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Trade Wrinkles.

A Good Dryer for news and poster ink may be made by mixing one quart of spirits of turpentine with six ounces balsam copaiba. Add a sufficent quantity to the ink to thin it to a proper consistency for working.

Moisture-proof Glue.—Dissolve sixteen ounces of glue in three pints of skim-milk, and if desired still stronger, add powdered lime.—For marine glue, heat moderately a mixture by weight of one part india-rubber, two parts mineral naphtha or tar, and add twenty parts of lac in powder. Heat to a temperature of 120° to use.

To Attach Labels to Metal.—If you wish to paste small labels on iron, tin, &c., rub onion-juice over the place of contact. The onion-juice has the peculiar quality of adhering in the most unremovable manner to any metal on which it has been rubbed, and thus when a label, show-card, hanger, &c., is pasted on to iron, zinc, tin, or any other metal surface with common paste, gum arabic, or glue, it cannot be taken off nor removed except by scraping, which of course destroys the entire label or card. Lithographers may discover in this merit of the onion-juice process a substitute for direct printing on tin, which might often be used with advantage.

To Transfer Prints to Glass.—The following recipe, says the National Druggist, is sold by itinerants at from three to five dollars: First coat the glass with damar varnish, or Canada balsam dissolved in an equal volume of turpentine, and let it dry till it is very sticky, which takes half-a-day or more. The printed paper to be transferred should be well soaked in soft water and carefully laid upon the prepared glass, after removing the surplus water with blotting-paper, and pressed upon it so that no air-bubbles or drops of water are seen underneath. This should dry a whole day before it is touched; then with wetted fingers begin to rub off the paper at the back. If this be skilfully done, almost the whole of the paper can be removed, leaving simply the ink upon the varnish. When the paper has been removed, another coat of varnish will serve to make the whole more transparent.

How to Clean Rubber Blankets.— From a business circular of R. Hoe & Co., New York, we extract the following:—The use of turpentine, in removing grease and color from rubber blankets, is increasing to such an extent that we desire to make a few suggestions as to its use and effect. The quantity used should be as small as possible, and great care taken that it is thoroughly dried out before the blanket is used in printing. Otherwise, as turpentine softens the rubber face, the blanket will be injured by the pressure of the cylinder causing wrinkles to appear on the face. It is preferable to clean the blanket after work at night, thereby giving ample time for the turpentine to dry out, rather than in the daytime when the press is in use. We strongly recommend the use of ammonia as a substitute for turpentine, and with less chance of damage to the blanket. The ammonia should be diluted to about six to nine degrees strength, (18-degree can be easily obtained and diluted with one or two parts water) and after using it the blanket should be dusted with powdered chalk or magnesia. Ammonia will dry out very quickly (in much less time than turpentine), and when dried out leaves the blanket perfect and ready for use.

Reproduction of Lithographic Designs.—Mr L. Bertling, of Penge, has patented an improved process, and improved compositions and paper, with the object of providing means whereby impressions may be taken in transfer-ink from a lithographic stone and so treated that at a subsequent period they may be reproduced upon, or transferred to, a lithographic stone from which copies can then be obtained in the usual manner, thus avoiding the necessity either for keeping a design or other work upon a stone for future use. The paper transfers are specially prepared, and to reproduce the design upon a lithographic stone there is fitted a perfectly clean and polished lithographic stone in the press, and warmed by applying boiling water. The paper transfer is placed on the damp stone, and pulled through the press as soon as possible. The paper is then damped with hot water and repeatedly pulled through the press until it can be easily removed from the stone. The stone must be allowed to dry without washing off the composition which has been transferred thereto from the paper, as this answers the purpose of preparing the stone. If the transfer is not a very old one, the stone is ready for « rubbing up; » should it be an old one, it is desirable to expose the stone for a short time to a gentle heat before a fire after the design has been transferred thereto, or the heating may be effected by passing the flame of a spirit lamp over the stone several times. The stone is then ready for use. Ordinary lithographic transfer ink may be used, but ink containing the following ingredients is preferred:—Mutton suet, 4oz; yellow beeswax, 3oz; white curd soap, 3oz; shellac, 6oz; vegetable black, 20oz; middle litho varnish, 3lb; sperm oil, 4oz; spermaceti, 3oz.

Transfers for Zinc-Etching.— A new method of preparing transfers for the zinc-etching process has lately been introduced by Jaffé and Albert of Vienna. With the usual method of making transfers in greasy ink, it happens sometimes, in transferring the developed greasy image to the zinc plate, that the lines or dots of the image will be crushed and become broader. To prevent this, Jaffé and Albert have modified the process in the following manner: The image on the bichromated paper is developed in the usual manner with greasy ink, but, after the paper has been dried, it is dusted with a powder, consisting of a mixture of asphaltum, colophony, and wax, then the whites of the paper are freed from any adhering powder with the aid of a pad of cotton, and an alum solution is applied, in order to tan the gelatine on the paper, so that it may become hard, and not give way afterward in the transferring process. The transfer is now warmed to a certain degree, and transferred to the zinc plate. It is not necessary to coat the print with greasy ink, and this is important. In this case we have a resin image on the metal plate, which offers sufficient resistance, so that we may commence with a strong first etching, by which the finest dots and lines of the image will all be preserved.

Engraving with Mercury and its Salts.— The following processes, described in the Memorial Industriel, appear to be of practical value:—It is known that, when mercury is deposited on a metal, fatty lithographic ink will not « take » upon it when an inking roller is passed over it, and that the black adheres to the untouched parts of the metal. If a well-polished and clean piece of zinc be taken and a design be traced thereon with mercury, the design will appear in brilliant white upon the grey background of the zinc. After tracing the design, an intaglio plate can be obtained by plunging the plate, without being coated with varnish, into a bath containing 100 parts of water and 2 parts at least, of nitric acid. The action of the acid is very rapid, and for a long time only attacks the parts touched by the mercury. When deep enough it can be used for lithographic work. If, instead of nitric, hydrochloric acid is used, the contrary effect takes place. The unaffected zinc is strongly attacked, and the traces of the mercury give a relief plate which can be used for ordinary typographical work. If the operator does not wish to draw upon zinc, the design can be traced upon paper with a salt of mercury. The sheet of paper being then applied for two hours to a plate of zinc, the drawing is sharply reproduced, in white lines of amalgam, on the grey surface of the metal, just as if it had been traced directly. The same result is obtained if the design is traced upon paper with a sticky substance (ink containing gum or sugar), and if it is dusted over a mercury salt in fine powder. On dusting off the surplus and applying the sheet containing the design to a plate of metal, the same result is obtained. The same result is obtained if a newly-printed proof is used, and is dusted with mercury salt while the ink is still wet and sticky. All the lines thus reproduced are chemically engraved, as has been described above. The same results are obtained by dusting with mercury salts a photographic carbon print containing a gummy substance, and the effect of half-tints is even secured. Biniodide of mercury is the salt to use.