It may not be unnecessary to maintain
that the difficulties of perfect washing--particularly if one do not
wash with running water--increase at least in quadruple proportion to
the quantity of emulsion manipulated.--_Franz Stoke, Ph.D., in Br. Jour,
of Photography_.
* * * * *
HOW TO MAKE EMULSION IN HOT WEATHER.
By A. L. HENDERSON.
Numerous complaints have reached me within the last few weeks of the
difficulty experienced in preparing emulsion and coating plates; one is
very likely to blame everything but the right, but doubtless the weather
is the culprit.
I have always held that to boil gelatine is to spoil it, and, even when
emulsification is made with a few grains to the ounce and cooled down
before adding the bulk, the damage is done to the smaller quantity,
so that when mixed it contaminates the whole mass; moreover, it is
impossible to set and wash the gelatine without the aid of ice.
I have lately made several batches (with the thermometer at 92 deg. in the
shade, and the washing water at 78 deg.) as follows:
Hard gelatine...............,...... 1/2 ounce.
Water.............................. 2 ounces.
Alcohol............................ 2 "
Bromide ammonia................
Pages:
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99