloride, got no further than had Wedgwood
and Davy, again due to an inability to arrest the darken-
ing effect of light. He too got within touching distance
of producing the fi rst photographic negative. Silver
nitrate—the chemical Niépce abandoned—would later
play a crucial role in the evolution of photographic mate-
rials. A decade later he turned his attention to a range of

SCIENCE

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