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Early
Photographic Processes
Ambrotype
or Collodion Positive
1851-1880s
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Discovery |
The
wet collodion process was discovered by Scott Archer. He published
the process in 1851 and allowed its use free of copyright.
The collodion process used
a thin film of collodion, poured onto glass, as a base for the image.
This glass plate negative that was normally used
for making one or more albumen prints.
However,
Scott Archer and Peter Fry
found that a thin glass negative could become
the photo itself, if it was viewed against a black background.
These
photos were sometimes known in Britain as 'Collodion Positives', but are
now known by the name by which they were patented in the USA in
1854 - "ambrotypes". |
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Process |
There were two stages to producing an
ambrotype:
A. Create a wet collodion
negative.
See
steps 1 to 8 of the
Wet Collodion Process.
B Present the negative
against a dark background:
1. Selectively
bleach the negative (if necessary)
2. Provide a black background,
either by painting the back of the glass with shellac or mounting the
the glass on top of black velvet.
3. Mount
in a case behind glass, as for daguerreotypes. |
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Result |
The Image
The
result was a unique image, consisting of a negative, usually
underexposed, mounted against a dark background then mounted in a
case.
Unlike
a daguerreotype, an ambrotype image can be seen when viewed from all
angles. For this reason the process became popular, even though
the finished result lacked the detail and tonal range of the
daguerreotype.
The
image would be either normal or reversed (left to right) according to
whether or not the emulsion side of the negative lay against the black
backing. |
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The Case
Ambrotypes
were often produced using one-eighth of a wholeplate (6.25 ins x 8.5 ins)
sheet of glass. This gave images about 3.125 x 2.125 ins).
 ©
Many
of the cases in which ambrotypes were mounted, Union Cases, were
made of thermoplastic with ornate patterns moulded on them.
Union cases were introduced
about 1853 by Samuel Peck & Co, New Haven, Connecticut, USA, and later
made by John Smith in the UK. Union Cases
were cheaper to produce than the earlier cases that had been used for
daguerreotypes. |
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Click
here to see examples of ambrotype photos. |
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In
Edinburgh
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Robert Armstrong
Here
is an ambrotype from the studio of Robert Armstrong of 75 Princes
Street, Edinburgh. Robert Armstrong was based at this address from
1855 until 1865.
©
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Thomas Buist
Here is an ambrotype
photograph of the Fife and Edinburgh
photographer, Thomas Bruist. Thank you to Frances Culham, Thomas'
great great grand-daughter for allowing me to reproduce this image.
© |
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Duchauffoir & McIntyre
Here
is the inside and outside of a cased ambrotype from the studio of
Duchauffoir & McIntyre, photographers, who were based at 33
Whitfield Place, Leith, for ten years from 1855.
©
©
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Today |
The wet collodion process is
still being practiced today by Mark Osterman and France Scully Osterman.
They work from the skylight
studio at their home.
©
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Click
here for further details
of Mark and France and their early experiments, publications, exhibitions
and workshops.
Click
here to see Mark's
web site. |
