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The photographic news
- Bandzählung
- 11.1867
- Erscheinungsdatum
- 1867
- Sprache
- Englisch
- Signatur
- F 135
- Vorlage
- Hochschule für Grafik und Buchkunst Leipzig
- Digitalisat
- Hochschule für Grafik und Buchkunst Leipzig
- Digitalisat
- SLUB Dresden
- Lizenz-/Rechtehinweis
- Public Domain Mark 1.0
- URN
- urn:nbn:de:bsz:14-db-id1780948042-186700008
- PURL
- http://digital.slub-dresden.de/id1780948042-18670000
- OAI-Identifier
- oai:de:slub-dresden:db:id-1780948042-18670000
- Sammlungen
- Fotografie
- LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
- Strukturtyp
- Band
- Parlamentsperiode
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- Wahlperiode
- -
- Bandzählung
- No. 446, March 22, 1867
- Digitalisat
- SLUB Dresden
- Strukturtyp
- Ausgabe
- Parlamentsperiode
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- Wahlperiode
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Zeitschrift
The photographic news
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Band
Band 11.1867
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- Titelblatt Titelblatt I
- Sonstiges Preface III
- Ausgabe Ausgabe 1
- Ausgabe Ausgabe 13
- Ausgabe Ausgabe 25
- Ausgabe Ausgabe 37
- Ausgabe Ausgabe 49
- Ausgabe Ausgabe 61
- Ausgabe Ausgabe 73
- Ausgabe Ausgabe 85
- Ausgabe Ausgabe 97
- Ausgabe Ausgabe 109
- Ausgabe Ausgabe 121
- Ausgabe Ausgabe 133
- Ausgabe Ausgabe 145
- Ausgabe Ausgabe 157
- Ausgabe Ausgabe 169
- Ausgabe Ausgabe 181
- Ausgabe Ausgabe 193
- Ausgabe Ausgabe 205
- Ausgabe Ausgabe 217
- Ausgabe Ausgabe 229
- Ausgabe Ausgabe 241
- Ausgabe Ausgabe 253
- Ausgabe Ausgabe 265
- Ausgabe Ausgabe 277
- Ausgabe Ausgabe 289
- Ausgabe Ausgabe 301
- Ausgabe Ausgabe 313
- Ausgabe Ausgabe 325
- Ausgabe Ausgabe 337
- Ausgabe Ausgabe 351
- Ausgabe Ausgabe 365
- Ausgabe Ausgabe 377
- Ausgabe Ausgabe 389
- Ausgabe Ausgabe 401
- Ausgabe Ausgabe 413
- Ausgabe Ausgabe 425
- Ausgabe Ausgabe 437
- Ausgabe Ausgabe 449
- Ausgabe Ausgabe 461
- Ausgabe Ausgabe 473
- Ausgabe Ausgabe 485
- Ausgabe Ausgabe 497
- Ausgabe Ausgabe 509
- Ausgabe Ausgabe 521
- Ausgabe Ausgabe 533
- Ausgabe Ausgabe 545
- Ausgabe Ausgabe 557
- Ausgabe Ausgabe 569
- Ausgabe Ausgabe 581
- Ausgabe Ausgabe 593
- Ausgabe Ausgabe 605
- Ausgabe Ausgabe 617
- Register Index 623
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Band
Band 11.1867
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- Titel
- The photographic news
- Autor
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in- ict er res 41, he ion ns lie. ted be ith ;an ual Yr. • to ink ’ be ou, as e a han i in r a lore the him will can s to r or ' the iign- you due sher unot pro- in is ct in ition :r for ether ircle uper- irged uper- ydro- first ution soda; nsfy- rdin- i and John t. J, and receive pels u5 >rne il essarilf THE PHOTOGRAPHIC NEWS. Vol. XI. No. 446.—March 22,1867. CONTENTS. PAGE Intensifying Under-exposed Negatives 133 Carbon Printing. By Nelson K. Cherrill 134 M. Chevallier’s Photographic Plane-Table 135 On Winter Photography. By Valentine Blanchard 135 On Papers—How to Write Thera, and What to Write About. By Jabez Hughes 1 G Opal Printing Frames. By Prof. Towler 138 On the Treatment of Under-exposed Negatives. By M. Carey Lea 139 INTENSIFYING UNDER-EXPOSED NEGATIVES. On another page we print an excellent article, by Mr. M. Carey Lea, on the treatment of under-exposed negatives. The article is full of valuable practical suggestion ; but there is one point upon which our experience does not exactly quadrate with that of Mr. Lea, unless the case be stated with additional qualifications. He remarks that it is a common opinion that in redevelop ing a plate—meaning, by redevelopment, intensifying before fixing—the dense parts acquire a more rapid deposit of silver than the thin parts ; and adds, that ho does not think this to be the case. He believes that the deposit is fully as great, in proportion, on the thin parts of the image, or half-tones, as on the denser parts, or lights. General experience is, we think, opposed to this view. It is certainly our own expe rience, and we believe common experience, that in under exposed negatives the deposit is much greater on the lights than on the half-tones, and that the former are rapidly acquiring density whilst the latter are merely struggling into existence. This is the case even with the first develop ment, but in the redevelopment or intensification the ten dency to aggregation of deposit on the lights is generally increased. This is, we believe, the common experience under the ordinary circumstances under which the majority of photographers work ; but the exact ratio in which this ten dency is present depends on certain conditions which ought to be defined. There are three things which materially affect this ques tion : first, the kind of collodion, and the salts it contains ; second, the developer or intensifier ; and third, the amount of free nitrate present. Each of these exercises its specific influence on the result. First. The Collodion.— A simply iodized collodion, or one having a large proportion of iodide and very little bromide, not only tends generally to density, but it tends especially to aggregation of deposit on the lights in cases of short exposure. The lights flash out rapidly, and steadily acquire density, whilst the details tardily appear. If the imago is then submitted to redevelopment or intensification, the same tendency to deposit most where the deposit is already greatest is manifest. If the iodizer be a potassium salt, this tendency is even more strongly marked than with cadmium and some other iodizers. If the collodion be old, it is fre quently found to have a similar tendency. In short, almost all the conditions which tend to increase contrast in the original image have been found, in our experience, in cases of under-exposure, to tend also to the aggregation of deposit on the lights in prolonged development or redevelopment. On the other hand, the conditions which tend to retard the production of density—such as the newness of the collo dion, the use of cadmium salts, and especially the plentiful use of a bromide in the collodion—tend, in all cases, to check On the Reversed Action of Light in Photography. By Joseph 140 Proceedings of Societies—Photographic Society of Marseilles— South London Photographic Society 141 Correspondence—Bitumen—Photographs of the Moon 142 Talk in the Studio 143 To Correspondents 144 Photographs Registered 144 this aggregation of deposit in the lights. The result of under-exposure is, at the outset, different under the different conditions we have mentioned. Under-exposure in the first- mentioned circumstances will give an image with excess of contrast; strong lights, but no detail. A collodion contain ing a full proportion of bromide will yield, on under-expo sure, an image thin, grey, and poor, without much vigour in the lights, but not lacking detail; the image is as fully im pressed by weak radiations as with the stronger light. Such an image will generally behave as described by Mr. Lea; the deposit of silver, in the process of redevelopment, will be as great on the half-tones as on the light, and by skilful management may be made to yield a presentable print. As a rule, however, it will always be a thin, poor negative, diffi cult to print, and lacking all the richness, roundness, and brilliancy of a properly exposed picture. Second. The Developer.—Much also depends on the deve loper. One of the greatest difficulties commonly experienced some years ago, when the pyrogallic acid developer was em ployed, was the difficulty of getting out detail sufficiently before the lights were too intense. If there were the slightest under-exposure, this rapid deposit of silver on the lights before the half-tones had received sufficient deposit was the frequent source of hard, black and white pictures, without gradation or delicacy. If the collodion were old, this ten dency was increased in very injurious degree. The gradual introduction into common use of bromo-iodized collodion for negatives—for which, some half dozen years ago, we stood almost alone as the advocate—and the general adoption of iron development, changed materially this aspect of affairs, and altogether improved the character of photographs. With iron developers, as most commonly used, and bromo iodized collodion, this tendency to increased deposit on the lights is rarely present in the first operation, unless the iron solution be very weak; but if pyrogallic acid be employed in the redeveloping process—in our hands, at least—the ten dency to increased proportional deposit on the lights has generally been apparent. If an iron solution be used for redevelopment, this tendency is less marked; but with Mr. Lea’s collo-iron developer and other organico-iron solutions, the tendency has approximated more to that present when pyrogallic acid was used. Third. The Free Nitrate present.—This is so closely con nected with the question of the developer, that it is scarcely possible to separate them. The greater the proportion of free nitrate of silver present, the greater the tendency to an aggregation of deposit on the lights. Every photo grapher is familiar with the fact that, if his negative, be weak and flat from over-exposure, he can, by the plentiful addition of silver, increase contrast and vigour; and this is, of course, effected by the more rapid accumulation of deposit on the lights than on the lower half-tones. On the con trary with under-exposure; slew development, with little
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