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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
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- Public Domain Mark 1.0
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- urn:nbn:de:bsz:14-db-id1780948042-186300004
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- http://digital.slub-dresden.de/id1780948042-18630000
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- oai:de:slub-dresden:db:id-1780948042-18630000
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- Fotografie
- LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
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- Parlamentsperiode
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- Bandzählung
- No. 257, August 7, 1863
- Digitalisat
- SLUB Dresden
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- Ausgabe
- Parlamentsperiode
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- Wahlperiode
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Zeitschrift
The photographic news
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Band
Band 7.1863
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- Register Index 619
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Band
Band 7.1863
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- Titel
- The photographic news
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August 7, 1863.] THE PHOTOGRAPHIC NEWS. 383 EBONITE BATHS. Sir.—Seeing in the last number of the Photographic News a letter of inquiry from Captain Dennis Wright re specting the efficacy of dipping baths made of ebonite, I beg you will allow me an opportunity of stating my expe rience in regard to this matter. Early in the summer of last year, whilst giving a course of instruction in photography to the officers attending the Royal Artillery Institution, I had frequent inquiries about the chemical efficacy of ebonite, which, on account of its lightness and indestructible character, had much to recom mend it to the favourable notice of tourists, and others, like my pupils, liable to frequent changes of residence. By way of putting this question to the test of experiment, two ebonite baths were purchased, and used side by side with others made of gutta-percha and glass. I took par ticular account of their performance, and, as the general result, it was found that the silver solution was more liable to change in the ebonite baths than when contained in vessels of the older materials. The negatives taken were wanting in vigour, and I found, in fact, that metallic silver had become, reduced in the form of a brilliant lining over the whole interior surface of the bath, and the solution had squired an acid reaction. Shortly afterwards I mentioned this circumstance to Mr. Hugh A. Silver, of the firm of S. W. Silver and Co., Bishopsgate Street, who suggested that the faulty baths might have been prepared from the refuse of the india-rubber manufacture, in which bronze powders and other metallic pigments were likely to be contained. That gentleman told me his firm had recently been engaged in some critical experiments preliminary to undertaking the manufacture of photographic apparatus in pure ebonite, and he kindly offered to place in my hands two of his new dipping baths for comparison with those in common use. W ith regard to the quality of the india-rubber employed in the composition of the ebonite for these baths it was then stated that all apparatus bearing the stamp of the firm should be made of “ virgin gum,” and that they, were prepared to guarantee that no re-worked rubber should at any time be used in their construction. Immediately on the arrival of these baths I proceeded to test them in the ordinary way ; one bath was started with a fresh solution of nitrate of silver, the other being filled with a supply transferred from a large glass bath, which was acting satisfactorily. By repeatedly testing, at intervals of a week and upwards, I could not detect any deterioration, nor was there any evidence of metallic reduction or libera tion of acid ; in fact, these vessels answered their purpose admirably, they preserved their shape, bulging but_very little, not nearly so much as gutta-percha would have done under like circumstances—their rigidity was, indeed, remark able, and the solutions left for nearly six months in them re mained unimpaired. In regard to weight I found that the bath and air-tight cover, with metal binding screws, hinged support, and dipper complete, weighed, in the aggregate, less than the solution which could be accommodated therein. It should likewise be mentioned that these bathsand dip pers for 10 by 8 plates were beautifully formed, having their interior surfaces lined with polished plates of ebonite, and the material appeared throughout, so far as one could judge by inspection, to he of uniformly good quality. As the practical conclusion from these observations, I would call attention to the fact that there arc different qualities of ebonite apparatus in the market, and it is, therefore, important to look for the guarantee of quality which the name or stamp of the maker affords, and by all means into decline accepting articles like those which first came to my hands, in regard to which it is almost needless to add that there was no trade mark or means of identifica tion.—I am, dear sir, yours faithfully, . John SPILLER. Woohoich, August 24th, 1863. [The bath to which we referred as proving satisfactory in our hands, was manufactured by Messrs. Silver and Co. If we are rightly informed, the manufacture of “ Ebonite ” is protected by a patent, and any imitation under the name of “ ebonite ” would be an infringement.—Ed.] A CASE OH NEED. My Dear Sir,—Having just returned from a small water ing place where I found the widow of a photographer of some repute struggling hard for a livelihood with a wretched lens and camera, may I ask the favour of your bringing her case before our photographic brethren, professional and ama teur, and soliciting their aid towards procuring for this worthy and industrious sister a suitable apparatus wherewith to support herself and three orphan children. At her hus band’s death, being then ignorant of the art, all her lenses, &c., were disposed of by a relative. She has since been taught, and only now fails to attain her object from not having a lens, &c., fit for the purpose. I am sure, sir, you will kindly consent to receive subscriptions, and the smallest donations will be thankfully received.—I remain, my dear sir, your constant reader, An Amateur Photographer. Aqotogruphit Zlotes and Quexies, Moisture and Actinism. Dear Sir,— I, with several of my photographic friends and not a few of your correspondents, have lately been complaining sadly about the want of intensity in their negatives, notwith standing the recent and present summer light. I should inform you, sir, that the floor of my glass room is paved with red tiles, and therefore you will readily understand that with a southern aspect the heat is usually very excessive and the atmosphere correspondingly dry. To alleviate the heat, the other morning, I poured through the “ rose ” of a watering pot a large quantity of water on the tiles, and although in a few moments the water was absorbed, the evaporation continued for several hours. To my gratification on taking a negative it not only camo up dense and standing out from the glass, but required no after intensifying from the iron developer. I do not absolutely assert that the dampness in the air of the room had anything to do with the improvement, but on trying the same thing this morning I met with the same pleasing result.— I am, sir, yours very truly, NOEL E. Fitch. ! [The fact stated by Mr. Fitch is curious, and as we know him to be a most careful and skilful photographer, his experi ments and opinions possess considerable weight.—Ed.] New Transparent Medium on to which Negatives may be Transferred. New Preservative. Sir,—I have not seen any reference to a substance which seems peculiarly adapted as a preservative in the dry plate process, also as a transparent sheet upon which to place negatives instead of glass plates that are so liable to get scratched and broken. I refer to a mixture of gelatine and glycerine ; the latter readily dissolves glue or gelatine by the aid of heat in an ordinary glue pot, forming a mixture which, when spread on glass and allowed to set, may be taken up as a beautifully transparent sheet, exceedingly flexible ; or the hot solution may bo poured on the unvarnished glass negative, and, when set, the impression becomes attached to the gelatine, and is then more convenient for all printing purposes, and the density of the negative is not impaired by varnishing as on glass plates. Such sheets, containing negative images, are most convenient for photolithographic purposes and for photographic printing surfaces generally, as, from its flexible nature, it adapts itself to the sensitive surface ot either stone or plate in the closest contact. Query—If a very dilute solution of the above be applied to a collodion plate sensitized, I feel certain it would prove a valuable preservative, it will certainly make a better combination than gum and honey. It retains its viscidity for years.—Your obedient servant, Joseph Lewis.
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