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
• Rechtehinweis: Public Domain Mark 1.0
• URN: urn:nbn:de:bsz:14-db-id1780948042-186700008
• PURL: http://digital.slub-dresden.de/id1780948042-18670000
• OAI: oai:de:slub-dresden:db:id-1780948042-18670000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

THE PHOTOGRAPHIC NEWS. Vor. XT. No. 466.—August 9,1867. CONTENTS. PAGE M. Davanne’s Report on the Duc de Luynes’ Prize Competition 377 Carbon versus Silver Printing 378 Origin of the Collodio-Chloride of Silver Process 380 On the Causes which Produce Insolubility in a Mixture of Gela tine and Bichromate of Potash, &c 381 The Naval Review from a Photographic Point. By Valentine Blanchard 382 The Reason Why. By the Photographer’s Assistant 383 Simple Method of Obtaining Gelatine from Ordinary Glue. By C. Puscher 384 Chromate of Mercury Printing Process. By M, Guardabassi ... 384 PAGE Recovery of Gold and Silver from Residues. By M. Dubois Captain 385 American Carbon Tissue 385 Some of the Causes of the Fading of Photographs. By G. C. L. 385 The Stability of Photography 386 Photogaphic Piracy of Engravings 38b Correspondence.—Carbon Printing, Sulphocyanide Toning Baths, &c.—Chlorized Collodion 387 Talk in the Studio 388 To Correspondents 388 M. DAVANNE'S REPORT ON THE DUC DE LUYNES’ PRIZE COMPETITION. The interesting and able report of the Commission for awarding the Duc de Luynes' prize for the best mechanical printing process, which was read to the French Photographic Society in April, and has since been published in our columns, demands a few words of comment. It presents a very interesting resume of the progress of photo-mechanical printing processes, and will probably hereafter be referred to as historical ; for this reason we think it is important that a few errors should be corrected in which it seems to us that the claims of others are somewhat overlooked or ignored, to give value to those of M. Poitevin. We should be the last in any degree to under-estimate the claims of this gentleman, for whose labours we entertain the highest esteem. Few men have contributed so much to the progress of permanent printing, and also to various other branches of photography ; and he is undoubtedly the fans et origo of practical carbon printing processes. Wo do not undertake to challenge the decision of the committee by which M. Poitevin received the prize, as it is probable that of those who entered the competition M. Poitevin had the highest claim ; and he has contributed much to the art by which others, and not himself, have profited. But it is to certain statements in the Report we feel bound to take exception. As the initial idea of utilizing bichromates, gelatine, &c., in carbon printing is due to M. Poitevin, so is the initial idea of employing the same agents in a system of photo engraving due to Mr. Fox Talbot, whose experiments were made in 1852, and not in 1853 as stated in the Report. In October of 1852 Mr. Talbot entered the specification of his patent, which describes, with considerable detail, not only the mode of securing an image on steel by photography, and etching it, but also the mode of securing grain or holding ground by means of “ veils ” or an aqua-tint ground. He also significantly adds that this method of producing a printing image is applicable to lithography as well as engraving. The claims of Mr. Talbot are not ignored in this Report, but they are dated a year late, and their germinal character, and their value, as showing the way to all who come after, is not sufficiently recognized. In like manner the claims of Herr Pretsch are underrated. We are informed in the Report that the process of photo-lithography and photo-engraving, upon which M. Poitevin’s claims in this competition are based, were announced to the French Society in December, 1855, and we find that they were patented in this country in the same month. The process of photo-engraving of Herr Pretsch was based on similar principles, and was patented more than twelve months earlier, being dated November, 1854. The Report, in referring to this, appears guilty of something like a double unfairness when it declares “ priority of invention of small importance,” and further states that Herr Pretsch's process was not applicable to litho graphy. So far from the latter statement being the fact, we find that in the specification it is distinctly stated that “ printing ink can be applied to the coating of the plate prepared as above described, taking the impression on paper laid thereon, which impression can be transferred to zinc or stone, and printed by the usual methods.” Here, then, is a distinct recognition that the image obtained by means of chromated gelatine is susceptible of being inked, and a transfer produced for use in lithography. There is a further injustice done to Herr Pretsch in stating that the method he employed in obtaining a raised design by swelling the unacted-upon gelatine with cold water was probably a copy of M. Poitevin’s method, when in truth Herr Pretsch had patented this very method, both in this country and in France, some time before M. Poitevin’s discovery of the same thing was either announced or patented. That M. Poitevin’s inventions were original, and not derived from those of others, except so far as the labours of his predecessors may have suggessed experiment with the same materials, we can readily admit; and that he worked out his results to a more practical issue is, we think, pretty clear ; and on this latter ground we are willing to admit his claim to the award ; but all this being so, surely there was more room for the Commission to exercise generous recogni tion of what was really effected by an unsuccessful com petitor. Again, in enumerating the claims of M. Poitevin as exist ing during the “ first period ” of the competition, the Report states that, besides securing plates in intaglio and relief by means of the action of light on chromated gelatine, he “ used the mould to obtain photographs in tinted gelatine;” and as it is stated that the competition was intended at first to close in 1859, it is thus clearly implied that these photographs in tinted gelatine, which are none other than the “ photo-mezzotints ” of Mr. Swan, or the “ photo-reliefs ” of Mr. Woodbury, were produced prior to that date. Is this true ? Is there a single line on record descriptive of such a mode of producing images, until we, in 1864, described the method discovered independently by Mr. Swan and Mr. Woodbury ? We believe not. Nay, more, the only approxi mation to such images exhibited by M. Poitevin are the impressions in coloured gelatine taken from coins or medals, and stated to have been produced in 1863, which certainly does not belong to the first period of the com petition. If M. Poitevin had produced photographs in coloured gelatine at an earlier period than MM. Swan and Woodbury, we may fairly assume that they would have been exhibited instead of impressions from medals, which are not photographs.