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

1862. I and ontribt- I y of the I iductions I aifs and I inburgh, I hich tbe | n under I series is I ild have I $ of pho I intaglio, I some of 1 ce; some I md some I ties, bul I lastyear I descrip- I Some of I ies, leave I tographs I We may I i, whilst I ssing a” I lesirable I ing, that I pecimeD, I Pretsch, I X” The I fond the I tance i* I s are at I oroduced I method 5 I cess has I ms at or I .‘produce I nything I by col plication 1 oductioa I y copies I Vases, | painted value in ailiar to f Edis fore dis, lotion of ly Booh' mnything the hi 5 * . d which I xhibite I of some I side b I ives, and I iterest different mmpleted > process y which or three to stone nk, thus » moil' 1 - 1 but any readily gelatin® I printers I JUNE 6, 1862.] THE PHOTOGRAPHIC NEWS 269 while ion, and the plate stuck * Continued from page 25’ concerned, are equally good : though I must add, I think it to be regretted, that at least a portion of them are not made a little better than they are, as regards workmanship. Their solidity is sacrificed to cheapness, and most of them soon go to pieces if they are much used, while, if they were properly made, they would bear very rough handling for a long period without getting out of order. Many, I think most, photographers would prefer to spend an extra shilling or so for a more substantial article, if they had the option. The special requirements for a holder to be used for developing the picture upon vary considerably from those for coating with collodion. The operator must be able to hold the plate firmly in any position, horizontal or vertical, and, at the same time, it is absolutely necessary that he should be able to look through the plate, and examine every part of the picture by transmitted light. The ordinary pneumatic holder evidently does not admit of this, as its bulk obstructs the view through the part to which it is made to adhere ; which being, for the sake of safety, generally about the middle of the glass, contains frequently the most important points of the picture. This is of less consequence if the plates are stereoscopic, as a portion of each, or, by placing the holder a little out of the centre, one whole pic ture can be seen; also, if the plates arc of considerable Ramage also contributes some of his very fine copies of engraving by photolithography. His image is also, we understand, produced from the negative direct on the stone. Mr. Pouncey exhibits some specimens of his carbon print ing, which will not enhance its reputation. In fact we sec nothing in carbon printing by means of light, in our own gallery, which will at all compare with the specimens in the French department. PLATEMOLDEES are required for holding the glasses the collodion is being poured on to them, and during the REMARKS UPON SOME OF THE APPARATUS EMPLOYED IN PHOTOGRAPHY.* BY F. B. WINDOW. Plate Holders, Developing Stands, &c. Mr. Field exhibits some very excellent specimens of photo lithography, but they are unfortunately hung so high as to render critical examination impossible. In this case the image, it is stated, is impressed on the stone by photography, and not by means of a transfer as in Col. James’s process. From the preface we learn that Mr. Field’s process is based on the special action of light on a surface of bitumen of Judea covering the stone, which was one of the first photo graphic processes which received attention from early inves tigators. Mr Contencin exhibits some photo-lithographs, regarding which we have no particulars, except that the image is impressed on the stone, and not transferred. Mr. In the early days of collodion, a piece of heated gutta Percha ’ or india rubber, was mostly used to hold the glasses w 116 they were coated with collodion, and the plate stuck on, or ell oft, as the case might be ; the chances were about SNua . 1' or a long time past the pneumatic holder has been almost exclusively employed for this purpose, for which it is 4dma 2 y adapted. There are several modifications of it in • ® • all °f which, as far as efficiency in principle is process of development. For the first-named use, or coating the plate, many photo graphers, especially professional men, prefer using the hand alone, the plate being held by a corner between the fore finger and the thumb of one hand, while the collodion is poured on with the other, the small portion which is in con tact with the hand being left bare. Although it is desirable that the photographer should be familiar with, and prac tised in this way of coating a plate with collodion, so that fie may not be awkwardly inconvenienced if the usual appliances be not at hand, still I do not think that, as a rule, the bare hand is the proper or best thing to use for this purpose. There arc other reasons against it, besides the chance of absolutely dirty fingers. A very large proportion of photographs are taken in summer, during the hot months of the year, when the hands are liable to be moist; and, besides this, at all seasons, the fingers have a certain amount of natural greasiness, which, when they are laid on highly- polished surfaces, leaves a mark. I think these considerations are sufficient to advise the use of a plateholder when it is Possible, in order to avoid the chance of soiling and staining the glass. Many of the specimens executed in printing ink by the aid of photography, leave, however, little to be desired. This, in an economic point, is one of the most important and interesting applications of the art. Here the images are depicted in carbon, one of the forms of matter least change able under the influence of moisture, light, or atmosphere, in fine particles, which are enveloped in a resinous coating, manifestly one of the least alterable conditions of this per manent substance. If photography had done nothing more I than produce and perfect such processes as the known pro cesses of photolithography and protozincogra] have been entitled to higher consideration from dimensions, the examination of one proportionately small part in the middle may be of diminished importance, but, unfortunately, as the size and weight of the plates increase the security of the pneumatic holder to sustain them during development is less to be depended on ; and as nothing can be more annoying than to lose a picture by breakage at this late stage, it is well not to trust large plates too confidently on the pneumatic holders for so long a time, and to such active movement, as the proper development generally demands. The prepared plate being wet during the process of deve lopment, and constantly covered with fluid, the clean hand will not have any deleterious effect upon it, and as it is found to be the most efficient holder without any additional apparatus, it is the most generally adopted, the plate being held, as for pouring on the collodion, by a corner between the fore finger and the thumb. It may safely be said, that of all the appliances suggested up to the present time, for the purpose of developing collodion plates the bare hand is the very best, and the “ tripod developing stand ” is the very worst. The tripod developing, or levelling stand, is a useful and serviceable apparatus for developing albumen or collodion plates with gallic acid, or for any operation which requires time for its fulfilment, and does not need constant attention or movement. But the case is very different with collodion plates developed with pyrogallic acid or iron solution, in which the changing effects must be noted from moment to moment, and the reaction stopped exactly when the best results are obtained, which requires to be kept in continual movement, and never to be left an instant alone. Here the developing stand is evidently unsuited to the work, and to supply its deficiencies the operator has constantly to lift up the plate in his fingers, both to keep the liquid in movement and to examine the progress of the development, and then to put it on tbe stand again, until he thinks he had better look again. It is needless to remark, that he would be able to observe much more minutely if he never laid the glass down at all on the stand, and the constant and repeated handling of the plate is more likely to injure it, and more certain to stain the fingers, than if it were grasped once for all in one place, and not set down till the operation was over. Although clean fingers have no injurious effect upon a plate when it is being developed, the said plate, unfortu nately, does not reciprocate the compliment, for it has a very marked and unpleasant effect upon clean fingers. This is doubly inconvenient, for it necessitates abundant use of cyanide of potassium to remove the stains, and this poisonous substance is never applied to the skin without some being absorbed, which has a deleterious effect on the protozincography, it would . deration from Her Majesty’s Commissioners than it has received in this Exhibition.