THE WOMBAT. 24 
Hot Hypo-alum Toning for Bromide Prints. For this 
method of toning it is not necessary that the prints should be 
washed after fixing—a mere rinse will be quite sufficient—but I 
think it is better that they should be dried before attempting to 
tone them, as this tends to harden the gelatine. 
Before placing tae prints in the hot hypo-alum bath, they 
must either be put in an alum bath or placed in a cold hypo and 
alum bath for a few minutes, and then transferred to the hot bath, 
which is made up as follows :— 
Sodium hyposulphite ... ne OEOZs 
Alum (common) ow ee ~ 1 02, 
Water on «-» 60 oz. 
This bath requires to be heated to about 120° before the 
prints are put in, and then kept to about that temperature. The 
prints take from twenty to forty minutes to tone. The quality of 
the tones obtained by this process depends mainly upon the quality 
of the print. Prints taken from brilliant negatives give very fine 
tones indeed, The best paper for this purpose is a toned or tinted 
one, such as Hastman’s Royal Bromide, and some very fine effects 
indeed may be obtained on this paper, almost approaching carbon 
in quality. It must be remembered that this method of toning 
tends to slightly reduce the prints, and therefore the prints for this 
purpose must be fully printed out.—Photography. 
SOME OF THE DEFECTS IN PLATINOTYPE 
WORK AND THEIR CAUSES. 
1, The pictures are vigorous, but more or less fogged. 
Cause.—The paper was affected by light, either in sensitising 
or copying, or there was too high a temperature in drying; 
it should not exceed 40° 0, 
Spoiled ferric solution. 
The ferric solution is best preserved iy hyalite flasks. If you 
are not sure of your solution, test it before using with red 
prussiate of potash to see that it is free from ferrite. 
Should it contain only a trace of ferrite, it can be made fit 
for use again by carefully adding red prussiate of potash. 
In order to try this, mix a few cub. centims. of the normo- 
ferric-chlorite solution with every 100 cub. centims of the 
iron solution, and ascertain by actual experiment on paper 
whether the restoration is complete. 
2. The prints appear weak under the developer. 
Paper which has become damp. 
