The Optical Magic Lantern Journal (June 1890)

The Optical Magic Lantern Journal and Photographic Enlargor. v. MARION & Co, 22.823, Soho Square, London COWAN’S Gelatino Chioro-Bromide Plates. (MARION & Co., SOLE PROPRIETORS.) Specially prepared fur making transparencies, in the Camera, ov by Contact printing mith gas or other artificial light, algo eminently suitable for reproductiun uf negatives ank guneral copying purposes. 33 by 32 1/0, 44 by 8341/0, 5 by 4 1/7, GL by 42 2/3, 74 by 5 3/5, S$ by 44.4/0, Sk by 6) 4/3, 9 by 75/0, 10 by 8 7/3 12 by 10 10/0, 13 by $ 10/0. These plates are much slower than the ordinary Bromide used for Portrait and Landscape work, but much quicker than the pure Chloride Plates ; in the camera they will be found togive, with full exposure, very brilliant images with clear glass in the unexposed parts, making them specially valuable for general copying purposes. The exposure for contact prioting by gaslight (using an ordinary fishtail burner at 12 inches distant) varies from 10 to 15 seconds upwards, according to the density of the Any other Sizes to Order charged in same proportion. negative: and with the camera, using leas with diaphragm ' about F24, and reflected sky as a source of light, 1 to 2 minutes will be required. Any developers may be employed that work well with ' Bromide Plates, but the following are recommended :—The : proportiong are given for 10 ounces of developer only, so that by easy calculation each one muy mix the quantity best suiting his requirements. COWAN’S Gelatino-Chlioride Pliates. MANUFACTURED AT SOUTHGATE BY MARION & Co., 22 & 23, Soho Square, London, W. 34 by 34.1/0, 44 by 34.1/0, 5 by 41/7, 64 by 42 2/3, 7} by 53/5, 84 by 42.4/0, $3 by 63 4/3, 9 by 7 5/0, 10 by $ 7/3, 12 by 10 10/0, 13 by S 10/0. , These plates in appearance differ entirely from the usual Bromide tilus, being very transparent, and of a deep orange colour by transmitted light, but are capable of development to any density required. Though extremely sensitive to daylight, they are much less so to gaslight; so that moreartificial light may be used during development than with Bromide Plates. Chis will be found to be of great advantage, as the plates may be examined from time to time within a reasonable distance LANTERN SLIDE MAKIN This Camera meets the long-felt want for an Instrument that is always ready at a moment's notice to produce Lantern Slides from the Photographer's Negative. The usu] preparations necessary (especially in the case of Amateurs) to take a Lantern Slide are only too well remembered for their inconveniences and vexations. Hither the focus is found to be not quite satisfactory, or the intended amount of picture is not on the plate, ur something else is wrong, with the result that it is very common to take several slides before a perfect one is secured. _ With this Camera such mistakes and difficulties are impossible, as it is fived accurately in perfect focus, size, and position. All that is required to expose a plate being to insert a negative in the grooves at one end (film towards the lens), and in the dark room put a lantern plate in the carrier provided for it at the other end. the caps effectualiy excluding all light except that passing through the lens. No dark slide or lens cap is required. _ When the Negative and plate are in position, the Camera is carried out and pointed to the light, the exposure being 1 or 2 minutes, according to circumstances. ‘I'he Camera is then carried back to the dark room, and the lantern plate taken out and developed. | ofla gas-flame,and the density thus regulated toa great nicety. Che exposure to diffused daylight will vary from 1 to5 seconds upwards, according to the density of the negative. For the reasons mentioned above, it is not recommended to make the exposures to gaslight, but a very reliable method, when a number of pictures are required exactly alike—or when it is necessary to work at night—is to burn a few inches of magnesium ribbon at from 6 to 1S inches. from the negative, according to its density. G C A M E R A . Ee) ay reD 7954. The Instrument is made in three sizes :—the smallest making slides from }-plate negative; the next making them from t-l-plate negative ; and the largest, an adjustable one, taking all sizes, from 12 by 10 downwards, most useful to the professional—but it must be remembered it requires setting for every size, like ordinary Cameras. The charm in always working from one size negative is, that there is: never any setting to do. Prices complete with excellent lens, 3-plate, 12/6. 1-1-plate, 15,-. 12 by 10, adjustable to any size, 21/-. NotTe.—Lantern Slides being square, it is usual to copy & square of the negative. ‘hese Cameras are square, and take in the full width of the negative, and an equil extent of the length; but when desired they are made the same shape as the negative, so as to take in the whole of it—it then being ef course vecessary toemploy aspecially shaped mask to mount the slide up to advantage. We providemask of the required shape. The latter form of Camera is te extra on the half-plate, and 2/6 extra on the whole plate. GRIFFITH’S ECONOMICAL ENLARGING CAMERA. Having received a considerable number of enquiries and requests for an Enlarging Apparatus of the same style as the Lantern Camera, we have had a modilication made which is properly adapted to enlarge from the ordinary negative.in a simple, quick, and effective manner, making the production of &nlargements as easy and pleasant an ri ae as the Lantern Slide Camera has rendered Slide aking. Its outward appearance and size is very similar to the 12 by 10 Lantern Camera. One eud has a carrier to hold either 3-plate or }-plate negative. A good and suitable lenz is mounted in the sliding partition in the middle of Camera, while the other ead ‘‘draws out’’ to focus, and is fitted with a specially designed ‘‘dark slide,” in which either paper or glass, and opal plates, may be held for exposure. Price Complete, with lens, 30/-; packing extra, 2/6. MARION & Co,, 22 & 23, SOHO SQUARE, LONDON, W,