Making Autochrome plates


Peter Marshall (petermarshall@cix.co.uk)
Fri, 16 Apr 1999 21:00 +0100 (BST)


A photographer friend (Jim Barron) recently lent me an intriguing book by
Charles Duncan 'A Photographic Pilgrims Progress' published by Focal Press
(NY and London) in 1954.

Duncan was born around 1871 and around the age of 11 or 12 he spent some
time accompanying and learning photography from an itinerant photographer,
Eduarde Jennings, in rural Kent. Jennings had been employed by Daguerre
during his collaborations with Niepce, and in the early 1880's was making
daguerreotype portraits and wet-plate pictures, apparently continuing to
use the superior collodion method even when dry plates became available.
(I remember being told by a well-known photographic historian that the
daguerreotype had completely disappeared in this country by the 1870s, so
that's one little revision to received wisdom.)

Of most interest to this list is Duncan's first hand account of the making
of Autochrome plates (p125):

'In the early part of the George V coronation year I went to Paris to see
if I could get some large Lumiere colour plates made on which to
photograph the celebrations ... and I saw there starch grains being
prepared in what seems to me a most unscientific manner.

Many kilos of the dry starch were soaked, with constant stirring, in vats
of red, green and blue dyes, and afterwards spread out to dry. When quite
dry, a man mixed them in a great bowl until the mass was grey; as he
blended the mixture he would add a touch of one or another colour as a
pastrycook would add flavouring to the ingredients for a cake, until he
got the dirty-looking neutral grey he wanted.

The whole process of making these delicate screen plates rather shocked me
because they were prepared under what seemed to be such crude conditions
rather than those of the laboratory. The grey powder was put on a tray at
the bottom of a dusting box about ten or twelve feet high and a fan blew
it until the chamber was filled with a cloud of the coloured particles.
About ten minutes later the man slid into the bottom of the contraption a
large sheet of glass which had been coated with a thin sticky film. A
minute or two later it was drawn out bearing and even layer of the
coloured starch grains which, when later rolled flat, formed a perfectly
balanced mosaic of the three primary colours.'

Duncan also met others working with colour processes - including Dr Joly
and also Finlay - as well as himself working with the Lippman process, but
doesn't give any similar descriptions. The book is a fascinating read for
anyone interested in the development of photography.

Peter Marshall

On Fixing Shadows and elsewhere:
http://www.people.virginia.edu/~ds8s
Family Pictures, German Indications, London demonstrations &
The Buildings of London etc: http://www.spelthorne.ac.uk/pm/



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