The Optical Magic Lantern Journal (October 1890)

37 condenser and a dented lens mount. Now-a-days with bamboo rods and rollers upon which the screen is screwed, accidents of this kind are unheard of. Although at the time this was a sad experience, still, after all these years, I have a certain pleasure in recounting to the present generation the result of my first public lantern entertainment. 10; Lantern Slide and Transparency Making.* By C. BEADLE. I po not'think there can be a more interesting branch of our fascinating art than the production of slides for the optical lantern, and in the remarks I shall make in connection with this topic, I trust to induce some who have not as yet tried this branch to.do so. Now that the holiday season is over, we are all anxious to show our work in the best possible way, and I think it cannot be denied that in a glass transparency we obtain more complete results of our negatives than by any other printing process. As to the production of those, I claim to have carefully followed instructions given by the makers of the plates rather than gone in for original research. I find in various articles upon this subject that great stress is laid upon cleanliness in connection with all dishes, measures, &c. This is perfectly correct; but at the same time it will be found that the ordinary care which has enabled you to produce a negative will in all probability enable you to obtain a good transparency from it. Although there are many ways of producing transparencies, nothing to my mind surpasses in beauty those produced by collodion process ; but it is not my intention to go into detail, for dry plates are now made in such perfection, the facilities so great in producing slides from them, and the obtainable results so good, that we amateurs of little leisure hardly need anything better. \Vith many itis a disputed point as to whether contact negatives or those made in the camera are the better. Although there may be little material difference, the result of my experiences is that those made by reduction are slightly sharper thantheothers. But however much our great artists may differ as to positive prints, we all find that when the subject has to be enlarged many times, the general fizziness is, asa rule, quite sufficient to satisfy any of us. Respecting the idea of one brand of plates being better than another, I think I am quite right in stating that any or all will produce good results, if treated according to their requirements, and I find that success generally attends the use of the formule issued with the plates ; but sometimes it may be necessary to slightly vary the same when allowing for a thin or overdense negative. With the plates of Mawson and Swan, Fry, Ilfords, and Thomas, a wonderful range of tone can be obtained according to theexposure and strength of the developer used. The tone usually produced by ferrous oxalate or hydrokinone—viz., a neutral grey—is, in my opinion, most generally liked. Personally, I chiefly use Thomas's plates, and acting upon the principle of a witty American, who advised that having found a good thing to freeze to it, I purpose using these by way of illustration. * Read before N. Middlesex Photo. Club. Although hydrokinone as a developer for negatives is somewhat uncertain, and has a tendency to choke the distance, still for transparency work and slow plates I think it has yet to be surpassed. It is both simple and clean. I intend using the same solution to develop both a lantern slide and a half-plate transparency. The developer is composed as follows :— A. Hydrokinone_... aca 160 grains. Sodium Sulphite ies 2 ounces. Citric Acid sis 60 grains. Potassium Bromide 30 a Water to make up ive 20 ounces. B. Sodium Hydrate 160 grains. Water 20 ounces. For development equal parts of A and B are employed. Perhaps the success of the finished picture hinges for the most part on giving a proper exposure. In my own practice I have generally obtained the best results by giving as long an exposure as the plate will stand and then developing smartly. When by reason of under exposure a yellow stain results from prolonged development, it can be removed by an application of Cyanide of Potassium ... 2 drachms. Water oes . 20 ounces. But as this has a tendency to reducing the density, it is well to avoid the stain when at all possible. Perhaps it is better to use the alum proto-sulphate of iron and citric acid clearing solutions ; but if the exposure has been correctly timed, there will be no necessity for their use. I find that the average time for exposure with an afternoon light with F22 to be about 15 minutes, when reducing from a half-plate negative to lantern size ; whilst by contact with a kerosene lamp, held at 12in. or 14in. distance, 45 seconds will suffice. I may here remark that as the result of experimenting with various developers in the same brand of plates, those developed with pyro, ammonia, ammonium, bromide, and carbonate of ammonia required a longer exposure than those developed with hydrokinone. When printing by contact, a dense negative should be held a few inches from the flame; whilst a thin one produces best results when held 1Sin. or 2ft. away. The same principle applies when making bromide prints. Of course, in speaking of transparencies, larger sizes than 3}in. square can be treated in a similar manner. I have for my own use made a box for reducing or enlarging, but since making have ascertained that one of a suitable nature for reductions has been put upon the market for about 15s. The plan I use saves all blocking out of the windows of the room in which it is used. It consists of two parts—a platform to hold negatives of any reasonable size, and a box to put the same in when the camera has been adjusted. The platform has a narrow groove down the entire length, to enable the camera to pass up and down, and can be fixed in any desired position by a thumb screw. At the extreme end is nested a set of frames to hold different-sized negatives, which are held in position by small brass buttons. When the exact position has been ascertained for different negatives a mark can be made upon the board, and the complete action of this apparatus is as follows :—The lantern plate being