A Wide Dynamic Range Photometer for Film Densitometry
A wide dynamic range photometer has been designed with a photomultiplier operated at constant anode current by means of a feedback circuit. The output of the photometer is accurately proportional to the logarithm of light intensity over a range as great as eight decades. The internal feedback loop is stable, with a unity-gain bandwidth up to 100 kHz, depending on the photomultiplier type and anode current. Day-long stability is better than 1% or 0.004 log units. The photometer is being used in a photographic film scanning microdensitometer.
- Print ISSN
- 0361-4573
- Published
- 1971-06
- Content type
- Original Research
- DOI
- 10.5594/J05788
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