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THE PTIOTOGRAPTITC NEWS. Voi. XXIX. No. 1391.—May 1, 1885. CONTENTS. PAGE Gelatine Plates for Making Film Negatives by Stripping 273 Photo-Engraving for the Decoration of Pottery 273 The Carbonates in the Alkaline Developer 274 Captain Abney’s Second Cantor Lecture 274 Thumb-Nail Notes 275 Artistic Feeling in Photography. By A. if. Wall 276 A Simple Method of Colouring and Enamelling Photographs. By T. G. Whaite 277 The Combination of Photography with Tricycling. By Francis Cobb 279 Printing-in Clouds in Landscapes. By E. Brightman 279 Notes 280 PAGE French Correspondence 282 Patent Intelligence 282 On a Few Dark Booms 283 An Attempt to Photograph the Corona 281 A Booking Apparatus for Use in Developing Dry Plates. By Dr. J. M. Eder 285 The Influence of Photography on Popular Taste and the Graphic Arts. By J. S. Pollitt 285 Correspondence 286 Proceedings of Societies 286 Talk in the Studio 288 Answers to Correspondents 288 GELATINE PLATES FOR MAKING FILM NEGA TIVES BY STRIPPING. To make gelatine plates from which the film can be readily stripped is quite an easy matter, but in this country the demand for reversed negatives is perhaps hardly sufficient to induce manufacturers of plates to introduce such plates into commerce. Not merely once have we described how to prepare plates from which the film can be stripped, but in order that our readers may have the full advantage of the new details given by M. Otto in the Bulhtin Beige, we now give a tolerably full abstract of his method of working. The plates are first cleaned by being well rubbed with a solution of caustic potash, after which they are thoroughly rinsed and polished with tripoli. The next proceeding is to wax them by rubbing one face over with a solution of twelve grains of bee’s wax on one ounce of ether, this being applied by means of a piece of cotton or linen cloth saturated with the solution. In polishing off the excess of waxing solution, care must be taken not to destroy the continuity of the extremely thin and almost invisible film of Wax which it is necessary to leave on the glass in order to ensure the easy and complete separation of the film. Some persons prefer to wax the plates by warming them to a temperature somewhat over the melting point of wax, then rubbing one face over with a lump of the article; the excess being now polished off with a piece of flannel before the temperature of the glass falls below the melting point of the wax. It may be mentioned that before waxing, it is as well to mark the working surface of each plate by making a diamond scratch in one corner. A small piece of cloth moistened with ether or benzole is now used to remove all traces of wax from the edges of the plates—a margin having a width of an inch being suffi cient ; and it is well to paint this margin with albumen and allow it to dry. If the edges of the plate were not denuded of all traces of wax, there would be a great pro bability of the film separating from the glasses attoo early a stage, and adhesion at the edges is made more certain by the use of albumen. A moderately dilute solution of silicate of soda may be used instead of albumen. The waxed side of each glass is now coated with collodion containing a little castor oil ; eight grains of tough pyroxy- line and three drops of castor oil to each ounce of mixed solvents (equal volume of alcohol and ether) being a con venient preparation. The collodion being dry, the plates are coated with emulsion. The emulsion flows very badly on the collodion- ized surface, but by using a bow made of a piece of sewing cotton stretched across an arc of thin iron wire the difficulty may be readily overcome. The thread is to be drawn over the surface of the plate after the required quantity of emulsion has been poured on, and it is scarcely necessary to say that the glass should he supported on a levelling stand. Plates prepared in this way are developed and fixed in the ordinary manner, and when a plate is dry it is suf ficient to cut through the film inside the edge which has been denuded of wax, when the film negative can be easily stripped off. In this case, however, the film is very thin, and it is often desirable to thicken it somewhat before stripping. For this purpose a piece of thin commercial sheet gelatine is taken and is soaked in water till it becomes quite flaccid, and this is laid on the negative, care being taken that no air is included between them. A sheet of wet paper or of mackintosh is now laid on the gelatine film, and all excess of water is expelled from between the negative and the soft gelatine film by stroking the upper surface of the paper or of the mackintosh cloth with a squeezee—that is to say, a strip of soft india-rubber set in a wooden handle. It is now easy to remove the paper or the india-rubber cloth which was used to protect the soft gelatine from the action of the squeezee, and the plate can be set up to dry. When dry, the film is cut through within the border from which the wax was cleared off, and the film will separate readily; but should there be any tendency towards a too early separation owing to the contractile force of the fresh thickness of gelatine, the edges of the plate may be bound with strips of gummed paper. PHOTO-ENGRAVING FOR THE DECORATION OF POTTERY. Readers of the News may possibly remember Mr. F. J. Emery’s recent communication on this subject, and it is interesting to note that he has, for his own manufactures (pottery), been producing copper-plates by this means during the past fifteen months. As exemplifying the celerity of production, the follow ing test was applied. At the request of Mr. Emery we despatched from London, by the night mail of April 23, a drawing, which, for the purpose of identification, we signed and dated on the face. This drawing was received at 7.45 a.m. of the 24th April at Mr. Emery’s manufactory in Burslem, Staffordshire. A copper-plate made therefrom, and bearing our signature, left Burslem at 11.40 the same morning, and was delivered in London in the evening. Thus, a drawing was converted into a potter’s copper-plate engraving and despatched from the works within four hours, also delivered in London a trifle over twenty-four hours from the time of the posting of the sketch ; a fired plaque from a transfer that had been printed from the plate reaching town twelve hours later.