Photocopying – Projection printing and copying cameras – Illumination systems or details
Patent
1975-06-26
1977-03-01
Adams, Jr., Russell E.
Photocopying
Projection printing and copying cameras
Illumination systems or details
352 91R, 355 18, G03B 2776, G03B 2136
Patent
active
040099598
ABSTRACT:
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.
REFERENCES:
patent: 2517250 (1950-08-01), Shea et al.
patent: 3480362 (1969-11-01), Dejoux
patent: 3580666 (1971-05-01), Vance
patent: 3682540 (1972-08-01), Oxberry et al.
Langrehr Larry L.
Steiner John H.
Watson Charles J.
Adams, Jr. Russell E.
Bell & Howell Company
Fitz-Gerald Roger M.
Hoffman John R.
Schneider Robert J.
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