GB495821A - Improvements relating to colour photography and colour cinematography - Google Patents

Abstract

495,821. Colour photography and kinematography. DAVIES, J. May 13, 1937, Nos. 14134/36, 30039/37, and 12949/38. [Classes 97 (i) and 98 (ii)] Colour separation negatives are produced by making the exposures through colour filters each comprising a yellow basic layer and a coloured secondary layer. The yellow basic layer is made by pouring gelatine solution on to a glass plate and after setting the gelatine film is stripped off, preferably hardened and dyed with auramine or tartrazine. The secondary layer may be produced in the same way and dyed with xylene red or rhodamine for a red filter or with patent blue and/or malachite green for a blue-green filter. The secondary layer may be of collodion and dyed while liquid, and run, while still liquid, on to the basic layer. Three colour filters may be used for producing three colour separation negatives for use in three-colour photo-mechanical printing. In taking colour separation negatives in kinematography the colour filters may be arranged over the upper and lower sections of a double lens mounted in the form of a detachable cap fitting over the usual camera lens and adapted to throw two images in each frame of the film. The upper and lower lens sections may be almost semicircular with their chords abutting to avoid parallax. Each frame pair of colour records is projected in superimposition upon a screen by the usual projector lens system fitted in front with a double lens similar to that used in taking the negative, one section being provided with an orange-red filter which may be provided on the lens itself and the other section unprovided with a filter. The red records are projected through the red filter lens section and the green records through the clear lens section. If desired a double-section part-colour filter lens as described above may be fitted in the projector after removal of the ordinary lens used for showing uncoloured pictures, but it may be formed as a separate cap lens adapted to be slipped on in front of the ordinary projecting lens. In order to avoid over-accentuation of red tints when colour separation negatives are taken in electric incandescent lighting an additional blue filter is disposed in front of or behind the camera lens so as to extend over the red filter only or over both colour filters.