GB717872A - Improvements in or relating to apparatus for ensuring registration in photographic reproduction processes - Google Patents

Abstract

717,872. Photographic apparatus. NICHOLLS, R. H., and STENT, A. H. Aug. 4, 1950 [May 4, 1949], No. 11691/52. Divided out of 717,821. Class 98(2) An apparatus for ensuring registration in reproduction processes, and described more particularly for use within a process camera, comprises a rectangular main frame 1 as of angle iron provided with lugs 2 for mounting the frame upon or in place of the normal half-tone screen carrier, and having an apertured mount at one or both sides of the main frame 1 and hingedly secured thereto, the mounts being shown as parallel to the frame on the left side and normal thereto on the right. Each mount is carried by a vertical bar 3 rotatably mounted in the frame 1 and comprises upper and lower members 11 connected to lugs 12 slidable longitudinally on the bar 3, with set screws 13 to secure the members 11 in adjusted position, and is completed by a rod 14 provided with similar lugs and set screws. The left hand mount has tongued clips 17 on the members 11 to hold a representation such as a diapositive and the other one has holders adapted to accommodate a half-tone screen. To permit swinging of one or other of the mounts into and out of position in front of a focusing screen or sensitive surface in a camera and also to allow for axial distancespacing of the screen without entrance of light each bar 3 has a lever arm 4 secured to its upper end. and each lever arm 4 has a pivot pin 5 which engages in and is slidable along a slot 6 in a co-operating lever arm 7 fixed to the lower end of a shaft 8 which projects through, the top 9 of the camera, and is bent to form an external handle 10. In use a colour transparency which may be mounted in the apparatus of the main Specification 717,821 is set up in front of the camera and a tracing of its image is made on linen or paper fixed to the focusing screen, then a diapositive of the line work made to the same scale as the finished job in the left hand mount is swung into position and adjusted for register, after which successive exposures with or without the line diapositive and the screen in position can be made for as many colour separation negatives as desired, registration being maintained. Exposure of the line work with the screen swung out of position gives better definition.