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GELATINO BROMIDE EMULSION WITH BROMIDE OF ZINC.


By this time of the year I have no doubt many, both amateur and
professional photographers, are either contemplating or are actually
at work making their stock of plates for the coming season, and it is
to be hoped that we shall have more favorable weather than we had last
year.

Some four or five years since I tried using bromide of zinc instead of
the ordinary salts, namely, bromide of ammonium or potassium. I only
made one batch of plates at the time, which possessed several
important features I considered an advantage, and I think well worth
while following out. I do not think it can be denied that ordinary
gelatine plates, if exposed in a weak light, fall very short of the
results obtained with wet collodion when compared side by side,
gelatine being almost useless under these conditions, and there is a
decided gain in the result in this respect if the emulsion be made
with zinc bromide.

In using bromide of zinc there is a slight difficulty to overcome, but
it _can_ be overcome, as I have succeeded in making a perfect
emulsion. It will, I have no doubt, be remembered that Mr. L. Warnerke
was the first to call attention to this salt in the days of collodion