The Dictionary Of Photography

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

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residue tank; don't use it again, and don't try and revive it by adding more gold. After toning place the prints in salt and water, and fix in an alkaline bath, and wash well in running water for from twenty to thirty minutes. Combined toning and fixing baths are a great convenience, so it is said, as by their use the number of solutions and operations requisite for making a tint are reduced. It is probable, however, that there is far less chance of the prints being permanent when treated with such a bath by the average worker. If a combined bath is properly made and properly used there is no reason why it should not yield as permanent results as any other ; but, as ordinarily used, these baths may be fatal to permanency. Hyposulphite of soda is decomposed by acid and alum, and sulphurous acid and free sulphur are set free and sulphur toning caused. For those who wish to use alum and lead salts the following may be adopted: -
Water           ...............500 parts.
Hyposulphite of soda         ... ... ... 200 ..
Ammonium sulphocyanide           ... ... 25 ,,
Nitrate of lead         ... ... ... ... 10 ..
Alum... ... ... ... ... ... 20 ,,
Dissolve the hypo in the water first, add the sulphocyanide, then dissolve the alum in a little water, and add to the hypo, with constant shaking. Then add the lead nitrate in the same way, that is, dissolved in water, heat the whole to 500 C. for ten minutes, allow to cool and filter, and to every 100 parts of this concentrated bath add 100 parts of water, and 7 to 8 parts of a 1 per cent, solution of gold.
I. Liesegang's Baths.
Solution A.
Chloride of gold ............ 2 grs.
Distilled water ... ......... 2 ozs.
Solution B.
Ammonium sulphocyanide            ... ...      30 grs.
Hyposulphite of soda         ......... 1 gr.
Distilled water ............ 3 ozs.
Mix for use by pouring 1 part of A into an equal quantity of B (never reverse this order). This gives a purplish tone.