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326 THE PHOTOGRAPHIC NEWS. [May 25, 1883.5 Transfer and re-transfer papers, for additions and re transfers. Thin proof paper, for taking the first-proof impressions. Plate paper, for fine printing, and making a damping book. Printing papers, thick and thin, of various kinds, accord ing to the nature and size of the work. Lithographic writing ink, pens, brushes, erasers, drawing materials, and instruments, will be required for corrections. Printing ink, black or coloured as required (see below). Re-transfer ink, for inkiug-in photo-transfer prints, and making transfers from plate or stone. Ordinary printing ink for letter-press, which contains soap, is sometimes suit able for this purpose. Lithographic varnish, thick, middle, and thin, for prepar ing or thinning printing-ink (see below). Gum-aralic, for “ gumming,” i.e., preparing the stone for printing (see below). Glycerine is a useful addition to the damping water in hot weather. Nutgalls and phosphoric acids, added to the etching solu tion for zinc printing. Turpentine, for washing off transfer ink, thinning trans fer ink ; cleaning rollers, inking slabs, &c., &c. Muriatic and sulphuric acids, for cleaning zinc plates. Nitric acid, for etching, preparing zinc plates for correc tion, &c. Olive oil is useful sometimes for thinning ink, and work ing up a weak subject. It may also be mixed with the turpentine for washing off transfer ink. Lubricating oil, for oiling presses, &o. Tallow and blacklead, for preparing tympan leathers. The only items that require particular notice are the press, rollers, printing ink, gum, and papers. Press.—The form of press generally used in England is shown in the figure, and consists of the following parts:— A, A, A. Side framings held together by B, B. Cross-frames, and C. The cross-head, through which passes D. The pressure screw, attached to B. The scraper box. F. The tympan frame, hinged to G. The bed, or carriage, which supports the stone, and runs in grooves on the side framings. In some forms of press the bed runs upon H. Friction rollers. I. The cylinder spindle, to which is attached J. The handle, of which there are two in large presses. K. The lever and handle attached to a shaft, carrying at each end an eccentric or cam, by which the cylinder is raised, and the bed pressed closely up against the scraper, the amount of pressure being regulated by the pressure screw, I. The Tympan, or outer covering of the press bed and stone, serves to protect the paper from the direct action of the scraper, and is usually made of fine calf skin leather, pre pared and rolled specially for this purpose, so as to be soft, and of fairly uniform thickness. Thin sheets of zinc (or, better, brass) are also used for this purpose. Leather tympans are prepared by rubbing them over on the side where the scraper comes with a little gum water, then dusting over blacklead, and when dry rubbing tallow or lard well in till the coating is thoroughly smooth. Metal tympans need only be oiled from time to time, and when using them the scraper should be covered with a piece of leather stretched on to it from end to end. New leather tympans must be passed a few times through the press, over a full-sized stone, and the slack caused by stretching, tightened up each time with the screws at the end of the tympan frame, till it works through without any further stretching. [To be continued.'} ON TRANSPARENCIES BY THE CARBON PROCESS. BY EDWARD BRIGHTMAN.* The production of lantern slides and other transparencies b y the carbon process is one of the most interesting and, at the same time, the most neglected branches of photography. This neglect certainly does not arise from any defects or want of excellence in the results obtainable by this process, for good transparencies in carbon are certainly superior to those produced by any other process, with the single exception of those on albumen. The fine transparencies by Ferrier on albumen are certainly un surpassed, but the difficulties and complications, together with the extreme care necessary in working the albumen process, are such as to prevent it ever obtaining general popularity : on the other hand, the carbon process by single transfer is so exceedingly • Head before the Bristol and West of England Amateur Photographic Association.