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

January 11, 1867.] THE PHOTOGRAPHIC NEWS. 21 an opportunity of making a sharp actinic impression of the different planes of the model—the back, middle, and front. "With but one exception, all our artistic friends—miniature and portrait painters and art photographers—are charmed with productions of the lens and the sunbeam. The single exception is a mere pretender to art. Nine months ago he sat cross-legged on a table plying the needle and the goose. He maintains he can make better pictures with his Mammoth tube, that there are no contrasts, no clear blacks and whites, and bids us compare the specimens with the works of his own hands. We begin to think seriously that when he changed his vocation he was metamorphosed by some evil spirit into the instrument he had so often used to planish the seams of our garments. We regard these prints as specimens of true art, and shall aim to rise to the same perfection by imitating them, by following them as models worthy of imitation.” Proceeding of Socicties. North London Photographic Association. The usual Monthly Meeting of this Society was held at Myddelton Hall on the evening of Wednesday, January 2nd, Mr. G. Wharton Simpson in the chair. The minutes of a former meeting were read and confirmed. In the absence of a paper, the meeting was chiefly engaged in a desultory conversational discussion. Mr. Simpson exhibited some examples he had recently received from America by Griswold’s opalo-ferrotypes. These consisted in pictures upon thin sheets of enamelled iron, which were first coated with an opal solution prepared by Mr. Griswold for the purpose. The white or opal surface being thus obtained, the image is produced by applying a sensitive coating, such as collodio-chloride of silver, and printing in the usual way. The pictures, when finished, could be varnished with a hard varnish. Mr. Foxlee asked if the nature of the white surface was described ? Mr. Simpson said he believed that was Mr. Griswold’s secret. He had only very recently received the pictures and examples of material, and had not yet carefully examined the subject. Ho was unable to say the exact extent to which Mr: Griswold described the preparation of the materials. He hoped at a future meeting to state the result of some experi ments with the materials sent to him. Mr. Bockett thought it would not be difficult to find a white coating for the purpose. Perhaps something could be mixed with the collodio-chloride itself. Mr. Simpson said ho would suggest a possible process, which might be worth bringing to the test of experiment. Dissolve chloride of barium in collodion, and then add sufficient of a soluble sulphate to decompose the chloride, and produce sulphate of baryta in suspension, and chloride of the base of the sulphate in solution. Now add nitrate of silver, which would, by a second double decomposition, form chloride of silver in suspension. The preparation would consist of collodio- chloride of silver with a white pigment in suspension, which would give body to the whole, and supply the whites of the picture. This was but an embryo suggestion, and could only be thrown out as a hint, the whole consequences of which had not been followed out. After some further conversation, the subject dropped. Mr. J. T. Taylor exhibited a collodion picture which had been transferred to one of the convex enamel tablets used for enamelling photographic miniatures, which, having a brilliant varnish, it resembled. Mr. Foxleu suggested that the enamels of Lafon de Camarsac were similar collodion pictures, covered with a film of microscopic glass, which was then fused. Mr. Simpson said the temperature at which any glass would fuse was sufficiently high to injure, if not to destroy, a collo dion image. In any case, the colour would be spoiled. There was little doubt that the pictures of Lafon de Camarsac were produced in vitreous materials, and probably by a process analogous to the patent process of Mr. Joubert. The plan suggested by Mr. Foxlee had been repeatedly tried, and found wanting. r Mr. Foxlee had seen one so treated. It was true the colon, was changed, but that, he thought, might possibly be got over He thought those of Camarsac were probably so produced, from the fact that in some of them there seemed a layer of glass over the image. Mr. Bockett exhibited some carbon prints produced on Swan’s tissue, and spoke of the extreme simplicity and certainty of the operations. After some further conversation, the proceedings terminated. London PHOTOGRAPIIIC Society. The usual Monthly Meeting was held in King s College on the evening of Tuesday, the 8th inst., Mr. FnANCI8 BEDFORD in the chair. The minutes of a previous meeting were read and confirmed, and Mr. J. W. Swan, of Newcastle-on-Tyne, was duly elected as a member. The Chairman also announced that Mr. Stephen Ayling would have been nominated for election, but the letter did not arrive in time to come before the Council in due form, so that the election would be delayed until the next meeting. Mr. CLAUDET wished, prior to the re-opening of the dis cussion on Mr. Dallmeyer's lens, to read a few words. Mr. Davis, who adjourned the discussion, and therefore had the ear of the meeting, having waived his right, The Rev. J. B. Reade read Mr. Claudet’s remarks. In reference to the relative value of the moving focus, and the lens with diffused focus, he invited comparison of results. He stated that M. Voigtlander approved his plan, and had sent him a mathematical calculation by his son-in-law, which proved that, by the simultaneous movement of the lenses of the com bination, the images produced would not vary in size. This calculation would be duly published in the journals. Mr. Reade, on concluding the paper, proceeded to some remarks on the subject. Ho wished to ask Mr. Dallmeyer what was to be under stood by diffusion of focus in his lens ‘I Did it consist in the rendering of a point by a series of concentric rings, or the production of coma? If the latter, it would be very objection able. It would materially enhance the value of this excellent lens if it were understood that the diffusion of focus it pro duced was not of .the character of coma. As to the question of novelty in form, he was not sure that it did not resemble some of those made by Mr. Andrew Ross, of which diagrams were on the table. As, however, he knew what minute differ ences in figure would materially alter the qualities and performance of a lens, it was scarcely of importance to point out general similarity in form. Some comment had been made on his remarks, at a former meeting, on the human eye, and it was alleged that the eye had great depth of focus on account of its small aperture. Now the contrary was the fact: it had really a large aperture, and no depth of focus. The ratio of the aperture to the focus was as one to three-and-a- half; whilst that of ordinary portrait lenses was one to four. The truth was, that the eye obtained depth of focus by con stantly varying its focus; and the aim of Mr. Olaudet was, as nearly as possible, to effect the same thing. Mr. Sebastian Davis, in resuming the discussion, differed from those who maintained that sharpness was inimical to softness. Softness was really a thing dependent on light and shade, and if perfect sharpness throughout could be obtained, it might be quite compatible with softness. Then came, however, the difficulty interposed by an invariable optical law, by which objects at different distances in front of the lens necessarily came to a focus at different points behind it, and could not be produced equally sharp on one plane ; and the question of a compromise became worth considering. He took exception to the statement in Mr. Claudet’s paper, that by moving the lenses of the combination the size of the image would not be altered. A conversation between Mr. Reade and Mr. Davis followed, from which it appeared, so far as the conversation was audible, that it was intended that the lenses should bo moved coinci dently, so as to preserve the optical centre stationary, and that the body of the camera should be moved at the same time. To this Mr. Davis objected, as interposing insuperable practical difficulties. Mr. Davis resumed, that in Mr. Dallmeyer’s lens it appeared a power was given of so arranging it that, instead of as in a perfectly corrected Jens, the image should have, one piano in perfect sharpness, the focus being a point merging into misti ness, it should be possible to merge from a circle into mistiness.