GB434434A - Improvements in or relating to the production of copies from multi-colour screen cinematograph films - Google Patents

Abstract

434,434. Colour photography. HARRISON, G. B., 23, Roden Street, Ilford, Essex. March 1, 1934, No. 6642. [Class 98 (ii)] In order to produce a large number of copies of a multicolour-screen master negative or positive without undue damage to the master, sets of intermediate colour-separation prints are made from the master on plain sensitive material, and from each set finished copies are prepared by printing the components, each with light of the appropriate colour, in register on multicolour-screen sensitive material. In either or both printing stages, the images may be slightly diffused in known manner to compensate for lack of registration of the screen elements on the master and the final copies. The separation prints 2, 3, 4 may be produced by contact printing from the master 1 as shown in Fig. 1, using parallel printing beams G<1> G<2> of the appropriate colours which are dispersed by prisms 5 and lenses 6 to form pure spectra at 7 from each of which unwanted light is masked by an appropriate masking plate produced as described in Specification 417,860. Instead of dispersing and masking the beams, a sharpcut filter may be inserted in the path of each beam. The light beams are concentrated on their respective gates by lenses 8, and registration is affected by the sprockets 10. Similar apparatus is used for printing the final copy from the intermediate separation prints. Advantage may be taken of the fact that the light beams at the printing gate are not parallel to produce slight diffusion of the image if provision is made for a slight separation between the films in the gate. To ensure that the correct set of images is printed in each image space, a perforation is made at the beginning of each of the printing and print films in appropriate position, and these perforations are registered by spring pins 16 before printing is begun.