Light, through a human lens.
NIST describes photometry as measuring light while accounting for the sensitivity of human vision. It differs from radiometry, which includes radiation beyond the visible range. A photometric value is therefore a defined measurement—not a complete description of how a room feels.
Source: NIST, Photometry (page updated 26 March 2025).
Read the number with its context.
Our editorial checklist: what quantity is reported, in which unit, under what conditions, and by whom? A manufacturer specification and an independent test should not silently become the same thing.
Boundary
This introduction does not evaluate a lamp’s effects on health, sleep or mood. Those would require separate, relevant evidence.
From terms to a practical question.
For ordinary task and display lighting, the next step can be simple: consider placement, reach, controls and care. No purchase is required to begin looking.
Read The Light Edit >— First source review and publication of this note.
A dated starting point, not a continuously monitored or systematic review. See the research log.