Patent GB-574138-A (GB)
Title: New or improved apparatus for stripping photographic multilayer film
IPC: G03C7/20
Filed: 1943-08-09
Abstract: 574, 138. Colour photography. KODAK, Ltd. Aug. 9, 1943, No. 12820. Convention date, Aug. 7, 1942. [Class 98 (ii)] Apparatus for use in transferring an emulsion layer-from a first perforated strip to a second similarly perforated strip by a process in which the adhesion of the emulsion layer to the first perforated strip is reduced by treatment with a liquid, comprises a vessel for the liquid, means in the vessel for registering the strips by their perforations and pressing them together, and rolls for directing the strips to the registering and pressing means and in which the rolls for guiding the first perforated strip are adjustable in position to enable the length of path of the first perforated strip in the vessel to be varied. A rubbing device may be provided in the vessel for removing from the emulsion surface fragments of stripping layer remaining from a previous stripping operation. The stripping, film of Specification 574,137 may be used, and the method of Specification 574,164 adopted. As shown, the perforated subbed support is drawn from supply roll 21 into water-tank 29 round rollers 23, 24 mounted on sliding bracket 28, between water-jets 40 and then over the driven sprocket 27 (or a pin-belt of suitable length). Film Frgb is drawn from supply roll 31 into the water-tank 29 round rollers 33, 34 also mounted on slidable bracket 28, and then passes between guide rollers 36 and wiping rollers 37 having perforated walls covered with sponge, liquid being forced through the roller perforations. The film Frgb then passes to sprocket wheel 27, where it is pressed into registered contact with film F by roller 39. Jet 41 removes air bubbles and particles, and an air-jet 42 removes surplus liquid. The films are taken off the sprocket wheel 27 over the flanged roller 43 between the guide roller 44 and the flanged roller 45, where they are separated, one film Fb carrying the blue sensitive layer (and the filter layer) being passed through drying chamber 49 to wind-up spool 51 and the other film Frg carrying the red and green sensitive layers being passed through drying chamber 46 to the wind-up spool 48. The filter layer is decolourised at a later stage in the processing. The speed of sprocket 27 and the position of bracket 28 are adjusted to control the length of time that the films are wetted in tank 29. The teeth of sprocket wheel 27 may completely fill the perforations on one side of the film and may leave a space in the perforations on the other side of the film to allow for transverse shrinkage or swelling of the film. The green-sensitive layer is transferred to a fresh support by a second passage through the machine. The stripping interlayer is removed from both films by a passage through a tank containing 25 per cent ethyl alcohol prior to development, the action being assisted by gentle wiping. The three separate films are developed, fixed, and washed, and may be printed on to positive stock and imbition relief printing matrices prepared therefrom and after dyeing up used to print a multicolour image. The invention may be applied to a two-layer film, which may be used in a two-colour process or may constitute one element of a bipack, the other element comprising a support carrying a single sensitive layer. Alternatively, the two-layer film may be used in conjunction with a one-layer film in a camera having a beam-splitting device. Specifications 447,748 and 529,440 also are referred to.