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photometer
Sign in to savethumb|A photometer A photometer is an instrument for measuring photometric quantities such as luminous flux, illuminance, or luminance.
Wikidata facts
- Subclass of
- optical instrument
Show 3 more facts
- described by source
- Internet Archive
- Commons category
- Photometers
- P13411
- Ivan Ukhov
Sources (2)
via Wikidata · CC0
~12 min read
Encyclopedic overview
13 sectionsContents
- History
- Rumford's photometer
- Ritchie's photometer
- Method of extinction of shadows
- Principle of photometers
- Photon counting
- Photography
- Visible light reflectance photometry
- UV and visible light transmission photometry
- Infrared light transmission photometry
- Atomic absorption photometry
- See also
- References
thumb|A photometer A photometer is an instrument for measuring photometric quantities such as luminous flux, illuminance, or luminance.
Historically, photometry was done by estimation, comparing the luminous flux of a source with a standard source. By the 19th century, common photometers included Rumford's photometer, which compared the depths of shadows cast by different light sources, and Ritchie's photometer, which relied on equal illumination of surfaces. Another type was based on the extinction of shadows.
Excerpted from Wikipedia’s “photometer” article, available under the CC BY-SA 4.0 licence.