Halogen bulbs seem to be nearly as alerting as most daylight CFL bulbs



  • I'm noticing that most daylight cfl and tubular lights whether 4000 through 6500K, don't have nearly the amount of alerting light as I would expect. In fact these lights usually don't feel as alerting as I would expect.

    Although halogen bulbs have considerably more red and orange, they also seem to have much more green light and about the same of aqua and blue as well. Am I right in believing that halogen bulbs emit similar amounts of alerting light, and would they be a good wake up light vs a daylight cfl?

    I don't need high quality colors for a wake up light but considering green is just as alerting as bluer light, up to an hour of exposure, would it give old halogens the advantage for alerting effects, or is the subdued orange and yellows of fluorescent bulbs the better spectrum for this purpose?


  • f.lux team

    You're talking about how you feel when looking at a light? That is not a bad way to understand what's going on - at least the subjective alertness measures seem to correlate well to EEG.

    The short answer is we don't know (for shorter exposures) exactly what spectrum is the most stimulating. The red light may reduce the impact somewhat, but the main thing at this level is intensity....so if you want to feel more alert, you should find ways to raise the light levels.