The ferrotype and how to make it - The Grian Press

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THE FERROTYPE.
posure, by varying the proportions of old and
new. If we have given, too ranch time in ex-
posure, we may weaken the solution with the
old ; if too short an exposure has been made, we
strengthen with new. If it is desired to produce
a white ground and purer high lights, the plate
may be flowed with a small portion of the old
unfiltered, which gives a heavy deposit of silver;
this, however, should not be done until after the
plate is partially developed by the ordinary so-
lution.
An excellent filter has been before described,
but is worthy of more careful attention in this
connection. A soft felt hat may be stretched on
a frame, or placed in a large glass funnel, over
which to develop all pictures; the surplus solu-
tion falling into the hat is more perfectly filtered,
and the deposit which remains in the filter, after
enough shall have collected to interfere with its
usefulness, being all silver, may be recovered in a
metallic state by any of the processes usually em-
ployed for that purpose, among which the follow-
ing will be found the most economical, and,
perhaps, within the means and ability of a
greater number than would by any other pro-
cess :
The residue may be taken from the filter, and
placed in a porcelain evaporating dish containing
a solution composed of equal parts of nitric acid
and water; the whole should be gently heated
until the action of the acid has ceased, when the