meetlicht

Meetlicht is a term used in metrology and optical sciences to denote a light source with known and stable properties that is used for measurements and calibration. The aim is to achieve repeatable and verifiable measurement results by controlling the lighting conditions.

Etymology and scope: The word is Dutch for “measurement light” from meet (to measure) and licht (light). In Dutch technical literature, meetlicht refers to standard or reference illumination sources whose spectral power distribution, color temperature, and luminance are specified. Meet lights can be artificial sources with defined SPD or, when necessary, calibrated natural light.

Characteristics: Key properties include spectral power distribution (SPD), correlated color temperature (CCT), luminance, temporal and spatial stability, and reproducibility. Measurement procedures rely on light that is stable across time and incident on the object or sensor being tested.

Applications: Used in color measurement and colorimetry, spectrometry, camera and display calibration, printing and textiles quality control, and lighting design research. Well-known examples of reference illuminants used as meetlicht in practice are standard illuminants such as D65 or A, which provide a defined daylight and incandescent reference respectively.

Relation to standards: International standards from CIE and ISO define standard illuminants and measurement procedures; these specifications are adopted as meetlicht in laboratories to ensure comparability of results across devices and institutions.

See also: metrology, colorimetry, standard illuminants, spectrometry, calibration, luminance.