Modern magic lanterns; a guide to the ... - Yesterday Image

ANIMATED LANTEBN PIOTUEES. 103revolving at a high rate of speed, and so appearing as apartially opaque screen only, are all examples of the employmentof the principle of persistence of vision. TheKinetescope of Friese Greene, which Edison's machine,subsequently introduced and far better known, resembledat any rate in principle, contained the germ which led toanimated lantern pictures. A long film of celluloid coatedwith a sensitive material was passed through a special formof camera, stopping several times a second, while a shutteruncapped the lens, and registered an exposure upon it.In this way upon development a long negative was obtainedconsisting entirely of a string of pictures one after the otherall taken from the same standpoint, but each differing fromits neighbours, when the subject was a moving one, byhaving the moving object in a slightly different position.From such a negative it was a comparatively easy matterto make a positive transparency, and this when illuminatedfrom behind, and lOoked at through a similar arrangementto that used for taking the negative, is the Kinetescopein outline. The eye blends the individual pictures seenone after another into one continuous view, in which themoving objects actually appear to move, and the fidelitywith which every motion is registered is very surprising.For lantern work it became necessary to run the film inthe same way through a lantern, stopping it rapidly, andwhen so stopping uncovering the lens so that one pictureafter another might faU upon the screen. It must be bornein mind that in the lantern the images are enlarged upenormously; aU the defects are magnified in the sameway, and the defects become very much greater than whenthe film is simply to be seen as a transparency. This wiUbe realised better when we mention that for conveniencein the photographic and other operations, each individualpicture on the film is not usually much larger than oneand a half square inches.Space prevents us from describing at any length the manyinstruments in the market for showing animated picturesupon the screen, known as the Biograph, the Kinematograph.etc., etc. They are all alike in principle. Along band of film is passed between the lens and