The American cinematographer (Jan-Dec 1924)

January, 1924 AMERICAN CINEMATOGRAPHER Nine "Cashing In11 On Stereoscopic Projection Fascinating subject discussed by prominent optometrist Herberts. TtlarsKutz, A, B., Opt. D. Chairman, Department Public Information, California State Association of Optometrists. Stereoscopic pictures from uieiupoint of the optometrist Mot ion picture technicians in all departments of their extensive profession and optical scientists hare at least one problem in common, — the practical development of stereoscopic motion pictures. Science is not standing still in its search for this improvement. The full possibilities of the stereoscopic projection of moving images arc only realized by those who hare viewed such an exhibition. Offhand, the motion picture or optical engineer would look with favor upon this new phase of the industry; he would see the benefit of photography with a much wider field of view and with a true impression of depth on the screen. But the commercial possibilities of this development in projection are rarely thought of — the box office angle of thrilling thousands with something they have never looked upon before, images moving about ostensibly in the air between their eyes and the screen. We see with our brains, optometrists have proven, and any violation of the life-time habits of vision impresses us greatly. Stereoscopic pictures with motion are very much a stranger to our mental habits of vision and such new optical illusion cannot be explained by our mental eyes as the images are received. Hitting the Cash Register There is a New York showman who is amazing his audiences with stereoscopic pictures. He employs a screen covering the full extent of the proscenium arch. There appears the shadow picture of a girl, the edges showing red and green until the on-looker places before the eyes a pair of cardboard spectacles with one red and one green celluloid "lens." The red and green of the moving image is of course immediately blended and the shadow picture seen stereoscopically. The illusion is that of seeing the girl on the screen move out over the audience. As the pictures are increased in size (due to the subjects coming closer to the source of light behind the screen) the shadows stand out over the heads of the audience like giant ghost faces, until the auditorium seems piled with huge women dancing, running, leaping into the air over the heads of the amazed onlookers. A shadow man throws a shadow-ball — it bounces out into the audience, each person seeing it come directly touxird him. The optics of the device, as described by C. H. Claudy, an optometrical writer, are these — two projection machines throwing red and green light on a screen ; persons acting and dancing between the screen and source of illumination; audience furnished with bi-colored spectacles. Explanation Is Simple The amazing effect must be explained by physiologic optics, or visual psychology, if you prefer. Because our "mind's eye" has learned to associate increase of size of an object with decreasing distance and vice-versa, when the shadow on the screen becomes solid — assuming the third dimension — it ap pears to advance or recede from the plane of the image as it «jets larger or smaller. As it cannot advance (as it becomes larger) to any position except in front of the screen, the visual effect is that of seeing in space. Should one toss a bulky object toward the screen from behind, the onlooker will see it approach him directly, and through years of intuitive self-protection will unconsciously dodge the "on-coming" missile. This is the only successful commercial use of the phenomenon of stereoscopic projection of moving images on ■ a screen that has come to the writer's attention, although many experiments and mechanical contrivances are known. Just what the future will bring is worthy of contemplation. There seems to be great possibilities in the development of "solid" photography. How far the ultimate adoption of such form of motion pictures will alter present day technique is interesting speculation. The Editor, American Cinematographer. I thought you might be interested to know that I have sold my second camera through the ad I carried in the American Cinematographer. When I bought my new Mitchell recently I advertised my old outfit, and in less than ten days I had received replies, including telegrams, from as far away as Maine and as near at home as San Francisco. May the good work continue. Very truly yours, (Signed) GEORGES BENOIT.