The Optical Magic Lantern Journal (November 1890)

48 Tho Optical Magio Lantern Journal and Photographic Enlargor. Messrs. TayLor, Taycor & Hosson are making a specialty of lantern objectives. * » IN connection with the Tunbridge Wells Photographic Exhibition, to be held from 26th to 29th inst., there will be a short lantern entertainment cach evening. Sir David Salomons has promised to send his magnificent lantern (made by Steward), and intends to manipulate it himself. s » * Ir has been suggested by Mr. T. H. Holding that white mackintosh having a matt surface might be employed for making lantern screens, the advantages claimed being opacity combined with thinness, and also a freedom from cracking when rolled up—many surfaced canvas screens having a tendency to crack when being opened after having been rolled up for any considerable period. We understand that Mr. F. W. Hart, of Kingsland-green, is experimenting with several samples of mackintosh to test its desir ability for screens. * *« * A NEW patent enlarging apparatus is about to be introduced by Mr. J.C. Shenstone, Colchester, the wholesale agents for which are Messrs. Wrench and Son, of Gray’s-inn-road, W.C. 2 R * Mr. ARTHUR E. Morton, the popular instructor of typewriting at the Regent-street Polytechnic, writes: —“ The following novel application of the typewriter may possibly be of interest to the numerous readers of your periodical. We are in the habit of utilising the limelight lantern in connection with advertising our numerous classes, entertainments, &c., and hitherto written or printed slides have been used; the thought occurred to me that if I could write on a transparent gelatine paper by the typewriter it would look much neater and bolder on the sheet, which is fixed on the opposite side of the roadway to | the lantern. The experiment was tried. [ found the gelatine would not hold sufficient of the ordinary ribbon ink, so that it was necessary to dust it over with powdered chalk before writing ; the gelatine sheet was then mounted between glass in the ordinary manner, and the result was extremely satisfactory in every respect. The display required a little ingenuity to get it in the limited space, but it was, as expected, much bolder and clearer than the old method.” » ” ” Iv has been decided, provided sufficient interest is taken in the movement, to hold an exhibition of the wark of the members of the Camera Club at the Bycullah Atheneum, Enfield, in the early part of January next, at which prizes and certificates will be given for the best photographic productions. Enfield ! The Advantage of Large Object Glasses for Lanterns. Tue topic of object glasses is one that is necessarily of interest to every possessor of a lantern ; for if there is one subject that all are agreed upon, It Lis to get the greatest possible amount of light thrown on the screen. Ata recent meeting of the London and Provincial Photographic Association it was said by one of the speakers that if the light was small, the condenser perfect, and the slide devoid of half tint, no matter what length of focus the object glass might be, one of small diameter would answer just as well as a large one ;. for as the light travels in a straight line, it would be projected forward in a cone, of which the apex would be reasonably small, and if the object glass were placed there, it would stand to reason that the whole of the light would pass through it. But as nearly every one knows, in ordinary practice the light is usually more or less large, and after passing through the condenser is projected ina variety of directions other than the conical form which might be assumed in geometric optics.. This being the case, a great gain in lighting is obtained by having the object glass so large as to take in all those straggling rays. The majority of optical lanterns in common use ‘have as an objective one of the French quarter- plate portrait combinations, the diameter of which seldom exceeds one and a quarter inches. While: these answer reasonably well, several experts find that an increased illumination is obtained by having an objective of much larger diameter. There is a class of portrait lenses that was. introduced some time ago, knownas quick acting carte portraits, in which the diameter ranged. !from two to two-and-a-half inches ; these should answer every requirement. In another column we give a resume’ of the arguments of the speakers on the occasion referred. to, and which pretty nearly exhausts this subject.. 10: Hand Cameras for Obtaining. Slides for the Lantern. No. 7.—‘‘ THE GRIFFIN.” THIS camera, which is manufactured by Griffin and: Sons (Limited), of (Garrick-street, Covent Garden,. possesses many novel points. Its external measure ments are Ijin. x §5in. x 4}in., and in appearance isa box provided with two knobs or handles at the side (Fig. 1). Unlike many hand cameras, the plates (12) are put into a grooved magazine, which is placed in the camera proper. As each magazine forms a neat and light