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
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• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
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• Strukturtyp: Band

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[July 4,1862. THE PHOTOGRAPHIC NEWS. 324 Ualk iu the Studio. Uo Uorkrespouvents. J. P. C.—Much depends on the character of the lens, as to whether it is suitable for enlarging or not. Of course it is desirable to have a very flat field, and the flatter the field, the more perfect the marginal definition. We cannot tell you what you will be able to do with the lens you have ; experiment only will inform you on that point. Remember you may be very easily deceived as to the exact amount of marginal definition you actually obtain, from the fact that it is very probable that the original nega tive often falls off a little to the edges ; and that although it may be so slightly as not to excite attention in the original, it will be very palpable in the enlargement. The lens of 4} inches focus, to which we referred in the article in the Almanac, has a very flat field. Perhaps you may gain something by using the front lens only of your combination for enlarging, stopping it well down. 2. The stereo enclosed is in all photographic qualities very satisfactory indeed. 11. B. B. —Whenever we describe a certain quality of collodion as suitable for a given process, we refer the reader to the formula by which it is produced at the same time. We admit that it may be somewhat tantalizing to those who have no facilities for manufacturing collodion, to refer to such samples, but it is the only course we can pursue. We are only familiar with com mercial samples by occasional trial, and cannot speak positively at all times of their qualities, and it would be obviously unfair therefore to dogmatize on the subject, or even recommend any especial maker. That which you refer to as having proved slow, is the one to which we refer as proving slow in our hands. We can only offer suggestions as to those you enumerate, as we have not tried several of them for dry plates ; we should give the preference, however, to some one of the first four; perhaps No. 1 will be as likely as any to answer the purpose. Photos is desired by a correspondent to send us the address of the house at which the orange glass, noticed in our last, as suitable for the dark room, was obtained. 8. J.—You do not state whether you are referring to negatives or glass posi tives. We presume the latter. The surface reduction to which you refer is really a certain amount of fog, and is not uncommon with certain con ditions of chemicals, especially in hot weather. The use of a weaker iron solution, with more acetic acid, is one method of getting rid of it. The addition of a little tincture of iodine to the collodion will sometimes Saving the Silver.— We have reason to believe that the operation of saving the silver from washing waters, clippings of prints, &c., is much less practised than it might be. It should be remembered, that not more than about ten per cent, of the silver used goes to form the completed picture, and that thus ninety per cent, is wasted, unless precautions be made for its recovery. Mr. S. Fry showed us an ingot the other day weighing upwards of fifteen ounces, for which he received five shillings and two pence an ounce, the produce of wash ing waters and clippings during two or three months. This did not include developing or fixing solutions. The result is, surely, worth a little trouble. Besides the individual gain, it is a saving, in the gross, io the commercial world, as in the case of waste, so much silver goes, practically, out of existence, and is lost to the world. South London Photographic Society.—The first out-door meeting of the season will take place on Saturday next, at Hampstead ; Jack Straw’s Castle being the trysting-place ; the hour from one to half-past. We hope the weather will be favourable, when a large attendance may be anticipated. REQUIESCAT in Pace !—The City of Glasgow Photographic Society, which for upwards of twelve months has been in a languishing condition, is now, we understand, entirely defunct. Francis Bedford has arrived in England from his Eastern tour, with a large number of very fine negatives. Marine Glue.—This cement is stated to be made according to the following recipe :—Take one pound of india-rubber, cut into small pieces, and dissolve it in about four gallons of coal- tar naptha ; the mixture being well stirred for some time till perfect solution has taken place. After ten or twelve days, when the liquid has acquired the consistence of cream, two parts by weight of shellac are added to one of the liquid. This mixture is put into an iron vessel, having a discharge pipe at the bottom, and heat applied, the whole being kept well stirred. The liquid which flows out of the pipe is spread upon slabs and preserved in the form of plates. When required for use, it is heated in an iron pot to about 248 Fah., and applied hot with a brush. The Electric Light.—The great advantages of printing by means of this light in winter, have been rendered unavailing to photographers by reason of its costly character. We hope, shortly, to be able to lay before our readers some information regarding a method of forming a cheap and powerful battery, invented by Mr. Fitzgerald, editor of The Electrician. Advertisements and Communications for the Publishe Pe2 current number, to be addressed to the Office, « P°3 noster Row, not later than 3 o’clock every ThursdPrps,' Office Orders arc to be made payable to Mr. Thoma 3 the Money-Order Office, St. Martin's-le-Grand. remove it. If these fail, it is probable that the bath is at fault, renis‘ neutral with oxide of silver or carbonate of soda, then sun it, and aT wards acidify properly again. The use of new collodion is often a awe ■ a similar trouble. Nero.—Pure chloride of silver contains a fraction more than three-W® of its weight (when dry) of pure silver. It will be therefore just t fourths of the value of pure silver, less the cost of reducing it im0 E metallic state, which would be but a trifle. We cannot tell you whutr you would obtain for it of the refiners. We believe they hesitate "on chase it untried, as it might contain insoluble foreign matter. T prefer to reduce it for a small charge, and hand over to the coso", either the sliver obtained, or its value as ascertained after reduction, such case you must trust to their honesty in rendering a correct accron, M. II., JI.D.—We are much surprised at the conduct you described,d utterly indefensible, and if not gross neglect, looks like dishonesty. . garding the pictures and the process, you do not lose much hr no: I ceiving the specimen you have paid for. Judging the process bE specimens we certainly should not recommend it. We should unqustL ably recommend the collodio-albumen process in preference, as ease, manipulate, and producing decidedly better results. We are disPo-3 regard the collodio-albumen process as the best and most certain in Ta of any of the dry processes. If, however, the tannin and honey P? further trial as satisfactory as we have hitherto found it, we should g" the preference to any we have tried. .w W. II. B.—If the lenses be fixed, without any lateral motion, they!" placed at a distance of from three inches to three and a quarter. 1 address of Messrs. ITopkin and Williams is New Cavendish Street, CaT dish Square. wr EXPEIINLEXTUNI.—Pure gold leaf is very suitable for converting into clP of gold. Rub it down first in a mortar, to get it into as small bulkasa sible, then pour over it nitric acid 1 part, and hydrochloric acid 2) ED water three parts, sufficient to cover it well, and digest with gentle C If the whole of the gold be not dissolved in an hour or two, add m Ca the aqua regia. When all is dissolved, evaporate to dryness overra bath to get rid of the acid, 2. The grey powder is chloride of silver. 1 be reduced to metallic silver by placing in a crucible with twice its of equal parts of carbonate and nitrate of potash, and submitting for Sei hours to a great heat. You may then either sell the silver or convg into nitrate of silver by digesting it with nitric acid, as described on P* 6 of our fifth volume. G. W. R.—The spots have every appearance of having been caused print having been touched with hypo previous to fixation, or with Iplof of silver just after fixation. Gum is the worst substance you can 6 for mounting. Use good glue, gelatine, or freshly made starch pastea fof A Tanner.—Acetic acid is better than nitric acid in a bath to be u55 dry plates. G. L. Morris.—There are two or three articles on the subject youniber, the numbers published during August and September last. Remzipt, however, that there is no successful method of turning positive good negatives. That is, if they are good positives they will not becont Wit negatives. A little longer exposure, and more complete developmenttico the iron, are always necessary fora good negative than would havesposed for a good positive. With a sharp, well detailed, and slightly overredtbe positive, you may proceed thus: moisten the film with water, •lips pour over it a solution consisting of one grain of iodine and two 8qoo) iodide of potassium in an ounce of water. After this has remaincins 0 few minutes, wash the plate well ; now take a solution of two E-at pyrogallic acid and one grain of citric acid in an ounce of distilleeed to which add a few drops of a 20-grain solution of silver, and 0 intensify and obtain the right density. You will find full informi gw modes of intensifying in the Photographic News Almanac for thsgc W. G.—The films of spoiled collodion positives may be saved withtssb) pings of paper prints, and burnt at some convenient season. I A5e" may then be placed in a crucible with a flux, such as borax, or ni potash, and by means of great heat reduced to metallic silver. F. L. G.—The strength of the fixing solution is varied by different OP v We prefer one ounce of hypo in five of water ; but it may be usedg, weaker or a little stronger. If it be too weak, imperfect fixation.18 J ensue ; if too strong, the tone is too much impoverished. Cyanide d energetic to serve as a fixing agent for paper prints. 2. The silvcp be obtained from old fixing baths of hypo, by precipitating it as a S1 with liver of sulphur. 3. We cannot form any idea of the sizeLcg” should cover from a statement of the diameter of the lens. It is t length which governs the size of the area of definition. :qe r G. U.—If your positive bath contain much nitric acid, it will not Elebox dense negatives ; the image will be thin and grey. The stronger tofo" the more acid it will require, as a general rule, to enable you ( clean. Verdant Green.—Flatted crown glass answers for glass positives p t3 well. It may be used for negatives also, if proper precautions st P to avoid breakage of the negative in the pressure frame. The lg t is, to try all glasses intended to be used for negatives, by screlcoopye down first in the pressure frame. It is better to have a plate ols pohhde glass break, than a negative, and the per centage of breakages "ate -e so large as to make the glass, anything like as costly as patent Pahouldg side of the glass is generally better than the other, and that Scjesb selected for the collodion film. 2. There are a variety of goodery 2 preparations : for new glass alcohol and rotten stone answers nt, pGuf if the glass have been used, and especially with iron develop perfete acid should be used for cleaning. Unless a leather have beeit If J cleansed, it is more likely to dirty the plate than to improve the P skin have been washed in alcohol, it is then valuable for giving ,, polish. yera1c0P R. G. and Alfred Harman.—Received: notice in our next. Se pondents in our next.