GB322454A - Improvements in or relating to apparatus for making mosaicscreens for colour photography - Google Patents

Abstract

322,454. Wade, H., (Compagnie d'Exploitation des ProcÚdÚs de Photographie en Couleurs L. Dufay, [known as Versicolor Dufay]. Aug. 4, 1928. Colour photography, multicolour screens for.- A machine is described for treating a long strip of dyed sheet material, e.g. a. cellulose acetate film, having a resist pattern printed thereon for the production of two-colour or multi-colour screens of the kind described in Specifications 217,557 and 322,432. The film or strip 14, Fig. 1, passes first over a decolourizing trough 15, for decolourizing the parts not protected by the resist. This trough is mounted on adjustable arms 16 so that the film is not immersed in the trough; and the rollers 20 under which the film passes are adjustable longitudinally so that the extent of the decolourizing can be regulated. This feature is more especially for providing a longer treatment during a second decolourizing treatment for making multi-colour screens. From the trough 15 the strip passes under a roller 21 upon which it receives dye from an ebonite roller 22. The latter dips into a dye trough 23 and is adjusted so that it rotates in proximity to, but not in contact with, the strip. It may rotate at a speed greater than the passing speed of the strip, or it may be rotated in the opposite direction. From the dye roller the strip passes under a larger roller 24 and is washed by jets from pipes 26. The strip then passes over absorbent rollers 29 in a zig-zag path to dry it, and passes thence through one or more troughs 31 containing a solvent for the resist and also provided with driven wiping rollers 44. It may then pass through a degreasing trough 32, also fitted with driven wiping rollers 44a acting on both sides of the strip, and then through a rinsing trough 33 which has no wiping rollers. Thereafter the strip passes over a staggered series of absorbent rollers, and then over heated drums to a storage reel. The troughs 31, 32, 33 are mounted on a vertically-adjustable, platform 34, and squeeze rollers 40 are fitted in conjunction with the driven rollers 38 over which the strip passes. In the machine, all rollers over which that side of the strip which carries the resist material passes preferably comprise two conical roller elements at the ends, so that only the edge of the strip is engaged.