The photographic news

• Bandzählung: 7.1863
• Erscheinungsdatum: 1863
• 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-id1780948042-186300004
• PURL: http://digital.slub-dresden.de/id1780948042-18630000
• OAI: oai:de:slub-dresden:db:id-1780948042-18630000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

May 8, 1863.] THE PHOTOGRAPHIC NEWS. 219 “Thenegative developed with pyrogallic acid mixed with formic acid, appears quickly, but the formic acid does not retard the reduction of the silver, producing on the film a greyish deposit of silver.” This result shows me, that Dr. Van Monckhoven has used too much formic acid, or that his acid was too strong to be introduced in the formula in the proportion that I have indicated. In fact, in the course of my experiments, I have also had the deposit of silver of which Dr. Van Monckhoven when the dose of formic acid has been too strong. When the collodion plate has been withdrawn from the nitrate of silver bath, decidedly acid with nitric acid, and well drained before putting in the slide, then exposed it in the camera, and a solution of pyrogallic acid mixed with formic acid applied, the image appears instantly, giving a very vigorous negative; and, however far the development bo pushed, there should be no reduction of metallic silver upon the plate. It is necessary that the exposure in the camera should be five times less than if developed with pyrogallic acid and acetic acid; and half the time necessary where it is developed with the sulphate of iron; having moreover the advantage over the latter that there will be no necessity for intensifying. If this result be not obtained, the most probable cause will be that the formic acid has been too strong. This should not, of course, discourage the experi mentalist, but simply induce him to continue changing the proportion of formic acid in the developer until he gets the results I have obtained daily for two years, and of which I am able to show the proof in the large photographs and the cartes de visite sent by my father to the exhibition of the “ Palace of Industry,” all of which have been done by my process. Having had the occasion to operate before M. Balard in his last visit to London, this illustrious savant was so much surprised at the rapidity of photogenic action resulting from the new addition of formic acid in the developing bath, that he himself proposed to me to present the communication of my process to the Academy of Sciences, as a discovery capable of rendering service to photography. I have frankly described the process with the desire of rendering it easy to all operators, and the formula that I have given succeeds with me perfectly. I recommend Dr. Van Monckhoven to, make new experiments. I need not say to him that the state of the nitrate bath, more or less acid, the constitution of the collodion and of the pyrogallic acid that he used, and, perhaps, the quality of light under which he operated, may cause a modification in the propor tions of formic acid necessary. He will, I think, be soon convinced that formic acid, added to the developer, is attended with the best results, as an accelerating agent, tlie most powerful in the formation of the photographic image.—Yours very truly, Henry CLAUDET. Critical zlotices. THE FAITHFUL SHEPHERDESS: A Statue, by Miss S. D. Durant. Photographed by Stephen Thompson. London: Marion & Co. We unhesitatingly affirm our conviction, at the risk of the double charge of bad taste and want of gallantry, that the photography is here, in our view, bettor than the sculp ture. The figure is one of a series of colossal statues executed for the Corporation of London, amongst which are some fine productions by good men. “ The Faithful Shep herdess ” is in illustration of Beaumont and Fletcher’s lines, running thus:— . “ Look and see The ring thou gavest me, and about my wrist The curious bracelet that thou thyself did twist 1' rom these fair tresses. Know’st thou Amoret ?" The expression and pose of the statue—which may now be seen in the Royal Academy, where we examined it— illustrate the lines sufficiently well; the drapery is also graceful, but the general effect of face and figure is “ sticky,” poor, and hard. Miss Durant, who is, we believe, a pupil of the Baron Trigueti’s, holds a good position in a certain school of sculpture, and it may be heresy to express our want of admiration for the work ; but it is so. Mr. Thompson has chosen a view which gives the best rendering to the subject and produces a really fine picture (12 by 10), which Her Royal Highness the Crown Princess of Prussia—we like the term Princess Royal of England better—for whom the work was photographed, has not only expressed her gracious approval of, but given permission for its publica tion. We have received some fine things Mr. Thompson has recently been executing in Warwickshire, which are not, however, ready for publication yet. THE DOUBLE SULPHATE OF IRON AND AMMO NIUM AS A DEVELOPER. BY H. S. N0VERRE. I have been using the double sulphate of iron and ammo nium for the last two months, and as its employment appears likely to become general, I send you the formulae I have found most useful. The advantages I find it to possess over the protosulphate of iron are the absence of all tendency to deposit on the shadows, that a shorter exposure is required in the camera, that the crystals keep well, and that, provided the solution has not been kept long, it may be mixed with solution of nitrate of silver, without becoming turpid, for several minutes. The following is my experience as regards the strength of the solution:— Sulphate iron and ammonia ... 25 grs. Acetic acid 15 mins. Water ... ... 1 oz. Alcohol q. s. The above is a convenient solution for general use for views and portraits well lighted, and it keeps well. Sulphate iron and ammonia ... 35 grs. Acetic acid 20 mins. Water 1 oz. Alcohol q. s. This solution I have found useful for subjects badly lighted and for interiors, but is too energetic for ordinary work. I enclose a carte de visite, the negative of which was developed with this solution; the image started out at once, and after applying the developer, and in about two minutes, was of sufficient density to require no further intensification. The exposure was two seconds, with Dallmeyer’s No. 1 B lens, with the X stop, in the open air. I do not think, however, that the result is as satisfactory as if it had been developed with the first-named solution, and intensified afterwards with pyrogallic acid. A stronger developer is made thus :— Sulphate iron and ammonia ... 100 grs. Acetic acid ... ... ... 30 mins. Water 1 oz. Alcohol q. s. It answers very well for instantaneous work ; it develops clearly and evenly, and is at the same time quite under con trol. This is best used fresh, as it may then be kept on the plate several minutes if the picture does not appear at once. The solutions of the double salt do not appear to keep any better than those of the protosulphate of iron, but the crystals keep exceedingly well. I have had some of the salt loosely wrapt in paper for about two months, which is as good as the day it was bought. 25, South Street, Park Lane.