Patent GB-905691-A (GB)
Title: Electronic motion picture printer
IPC: H04N1/60
Filed: 1959-04-09
Abstract: 905,691. Copying by scanning. HORSLEY, D. S. April 9, 1959 [April 17, 1958], No. 12068/59. Class 40 (3). An arrangement for copying motion picture film by scanning the latter to derive video signals from which a visible image is reproduced and recorded photographically on a second film includes means comprising an electronic computer for controlling the contrast, gamma and, when colour film is being copied, the colour, balance of the copy film and for producing the changes of format necessary when the copy image is to differ from the original in such parameters as size, orientation and speed of film transport. In the illustrated embodiment, which is concerned with copying continuouslymoving colour motion picture film 9 (Fig. 1), the latter is scanned by a single luminous trace line from a flying-spot scanning tube 1 to produce, via conventional electro-optical means, video signals representative of the red, green and blue components in respective channels 30, 31, 32. These signals are then supplied via individual limiting devices 33, 34, 35, in which peak signals produced by scratches on film 9 are replaced by signals representative of the average level of film opacity, to respective amplifiers 36, 37, 38 the gains and gammas of which are controlled in a desired manner in accordance with signals derived from information recorded on e punched (or magnetic) tape in the tape reader portion 39 of the computer. The outputs of the latter amplifier are then supplied to a colour picture monitor tube 94, individual monitor tubes 58R, 58G and 58B which show the amplitudes of the component colour signals and individual singleline scanned picture tubes 46, 47, 48, the images produced by which are projected by conventional optical means in register and in appropriate colours on a continuously moving film 52 on which the copy is produced. When the format of the latter film is to differ from that of film 9 signals derived from information on a punched card in card reader 5 (also forming part of the computer) are employed to (1) supply a vertical deflection component via a vertical adjustment circuit 7 to the scanning yolks of the tubes 1, 46, 47 and 48 and also to impart a vertical tilting motion to such tubes via cams 16 and 66 when the relative speeds and/or vertical dimensions of the frames or the two films are to differ, and (2) turn the direction of the (horizontal) scanning line through 90 degrees by turning the scanning yolks through this angle via worm drivers 12 and 59, when, e.g., the film 9 has pairs of frames side-by-side which are to appear in separate successive frames on film 52. In order to maintain a constant relationship between the motion of the two films and the horizontal scanning thereof the horizontal scanning generator 4 is locked to a reference frequency source, which may comprise a crystal-controlled oscillator or the alternating current power system and a servo control unit 87, controlled by such standard frequency and by signals derived photo-electrically by the motion of the sprocket holes in film 9, supplies driving power to selsyn units 70 and 90 which control the motion of films 9 and 52, respectively. In the arrangement described, only those of the pulses generated by the sprocket holes (of film 9) in the photo-electric assembly 80 . . . 83 which are positioned either just above or just below each film frame (such, in two different film registration systems, being precisely located with respect to the film frames) are gated out in 85 by the passage of each film frame dividing line (a gating pulse for this purpose being derived from the green channel) and supplied to the servo control unit 87, the position of the assembly 80 . . . 83 being adjustable in accordance with control signals from card reader 5 to cater for either system of registration. To produce a sharp pulse from the sprocket holes a mask 125 (Figs. 3 and 4) apertured at 126, 127 is positioned adjacent the film 9 in the optical path between light source 115 and photo-electric device 122, the arrangement being such that as the sprocket hole 124 moves past the apertures the signal generated in device 122 has the form shown in Fig. 5 in which a sharp peak 131, 132, 133, due to reflection from the edges of sprocket hole 124 is superimposed on the lower level signal due to light transmitted through the sprocket hole. This peak signal is then gated out and fed to the servo control unit 87. The Specification describes the use of the apparatus for producing fade-in fade-out effects, copying in monochrome and producing single copy films from a plurality of films for the purpose of producing composite images and for masking effects.