" Ghost" Photographs Giphantia
mixture of hypo and uranium nitrate, and states that it gives very good results. He suggests a cold saturated solution of hypo diluted with four times the quantity of water, and to every ioo parts of this liquid one part of a 10 per cent, solution of uranium nitrate is added. This acts very evenly and slowly, and gives excellent results, as we can testify. Valenta states that prints treated with
Thiosinamine ... ... ... ... 5 parts
Water ... ... ... ... ... 100 ..
Solution of uranium nitrate (10 per cent.) 5-10 ,,
assume a brilliant red tone, which gives place in toning to a rich sepia. All chloride papers can be toned with platinum, by ob-serving the directions given under Platinum Toning (^.z/.). Since the introduction of matt-surface chloride papers there has not been so much need for obtaining matt surfaces on glossy papers ; but this can be done either by rubbing down the dry print with powdered pumice stone or squeegeeing to fine ground-glass or celluloid, both of which should be previously smeared with a little oil. To obtain a high glaze or polish, plate-glass, ebonite, metal plates, or wood-pulp slabs can be used; but the first gives the finest surface. Whichever material is used, it should be first rubbed with solution of wax, as used for the carbon tissue, en-caustic paste, or a little oil, and the wet print well squeegeed down to it and allowed to dry, and then stripped. For mounting such prints it is advisable to paste on the back a sheet of the waterproof backing-paper, which can be obtained commercially, whilst the print is damp, and allowing the two to dry together, and then mounting with one of the gelatine mountants, now placed on the market, or a formula for which is given under Mountant (q.v.). For a list of books dealing with gelatino-chloride and collidio-chloride, see Aristotype.
"Ghost" Photographs, How to make. See "Spirit" Photography.
Giphantia. The title of a Utopian romance, written in 1761 by Tiphaine de la Roche, in which there is an interesting fore-cast of photography; the author having apparently based his forecast on previous observations of Schulze(i727) and Beccarius (1757) regarding the darkening of chloride of silver when exposed to light. The following is an extract from an English translation