The Dictionary Of Photography

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

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Platinotype
has been dissolved 5 grains of oxalate of lead: the operation of sensitising being conducted as described above. This gives a soft printing paper suited for vigorous negatives. To obtain a paper suited for soft negatives, add a 10 per cent, solution of sodium chloro-platinite to the sensitising solution, from 3 to 10 drops to the ounce, according to the degree of vigour wished for.
Cold Bath Development. Dissolve 2 ozs. of potassium oxalate and \ oz. of potacsium phosphate in a pint of hot water, and allow this to cool. Float the exposed paper face downwards on this solu-tion, or immerse entirely. When the image is sufficiently vigorous the sheet is treated as in the case of the hot bath method.
Considerable control over results may be obtained by the use of glycerine in the following manner. Three solutions should be prepared: -
No. 1. Solution of oxalate of potash           ... ... 2 parts.
Pure glycerine... ............2 ,,
No. 2. Solution of oxalate of potash           ... ... 1 part.
Pure glycerine... ... ... ... ... 4 parts.
No. 3. Pure glycerine.
The print should be pinned to a board and a small pool of the pure glycerine poured on to the print and evenly distributed all over it by means of a soft pad of linen. If there are any portions of the print which have a tendency to appear too white, or wanting in detail, a broad mop or flat brush charged with solution No. 2 should be applied to those places, and then gradually over the whole of the print, except in the very deepest shadows, which should be left untouched. As soon as the image begins to develop, the brush should be charged with No. 1 solution, and passed rapidly and evenly over the whole print; the print will gradually gain in intensity, and by careful use of solutions No. 1 and 3 with brushes, it will be possible to hold back one portion and coax another out. As with most other processes, success is not always attained at first, and it may happen that our finished prints are too dark or too light. In the former case there is not much to be done, as platinum is one of those intract-able metals not easily amenable to reagents; strong chlorine
5"