The photographic news

• Bandzählung: 12.1868
• Erscheinungsdatum: 1868
• 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-id1780948042-186800009
• PURL: http://digital.slub-dresden.de/id1780948042-18680000
• OAI: oai:de:slub-dresden:db:id-1780948042-18680000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

142 THE PHOTOGRAPHIC NEWS. [March 20, 1868. ate were added a little at a time, the whole of the alcohol and ether would be oxidized before any excess of permanganate would remain. Mr. SIMPSON said it would be scarcely desirable to proceed to that point, inasmuch as alcohol and ether in their normal con dition would not exercise any injurious eftect, and their perfect oxidation would cause an accumulation of carbonate and acetate of potash in the bath. As it fortunately happened that the aldehyde formed by the decomposition of the alcohol, &c., which was the source of fogging, was’acted upon and removed first by the permanganate, there was no need to add excess, which would tend to waste silver and injure sensitiveness. Any body which readily gave up oxygen would necessarily retard the for mation and the development of the images. Mr. Sebastian Davis, after referring to the old method of testing water for organic matter, in which, after evaporation, the residue was burnt to ascertain the proportion of organic matter present, and pointing out the superiority of the present method, remarked that in order to examine the colour more perfectly it was customary to place the water to be tested in a tube two or three feet in length, in which the colour could be readily seen. He agreed with Mr. Simpson as to the retarding action of a permanganate, as it was a salt containing seven equivalents of oxygen, which it readily gave up ; and the pre sence of such a salt during development, by peroxidizing the iron, would materially check its reducing action. Mr. Hart suggested, in order to avoid the risk of adding excess of permanganate, that a small portion of the bath might be taken, and, after precipitating the silver with a chloride, the permanganate might be added to the water cautiously until all organic matter was removed. By this means an estimate of the quantity required for the whole bath might be formed. He would like to know if Mr. Johnson had examined the preci pitate to ascertain if nothing but sesquioxide of manganese was thrown down. Mr. Johnson said the quantity of precipitate was so small that he had not attempted such an examination. He thought, however, that the reactions had been so fully stated by Mr. Crookes in the News, that no doubt need be entertained on the subject. After some desultory conversation, in which Mr. Hart sug gested the importance of photographers publishing a record of their results with this remedy, and stated hie thought that a portion of the silver would be thrown down as well as oxide of manganese, Mr. Simpson stated that he believed not until excess had been added. The precipitate thrown down in the first case he had described, in which he used care to avoid excess, was of a different character to that thrown down when excess was added. The first was of a cold brown tint, the second of a purple brown tint, and, when examined, was found to contain permanganate of silver. Mr. Johnson said that there could be little doubt that the safest and most efficient plan would be to use permanganate of silver, as suggested by Mr. Crookes. Mr. Blanchard said that he had used Condy’s fluid in one case to a bath, and had doubtless, although he used very little, added more than was necessary. A plate he tried was free from fog, but it was covered with fine needle-shaped crystals. On diluting and filtering, all this was removed, but still the bath worked a little slower. Mr. Johnson again said that he thought it unwise to use Condy’s fluid. After some further conversation, Mr. Foxlee said that he had never had any difficulty in getting cleanness with doctored baths, but they never gave him so much sensitiveness as an undoctored bath. Mr. Simpson said that in the bath he had tried the sensi tiveness was greater after treatment than before. He believed that Mr. Blanchard had repeatedly found a corrected bath gave quicker results, as well as better, than he could obtain from an uncorrected bath. Mr. Blanchard said that he often found that a bath treated with carbonate of soda and sunned gave him the highest sensi tiveness and the highest quality. Mr. Fitch confirmed this view. Mr. Foxlee said that his corrected baths were not slower than before correction, but slower than the new bath made with the purest fused nitrate of silver in the market. After some further conversation, Mr. Foxlee described a bath which sunning failed to improve, its fault being a ten dency to turning red in the shadows during intensifying. It was suggested that this defect would furnish matter for an evening’s discussion. The subject was then closed with a vote of thanks to Mr. Johnson. The Secretary exhibited an old developed Talbotype, of which scarcely any trace was left. The print was cut up and divided amongst several members for experiments in revival. Mr. Simpson exhibited a carbon print, produced in Berlin, by Swan’s process, which appeared as the frontispiece to a German translation of his (Mr. Simpson’s) work on Photo graphy in Pigments. The proceedings then terminated. The next meeting, in April, will be devoted to examination and conversation upon photographs, which members are re quested to bring for the purpose. Correspondente. PHOTOGRAPHY AND DISEASE. Sir,—I think the question now being discussed in your columns, as to whether the practice of photography is un healthy or not, must in a great degree bo settled by the testi mony of experience. After sixteen years’ handling and inhaling the deadly agents we use, I have had no symptoms of suftering from poison, and I am convinced that if the dictates of common sense were followed, no danger need be apprehended from their use ; but if discretion is not used, we know that a man may lose his life by eating roast-beef and plum pudding. If prudence is neces sary in the one case, it is surely doubly so in the other ; other wise the consequences will be the same. During this period of my practice I do not pretend to say that I have not many a time been ailing with headache, and, I am not ashamed to say, “ heartache ” also. What with the everlearning which the progress of the art has rendered neces sary, and the hard struggle to keep the “ cart on the wheels " through the withering blast of unscrupulous competition, I have often wondered at iny own endurance. I am sure, sir, that you will agree with me when I say that I feel it no small mercy to have come thus far out of the battle with unimpaired health and a comfortable prospect. I have watched the course of many who prefer “ gold to honoursome have gained the prize ; others, in their haste to be rich, have fallen, to rise no more. This hit-or-miss policy has of late come sadly to grief, for the good and honest reason that it has out-generalled itself; but for photographers proper there never has been a brighter prospect. Those who have striven to do their best for the art and their patrons have gained a position which is as essential in the science of trade as it is in the science of war. Photography must always be a worrying and trying profes sion, but I believe that the worst is past, and that health and wealth are in store for the future. W. Hall. Brighton, March 17th, 1868. THE USE OF DISTILLED WATER. Sir,—The important question recently raised in your columns by Mr. Cherrill, as to the necessity of using distilled water in photography, although ably discussed by some of your correspondents as well as by the gentleman raising the question, has scarcely, I think, been set at rest. Mr. Cherrill himself tells us that he dispenses with distilled water; Mr. Russell Sedgefield, an old and experienced photographer, makes a similar statement. Statements of practice are always of considerable importance ; but I should like to know the reason why of two or three points. In the first place, what consti tutes “ common water”? In the next place, presuming it to be, as I fancy it is, the ordinary water used for domestic pur poses, does not this vary considerably in quality, according to the source from whence it is derived? And do not many samples contain chlorides, carbonates, sulphates, &c., as well as organic matter ? If this be so, do we not run considerable risk of introducing contaminations into a new silver bath, which may subsequently cost us much trouble to get rid of? , I am a great advocate for simplicity wherever it can be obtained without paying too great a price. Will you enlighten