The photographic news

• Bandzählung: 13.1869
• Erscheinungsdatum: 1869
• 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-id1780948042-186900000
• PURL: http://digital.slub-dresden.de/id1780948042-18690000
• OAI: oai:de:slub-dresden:db:id-1780948042-18690000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Bemerkung: Heft 545 (S. 73-84), Heft 547 (S. 97-108), Heft 589 (S. 599-610) fehlen in der Vorlage. Paginierfehler: Auf Seite 444 folgt Seite 443
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

June 4, 1869.] THE PHOTOGRAPHIC NEWS. 269 nature of the contents, or, rather, as to its actual relative value, in so far as the novelty of the manipulations described is concerned. Dr. Vogel, in the MUthciluiujcn, affords the following information in regard to M. Ost’s work :— The pamphlet of M. A. Ost, containing information relative to the production and.employment of transfer paper, collodion paper, the multiplication of negatives, &c., is in our hands, and we are in a position, therefore, to report upon his methods. The basis of bis processes is the collodio- chloride, the preparation of which is described ; the details we do not feel ourselves justified to communicate, but the compound is itself purchasable in a condition fit for use. The collodio-chloride film is, by means of transfer paper, brought upon a sheet of paper previously coated with a gelatine solution prepared in the proportion of 1 to 13. The collodio-chloride is applied to a surface in the same manner as ordinary collodion, with the exception that two coatings are given, the second being poured on as soon as the first has dried upon the paper, and in an opposite direc tion to that of the first application, in order to secure a stout film of equal thickness ; the prepared paper may be kept for months. In producing positive pictures the collodio-chloride paper is printed under a negative, washed, toned in a sulphocyanide of gold bath (as with the Obernettor paper), and fixed. These are operations with which the majority of photo graphers are acquainted; it is not, however, the same with the method of transferring which M. Ost thus describes :— Tub Transfer. After the final washing, the prints, owing to the stoutness of the film, display a tendency to roll up, a feature decidedly unfavourable to the operation of transferring. This difficulty is easily overcome by drawing the prints, one by one, rapidly through warm water; they at once become flat, and remain so if subsequently placed in a dish of cold water, and the whole operation of thus treating several hundred prints necessitates a period of but a few minutes. To transfer the image to glass or paper, the photograph is placed face downwards upon a sheet of so-called glass paper* and immersed for half a minute in lukewarm water; by these means the collodion film, carrying with it the image, becomes separated with the greatest case from its original support. The glass-paper bearing the collodion film is placed upon a largo glass plate, and any gelatine still attaching to the film removed by means of a flat camel- hair brush and warm water; this operation is finished in a couple of seconds, and the film is then ready for final trans fer. For this purpose cardboard coated with shellac is most appropriate, as the finished print thus acquires a more bril liant appearance; a sheet of this material is placed upon a piece of clean blotting-paper, and a teaspoonful of a thin boiled solution of gelatine t poured over it. The film and its support arc then placed, face downwards, upon the sur face of gelatine, a broad camel-hair brush is drawn back wardsand forwards upon the back of the glass-paper to press out the superfluous gelatine, and the paper afterwards care fully lifted off by means of one of its corners. The collodion picture now rests upon the cardboard, and the slight creases still remaining in the film disappear upon its becoming, per fectly dry. To effect this, the pictures are laid upon large sheets of paper previously impregnated with a hot composi tion made by mixing together equal proportions of lard and wax, so that no fear need be entertained of superfluous gelatine causing the margins of the cardboard to adhere to the surface on which they are placed. Greased sheets pre pared in this manner maybe preserved for any length of time. The transfer of photographs to glass is proceeded with in * This glass-paper is simply paper coated witli a film of good copa var- nish, which imparts a glassy transparency to the surface. t Tlie proportions of the gelatine solution are Fine gelatine 1 ounce Water 125 ounces. like manner, excepting that a glass surface is employed, and vigorously printed proofs selected for the purpose. Care must bo exercised, during the operation of transfer, to pre vent the formation of air-bubbles between the collodion film and its support; after a little practice sufficient skill will be acquired to overcome any difficulties of this kind which may be experienced, either in the application of the film, or its subsequent treatment with the camel-hair brush. It should be mentioned that, during the tranfer, a supply of warm water must be always ready at hand, an arrange ment of the following kind being very desirable : —On the work-table is placed an iron tripod, about three inches in height, on which stands an enamel-lined saucepan; the latter has a diameter of nine or ten inches, and is about three inches deep. It is filled half full of water, which is kept warm by means of a spirit-lamp, and is used for the purposes of removing and cleaning the film from gelatine, of moisten ing and warming the brush, and likewise of heating the gelatine. TRAXSFERnING upon Oval and Round Porcelain Plates. The transfer of pictures to porcelain differs from the former manipulations in the description of the cementing material used, which, in this instance, is not gelatine, but copal varnish. To effect a transfer upon porcelain or enamel, the picture must, in the first instance, be cut down until it is about a quarter of an inch larger on every side than the plate ; it is then laid, as previously described, face downwards upon glass-paper, and freed from gelatine and paper by means of warm water. The edges and surface of tire porcelain plate are then coated with a light copal varnish, much diluted with chloroform, in the proportion of 1 part of copal varnish to 5 or C parts of chloroform. The varnish thus prepared must be preserved in a well-corked bottle, small quantities only being withdrawn at a time, as the chloroform is a very volatile liquid. The varnish is applied very spaiingly, by means of a half- filled brush, in rapid and regular strokes, and the plate then placed in a convenient position at the edge of the work table ; the photographic film, resting upon the glass-paper, is clapped downwards upon the plate, and its edges pressed round the margins of the porcelain, attention being paid to the prevention and remedying of creases forming in the film. Any imperfections of this kind may also be subsequently removed by rubbing over with a tuft of fine cotton wool. It is not to bo denied that the production of medallions by means of transferring with copal varnish requires the possession of a certain amount of skill, and, at the commence ment of operations, therefore, mishaps may not unfrequently occur ; at the same time, when the difficulties are once over come, the work may be conducted with rapidity, and with out drawbacks. I have been able to transfer as many as forty medallions in the space of an hour, without experi encing one single failure. On the spoilt plates the collodion film will be found to adhere very firmly to the porcelain, and extremely difficult to remove; they are best cleaned by immersion for a night in caustic potash. Only upon such articles around the edges of which the collodion film can be thrown are trans fers possible, as otherwise the varnish has a tendency to draw up the film, and to render it shrivelled and full of creases. Vases, cups, goblets, glasses, bottles, &c., which are in frequent use ami often cleansed with water, must not be treated with gelatine, as the same is easily soluble in water; for articles of this description an insoluble transfer is most simply produced by employing albumen (white of egg) as a cementing material. The white of egg is beaten IIP into a froth, and allowed to subside; the fluid portion of the same is then separated and used in the same way as the gelatine, and upon this the collodion film will be found to adhere very firmly. Finally, the objects bearing the photographs arc heated to a temperature of 70°R (about 190° Fah.),