Photocopying – Projection printing and copying cameras – Illumination systems or details
Patent
1994-03-23
1995-06-13
Wintercorn, Richard A.
Photocopying
Projection printing and copying cameras
Illumination systems or details
355 77, G03B 2774, G03B 2780
Patent
active
054248043
ABSTRACT:
A method and apparatus for establishing optimum film exposure time for documents of different reflectances, A photo-sensor is used to produce a signal proportional to the intensity of light reflected from the document to be microfilmed, The signal is integrated and a time is determined for the integrated signal to reach a threshold or reference value, The time needed to reach the threshold value is measured very accurately by a microprocessor, The measured time is then convened to new time by using a look-up table, The new or desired shutter time is controlled by the microprocessor by terminating the exposure when the total time the shutter was open equals new exposure time found in this look-up table.
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Arndt Dennis R.
Eastman Kodak Company
Wintercorn Richard A.
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