The Dictionary Of Photography

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

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Gelatino-Chloride
Valenta suggested the use of acid hydroquinone and pyrogallol developers.
Hydroquinone Developer.
A.   Hydroquinone          ... ... ... ... io parts.
Alcohol          ............... ioo ..
B.   Sodium sulphite ............ ioo parts.
Distilled water         ............500 ,,
Citric acid ...... ... ... ... 5 ,,
For use, 50 parts of Solution A should be mixed with 50 parts of Solution B, and 1000 parts of water added.
Pyrogallol Developer.
Distilled water ............   1000 parts.
Sodium sulphite ...... ......     100 ..
Pyrogallol ... ............      10 ..
Citric acid ... ... ... ... ...      11 ,,
The ingredients should be dissolved in the water in the above, and the clear and almost colourless solution used immediately. The hydroquinone developer works clear and slowly; the violet tone of the printed-out image turns in developing into a yellowish-brown. The prints were toned and fixed in the combined toning and fixing bath composed as follows: -
Distilled water         ... ... ... ...    500 parts.
Hyposulphite of soda         ... ... ...    200 ,,
Sulphocyanide of ammonia           ... ... 25 ,,
Alum............... ... 30 ,,
Acetate of lead solution (1 : 10)...... 40 ,,
This solution is to be heated on a water bath to about 6oo C, by which a quick deposition of the precipitate formed is obtained. It should then be filtered, and 100 parts of it mixed with 50 parts of water and 10 parts of 1 per cent, solution of choride of gold. In this combined bath the yellowish-brown developed prints assume a yellow tone, which very soon turns into brownish-red, and into a beautiful deep, purple brown. The toning process should be stopped when the prints have assumed the desired tone, and it should be noted that after washing the tone is rather deeper. Liesegang specially recommends the following for his own paper, but for others it is not suitable : -
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