The Optical Magic Lantern Journal (November 1901)

The Optical Magic Lantern J ournal and Photographic Enlarger. 87 rocates a rod c which is conveniently guided. This rod c has projecting from it an arm carrying pins Fr ¥, which engage in the perforation in the film. In order that the film is only moved on the upward stroke, the cam surface E on the disc p puts the pins Fr F out of gear on the downward stroke. The pins F F are thus given a vertical reciprocating and also horizontal receding motion. Fig. IV. shows a method of feeding short lengths of the film, and this is brought about by a rocking feeding lever A, which has a roller at its upper end ; the roller serving to force the filin D between two rollers cc, and thus forms a loop; the loop focming the ai:nount of film required for each picture. The rocking lever A reccives its motion from an eccentric k. A pawl p is arranged to prevent the film from slipping in one direction. Wet Collodion Lantern Slide Making.—No. I. By ALFRED H. SAUNDERS. © many excellent dry plates for slide making are on the market, which give many different tones according to developers used, that some may ask, why go back to the ‘‘ black art” of the wet collodion days? SC m3thod? and, What will it cost? To the first query I reply—let those -who are ‘satished with the results they get from dry ‘plates, keep to them. But large numbers are very dissatished, and waste so many plates in getting, after all, but poor results, while no professional slide maker with a reputation to keep would risk it by making slides with dry plates, when the wet process is in every respect superior. The second query opens a larger field for reply. How many camera disciples (and What H advantage shall I gain by adopting this | their name is legion) throw away negatives that on development turn out underexposed, flat, and Jacking sparkle, but of scenes and incidents it is impossible to repeat? Slides are wanted, but cannot be made by dry plates worth exhibiting; but with collodion, passable slides can be produced which call forth expressions of woncer at the results from such poor material, while from good negatives the best slides ‘on this earth”’ may be made, full of beauty, vigour, half-tone and detail, with clear glass for the sky and whites (except, of course, where clouds are in the negatives), and to the slide colourist they are a sine qua non. Are not these advantages sufficient? As regards the last query, that largely depends on the pocket of the pupil. It is the first outlay that causes trouble. Ihave fixed up pupils from £2 10s. to £15 (according to apparatus each thought necessary), and for this outlay material was procured that will last for years to come. The requirements to commence are:—A }-plate square bellows studio camera of the old school, such as may be purchased for a few shillings at some antique lumber dealers, a few (three each to start) of 40, 30, 20, and 10 oz. stoppered bottles, half dozen 4 02, wide mouth stoppered bottles, two t-plate glass dipping baths, with dippers, a cometless collodion pouring bottle (8 oz. is a useful size), an argentometer with test tube for silver bath, and the following chemicals :— Acetio Acid gernotal) 4 lb. Acid, Citric ‘ 1 oz. Acid, Nitric 4 Ib. Alcohol 20 ozs, Barium, Nitrate of. 1 oz. Copper, Sulphate .. $ lb. Tron, Protosulphate 3 1b. Potassium, Cyanide (sticks) 2 1b. Potassium, Iodide 1 cz. Potassium, Sulphide 3 lb. Silver, Nitrate of .. 4 ozs. Spirits, Methylated oe 20 ozs. Varnish, Best White Hard ee . 4 028. Water, Distilled, a Winchester quart Collodion and Iodizer (separate) 20 czs. Two glass funnels, bundle filter papers, 1 book blue litmus paper, } lb. wool (absorbent), measure glasses, stirring rod, and 6 gross squares of glass 34 by 3}inches. (The quantities of chemicals here given are sufficient to make about 1,000 slides and may be reduced onehalf, except silver nitrate. I always advocate full baths of this, as it tends to cleaner working and does not get out of order so quickly as smaller quantities.) If the pupil is handy with tools, an item of expense may now be saved; if not, get a jobbing carpenter to make a box without lid or bottom { 18 inches square by 6 inches deep (outside