GB630014A - Improvements relating to colour cinematography - Google Patents

Abstract

630,014. Colour kinematography. COMBES, M. B. Aug. 28, 1946, No. 25822. Convention date, May 15, 1941. [Classes 97 (i) and 98 (ii)] In a process of colour kinematography which comprises the production of film negatives by exposure through a multi-coloured screen in contact with a light-sensitive panchromatic film and the printing of positives from such negatives by projection through a lens, the magnification (or reduction) is varied to compensate for contraction or expansion of the negatives after exposure so that the positive images will all be of the same size and can all be placed in register with a multi-colour screen of predetermined size. In one manner of carrying out the process, panchromatic film is exposed through a colour screen, which includes two opaque lines in the margin thereof, so that two transparent datum lines are formed in the side margin of the film or in the spaces between adjacent frames. After processing, the distance between the datum lines on the negative is measured to give a measure of the contraction or expansion of the film, and the required intensity of light for printing positives of each scene is also determined. Lateral notches are then formed in the negative at points along the length of the negative where a change in either light intensity or magnification (or reduction) is required during printing. Such notches, as they pass a given point in the printing machine, actuate electrical contacts which, through a pawl and ratchet mechanism. for example, serve to advance a pilot band of insulating material through one step. This pilot band has been provided with holes or slots at different points in its width, some of which serve to close electrical contacts in a solenoid circuit to vary the printing light intensity, while others actuate a similar arrangement which moves the lens mount relatively to the negative and the positive films for varying the magnification (or reduction). After processing, the positive has printed thereon a multi-coloured viewing screen, the coloured lines of which are caused to register exactly with the elements of each image formed through the coloured lines of the exposure screen, for example, by means of a microscope used in conjunction with the printing roller for the viewing screen. When punching the holes or slots in the pilot band, account may be taken of the contraction or expansion which it is estimated will take place in the positive after processing. Two pilot bands may be advanced by the notched negative, one serving to vary the magnification (or reduction) and the other serving to vary the printing light intensity.