Page 65 - The Wellington photographic handbook

If preferred, the following acid hypo bath may be employed : —
ACID FIXING BATH."
Hypo ... ... ... ... 4 ounces 1 00 grammes
Potassium Metabisulphite ... 200 grains 13 „
Water to ... ... ... 20 ounces 500 c.c.
There are other methods of making up an acid fixing bath,
but none are more simple or more effective than the above. The
water may be warmed to make solution take place more quickly,
but it must not be hot, or the potassium metabisulphite will have
its power greatly reduced. The bath must, of course, not be
employed until quite cold. This hypo bath does not discolour
as is the case with a plain hypo solution ; it should, however, not
be kept from day to day. Proper fixing is essential, both for the
purity of the prints and to ensure their permanence.
In either of the above baths fixation will be complete in about
ten minutes, provided the prints are not allowed to cling together.
At intervals, and especially during the first few moments after
immersion, they should be moved about, or the dish should be
rocked.
In cases where many prints are being made it is an excellent
plan to use two fixing baths, giving the prints an immersion of
five minutes in each. When the first bath begins to show signs of
discoloration or exhaustion it should be discarded and the second
bath should take its place, a fresh bath being used for the final
period of fixation.
There is rarely any need to use a hardening bath with the
WELLINGTON Bromides. If blistering or softening of the
film occurs the cause should be looked for in the manipulation.
It should be made a rule to use all the solutions at approximately
the same temperature, and never above 65° Fahr. Great difference
in temperature between the various solutions, or between the
solutions and the washing water, will sometimes—though by no
means always—cause blisters to appear. The fact that this rule
may often be transgressed with impunity does not excuse care-
lessness.
* Before making up any formula, read the notes on pages 125, 126 and 134.
49