The photographic news

• Bandzählung: 6.1862
• Erscheinungsdatum: 1862
• 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-id1780948042-186200003
• PURL: http://digital.slub-dresden.de/id1780948042-18620000
• OAI: oai:de:slub-dresden:db:id-1780948042-18620000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Bemerkung: Seite 1-72 fehlen in der Vorlage. Vorlagebedingter Textverlust.
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

[August 8, 1862. THE PHOTOGRAPHIC NEWS. 374 Av one in some * Part I., price la. London : Simpkin, Marshall, and Co. materials ; and oo p. — . place, with materials of a similar nature, but not exact!! the same, how he may hope to obtain equal results Receipts should be looked upon rather as valuable hint • SERI "9grapl Wus ion, b "tain st: , imita > S 1K " "lson IS ' many , BDerain Aan We with i e Ventn . A receni POpular " "sional i ad particular circumstances, and with certain d to suggest to another person in another than as arbitrary prescriptions.” A very important property of carbolic acid has recent! been described by Mr. J. E. Ashby. Our readers ma, perhaps, be aware, that this is one of the products o the distillation of coal, and is now made in somewhaf large quantities, on account of its most energetic deo dorizing, and disinfecting properties. When perfectly puI& it is a white crystalline solid, which by absorbing moistur. soon changes into a colourless, refractive liquid having* faint odour of roses and tar. It is not an acid in th popular sense, not being either sour or corrosive, Al should, therefore, perhaps, be generally designated by 1 “ other title of phenol. Crude carbolic acid may be nos o tained in bulk for about a shilling per gallon ; it is a danj tarry' liquid, containing, perhaps, from ten to twenty diis rent substances in a state of mechanical admixture. * of sulphate of ammonia have been dissolved. The liquid is to be evaporated down, by preference over a water bath until it begins to show signs of crystallization; it is then allowed to remain at rest until it is perfectly cold, when the double salt will be found to have separated in the form of hard crystals : they preserve their transparency per fectly, even when kept in an imperfectly stoppered bottle, thereby showing that no alteration has taken place in their constitution. In using this salt, it must be remembered that its equivalent is greater than that of sulphate of iron, by the amount of sulphate of ammonia which it contains. On this account 196 parts, by weight, of the double sulphate will he required to effect the same amount of reduction as 139 parts of sulphate of iron. Whilst writing on this subject, it may not be out of place to mention a method frequently employed in chemical laboratories for preparing sulphate of iron in a form in which it does not readily peroxidize. A saturated aqueous solution of protosulphate of iron is prepared, and then mixed with twice its bulk of alcohol. The salt is immediately precipitated in a partially dehydrated fonn as a white powder; this is filtered off and drained from the adhering liquid (nowashing is needed). When dry, it may be preserved for use in a stoppered bottle. Owing to its being in a fine state of division it is very convenient for weighing out definite quantities, and it also has the advantage of dissolving with great rapidity in water. Owing to its having lost part of the water of crystallization, it is slightly stronger in its reducing or developing power's, weight for weight, than the crystallized sulphate. We are not aware that either of these forms of sulphate of iron have been used, but from our own experiments, as well as from their more obvious valuable properties, we do not hesitate to recommend our readers to make trial of them as developing agents. We shall be glad to hear of their success. A Dictionary of Dyeing and Calico Printing, by Charles O’Neill,* can scarce be expected to contain much that is of interest to photographers, although it is a work which will not fail to prove of the greatest value to those for whom it is specially' written. Some of the author’s remarks in the introduction arc, however, so excellent, and are of such universal application, that, for the benefit of our younger readers, we transcribe a portion of them, which will apply quite as forcibly to photographers as to dyers. He writes: —“ It is not necessary to say to practical and experienced colour-mixers and dyers what amateurs must be strongly reminded of, that receipts, in themselves, are valueless without preliminary experience. The failure of a receipt, in nine cases out of ten, is not necessarily a condemnation of its correctness, but is frequently a reflection upon the skill of the operator. The real use of receipts in a work of this nature, is to show how things have been done by Soll) this Act will be deemed personal estate ; and any sale must be the subject of a written memorandum, written licences to use such copyright may be also given ; but it is necessary that sale made, or license allowed, shall be duly registered at Stationers’ Hall. For the various conditions governing the examination of such registry, of securing certified copies for reception in evidence, &c. &c., reference is made to the existing Act on literary copyright, which enacts that the register shall be, at all convenient times, open for inspection on payment of one shilling for every entry searched for; and that a stamped and certified copy of such entry, which shall be received as evidence in all courts, in case of legal proceedings, shall be furnished by the proper officer for the sum of five shillings. As regards the penalties by which the protection is enforced, there is not much aubiguity. For every offence the pirate is liable to a penalty often pounds, and all “copies, repeti tions, and imitations,” and all negatives are to be forfeited and, together with the penalties, given up to the proprietor of the copyright. In England and Ireland the penalties are to be recovered by summary proceedings before two justices of the peace, having jurisdiction where the offending party resides. In Scotland they are to be recovered by action before the Court of Session, or by summary action before the sherif of the county. Provision is also made for seizing importations of piracies, and also for including in this Act, in relation to paintings, drawings, and photographs, the provisions of the Interna tional Copyright Act. We again congratulate photographers that they have, though tardily, obtained this measure of justice, which will do much, we believe, to improve the productions of the art. by giving the artist exclusive property in the excellence of his works, and will contribute towards raising photography in the eyes of the public, by removing from the market the vile copies with which it has been recently increasingly inundated. Stientifir Gossiy. SEPARATOX of Silver prom its Alloys—New Iron Develop ing S,urs—O’Neil’s Dictionary, Advice to young Experi mentalists—New and important Property of Carbolic Acid. An improved method of separating pure silver from an alloy of silver and copper, has just come before our notice ; it has been proposed by Berlandt. He dissolves the mixed metals in nitric acid, and evaporates the solution to dryness to get rid of excess of acid. He then dissolves an ounce of the salts in five ounces of water, filters the solution, adds fourteen ounces of a solution of protosulphate of iron (five and a half parts sulphate to eight and a half parts water), mixes and stirs well. The greyish white deposit, washed with very dilute sulphuric acid, and afterwards with water, is found to be pure silver. By dissolving this in nitric acid, taking the precautions mentioned in one of our early chapters on photographic chemicals, the photographer will be in possession of nitrate of silver pure enough for all ordinary purposes. The employment of protosulphate of iron in developing solutions is becoming so general, that our readers may be glad to know an easy method of preventing the peroxidation of this salt in the atmosphere. The value of protosulphate of iron as a developing agent depends upon its rapid absorp tion of oxygen, and conversion into a per-salt of iron. If, however, this oxidation has partially taken place before it is used—if part of its reducing propensities have been grati fied before it comes in contact with the latent negative image —it is evident that its action will be much weaker. Instead of using sulphate of iron alone we would suggest a trial of the double sulphate of iron and ammonia, FeO.SO,++NH,O. S0.,-|-6H0. This salt is easily obtained in crystals from a solution in which 139 parts of green vitriol, and 66 parts crude. is now pheno] appear a thin bite an aman from b convin clean a broad curious Hms a betweer some at been ap And san dissolve it forms *ould 1 water w Point oi kinty. ktifice ’ B prest Brpenti ma Onmon trpenti nust be Me thr use ing the , and amo in extra broken c And turn Gnd thro *ben the Ihto it, c Bents of Carjolic “lan tur Neithe "ficient 'Me. 'J Ss; wh 32mi tecon