The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

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water will reduce the image slightly. Platinotype prints can be far more easily intensified, and several processes have been suggested for this purpose, by means of which also various modifications of tone are possible. Dollond suggests what is practically a gold toning process which he describes as follows. The solutions required are : -
1.   Gold chloride          ............ 15 gr.
Distilled water ... ... ... ... drachms.
Neutralised with chalk, filtered, and one drop of strong hydro-chloric acid added.
2.   Glycerine.
3.   Sodium sulphite
Water to .....
Metol           .....
4.   Potassium carbonate
1 oz.
... 10 .. ... 5o gr-1 oz.
Water to .....,
The following is • the method of application : - The platinotype print developed, cleared and dried in the usual way, is soaked for two or three minutes in water, then laid upon a flat surface, preferably a sheet of opal glass, and blotted to remove the excess of water. Next glycerine is gently spread over the whole surface of the print with a soft brush or the finger-tip. When evenly coated, a few minims of the gold solution are dropped on and rapidly mixed with the glycerine with a soft camel-hair brush. Very soon the print will begin to gain in strength and assume the blue-black colour. During the whole time the toning is proceed-ing, the surface of the print should be brushed lightly and quickly, in order to insure even action and to constantly bring fresh gold chloride into contact with the platinum image ; also there seems to be less tendency for a deposit to be formed on the high lights if the solution is kept in motion. The high lights should be watched, and as long as they remain clear the action may be allowed to continue. When the desired effect is obtained or when any coloration is seen in the high lights, the print should be quickly rinsed to remove the adhering glycerine and gold. After this a mixture of equal parts of metol and potash solutions is sponged over both front and back of the print. Washing for half an hour completes the operation. Prints may