The photographic news

• Bandzählung: 35.1891
• Erscheinungsdatum: 1891
• 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-id1780948042-189100009
• PURL: http://digital.slub-dresden.de/id1780948042-18910000
• OAI: oai:de:slub-dresden:db:id-1780948042-18910000
• Sammlungen: LDP: Historische Bestände der Hochschule für Grafik und Buchkunst Leipzig
• Sammlungen: Fotografie
• Strukturtyp: Band

• Digitalisat: SLUB Dresden
• Strukturtyp: Ausgabe

No. 3.—Orange. No. 4.—Purple. Sandarac Mastic in Sulphuric Benzole ( Benzole (pure) ... 1 "..V. °f bMMI- paper. I fragments before joining them together. I yield a print upon which no trace of Brmvi * Read before the Franklin Institute (Chemical Section). tears . ; ether 50 grains 10 ounces 50 grains 10 ounces 60 grains 10 ounces 6 grains 30 grains 10 ounces 45 grains Eikonogen Water Water (distilled) Gelatine ... Primuline Chrome alum Crystallised Water Resorcin ... Water Caustic soda No. 1 develops a red colour. No. 2 produces a yellow. No. 3 produces an orange. No. 4 produces a purple. No. 5 produces a dark brown or black. Betanaphthol Caustic soda Water ... 30 grains 40 „ 10 ounces Naphthylamin Water Oxalic acid 3 grammes 3 >, 50 „ 25 20 ounces 1 ounce 80 grains 2 » Transparencies on glass, and positives on celluloid and opal, can be produced, as shown by the specimens I have here. The composition of the coating is as follows :— transparency, the greater will be the contrast in the finished print, the action of daylight being to decompose the azo derivative, and so prevent reaction with the “ developers,” so-called, to be afterwards applied ; but if we take a piece of the sensitive material that has not been exposed to light, and apply one or more of the developers, or, as a dyer would call it, a “ mordant,” we at once develop the full tint or colour by the action of that particular solution used. This I will now illustrate. Developing.—I have here a piece of porcelain coated with a solution of gelatine and primuline, and sensitised - . . -g-. This process will yield a print upon which no trace of breaking is to be seen. Broken Negatives.—A very useful receipt for repairing broken negatives is given by Wilson’s Photographic Magazine. Place the negative, gelatine side down, on a plate rather larger than the negative. Coat the edges of the fragments with warm Canada balsam; join them together, using strong pressure. Remove the excess of balsam, then cover the negative with another plate exactly of the same size, and previously coated on one side with the following varnish t— Put the gelatine to soak in six ounces of water, dissolve the primuline in twelve ounces of hot distilled water, and when dissolved add the gelatine and the chrome alum- dissolved in the remaining two ounces of water filter through cotton, and flow while warm on the glass or porcelain. When dry, immerse for two minutes in the sensitising solution, wash for five minutes, and allow to dry in the dark. The operation of printing and develop ing is the same as for prints, or cotton, &c. in the same bath as the cotton cloth. I now paint over one-fifth of its surface, consecutively, with each of the following five solutions or developers: — THE DIAZOTYPE PROCESS OF PHOTOGRAPHIC DYEING AND PRINTING* 1 BY JOHN CARBUTT. The subject I have the pleasure to bring before the Sec tion this evening is the “Diazotype Process of Photo graphic Dyeing and Printing,” the discovery of Mr. Arthur G. Green, of London. It is a new method of producing designs in fast colours on cotton, linen, silk, paper, &c., either from hand-drawn designs on a transparent or semi transparent medium, or by use of a photographic trans parency. It was first made public at a meeting of the British Association for the Advancement of Science, held at Leeds last September. It is distinctly a positive process; that is, it yields a positive from a positive. The operations are five in num ber, viz., dyeing, sensitising, printing, developing, and washing, corresponding very closely in number of opera tions required in preparing and printing on paper by the direct silver process of photographic printing. Primuline is the base of the new “ diazotype,” and is already in extensive use for dyeing calico in various tints. Dyeing.—The first operation, then, is to dye our material with “ primuline.” To do this take 100 grains of “ primu- No. 5.—Black. Lift together the three plates, turn them over, remove the large one that has served as a support, scrape off from the gela tine side the balsam that may have exuded, then surround the two plates with strips of gummed paper. Heat slightly the No. 2.— Yellow, carbolic acid It only remains to well rinse this in water, when the colours will be found fixed and permanent. This demon stration will illustrate the possibility of producing the several colours on one and the same picture, as follows: Mix a portion of each developer with a thin starch paste, and, with a camel’s-hair pencil, paint over the parts wanted of a particular colour with the particular solution intended to supply that colour, of course in a weak light, as the image is faintly visible after exposure under the transparency. The composition of the five developers just used is as follows—and it is only right to say here that I am indebted for the formute of these solutions to two photographic journals, The British Journal of Photography, and Anthony's Photographic Bulletin:— DEVELOPERS. No. l.—Red. line,” add to it 20 ounces of distilled water brought to a boil in a flask over a Bunsen burner; when dissolved, pour into a porcelain dish, and immerse the fabric, cotton cloth (the cotton must be free from dressing), or silk, and as soon as the pieces seem thoroughly impregnated with the dye, remove and rinse in plain water, and squeeze as dry as possible, or place between sheets of blotting- paper. The fabric so prepared has a primrose hue, and so far is insensitive to light. Sensitising.—The second operation, or sensitising, is accomplished by immersing the dyed fabric in a solution formed of sodium nitrate, 60 grains; cold water, 32 ounces; oxalic acid, 100 grains, previously dissolved in two ounces of water. Each piece is immersed separately and soaked for two or three minutes; it is then rinsed in water and dried. The colour of the fabric should be of a reddish-yellow hue, and is sensitive to light. The operation should be performed in a weak light, and the pieces dried in the dark. Printing.—Place in a printing frame a glass trans parency, and place over it a diazotised fabric in contact, and expose to daylight ten to twenty minutes, or sunlight four to seven minutes. The greater the contrast in the