HF The History of Photography 600pág

3 12 The collodion period
Fig 43 Woodward's enlarger, 1857
Fig 43
The 'solar camera' patented in 1857 by DAVID A. WOODWARD, a photographer and
professor of drawing at the Government School of Design, Baltimore, was an
adaptation of the solar microscope in use since 1740. It was made in two sizes : (1)
fitted with a 9 in. condenser for half-plates, it cost £21 ; (2) with a 5 in. condenser
for quarter-plates, £ 13. The solar camera was a considerable improvement on
previous enlargers, and Woodward explained that it originated in his desire to make
enlarged copies of photographs on canvas to paint over. He proved his point by
showing a life-size half-length portrait (18 in. x 22 in.) enlarged from a half-plate
negative in 45 minutes.4 Despite the apparent advantages of enlarging, the solar
camera was not used to a great extent, for those who wanted large pictures preferred
to take them on large plates, without being involved in a second operation.
The well-known microscopist GEORGE SHADBOLT was among the few far-sighted
people who believed that the future of photography lay in enlarging small instantaneous
photographs in order to overcome the regrettable absence of life in larger
negatives.5 But although a number of ingenious miniature cameras were constructed
(see chapter 20) few used them except their inventors.
With the new fashion for carte portraits in 1860, the need for enlarging arose afresh.
It was not unusual for a client to ask for a larger copy of his favourite carte portrait,
and however much the photographer tried to persuade him to have a new portrait
taken on a larger plate, the client would usually insist on an enlargement of the
portrait which he knew, rather than risk getting something he might not like.
It was chiefly due to ANTOINE CLAUDET's enthusiasm for Woodward's instrument
that its introduction into Europe met with success. Claudet read a paper on it before
the British Association in 1860, and exhibited life-size portraits made from carte
negatives at the International Exhibition, London, 1862. The Austrian court photographer
Viktor Angerer (brother of Ludwig) travelled specially to London to see
Claudet's enlarging arrangements, which he introduced in Vienna.6
In Woodward's solar camera, the negative was placed in the back of the instrument,
which was set up in a darkroom at an opening in the window-shutter, preferably
facing south. A mirror projecting through the aperture reflected the sun's rays on to
a condenser which concentrated the light on to the negative and thence through a
lens on to a screen in the room. As enlargements on printing-out albumen paper
required several hours' sunshine, Blanquart-Evrard's paper with development was
usually employed (see chapter 15) and this reduced the exposure to IO minutes to
half an hour in sunshine. On dull days, enlargements were usually made on wet collodion,
in order to keep the exposure to a reasonable length. In this case the negative