GB437414A - Improvements in natural colour kinematography - Google Patents

Abstract

437,414. Colour kinematography. GUTMANN, J. M., 40, Rue de la Voie-Verte, and ANGENIEUX, P., 1, Avenue Richerand, both in Paris. Feb. 18, 1935, No. 5234. [Class 97 (i)] Apparatus for taking kinematographic pictures in natural colours comprises three objectives O1, 02, 03, Figs. 2, 3 and 4 mounted close enough together to give simultaneously three separate images R, G, B, Fig. 1, in one normal picture space A of a standard kinematograph film, three colour filters for the three colours each associated with one of the three objectives, an optical system in front of the objectives having a semi-reflecting surface M1, Fig. 2, and a totally-reflecting surface M2 located to secure two of the images R, G, from a single point of view, and an oblique prism Q, Fig. 4, with parallel faces placed against the optical system to secure the third image B from a different point of view, the optical system and the oblique prism being so disposed that none of their faces or edges cut off any part of the field of view of any of the three objectives. The optical system may consist of a prism block having the semi-reflecting surface M1 and totally-reflecting surface M2 inclined at 45‹ so that the incident beam I1 is divided between the two objectives O1, 02, the surface M1 being half-silvered to a suitable density or fully-silvered with parts of the silvering removed ; alternatively, two parallel mirrors one semi-transparent and the other totally reflecting may be used instead of the prism block. In a modification, in order to avoid parallax, that is, to secure the third image from the same point of view as the first two a second optical system similar to the optical system P may be arranged obliquely in front of the above-described arrangement. In a further modification, suitable for use in poorer light, the arrangement of prisms P, Q, is supplemented by an adjustable focusing lens placed in front to focus the feature of greatest interest at a constant distance from the objectives. A second lens may be added to form an afocal system when focusing is effected at infinity. Specifications 306,329, [Class 97 (i)], 385,141, and 419,894 are referred to.