Title: attenuance filter
Long Title: IUPAC Gold Book - attenuance filter
DOI: 10.1351/goldbook.A00514
Status: current

Definition
An optical device (filter) which reduces the radiant power of a light beam by a constant factor over all wavelengths within its operating range. Sometimes called attenuator or neutral density filter.

Related Terms
- filter: https://goldbook.iupac.org/terms/view/F02384
- radiant power: https://goldbook.iupac.org/terms/view/R05046

Source
- PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2229 (https://doi.org/10.1351/pac199668122223)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/A00514/html
- json: https://goldbook.iupac.org/terms/view/A00514/json
- xml: https://goldbook.iupac.org/terms/view/A00514/xml

Citation: Citation: 'attenuance filter' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.A00514
License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.
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Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.
Accessed: 2026-06-28T21:08:57+00:00