A spectrometer calibrated in absolute radiometric units that records the spectral power distribution of a source or of light falling on a surface. From one reading it can compute illuminance, chromaticity, CCT, Duv, CRI, TM-30 values, melanopic quantities and flicker on some models. Handheld units are standard for field verification and mock-ups; lab units attach to integrating spheres and goniophotometers.
Take the spectroradiometer to the mock-up and get CCT and Duv for each sample, the eye can't tell us which one is greener.
Also heard as
- spectro
Related terms
SPD
Spectral Power Distribution: a graph of how much power a light source emits at each wavelength.
Illuminance meter
A handheld meter that reads the light falling on a surface in lux or foot-candles, commonly called a light meter.
Integrating sphere
A white-lined hollow ball that spreads a source's light evenly so one detector can read its total lumens and color.
Duv
How far a white light's color sits above or below the blackbody line, giving it a green or pink tint.
Melanopic EDI
Melanopic Equivalent Daylight Illuminance: a measure, in lux, of how strongly light stimulates the eye's circadian system.