Kinematograph Year Book 1942 (1942)

Film Exhibition and Kinema Technique ' 233 between all sections of the industry and the flow of new regulations has on several occasions emphasised the necessity of collective approach to the Government Departments concerned. An instance of the value to the industry of the Association's activities has been exemplified by the considerable work put in in connection with the supply of valves. Membership now includes most of the leading manufacturers and suppliers of kinema equipment. The Workers' Film Association have shown increased activity during the year. In conjunction with the A.C.T., the Association held a very successful summer school, designed to organise technical assistance to those responsible for film exhibition and, secondly, to assist those interested in the production of 16 mm. films for exhibition to working-class audiences. The whole kinema field was adequately surveyed by a number of competent speakers. Secretary of the Association is Aid. J. Reeves, who was formerly in the Films Division of the Ministry of Information. STEREOSCOPY. IN the earliest days of colour the argument was advanced that this medium lends itself more readily than monochrome to the stereoscopic effect. The presentation last year of the Technicolor film "Moon Over Miami " corroborated that view, for one or two studio-shot sequences were the nearest approach to three-dimensional effect yet seen. Although no' technical details were available, it was obvious that a new type of camera was employed or, alternatively, a new lighting technique was responsible for the striking result achieved. The use of colour in a motion picture affords a much wider gradation of light and shade, which contributes a degree of perspective, and, to a certain extent, a pseudo-stereoscopic effect. It will be appreciated that when a high degree of plane separation is possible as the result of greater depth of focus, the stereoscopic effect will be correspondingly enhanced. Until recently the drawback to most colour systems has been their comparatively shaHow depth of focus. Speaking to the Association of Engineers in Burma, L. H. Huitt, B.Sc, of London, revealed details of a novel principle — " foveal circle seaming." This principle has the virtue of being essentially a kinematographic process, says R. D. H. Cricks in the Kine., and definitely rejects the method of binocular vision. The fovea is the centre of the retina, and the part of the image which falls upon it, is viewed sharply and clearly, and the rest of the image is less clearly defined. This central point of fixation is continually moving as the eye scans the object. The method involves the exposure of a single film through twin optical systems, producing a double image except in the "foveal" area — the centre of interest in the picture. Furthermore, this central area is slightly brighter than the rest of the picture, and continually moves over the picture, in imitation of the natural manner of scanning a scene with the eye. It is claimed that this method imitated the change of focus which occurred when the eyes shifted from a near object to something farther off. Normal film was used in the process and no alteration in projection was necessary. The only special equipment required was the camera. Details have appeared of research by Russian scientists into three-dimensional principles. One of the most advanced systems employs two mirrors placed in front of the objective lens of the camera, which divide the image into two, these being recorded side by side on the film. A similar mirror is at the aperture of the projector and the reflection of the double image is projected on to a grid of radiating wires erected in front of the screen proper. Part of the light rays from each image are arrested by the grid, the remainder passing through to the white screen, the difference being that the rays arrested from one image are those passed through from the other image. When the images reach the screen the resulting picture is in fan formation, each spoke of which is an element meant for viewing by the left or right eye. Obvious defects are the weight of the grid and the necessity on the part of the spectator, if he moves, to readjust his vision to a new viewpoint.