HF The History of Photography 600pág

33 Photography by artificial light
From the earliest days of photography attempts were made to take pictures by
artificial light in order to shorten the exposure, and also to enable portraits to be
taken on dull days and in the late afternoon. Though only fast gelatine plates made
this possible for general adoption, the following pages give a summary of some
notable early experiments with different forms of artificial light, which in progressive
stages laid the groundwork for its application after l 880.
OXY-HYDROGEN LIGHT (LIMELIGHT)
L. L. B. IBBETSON of the Royal Polytechnic Institution, London, in the winter and
spring of l 839-40 experimented with the oxy-hydrogen light-a jet of oxygen projected
through a flame of hydrogen impinging on a disk or cylinder of lime, which
became brilliantly incandescent. He succeeded in making in less than 5 minutes a
daguerreotype of a piece of coral magnified lzt times in a microscope-a subject
which he said would have required 25 minutes by sunlight.1
One of J. F. GODDARD's most popular demonstrations of the daguerreotype process
during his lectures at the Royal Institution and the Polytechnic Institution in
March 1841 was to photograph a white bust by the oxy-hydrogen light with an
exposure of 3 minutes. Two months later ANTOINE CLAUDET went a step farther by
taking portraits from life by the oxy-hydrogen light in l 5 seconds.2 This, and other
artificial light sources 'employed to take portraits at night' were patented by him on
l 8 Dec. l 84r. These specimens were exhibited to the Royal Institution as a curiosity
proving the relative speeds of Goddard's and Claudet's acceleration methods, rather
than suggesting the application oflimelight to portraiture. Claudet admitted that the
light was too harsh, resulting in chalk-white faces.3
PYROTECHNIC LIGHT
JOHN MOULE's 'Photogen' (patented February 1857) was better suited to portrait
photography. A pyrotechnic compound giving a brilliant bluish-white light (Bengal
light) was burned in a big hexagonal lantern with glass sides. The time of combustion
was about 15 seconds, during which the exposure was completed; the fumes were
carried out of the window by a stove-pipe. A screen of blue glass sheltered the sitter
from the dazzling light and softened the effect. The pyrotechnic compound was cheap
(about 2d. per exposure), and Moule's offer to the profession to take a specimen
portrait for 5s. so that they might see the result before paying £5 IOs. for the apparatus
proved his confidence, and portraiture at night became for a while a novel