GB346406A - Process for the production of cinematographic effects in colour and means therefor - Google Patents

Abstract

346,406. Colour kinematography. DAPONTE, D., 39, Coventry Street, London. Jan. 9, 1930, No. 11417/29. [Class 97 (i).] To permit the use of large aperture lenses having a short focal length in the production of complementary colour pictures arranged side by side lengthwise of an ordinary kinematograph film a light beam-dividing system is provided in which the beams are separated to such an extent or at such an angle as will enable such lenses to be used, one or both of the beams being subsequently redirected by a reflecting surface into the required position on the film. Several examples of these systems are described in the Specification, of which those shown in Fig. 3, and Figs. 5, 6 and 7 are typical. The incident light beam 1, Fig. 3, is divided at the partially reflecting surface d, the part 2 passing through the prisms 3, 5 and being reflected by the surface 5a to the lens 6 by which the image 9 is formed. The direct beam is reflected at the surface 4a of the prism 4 to the lens 7 by which the image 10 is formed after reflection of the rays by the reflector 8. This arrangement enables the positions of the lenses to be such that large diameter lenses may be used. The length of the ray paths and the refractive indices of the prisms are so proportioned that the paths of the divided beam are optically equal before reaching the lenses. The ray paths of the system shown in Figs. 5, 6 and 7 are substantially the same as those of Fig. 3 but reflections take place at right-angles instead of obtuse angles as in that Figure. Specification 346,454 is referred to.