Motion Picture News (Jul-Aug 1916)

490 ACCESSORY NE W S SECTION Vol. 14. No. 3 ■ ■• --I iliiilll _.JIiliilillilil!iiiiilllilIliliiii The Camera llilWliaBlBPMr'Prf ppffifijiBlllir! A Department Devoted to Motion Picture Photography in All Its Phases, Studio and Laboratory Work Stereoscopic Cinematography The Anaglyph Was De^dsed Many Years Ago by Ducos du Hauron — From a Pair of Smtable Stereoscopic Photographs Two Half-Tone Blocks Were Made — One of These, the Picture Meant for the Left Eye. Was Printed on Paper Using Green Ink '^-^ {Continued from last week) * ^ IT should hardly be necessary to dwell here upon the desirability of giving exactly the same exposure and development to the two negatives comprising a stereoscopic pair. The focus should be equally crisp in each negative also. Before printing up stereoscopic negatives they are generaly transposed, the right-hand print being made from the left-hand negative (as taken) and vice versa. We have seen in an earlier paragraph how the image of an object received by the retina of one eye is dissimilar to the .image of the same object received by the other eye and a properly photographed pair of stereoscopic pictures exhibits this dissimilarity also. In practice it is found desirable that the right hand picture should embrace more of the view on its left-hand side than does the kft-hand picture, while the left-hand picture should include more of the view on its right-hand side than does the right-hand picture. With -the fundamentals of stereoscopic perception and photography now established we may next consider methods of securing relief in lantern and motion picture projection. Before entering upon a description of the various methods which have been experimented with in the effort to produce motion pictures which would exhibit an appearance of stereoscopic relief when projected, we will describe one more method by which stereoscopic effects were secured in looking at pictures printed on paper. This was the Anaglyph, which was devised many years ago by Ducos du Hauron, a well-known pioneer in color photography. From a pair of suitable stereoscopic photographs two half-tone blocks were mad,':. One of these — for instance, the picture meant for the left eye — was printed upon paper using green ink. The other picture — meant for the right eye — was printed right on top of the green impression in red ink. The superimposed or combined print appeared very vague or confusing to the naked eye. Experiments with Processes Like Anaglyph Method But when viewed through discriminating glasses or spectacles, having a red glass for the left eye and a green glass for the right eye, a good stereoscopic effect was obtained as the pictures were transposed and properly conveyed to the eyes by the ■discriminating action of the red and green glasses. We describe "the Anaglyph here because — in addition to having been often seen a few years back — similar processes are now being experimented with by some investigators in an endeavor to apply the same principle to the motion picture, with the end in view of securing relief in their film subjects. Lantern or stereopticon projection giving a good stereoscopic effect was attained many years ago, the first tolerable results having been secured by J. Ch. D'Almeida as early as 1858. D'Almeida's first results were obtained in a manner similar to the principle •of the Anaglyph, which has just been described. Two slides having stereoscopic relationship to each other were projected onto a screen superimposed (one over the other). In the slide carriers of the lanterns were placed — a red glass in front of one slide and a green glass in front of the other. In observing the projected result, green and red glasses were held in front of the respective eyes, whereupon the screen image appeared to possess relief just as in the case .^f_ the .^Anaglyph. As _a result of iur ther experiments D'Almeida conceived his Eclipse system of stereoscopic projection, which was accomplished as follows: Two stereoscopic lantern slides (in black and white) were projected one over the other onto the screen by means of two stereopticons. A shutter was revolved in front of the lenses of the lanterns in such a manner that the lens of one lantern was covered while the lens of the other lantern was projecting its image onto the screen and vice versa. In viewing the screen results a device bearing a similar revolving shutter was looked through ; the shutter of the viewing device working in unison with the shutter before the lantern lenses and shutting oft the view from one eye while a picture was being perceived by the other eye and so on. As these eclipsing shutters were rotated rapidly it will be seen that the stereoscopic effect was due to persistence of vision, which is the principle involved in showing and viewing an ordinary motion picture. G. R. Wilson One of First to Make Experiments G. R. Wilson, an Englishman, was one of the first to attempt the making of motion pictures which would appear stereoscopic when projected. He obtained a patent in 1898 for a double cinematographic camera taking two series of views on a wide film. These stereoscopically photographed film strips were projected so that the two series of views were superimposed on the screen, and the result was then viewed through a device similar to D'Almeida's Eclipse shutter. It will readily be seen that any stereoscopic projection system which requires its results to be viewed through a shutter arrangement, can only be viewed by a few persons at a time and could therefore not be utilized to entertain a theatre audience. The very best stereoscopic motion pictures which have yet been made and shown, however, are the, result of the study and efforts of Theodore Brown, of Salisbury, England. In securing his results Mr. Brown takes into account the laws of motional perspective, which is basically perhaps the best method to follow in attempting the production Of stereo motion pictures. As the effect of motional perspective has not been given the amount of consideration, by experimenters in this country, which its importance (as applied to the class of work under consideration) warrants, we will briefly outline the workings of the laws governing it. A one-eyed person estimates the distance of a given object in nature by its size in comparison with objects nearer or farther away and by its perspective. If the object is in motion the speed of its motion greatly aids his judgment of its distance from him. This may be readily demonstrated by a study of the diagram Fig. 3. In Fig. 3, A is the observer's eye which is viewing two men at B and C. While the men remain stationary the observer will know that B is farther away than C by reason of the fact that B is imaged on the retina as being of less magnitude than C. However, if both men advance five steps across the field of vision the brain is immediately made aware that the image of G on the retina has undergone a greater displacement than has the image of B. During the proportionate movements of the men the brain has formed an accurate idea of the distance between them. j^,. ...mmM