The photographic news

• Bandzählung: 29.1885
• Erscheinungsdatum: 1885
• 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
• URN: urn:nbn:de:bsz:14-db-id1780948042-188500006
• PURL: http://digital.slub-dresden.de/id1780948042-18850000
• OAI: oai:de:slub-dresden:db:id-1780948042-18850000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Bemerkung: Seite I-II fehlen in der Vorlage. Paginierfehler: Seite 160 als Seite 144 gezählt.
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

THE PHOTOGRAPHIC NEWS. [January 2, 1885. To change the plates, the collar is loosened, then the camera is twisted or turned round to eject them without having to disturb the stand. Anyone of a mechanical turn of mind could make one for himself in a short time, as brass tubing can be bought of sufficient diameter. It is almost superfluous to state that when finished it should receive a coating of dead black varnish. A Mr. Metinkoff, of Ekaterinburg, sent some pictures taken with a new camera of his own invention, which, according to the photograph sent of it, is so constructed that objects in different planes are all in focus. It was noticed, however, that the resulting pictures were devoid of serial perspective. The plate carrier admits of a part of the plate being exposed, the focus altered, then the second and third plates are taken in a like manner. How the joints are masked was not explained. Some of the pictures were passable, the figures and objects all being sharp ; but on close examination their relative sizes were found to be incorrect. The President read a letter from the VII section (serial navigation), asking the co-operation of the V section in their proposed experiments in balloon photography. The secretary remarked that it would be as well to become acquainted as far as possible with the trials which had been made abroad in that direction, and asked Mr. Chesterman, in the name of those present, to collect data and lay them before the Society at a future meeting. Several others brought prints, among whom was Herr Reinhardt. This gentleman has been experimenting with collotype plates for transfers to lithographic stones, and recommends the following instead of the ordinary transfer ink, as it does not smear like the latter. 20 to 25 parts of yellow wax, 15 parts of mutton fat, and 100 parts of a good chalk litho ink, are heated together in a pipkin over a fire, until thoroughly incorporated ; pour on to a stone slab, and grind with a muller while hot. Thus prepared, the ink spreads evenly, and makes a strong transfer without blurring, sinking deep into the stone. The transfer paper he prepares by coating paper of an even texture with the following mixture, used warm :— Dextrin 10 parts Gelatine ... ... ... ... 6 „ Gum tragacanth ... ... ... 5 „ Water ... ... 100 „ Boil and strain through a cloth, then add a few drops of nitric acid, or quant, suff. of a concentrated solution of pot. bichromate to tinge a slight yellow. Paper prepared with the latter is unfit for use after the lapse of a month. By introducing acetic acid into the chromated gelatine, M. Scamoni says he has obtained a grain or stipple similar to that in the “ photo-ink ” supplements to the News. Perhaps transfers to stone could be made from such plates. Spiller's Solutionfor Reducing Over-dense Negatives.—Having on hand a few negatives which yielded unsatisfactory prints, we set to work to reduce them by the above method. The subjects were all studies from the nude figure, taken for an academician ; and which, owing to the difficulty of the model retaining the constrained positions fer a suf ficient length of time, bad all turned out very chalky in the high lights, and lacking vigour in the shadows. The first negative experimented on was immersed in the solution until whitened through ; afterwards a print was made, but it proved that we had overstepped the mark, and had made it too weak. We attempted to re-intensify, or at least change its colour, but did not succeed in our endeavours, as it refused to change in the least, although we rang the changes with several intensifiers. At last we tried to blacken it with sodium sulphite instead of am monia, when lo and behold, the image was nearly obliter ated therein ! We determined to risk another negative, but this time took one that had been previously intensified with bichloride of mercury. This behaved altogether different from the preceding one, as we found it could be bleached and re-intensified at will by simple immersion in weak ammonia. The remainder of our batch of negatives were therefore subjected to a preliminary sojourn in the bichloride of mercury sol. 1-100, before placing them in the chloride of copper bath, and we were rewarded with negatives which had gained detail in the shadows and were sufficiently transparent to show the most delicate gradations in the flesh tints. Some exquisite prints from them were after wards obtained on Herr E. Risse’s collodio-chloride emulsion ; this, I may remark, is invaluable for very thin negatives rich in detail, such as one sometimes gets through over-exposure, and which give sickly looking prints on albumenized paper. An Inexpensive Battery for Electric Bells. — My apology for introducing the above is, that I believe more photographers would fit up electric bells in their studios if they could obtain a battery that would neither require a large sum of money nor the aid of special workmen to renew. To make such a battery, take a jam jar or glass tumbler (mine are about 3 ins. high and 2 ins. diameter), then make a little sack of canvas or coarse linen with an opening about half the diameter of the jar, fill this with equal parts of coke and black oxide of manganese broken in pieces about the size of a pea ; then introduce a pencil of carbon (one from a Jablochkoff candle will do), leaving about an inch of the same protruding out of the mouth of the sack ; a strip or rod of zinc the length of the jar and a few ounces of a strong solution of ammonium chloride are all that is required. The connecting wires are made by filing grooves near the top of the carbon and zinc, and winding short pieces of soft copper wire round them, leaving a few inches free to make the connections; a little asphalt or other varnish smeared over these joints will prevent corrosion. The accompanying sketch will clearly explain how to put the whole together. The zinc Z should not be allowed to touch the bottom of the jar, and a space must remain between it and the sack S. When all is in position, nearly fill with the solution and the battery is ready. Two such batteries placed in a box and surrounded with saw-dust will be found very portable and sufficiently strong for most purposes—of course more strength can be obtained by connecting extra batteries, being careful, however, to join zinc to carbon, and to scour the wires with emery- paper before making the connections.