Suche löschen...
The photographic news
- Bandzählung
- 24.1880
- Erscheinungsdatum
- 1880
- 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-id1780948042-188000001
- PURL
- http://digital.slub-dresden.de/id1780948042-18800000
- OAI-Identifier
- oai:de:slub-dresden:db:id-1780948042-18800000
- Sammlungen
- Fotografie
- LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
- Bemerkung
- Exemplar unvollständig: Seite 1-82 in der Vorlage nicht vorhanden
- Strukturtyp
- Band
- Parlamentsperiode
- -
- Wahlperiode
- -
- Bandzählung
- No. 1125, March 25, 1880
- Digitalisat
- SLUB Dresden
- Strukturtyp
- Ausgabe
- Parlamentsperiode
- -
- Wahlperiode
- -
-
Zeitschrift
The photographic news
-
Band
Band 24.1880
-
- Ausgabe Ausgabe I
- Ausgabe Ausgabe I
- Ausgabe Ausgabe I
- Ausgabe Ausgabe I
- Ausgabe Ausgabe I
- Ausgabe Ausgabe I
- Ausgabe Ausgabe 83
- 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 349
- Ausgabe Ausgabe 361
- Ausgabe Ausgabe 373
- Ausgabe Ausgabe 385
- Ausgabe Ausgabe 397
- Ausgabe Ausgabe 409
- Ausgabe Ausgabe 421
- Ausgabe Ausgabe 433
- Ausgabe Ausgabe 445
- Ausgabe Ausgabe 457
- Ausgabe Ausgabe 469
- Ausgabe Ausgabe 481
- Ausgabe Ausgabe 493
- Ausgabe Ausgabe 505
- Ausgabe Ausgabe 517
- Ausgabe Ausgabe 529
- Ausgabe Ausgabe 541
- Ausgabe Ausgabe 553
- Ausgabe Ausgabe 565
- Ausgabe Ausgabe 577
- Ausgabe Ausgabe 589
- Ausgabe Ausgabe 601
- Ausgabe Ausgabe 613
- Ausgabe Ausgabe 625
- Register Index 631
-
Band
Band 24.1880
-
- Titel
- The photographic news
- Autor
- Links
- Downloads
- Einzelseite als Bild herunterladen (JPG)
-
Volltext Seite (XML)
THE PHOTOGRAPHIC HEWS. [MARCH 25, 1880. 146 Et ome. AND relief. The gelatin becomes insoluble i ON THE REDUCTION OF COLLODION GELATINE EMULSION RESIDUES. BY CAPTAIN w. DE W. ABNEY, B.E., F.R.s.* THE WOODBURY PERMANENT PRINTING COM PANY AT KENT GARDENS, EALING. In a remote corner of Ealing, where the surburban villas come to an end, and the meadowland slopes away to the green hills about Harrow and Pinner, are to be found the works of the Woodbury Permanent Printing Company. The Company has evidently a notion of taking care of itself, for at Brompton, we remember, where it was last located, the neighbourhood was an exceedingly agreeable one, and, there are certainly few working establishments in and about London which can boast so fine a site as Kent Gardens, Ealing. The building is nothing less than one of the fine villas that are here to be seen in goodly number, or rather, we believe, an hotel, it is so spacious ; the rooms are light, airy, and lofty, and the grounds amply suffice for the outhouses—printing sheds, studios, developing rooms, &c.—which are necessary to the carrying on of the multifarious duties with which the Company occupies itself. The Company produces its own carbon tissue, for, as our readers are aware, it has acquired for some years past a high reputation for enlargements printed in permanent i pigments, and possesses all the necessary facilities for printing and developing ; but, as a matter of course, it is the photo-relief, or Woodbury, process that constitutes the chief feature of the Kent Gardens establishment. The Company has it all its own way when it comes to a ques tion of rapid printing from portrait negatives, and, what between electioneering orders and orders connected with Royal marriages, there is plenty to do just now. Election agents are very much alive to the publicity which photography is capable of giving to the features of the respective candidates, and orders are sometimes given for as many portraits of a would-be member as there are voters on the election roll. Again, the daughter of King Rumpeltiltskin is a favourite just now, the Princess Badoura, for she is shortly to be married, and Continental dealers are clamouring for her portrait. Comes an agent across the seas with a couple of negatives of the fair Prin cess ; he will not leave them—they are too precious—but waits uncomfortably for a few hours at Ealing, while the necessary gelatine moulds are made for printing off the pictures mechanically. Then he travels back again post haste to continue solar printing, which has been moment arily interrupted, leaving behind him instructions to des patch 50,000 copies of the fair Princess as soon as Ealing has stamped them off. Our readers are well acquainted with the Woodbury process, we know, but we shall nevertheless take the liberty of briefly describing it once more as it stands in its present state of perfection. The first room is where the sensitive film is kept. It is in thin transparent sheets, and consists of gelatine with a backing of collodion treated with bichromate solution ; it very much resembles the gelatine employed for cracker bonbons, only it is tougher and a little stouter. After sensitizing, it is put into a chloride of calcium box to dry, the operation being there very steadily and thoroughly carried out. The sensitive gelatine film is put under a negative in an ordinary printing frame, and printed in the sun. They used, at Brompton, to put the printing frames at the bottom of a box, to ensure the rays coming straight down upon the film ; but this they find is not necessary if the frames are made to face in the direction of the sun. But direct is printed : " Your vote and interest is requested for .” This is decidedly a happy idea, since the canvassers are able to bring, face to face with the candidate, all the electors, even those who are unwilling to go through the ordeal of a public meeting. There is the advantage, too, that the candidate is shown at his best. The excitement of the platform gives place to the calm of ordinary society, and the nervous and usually ugly tricks with the hands, legs, and arms, or with all, which so often are seen during the “ stump,” cannot be imagined as possible in the polished individual pourtrayed in the photograph. More than one vote has been obtained for a candidate whose forte was not speaking, but being good looking. The daughters say, “ He’s a duck ; ” and the mother says, “ Well, he do look a gentleman ; ” and the father, the voter, gives in—he’s not a home ruler! rays are indispensable to the production of a good photo- The gelatine film, by printing under a negative, 1 - in parts (where the light has got at it) and the consequence is, that when immersed in warm water, only a portion of the film washes away, leaving an image of the negative in relief. The washing takes place very gradually, the film being placed on end, and the The question has often been raised as to which is the best plan to recover the silver from the waste gelatine emulsions. I have seen it stated that there is nothing for it but to dry the emulsion and burn it. This, to say the least of it, is a tedious plan, and not one which I can recommend by theory or practice. A much neater method may be adopted, and one which is so simple that any one may cany it out. If a solution of gelatine be boiled with a solution of caustic potash or soda, it rapidly loses its viscous character, and becomes incapable of holding any matter in suspension. It is on this principle that the silver residues from gelatine or collodion emulsions can be utilized without resort to the crucible, except for a very minor operation. The waste gelatine, or collodion emulsions or films, are collected, and when a fair quantity have accumulated they should be placed in a boiling flask or dish, and well covered with a saturated solution of caustic potash (commercial will answer admirably) or soda. The flask or dish should then be warmed gradually till it is in a boiling sate, but care must be taken to prevent the solution boiling over, as it is liable to do if the heat be intense. It will be noticed, as the operation proceeds, that the liquid mass becomes of a deep brown to a black colour. After this occurs the boiling should be continued for a quarter of an hour, after which time it will be found that the whole of the solid matter has been dissolved and the silver bromide has disappeared. The liquid may be filtered through filter-paper, when the filtrate should be nearly colourless, leaving the black colouring matter in the filter paper. It may be found necessary to pass the first part of the filtered solution once or twice through the filter paper to attain this decolourized liquid, but when once the drops are colourless the whole of the remaining solution, when filtered, will do so. If time be no object, the solution, instead of being filtered, may be allowed to settle, and the colourless liquid can then be decanted off, merely the last traces of liquid being filtered off from the residue. This residue consists principally of metallic silver with a little organic matter present. If it be well washed in the filter it may be dried and placed in a small crucible over a Bunsen burner till all organic matter has been burntoff, and be treated with dilute nitric acid to form silver nitrate, or it may at ouce be treated with the acid and, after filtration again, it may be precipitated as chloride and added to the ordinary residues. The rationale of the process is evident: the gelatine or collo dion, caustic potash, and silver bromide are respectively the organic matter, the alkali, and the metallic salt, which are placed together to reduce the last to the metallic state. The same principle is used for preparing silvering solutions for silvering mirrors, where we have sugar, potash, and ammonio- nitrate of silver; and it is the same also for alkaline deve lopment. The process is really very simple, and easily carried out. • Communicated to the Journal of the Photographic Society.
- Aktuelle Seite (TXT)
- METS Datei (XML)
- IIIF Manifest (JSON)