GB404307A - Improvements in optical systems for photography or kinematography particularly in colour - Google Patents

Abstract

404,307. Colour photography. HILLMANN, A. G., and COLOURGRAVURE, Ltd., Victoria House, Vernon Place, Southampton Row, London. April 12, 1932, Nos. 10489/32 and 10170/33. [Class 97 (i).] An optical light-dividing system for obtaining multiple images simultaneously for colour photography or kinematography comprises a non- refracting reflector device perforated with multiple holes which diminish in size through the reflector thickness towards the reflecting plane or planes, the non-reflecting walls of the holes having portions so inclined to the optical axis towards the margins of the surface receiving light transmitted through the holes as to facilitate the passage of light to the said margins, and also having portions which partially obstruct the passage of light to the central part of the said surface, so as to produce even illumination of the image obtained by transmitted light. The Figs. show a pair of reflectors 1, 2 arranged in the form of a V in rear of the objective 4 to produce two images by reflected light and one image by transmitted light. The reflectors are made of polished steel &c. and are provided with medial groups of perforations 7, 8 and with marginal groups 9, 10 all having their axes parallel to the optical axis of the objective, and also with groups 11, 12 having their axes inclined to the horizontal plane containing the optical axes. The axes of all the holes 11 or 12 in a given reflector above the transverse centre line C, D are inclined downwards substantially in parallelism, and those of the holes below the centre line are inclined upwards substantially in parallelism towards the front of the system so that the axes of all the holes intersect the said horizontal plane in front of the system. All the apertures are expanded towards the rear of the thickness of the reflectors, to facilitate the passage of light to the marginal portions of the direct image. To obtain more even illumination the diameters of the holes in any given reflector increase as their distance from the objective increases. To accommodate for the different filter factors for the two reflected images, the perforations in one reflector may be made smaller than those in the other, leaving a larger reflecting area. The reflectors are provided with interengaging tongues 13 and are mounted on supports 32, 33 in such a way that they can be adjusted as required in relation to the objective. An arrangement for two colour photography is also described, comprising a single perforated reflector and a plane mirror receiving the reflected rays and directing them parallel to the transmitted rays.