| 摘要 |
A programmable exposure control device for use on a photographic film printer for producing special effects in motion pictures such as a fade-in, fade-out, lap dissolve or other numerous special effects requiring variations in printing beam intensity. The exposure control device comprises a mechanical shutter capable of progressively varying the intensity of the printing beam at any predetermined rate. A control system is provided for operating the shutter and includes a memory portion for storing preselected operating curves for a plurality of film exposure characteristics. The control unit is connected to a tape reader for supplying information to the control unit, for example, relating to the length of the particular fade desired. The tape reader also may provide information for controlling the position at which a fade or other special effect is to begin or end. The control unit also includes a multiple feedback servoloop portion including both position and velocity feedback of the shutter to correct for any deviation from the programmed values. An auxiliary manual control is provided for opening and closing of the shutter, and the entire control unit is optically isolated from the film printer.
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