Two different glare questions
Discomfort glare causes discomfort without necessarily reducing visual performance. Disability glare involves stray light in the eye that reduces retinal-image contrast and visibility. Both can occur together. Identifying which effect is at issue helps avoid an ineffective remedy. [1] [2]
A glare rating has conditions
IES defines UGR as a measure of discomfort from a lighting system. Do not treat a product label as a universal guarantee for every room and observer position. Ask what layout, viewing direction and calculation conditions accompany the claim. [3]
Inspect the actual field of view
Our review method begins with the occupied position: seated at a desk, approaching a stair or walking past a bright facade. Note exposed sources, bright reflections and surrounding luminance. Try changes in aiming, shielding, source area and placement before assuming a higher or lower lumen package will solve the problem.
Flicker is an imprecise word
IES notes that flicker can refer to physical temporal modulation and to a perceived visual artifact. A useful report identifies the waveform or measurement method, operating condition and the phenomenon being evaluated. A phone video is a troubleshooting clue; it is not a complete laboratory characterization. [4]
Evaluate the operating range
Test controls at full output, dimmed states, fades and transitions. Record the driver and control combination. Our commissioning checklist asks whether occupants, moving tasks and cameras have been considered separately; a successful result for one use does not automatically answer the others.