Page 76 - The Wellington photographic handbook

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in solution adding two ounces of Alum little by little. A whitish
liquid results. This will keep indefinitely ; it should not be filtered,
nor thrown away after use, as the older it is the better it works.
In proportion as the volume is reduced by evaporation it should
be replenished with new stock solution.
Before using a new bath, it should be " ripened " by immersing
waste prints in the solution and raising the temperature to 140°
Fahr., allowing the solution to cool, and then raising the tempera-
ture again to 140° Fahr., and again allowing it to cool. Or a small
quantity of Nitrate of Silver (about 20 grains) previously dissolved
in one ounce of distilled water and added to the stock toning solution
may be employed as the " ripening " agent. If this " ripening "
is omitted with a new bath the more delicate tones of the prints
may become reduced.
To tone the prints, they are placed face downwards in an
enamelled iron dish, and enough of the cold toning solution added
to completely cover them. The dish is placed over a gas stove
or spirit lamp, and the liquid gradually heated to 120° Fahr., and
kept at that point until toning is complete. The prints are then
taken out of the toning bath, rinsed in warm water, washed in cold
water, and hung up to dry.
It is advisable to use a combined hardening and fixing bath
for prints intended for toning in the Hot Hypo and Alum Bath,
and if the prints appear slightly darker than would seem desirable,
so much the better, as slight reduction takes place in toning.

TONING WITH COPPER AND IRON.
Very pleasant colours ranging from a warm black to a bright
crimson can be obtained by what is known as Ferguson's process.
Three stock solutions are required.*
A. Neutral Potassium Citrate 4 ounces 100 grammes
Water to . . 40 „ 1 litre
Potassium Ferricyanide 1 ounce 25 grammes
Water in . . 1 0 ounces 250 c.c.
C. Copper Sulphate . . 1 ounce 25 grammes
Water to . . 10 ounces 250 c.c.
Before making up any formula, read the notes on pages 125, 126 and 134.
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