Improvements in processes of effecting colour and contrast masking in monochrome or colour photography, and in apparatus for use therein

摘要

730,376. Photographic colour and contrast masking. SMITH, F. H., and NICOLL, D. O. June 9, 1952 [June 22, 1951; June 27, 1951], Nos. 14920/51 and 15270/51. Classes 98 (1) and 98 (2). A colour or contrast masking process, available for making a masked record of an opaque subject or a three-dimensional object directly, utilizes a main camera and a camera-projector mounted in fixed spatial relationship, and comprises intercepting fast of the light passing between the subject or object and the image plane of the main camera, directing this light to a sensitive material in the camera-projector, processing the material, replacing it in its initial position in the camera-projector, placing a sensitive material in the main camera, exposing the latter material to light both from the subject or object and, using the principle of reversibility of light, from the processed material in the camera-projector, and processing the material so exposed. Colour filter or coloured light sources as required may be used in the exposures. A half-tone screen may be provided in the main camera. As shown, Fig. 1, light from the subject plane 1 to the image plane 2 of the main camera 10 is diverted by semi-transparent mirror 3 and reflex mirror 7 to the image plane 5 of the camera projector 8, and subsequently light 9 is used for masking exposure. In the apparatus of Fig. 2, exposing light is diverted to and from the camera-projector with the aid of a diffuse reflecting screen 12 in addition to the semi-transparent mirror 3. Specification 693,703 and an article in the Process Engravers Monthly for November, 1950, pages 325, 326, are referred to.