GB637448A - An improved process for the manufacture of composite photographic or cinematographic pictures - Google Patents

Abstract

637,448. Composite photographs. DENHAM LABORATORIES, Ltd., and HARCOURT, W. M. April 15, 1947, No. 10011. Drawings to Specification. [Class 98 (ii)] A process for producing composite photographs or kinematograph pictures comprises separately illuminating (a) the foreground objects and (b) a plain, preferably blue, background, receiving the composite beam from foreground objects and background in a camera provided with a beam-splitting device so that optical images, each including both foreground objects and background, are focused on two separate films of appropriately different sensitivities presented simultaneously at two separate gates, the main film recording a correctly exposed negative picture of the foreground objects against an opaque background, and the other film being sensitive to light (e.g. blue light) received from the background and recording an opague background with clear film for the objects, this result being secured at least in part by the use of such an illumination for the background as will lead to correct exposure on the background film in .respect of the background and at the same time a gross under-exposure on that film in respect of the objects. The foreground objects are illuminated by light at 100 foot-candles intensity and photographed in front of a plain background, coated with a mixture of 50 per cent cobalt blue and 50 per cent white and illuminated with white light at 300-500 foot-candles intensity, by a camera with a beam-splitting device dividing the light to form images on two photographic films presented simultaneously at two gates. One film (A) is yellow-sensitive (e.g. panchromatic) and records a correctly-exposed negative image of the objects on an opaque background. The other film (B) is a highcontrast blue-sensitive film, and records an image of the objects so under-exposed as to provide, on development, substantially clear film on a correctly-exposed background image. To enhance the contrast the objects may be illuminated with yellow light, or a blue filter may be placed before film B. Alternatively, film A may be a multilayer film for colour printing; as such film is of slower speed than panchromatic film, equal intensity of illumination of foreground objects and background will lead to correctly-exposed image of the objects on film A and an under-exposed image thereof on film B. After development, film B is printed to provide a film C bearing a silhouette of the foreground objects on a clear background. Film C is then printed in register with a film bearing a desired background negative on to a sensitive film which is then exposed under film A and developed, providing an image of the foreground objects against the desired background. The final image may be made positive or negative by varying the procedure. U.S.A. Specification 1,982,211 is referred to.