GB492523A - Improvements in copying photographically subtractive multi-colour pictures - Google Patents

Abstract

492,523. Colour photography. I. G. FARBENINDUSTRIE AKT.-GES. Feb. 19, 1937, Nos. 5022 and 5023. Convention dates, Feb. 21, 1936 and May 26, 1936. [Class 98 (ii)] A multi-colour subtractive picture is copied on to multilayer copying material with uncoloured layers for colour development by means of light of ranges of wave-length amounting to less than one-third of the visible spectrum. The picture may be produced by colour development, the silver dyestuff bleaching out process, or the silver-antidiazotate process. The copying exposure may be made with a multicolour screen filter or with a rotating disc filter having differently coloured segments which may be selectively screened mechanically or optically to control the colour of the copying light. The filtered light may be reunited to form a synthetic white surface, for example by means of an Ulbricht Sphere. The light source may be a glow-discharge, gaseous discharge or metal vapour lamp. The process is particularly applicable to colour kinematography. The variation of the light may be controlled selectively or as a whole by providing the negative film with guide marks or by using a separate control film to control the intensity of one, two or all the spectral components or to control the insertion of a screen in front of the copying light. The copy may be by contact or by projection. Both the original and the copy may be processed by reversal, or the negative original and positive copy may both be processed by colour development.