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The photographic news
- Bandzählung
- 27.1883
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- 1883
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- F 135
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- Hochschule für Grafik und Buchkunst Leipzig
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Zeitschrift
The photographic news
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Band
Band 27.1883
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- Titelblatt Titelblatt I
- Register Index III
- Ausgabe No. 1270, January 5, 1883 1
- Ausgabe No. 1271, January 12, 1883 17
- Ausgabe No. 1272, January 19, 1883 33
- Ausgabe No. 1273, January 26, 1883 49
- Ausgabe No. 1274, February 2, 1883 65
- Ausgabe No. 1275, February 9, 1883 81
- Ausgabe No. 1276, February 16, 1883 97
- Ausgabe No. 1277, February 23, 1883 113
- Ausgabe No. 1278, March 2, 1883 129
- Ausgabe No. 1279, March 9, 1883 145
- Ausgabe No. 1280, March 16, 1883 161
- Ausgabe No. 1281, March 22, 1883 177
- Ausgabe No. 1282, March 30, 1883 193
- Ausgabe No. 1283, April 6, 1883 209
- Ausgabe No. 1284, April 13, 1883 225
- Ausgabe No. 1285, April 20, 1883 241
- Ausgabe No. 1286, April 27, 1883 257
- Ausgabe No. 1287, May 4, 1883 273
- Ausgabe No. 1288, May 11, 1883 289
- Ausgabe No. 1289, May 18, 1883 305
- Ausgabe No. 1290, May 25, 1883 321
- Ausgabe No. 1291, June 1, 1883 337
- Ausgabe No. 1292, June 8, 1883 353
- Ausgabe No. 1293, June 15, 1883 369
- Ausgabe No. 1294, June 22, 1883 385
- Ausgabe No. 1295, June 29, 1883 401
- Ausgabe No. 1296, July 6, 1883 417
- Ausgabe No. 1297, July 13, 1883 433
- Ausgabe No. 1298, July 20, 1883 449
- Ausgabe No. 1299, July 27, 1883 465
- Ausgabe No. 1300, August 3, 1883 481
- Ausgabe No. 1301, August 10, 1883 497
- Ausgabe No. 1302, August 17, 1883 513
- Ausgabe No. 1303, August 24, 1883 529
- Ausgabe No. 1304, August 31, 1883 545
- Ausgabe No. 1305, September 7, 1883 561
- Ausgabe No. 1306, September 14, 1883 577
- Ausgabe No. 1307, September 21, 1883 593
- Ausgabe No. 1308, September 28, 1883 609
- Ausgabe No. 1309, October 5, 1883 625
- Ausgabe No. 1310, October 12, 1883 641
- Ausgabe No. 1311, October 19, 1883 657
- Ausgabe No. 1312, October 26, 1883 673
- Ausgabe No. 1313, November 2, 1883 689
- Ausgabe No. 1314, November 9, 1883 705
- Ausgabe No. 1315, November 16, 1883 721
- Ausgabe No. 1316, November 23, 1883 737
- Ausgabe No. 1317, November 30, 1883 753
- Ausgabe No. 1318, December 7, 1883 769
- Ausgabe No. 1319, December 14, 1883 785
- Ausgabe No. 1320, December 21, 1883 801
- Ausgabe No. 1321, December 28, 1883 817
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THE PHOTOGRAPHIC NEWS. 135 of reducing density:—1. The image may be changed in colour, so as to be more transparent to actinic light. 2. It can be partially converted into some compound which can be dissolved out in hyposulphite or other solvent. 3. The gelatine film can be reduced in thickness by solution or mechanical means. Mr. Debenham's Method with Ozone Bleach.—Two solu tions are required :— No. 1.—Chrome alum ... ... ... 1 ounce Water ... ... ... ... 1 pint No. 2.—Ozone bleach The plate is immersed in a solution composed of half an ounce of each of these in five ounces of water, and then in the hyposulphite bath. To reduce locally, a stronger solu tion is poured in a stream on the part desired, the opera tion being repeated if necessary. Method with Chloride of Lime or with Eau deJavelle (Hypo chlorite of Potash).— For the first, a saturated solution of chloride of lime is prepared, and for the second ’Chloride of lime ... ... 2 ounces Carbonate of potash 4 „ Water 40 „ The lime is mixed with 30 ounces of the water, and the carbonate dissolved in the other 10 ounces. The solutions are mixed, boiled, and filtered. Either of these are diluted, and the plate immersed until the required reduc tion is produced ; it is then passed through the fixing bath and washed. In these cases a double action occurs, part of the film being dissolved off, and a portion of the silver being con verted into chloride, which is removed in the fixing bath. Method with Ferric Chloride.—A solution is prepared with— Ferric chloride 1 drachm Water ... ... 4 ounces The plate is immersed in this, which converts the silver into silver chloride ; on washing and immersion in the hyposulphite bath, this is dissolved out. Other Methods.—There are various other methods extant for reducing density ; one or two only required a single solution I have found answer very well :— No. 1. Copper sulphate ... } ounce Ammonia sufficient Water 1 pint The quantity of ammonia is such as to redissolve the precipitate which is first formed on adding it to the copper sulphate. No. 2. Potassium ferricyanide (red prus siate of potash) 1 ounce Water 1 pint A few drops of either of these should be added to an ounce of the hyposulphite bath, diluted with four ounces of water, the plate immersed until the requisite reduction is obtained, and washed. In the first case silver sulphate, and in the second silver ferrocyanide, are formed, and immediately dissolved outby the hyposulphite. SULPHOCYANIDE OF AMMONIUM A SOLVENT OF GELATINE. BY H. L. T. HAAKMAN. I Believe it is not generally known that sulphocyanide of ammonium is a perfect solvent of gelatine emulsion. I discovered this when trying to fix and tone a bromide negative in a cold solution of sulphocyanide and gold. Even when the solution is weak, the emulsion film dis appears as by magic. This property makes it valuable for the prompt cleaning, without application of beat, of funnels, beakers, &c., when they cannot be so readily cleaned by immersion in hot water. • “ Instruction in Photography," 5th edition, THE REMOVAL OF FIXED GLASS STOPPERS* When the glass stopper of a bottle is ground fine enough to prevent leakage, and is well put into its seat, it is generally somewhat difficult to get out. Often it is impossible to remove it by the ordinary means of tapping it and unscrewing with the fingers, and then most persons sacrifice the bottle by breaking off the neck. A glass-stoppered bottle that is so well ground as not to require the slovenly use of grease, or other aids to bad work, involves a good deal of skilled labour, and it is a real waste to destroy it, even if this can be done without any loss of the con tents in breaking it. It is a fact not generally known that the very finest and most skilful stoppering that is practicable on a large scale and at moderate cost is not entirely effective against loss of many volatile liquids. A tray of fifty one-pound bottles of ether, kept in a cool cellar, and carefully weighed from time to time, lost at the rate of more than an ounce a month throughout the whole experiment, although stoppered as well as practicable, and never agitated. When agitated, as by transportation, and especially when transported in warm weather, the loss must be many times greater, and accidental imperfection in stoppering, or in the exposure of a box of bottles to a summer sun in long transportations, will occasionally cause the loss of a considerable part, or even the entire contents of some bottles, so that they reach their destination partly or entirely empty, but with little or no sign of leakage perceptible, so that the bottles look as though they had been put up partly full or empty ; and leaks so small as not to be discoverable when put up are quite sufficient to empty a bottle during transportation. These difficulties are greatest with such liquids as chloroform, ether, and nitrite of amyl, and the latter is the most difficult of all. All these stoppers require to be put in as tightly .as it is possible to put them in, and all stoppers are screwed in with what is called a stopper wrench, and such a wrench is needed to take them out. This is a piece of hard wood about 34 inches long by about 1 or 14 inches in breadth and depth. In the middle of one side a mortise is cut nearly through just long enough and wide enough to admit the flat part of the largest size stopper. This applied to the stopper gives a very considerable leverage, and with it stoppers are screwed in by turning them in the direction of the movement of the hands of a watch, as all right-hand screws are put in. To take the stopper out it must, of course, be unscrewed or turned in the opposite direction. In this way almost all stoppers may be taken out safely if the neck of the stopper be strong enough to bear the strain, especially if the stopper be smartly tapped, first on one side and then on the other, by the wooden wrench before it is applied to unscrew it. But some liquids have a tendency to cement the stoppers into their seats either by drying in the joint or by a slight action upon the glass surfaces. Such liquids as solutions of soda and potassa, and especially the disinfectant solution of chlorinated soda, almost always render the stoppers immovable by any ordinary means, and even the stopper wrench will often fail to start them. It is highly probable that half the bottles used with such liquids arc sacrificed before the contents can be got at, and in breaking off the necks the break often extends so that a part of the con tents is liable to be lost. When a stopper resists all management—by warming the neck with a cloth wet with hot water, by tapping, and by the wrench, or by all these in combination -there is another means which will almost always succeed. Let the bottle be inverted so as to stand on the stopper in a vessel of water, so filled that the water reaches up to the shoulder of the bottle, but not up to the label. The vessel should be so large that the bottle stands in an inclined position, or otherwise a portion of air may be trapped in the gutter between the mouth of the bottle and the stopper, and thus prevent the access of the water to the joint which is to be soaked out. The bottle should stand in this position over night, and if still refractory, for another day and night, and if still tight, three or more days, and in such cases the water should be warm at first and again quite hot for the last five minutes before the wrench is applied. There are many bottles which are very valuable, and the better the stoppering the more valuable they are. Almost all such may be saved by the means indicated, if the necessary time and patience be given. Many bottles which are hardest to unstopper by reason of the action of the liquids on the glass are unfit for any after use, and might about as well be sacrificed as not, were it not for the 1 liability of losing the contents iu breaking them. • Squibbs Materia Medica, quoted in the Chemical Newt.
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