GB357625A - Improvements in or relating to colour photography - Google Patents

Abstract

357,625. Colour photography. SOMMAVILLA, E., 28, Guilford Street, Russell Square, London. June 20, 1930, No. 18872. [Class 98 (ii).] In the production of colour photographs comprising two or more superposed component colour positives, two of the positives are formed in register on opposite sides of a single support by printing from negatives placed one on each side on to ready-coloured emulsions and employing coloured printing lights, which, acting together with the colours of the emulsions, prevent printing through the support. For a tri-colour result the red, green and blue negative records rf, gf, and bf may be made in any known manner in juxtaposition on a single film 1 which, for the printing operation, is bent as shown in the Figure round a positive film 2 bearing an emulsion 4 as of ammonium bichromate and fish glue or gelatin over the whole of one face and over half the other face, the remaining half 5 of this face being coated with a white pigment. The emulsions in contact with the red, green and blue negative records are permanently coloured blue, red, and yellow respectively. Each of the prints from the red and green positives is preferably made through a line screen, the lines of the two screens being crossed at right angles. After development as by washing in water to remove the unexposed parts of the emulsions, the tricolour picture is completed by folding the film about its middle so that the three positives may be viewed in superimposition against the white background 5. For a two-colour result, a film bearing juxtaposed red and blue-green colour-record negatives is bent round a film sensitized on opposite sides with emulsions coloured greenish-blue and red, and after printing and developing as before, is mounted on a white background as of paper. The Provisional Specification describes also a similar process in which sensitive material is used which is not ready-coloured but is coloured after development; and which is not printed with specially-coloured lights, but contains a washout stain in the support to prevent printing through.