The photographic news

• Bandzählung: 11.1867
• Erscheinungsdatum: 1867
• 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-id1780948042-186700008
• PURL: http://digital.slub-dresden.de/id1780948042-18670000
• OAI: oai:de:slub-dresden:db:id-1780948042-18670000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

THE PHOTOGRAPHIC NEWS. Vol. XL No. 452.—May 3,1867. CONTENTS. riot Commercial Dry Plates 205 Cabinet Portraiture 206 The Bight to Publish Private Portraits 208 Echoes of the Month. By an Old Photographer 208 Reason Why. By the Photographer's Assistant 210 On the Most Simple and Beady Method of Binding the Exact Bocal Distance of a Lens. By Dr. D. V. Monckhoven 211 Foreign Miscellanea 212 On Subiodide of Silver. By Dr. w. Reissig 212 The Angular Measurement of a Picture. By II. It. Twining ... 213 PAGm Magnesium Ribbon : A New Sensation. By Diogenes 213 The Invisible made Visible 214 Proceedings of Societies—Amateur Photographic Association... 214 Correspondence—French and English Portraiture : Cabinet Portraits—French and English Portraiture—Publishers and Others 214 Talk in the Studio 215 To Correspondents 216 Photographs Begistered 216 COMMERCIAL DRY PLATES. The commercial supply of prepared dry plates has frequently been attempted ; but from a variety of causes, arising out of the uncertainty of some processes and the imperfect keep ing qualities possessed by others, it lias rarely been successful. With one exception, we believe, until recently, all the attempts to establish such a business have been failures. This circumstance has often been very naturally regretted ; for although few photographers would be content to limit their photographic experiences to the exposure and develop ment of the plate, yet there are few to whom the facility of obtaining plates prepared at a brief notice would not be a great boon. During the earlier stages of the amateur’s enthusiasm every difficulty has its charm, and the prepara- j tion and comparative trial of plates by various processes has, to many, a fascination not easily to be given up. We have known many gentlemen who, after an anxious or hard day’s business, would sit up till long after midnight, some times in an improvised dark room, sometimes in a back kitchen, preparing dry plates for a few days’ photographic ramble in the country. But there comes a time with many amateurs when, with all the love for securing charming bits ef rural scenery, when the time for preparation can be ill- spared, or when the drudgery of preparing a few dozen dry plates is weariness, and the possibility of securing a batch of plates ready for exposure is chance ardently desired. The professional portraitist, too, unused to the preparation of dry plates, may not unfrequently desire, for business or pleasure, to ramble without the impedimenta of the wet pro cess ; and he frequently desires to meet with prepared plates upon which he can rely with some degree of certainty for good results. In short, good, sensitive, and trustworthy dry plates, to be procured ready for use, which will keep a reason able time, and may be purchased at a reasonable price, are decidedly amongst the things which will at all times be hailed with satisfaction by photographers. We have recently been trying the dry plates prepared by the “ Liverpool Dry Plate and Photographic Printing Com pany.” A few weeks ago we received a case of plates from the Company, with a request that we would try them and report upon them candidly. It so happened that, owing to the long prevalence of bad weather after receiving the plates, and the presence of other imperative editorial duties during the few transient gleams of bright weather which inter vened, we were unable to expose any of the plates until up wards of a fortnight after wo received them; and as they must have been prepared some days previous to that, we had at the outset a moderately good opportunity of testing their keeping qualities. We have now exposed and developed several of them under varying conditions ; but all, as it hap pened, in a dull light, the bright morning we had set aside lor testing them clouding over before the first plate was exposed. We are, however, highly delighted with the plates, which have in our hands proved excellent in every respect. The instructions accompanying the plates recommend an exposure of three times as long as a wet collodion plate would require. We exposed the first plate with a pair of stereoscopic lenses, using an aperture with which we should have given a wet plate about fifteen seconds’ exposure. With the dry plate we gave one half thirty seconds, and the other half sixty seconds. Proceeding to develop accord ing to the instructions accompanying the plates, we found the plate which had received an exposure of sixty seconds over-done ; that which had received thirty seconds, although exhibiting a trace of under-exposure, was the most satisfac tory negative; and although we have a strong objection to under-exposure, we preferred, in this instance, the half with the least exposure. Before describing further experiments, it may be as well to explain the mode of developing these plates, which differs, in some material particulars, from the ordinary treatment of sensitive dry collodions. Although we are informed, in confidence, of the process by which the plates are prepared, it is not published. Their productions being a commercial undertaking, the Company keep their own counsel as to their mode of working. We think it is probable that they are right. Sinking altogether the consideration of the commercial value of secrets, it is not improbable that many photographers will produce better results by taking the plates and faithfully carrying out the instructions as to their treatment, in entire ignorance of the exact processes by which they are produced, than if they proceeded to work with the foregone conclusion in their minds which prevails among so many photographers in regard to many processes. If told they were collodio- albumen, one experimentalist would feel certain they would blister ; if another were told they were prepared with malt, he would be satisfied that they would fog ; if a third were informed they were prepared with gelatine, he would despair of being able to give them sufficient exposure; let it be stated that they are by the Gordon or England process, and some would lose all faith in their keeping qualities; describe them as tannin plates, and many more would be convinced that they possessed all these evils, besides some special ones of their own. As the process is not published, the trials they will receive will not be embarrassed by fore gone conclusions, and the plates will be estimated by their own merits, which will, we think, if all the plates sent out be as good as these we have tried, form a firm basis for popu larity. The developing instructions, as stated by the Com pany, arc as follows :— If the plate be coloured on the back,* take a piece of rag or sponge (rag is preferable) which has been well wet and wrung out, * The plates, if desired, are sent out coloured at the back, to prevent fogging by reflection, when the lens is pointed directly towards a strongly lighted window, or to the sky, with imperfectly lighted foreground objects