The ferrotype and how to make it - The Grian Press

62 THE FERROTYPE.
I
The iodide of Cadmium, in addition to the
valuable property of giving a stable Collodion, is
likewise extremely soluble without being deli-
quescent, and being beautifully crystalline, is not
liable to adulterations or impurities, and is, there-
fore, deserving its good reputation.
Mr. Bingham, in the " Photographic World,"
vol. 1, page 173, gives some formulas for the
preparation of double iodides and bromides, the
use of which, for exciting or salting Collodion,
he very highly recommends, and which appear
to me to be valuable. For the double iodide of
cadmium and potassium his formula is as fol-
lows: ' "^
" Iodide of Cadmium, 182 grammes;
Iodide of Potassium, 165 "
Warm water 300 "
Shake well and filter; then evaporate in a small evapo-
rating dish over a slow heat.
" For ammonium and cadmium
—
"Iodide of Cadmium, 149 grammes;
Iodide of Ammonium, 144
"
Water (same as before.)
"
" Double bromides can be made as well by using
these equivalents.
"The great advantage gained is, of the potas-
sium, without any water to dissolve it, as the
double iodides dissolve very readily in alcohol and
ether.
" I use about the following proportions to salt
my Collodion, which works soft and beautiful
: