The photographic news

• Bandzählung: 6.1862
• Erscheinungsdatum: 1862
• Sprache: Englisch
• Signatur: F 135
• Vorlage: Hochschule für Grafik und Buchkunst Leipzig
• Digitalisat: Hochschule für Grafik und Buchkunst Leipzig
• Digitalisat: SLUB Dresden
• Rechtehinweis: Public Domain Mark 1.0
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• Sammlungen: Fotografie
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• Strukturtyp: Band

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250 THE PHOTOGRAPHIC NEWS. [May 23, 186- been sensitized in the ordinary silver bath, and well washed. These plates, several days after this operation, and conse quently quite dry, were found to be at least as sensitive as those prepared by Mr. Sisson's process, for stereoscopic views were obtained upon them in three seconds, while with the most sensitive collodions previously employed, they re- quired at least 30 seconds exposure with the same objective. With the same collodion in a humid state the result was scarcely less prompt. Mr. Sisson, by his discovery, undoubtedly made a great step towards obtaining an instantaneous dry collodion, but I think that his process might be rendered much simpler, either by covering the sensitized and well washed plates with a solution of dextrine in water, simply saturated with borax, or rather with a very weak aqueous solu tion of caustic soda. It is very probable that some other alkaline salts will give as good or even better results. I have tried phosphate of soda, but the results it gave were less satisfactory with respect to rapidity, than with soda or borax, for it required no less than 4 or 5 seconds exposure to obtain a good negative. There is an advantage in using borax which deserves mention, this salt, but slightly soluble in water, admits of its saturated solu tion being employed without the fear of seeing the film blacken immediately under the developer, an accident that frequently occurs when we employ a too concentrated alkaline solution. Other alkaline salts will therefore require to be carefully weighed. The science of all sciences, Anthropology, the “ science of man,” is one of those which receives most valuable aid from the art of photography. Our photographic society has recently received a series of proofs, taken by M. Gavet, a missionary, representing various types of the natives of Nova Zembla, taken under the most difficult circumstances The artist remarks that photography, by its marvellous results, has, in the hands of the missionaries, become one of the most powerful agents in converting the untutored natives to Christianity. M. Hammerschmitz, of Cairo, has also made a similar contribution of a number of proofs, representing various Egyptian types of the human family. A method of photographic engraving, invented by M. Fontaine, of Marseilles, is thus described :—“ Having a photographic negative of the object which it is desired to engrave upon copper, I expose it fin a pressure frame to the light in contact with a plate of that metal, covered with a solution composed of pure gelatine, bichromate of potassa, and fish glue. After exposure to the light, I immerse the plate in a dish containing lukewarm water, the bichromate of the soluble portion of the gelatined plate being dissolved, I obtain the design from the negative en ereux (intaglio) ; then I pour upon it some pyrogallic acid to harden the gelatine and fix it, so that the minute details should not disappear upon its drying. When dried, I pour upon the plate a solution of pure gutta-percha in sulphide of carbon, and afterwards I take a piece of gutta-percha of the same size as the plate, and warm it on one side. I then put it in contact with the side of the plate, which I had covered with the solution of gutta-percha, and put in a press. Next removing the whole from the press, I remove the gutta percha from the gelatined plate, which is perfectly united with the purified gutta-percha, and I have then obtained in relief in great purity the design of the negative which I desire to engrave. After black-leading it, I place it in an electrotype bath, and thus obtain an engraved plate.” M. Mathieu Plessy communicates the following, upon the use of a bath of acetate of soda for washing positive proofs, by immersing them, upon removal from the pressure frame, in a solution of that salt, of the strength of two per cent., for ten minutes. The proofs tone much better, more quickly, and of very superior vigour and intensity. In this particular, M. Plessy’s experience exhibits a remarkable coincidence with that of Mr. Fry in England. M. Aime Girard, upon presenting to our photographic society some stereoscopic proofs, obtained from negatives THE NITRATE OF MORPHINE DRY PROCESS , Sir,—I am surprised that we see nothing in the pag" the News, to indicate that this very important process’’ been deemed even worthy of a trial by any of your read Had Mr. Bartholomew’s experiments been published, e! by an anonymous writer, and had his communica betrayed any evidence of his ignorance of chemical cha080 one would have thought that, at all events, some of !O many readers, even if for the purpose only of placing otb on their guard, in common fairness to your correspondn have done him the justice to test his good faith, and w0 have given others the benefit of their report. But when 3 prefaced the insertion of your correspondent’s letters " a notice of the valuable hints which his former experim in photography had suggested in the pages of your jour the silence, on which 1 beg to remark, seems the more ub countable. The reason, perhaps, is not hard to divine. 1 introduction of organic matter into the nitrate bath is oDl• those things which photographers are most anxiotsw eschew. It seems, with reckless hand, to assail one of W very axioms of our art—to soil with known impurity t which we have been taught to keep with such serupu. j care intact from all contamination. Theory, and that 2 hastily formed; practice, too, long acquired, seem "l united voice to say, “ Beware of such nostrums!” and "da run the risk of spoiling your bath “ place this proceSs the category of crude notions which ought to have noquop with any photographer who knows what he is about.” . j judice would be, perhaps, too harsh a name to affix to St conclusions ; and yet, if they form a hindrance to that in tigation, which may tend to give us a deeper insight 1 those mysterious molecular changes, which arc brought > . play in the production of a picture, I know not whe W this twin-sister of ignorance has not had something t°e with such contempt prior to examination. Now, ib absence of any other communication on the subject by » j hands than mine, I venture to hope that the follo 11) account of some very interesting, and, I may add (eventuazo successful experiments, which I have recently undertor may prove not unwelcome, nor unprofitable, to some of ‘ee readers, who may, perchance, employ photography 10 pursuit of Icnowledye, as well as of pleasure or profit:" . 1. I added about 3 grains of muriate of morphine " taken by Mr. Warren de la Rue, remarked, “ We knowti the planets, in consequence of their remoteness from J earth, appear like plane surfaces, even in the most ponet instruments. Mr. De la Rue conceived the ingenious 2 of producing proofs of those stars in relief, by placing ferent views of them in the stereoscope. But as it wow’l impossible to find on the surface of the earth stations si® ciently wide apart, he obtained the desired result by8. cuting two views of the same star taken at different tin when its aspect had become sufficiently modified. OR views, when placed in the stereoscope, furnish an imago" the star in relief. In connection with the important question of dry Co dion plates, M. Aime Girard remarks that it would be" for photographers to direct their attention to the qualit. primarily attributed to the Taupenot process by its invent who had, in fact, presented his method as capable of 10 nishing instantaneous pictures. M. Girard exhibited to" I photographic society an album, the proofs in which a been obtained, if not absolutely instantaneous, at least" remarkable rapidity. Beside, the Taupenot process so very apt to furnish good results, in consequence of’’I almost indefinite resistance it offer's to the developing soI tions. M. Ferrier added that he had tried the Taupe process, but had hitherto found it too slow in his hands,*I it always required at least an exposure of a second under" most favourable conditions; but he had every reason toho I that with more experience, it would eventually accompl , all that could be desired, in an instantaneous dry process I May viously ounces led to tl combin: the mo morphil nation ’ nb/tam I think “ yproi expect exposed toacer success, vhether tages it 2. Th free it f highly f the addi The quo to reme tile com the cur mined, deposit vill ha’ excess. 3. la until bl diate ch capable collodio and dry 4. Th required 5. I r moisteni 6. Th dion, bo leave th albumer (orrespo found h Gxperim discover thoroug degree 3 f «nair SIR,- must rei posed b so far ai help thi cover ii leave, d beg you 1. I • Collodic by the ’ also wo . 2. In in three of boile rocking