The Dictionary Of Photography

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

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very sharp snap-shots use a one-solution developer compounded on Warnerke's formula, which is as follows: -
Eikonogen ... ... ... ... ...        i oz.
Caustic potash         ............        I ,,
Sodium sulphite (crystals)...... ...        2 ozs.
Distilled water (boiling) .........      10 ..
We have deprecated the use of one-solution developers, but as the addition of caustic alkali enables us to obtain a much greater concentration of solution, it is useful for instantaneous work. (For a useful device for keeping a one-solution developer, see the preservative bottle described under Atmosphere.) The above solution should be diluted with from three to ten parts of water as required, more water giving softer results. Where only slight under-exposure exists the use of a mixed accelerator of caustic and carbonate will be found useful, and the caustic may be increased as desired or found necessary. Normal ex-posure: For portraiture, carbonate of soda should be used, as in all cases where softer effects are desired; for outdoor or land-scape work, carbonate of potash should be used, and with a small addition of bromide of potash. Over-exposure : in cases where over-exposure is known to exist, practically the same method of development may be adopted as with pyro - viz., increase of bromide and reduction of accelerator, which should be carbonate of potash. We have given some formulae for stock solutions of eikonogen ; we now come to stock accelerators.
Carbonate of Soda Accelerator. Carbonate of soda ... ... ... ... 300 grs.
Distilled water, to ... ... ... ... 10 ozs.
Carbonate of Potash Accelerator.
Carbonate of potash           ......... 150 grs.
Distilled water, to ... ... ... ... 10 ozs.
One part of these may be mixed with an equal quantity of eikonogen stock solution and applied to the plate. The caustic alkalies should only be used in cases where such are indicated as above, and stock solutions may be prepared either in 10 per cent, or 20 per cent, as desired, and they should be added, drop by drop, so as to avoid frilling and fogging of the film. A good all-round accelerator, which