The photographic news

• Bandzählung: 35.1891
• Erscheinungsdatum: 1891
• 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-id1780948042-189100009
• PURL: http://digital.slub-dresden.de/id1780948042-18910000
• OAI: oai:de:slub-dresden:db:id-1780948042-18910000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

July 17, 1891.] THE PHOTOGRAPHIC NEWS. 517 ance of the image being very much the same as in platino- in producing a practicable printing method by makin; borax, and a small quantity of hydrochloric acid. In all a 20 per cent, solution of an alkaline tartrate or citrate, ■was very liable to stain the fingers of the operator, and chloric acid. (To be continued.) Read at the Photographic Convention. 80 parts 1 part image is formed, just as in platinotype, and the image is developed by treating it with a solution containing 10 per cent, of sodium citrate, 1 per cent, of silver nitrate, and sufficient ammonia to just keep the silver in solution. The patentee recommends a solution containing 15 per cent, of silver nitrate ; but I find that better results are obtained with only 1 per cent., and the best method of making up the solution is to dissolve the silver nitrate in a small quantity of water, add dilute ammonia very carefully considerable alteration in the details of the process. Kallitype, in fact, is an excellent example of the way in which an old observation, apparently of little practical value, may become of very great utility in the hands of a sium dichromate must be added. The dichromate keeps the whites clear, and increases the contrasts, and the character of the prints can be altered by varying the pro portion of this salt; too high a proportion destroys the half-tones. The examples shown demonstrate this point very clearly ; in each case two prints were made of as nearly as possible the same intensity, and one was dove- minutes in— Water Strong ammonia solution loped with a solution containing no dichromate, the other with a solution to which the dichromate had been added. The prints are allowed to remain in the developing solution for some time, in order that the Rochelle salt may remove the iron from the paper ; and the excess of silver salt is then removed by immersing for about fifteen a - p- — varuav ui cazute. The black prints have a good colour, with a very slight made strongly alkaline with ammonia, and afterwards in bluish tinge, the whites are clear, and the gradations good. salt, and 10 per cent of borax ; for purple prints, 10 per cent, of Rochelle salt, and 2 to 5 per cent of borax ; for sepia prints, 5 per cent of Rochelle salt, 1 -25 per cent, of great importance. The paper is exposed until the detail in the densest parts of the negative is very faintly indicated, the appear- give a character of novelty when put forward with energy and some freshness of expression. Within living memory such attempts at upheaval have occurred in the fields of THE CULT OF INDISTINCTNESS* BY W. E. DEBENHAM. Every now and then, in some field or other of art, a dis turbance occurs which threatens to be in the nature of a revolution. Some few active minds take up an idea which has been brought into prominence by the peculiarities of some one or more professors of the particular art, and carry on a vigorous crusade on behalf of a view which, to judge from their professions and actions, they think destined to create a revolution. The leading ideas may not be—and, indeed, generally are not—new, but are in the nature of a revival, conscious or unconscious of something which has before been practised to a certain extent, but has been allowed to fall into neglect and so much of oblivion as to two successive baths of a dilute solution of sodium citrate The sepia prints are not so satisfactory ; the colour is containing free ammonia. The alkaline tartrate or citrate often too red, and is sometimes not uniform throughout removes the iron compounds, whilst the ammonia removes the print. It seems, in fact, that it is more important in the silver compounds, and, finally, the prints are washed I this case that the paper should have been kept thoroughly in water. I dry. Prints should be somewhat deeper than for the The chief objection to this process was the use of silver other developers, and the developer, if used frequently, compounds in the developing solution, which, of course, must be kept acid by addition of a few drops of hydro- quite recently a modification of the process has been made, which not only removes this objection, but also enables prints to be obtained with a very warm colour. The silver salt is in the paper instead of being in the developer, and it is interesting to note that the modifications in kallitype j have followed the reverse order to the modifications of , platinotype ; in the latter, the platinum was at first in the paper, but in the latest modification it is in the developer. The specification of the patent of kallitype No. 2 is not yet published, but Dr. Nicol has kindly informed me that the paper is coated with a solution containing ferric oxalate, ferric nitrate, silver oxalate, silver nitrate, and nitric acid. It must be kept as dry as possible, but does not require the same minute precautions as the old platino type paper. The pads, &c., of the printing frame must also be dry. My own experience leads me to the conclusion that care in this matter of keeping the paper dry is of very part of the surface. Until quite recently these facts had not been utilised, but Dr. W. W. J. Nicol, working with a full small quantity of potassium dichromate should be added, developer, the prints should be immersed in a ten per cent. The sodium citrate has the double function of dissolving solution of Rochelle salt before being put into the ammonia, the ferrous salt, and thus enabling it to reduce the silver After the Rochelle salt has been used frequently for this nitrate, and of preventing precipitation of the iron by the purpose, it may be utilised for making up fresh developing ammonia. After development, the print is immersed ini solution. The details of the process, as first published, are to be found in patent specification No. 5,374, February 15th, 1890 (the British Journal of Photocjraphy, xxxvii., 170-171; Photographic News, xxxiv., 207). Paper is coated with a solution of ferric citrate, ferric tartrate, or ferric oxalate, or mixtures of all or any of them, and is dried. It is then exposed behind a negative until a faint man who has sufficient knowledge of chemical and other borax, and a small quantity of hydrochloric acid. In all principles to develop it in the right direction and in the three cases a small quantity of a dilute solution of potas- right manner. I The prints are afterwards washed in water. My own experience indicates that, even after prolonged immersion in the developer, there is danger of iron salts remaining in the paper, with, of course, loss of purity in . the whites, and I recommend that, after removal from the _ type, and it is then developed, the composition of the knowledge of the chemical changes involved, has succeeded developing solution varying with the colour required in in producing a practicable printing method by making the finished print. For black prints, the exposed paper is immersed in a solution containing 10 per cent, of Rochelle