A Calotype
or Talbotype was a very early photographic process
which used sensitized paper to make the picture.
It was devised
by the clever Willia Henry Fox Talbot
(1800-1877) in 1840 as an improvement on his earlier, much slower
process.
The paper which was treated with
silver chloride, was exposed
in a camera for about 1 minute.
It was developed with
gallic acid and fixed with sodium hyposulphate, the
same "hypo" used today.
The prints
were rough because of the weave of the paper and the process was
somewhat slower than Louis Daguerre's
system of the same date.
Estimated basic value: Quite
Rare
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