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The photographic news
- Bandzählung
- 27.1883
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- 1883
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- Hochschule für Grafik und Buchkunst Leipzig
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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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Band 27.1883
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412 THE PHOTOGRAPHIC NEWS. [June 29, 1883. There is one fact deserving of mention, if only to induce photographers to examine more frequently the specimens they set before the public. About the time these experiments were undertaken, some show-cases for out-of-doors were re filled. Through inadvertence, one of them was not properly closed, and sufficient rain found its way inside to duly re cord the fact on a choice subject which happened to be in the way of its descent. For more than a week this state of things existed, the weather being showery in the interval ; when a cursory glance one day at this particular specimen case revealed the fact that a broad yellow band over an inch in width descended through the centre of the picture, clearly indicating that something was wrong. Upon closer scrutiny, other prints were found to be damaged more or less in a similar manner. It is needless to say that such an exhibi tion of one’s skill is not likely to enhance business. The markings referred to point to one of two causes: either the cardboard contained hypochlorites, or hyposul phite—perhaps both—but in all probability hyposulphite alone, for upon removing the photographs, it was noticed that water had penetrated through from the back of the mount in each case, thus destroying the print. To prevent such an occurrence as here related, mounts should always be tested before they are taken into stock; this can be done very easily in the following manner. Cut the sample cardboard into small pieces ; place a few fragments intotwoseparate vessels—test-tubes by preference ; cover them with distilled water, and allow them to soak for an hour or two. With a portion of the liquid from one of the tubes, mix in another tube with a small quantity of boiled starch (the starch paste used for mounting will do). When thoroughly mixed, add a drop or two of iodine tincture, and shake vigorously. Upon placing the tube over a sheet of white paper, a pale blue tint will pervade the mixture; should this colour disappear, it will indicate the presence of hyposulphite, and the mount will not be safe to use; but should the colour be retained, no danger is likely to accrue, so far as minute traces of hyposulphite are concerned. In the case of white or light mounts, it will be well to test for chlorides or bleaching agents which may have been used in the manufacture, and imperfectly washed out. To a portion of the liquid in the second tube, add a few drops of dilute nitric acid until the liquid is quite acid, using a clean test-tube for the experiment. To this, add a crystal of silver nitrate. If the liquid becomes cloudy, a precipitate will fall to the bottom of the tube, indicating tbe presence of either chloride, cyanide, bromide, or iodide. If the precipitate be white, chloride or cyanide is present; if yellowish or yellow, bromide or iodide is present. The two latter are, however, not used in the manufacture of cardboard, therefore there is no need to test for their pre sence just now, as they will be treated exhaustively at no distant date. Should a white precipitate be formed, add a few drops of liq. ammonia, fort. s.g. - 880, when, if chlo ride of silver has been formed, it will dissolve, leaving the liquid clear ; but if the liquid does not clear upon adding a considerable quantity of ammonia, it may be considered that no chloride has been soaked out of the sample of card board ; and the same remark applies to the liquid remain ing clear upon the addition of silver nitrate. In order to verify the experiment, the remaining portion of the liquid which has not been experimented with may be heated up in a gas flame to concentrate it. When cool, add a crystal of potassium iodide. If chlorine be present, the liquid will become slightly reddish, due to the liberation of iodine and formation of potassium chloride. Whether we are right in assuming that damp and dele terious substances are the prime causes of such wholesale destruction of silver prints, has yet to be proved ; but it is a pretty generally admitted fact that prints of recent date fade more rapidly than those produced twenty years ago. But why ? No one seems to be able to show. Let us try to unearth the mystery. FIXING A NUMBER OF NEGATIVES IN SAME SOLUTION OF HYPO. BY M. A. DAVANNE. Our trial commission has received from M. de la Ferronays a bottle of a solution of hyposulphite of soda which, for more than a month, has served him to fix a large number of negatives. The negatives in question, and those which we present, appear excellent, and give good prints. They are those of which we made the trial of paper deposited two months ago by M. Mey. The fixing bath sent by M. de la Ferronays has been made up as follows:— Water... ... ... ... ... 100 c.c. Hyposulphite of soda ... ... 15 „ Alum 4 „ Dissolve while warm, and filter. It is slightly coloured by traces of the developer, and clouded by a brownish deposit of sulphide of silver, which is formed in the liquid, and falls to the bottom of the bottle. This liquid has fixed, for more than a month, a very con siderable number of prints ; it still possesses its active properties, for in a few moments it dissolved all the bro mide of silver which the immersed part of the plate now shown contained. This does not, however, confirm the theory held by several that the same hypo bath may be used indefinitely. For this reason we made up a fifteen per cent, solution of hypo, and rapidly saturated it with bromide of silver ; the amount dissolved (about 5-52 grammes) being equivalent to 5 grammes of nitrate of silver to 17 of hyposulphite of soda. Four grammes of alum were added, and the solution was left for a time. A brownish black precipitate of sul phide of silver formed incessantly. After a fortnight we tried the effect of the solution upon a gelatino-bromide plate, and after twelve hours’ contact, only a very slight dissolving action was obtained at the edges; the liquid was incapable of fixing a negative. This slight action makes us think that the first saturation was not quite complete ; indeed, by proceeding patiently, it was found that the 17 grammes of hypo employed gradually dissolved an amount of bromide of silver equal to about 6 grammes of silver nitrate. The theory of the action of hyposulphite of soda on silver salts, and its limit of saturation, will be found in the re searches published by MM. Davanne and Girard on the fixing of prints; we find that one part of nitrate of silver requires, theoretically, three parts of hyposulphite of soda to fix it. Practically, one must allow for the indispensable excess to compensate for the impurities of the product, the tardy action of a liquid when nearly saturated, and the secondary reactions modifying or diminishing the soluble properties of hyposulphite of soda. We have not to stop for theoretical questions, but simply to state the facts these theories explain. Taking up our research upon the bath under the above conditions, we find that one litre containing 150 grammes of hypo can only fix the products of 53 grammes of nitrate of silver; or, in M. Andra’s method, who prefers films very rich in bromide of silver, we find that the 53 grammes of nitrate of silver serve to prepare about 1,100 c.c. of gelatino-bromide of silver, with which about 55 plates 10 by 8, or 100 plates 8 by 5, may be coated, and we are not surprised if the hypo bath fixes a great number of negatives, especially if the plates have not been prepared with emulsion containing much silver. But does not the sulphide of silver, which is deposited on separating itself from the solution, take part in these primary proper ties? We think not. An accurate experiment made on the lines laid down by M. de la Ferronays will confirm us in this respect in a month’s time. For the present, theo retically we know that the sulphide of silver is thrown down from the decomposition of the hypo, and from the
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