Debunking Full-Spectrum Lighting Claims

GreenSwirl writes "Full-spectrum light sources often are claimed to promote health, mood and productivity in schools and offices. The Lighting Research Center at Rensselaer Polytechnic Institute in Troy, New York, has published an independent report evaluating full-spectrum light sources. Practically all health claims are debunked and many products are shown to have a less-than-full spectrum. The report was produced as part of the National Lighting Product Information Program, an objective third-party funded by government and utilities."

Comments

Re:Bah, it just looks nicer!

[moof1138]

Color temperature and 'full spectrum' are not really the same thing. A lot of cheap fluorescents have a low color temp around 2700 that looks yellowish, but you can buy fluorescents that have a higher color temp. Depending on what you like 3500-4100 bulbs are out there that will put out light that looks 'whiter', though if you go high you get a bluish look about 4500.

it's because of your flourescent bulbs

[SuperBanana]

However, we use full-spectrum bulbs a few places around the house, anywhere we don't have flourescent bulbs. Why? It just looks nicer! My SO and I can't stand the yellowness of regular bulbs, and we prever the whiter light of the full-spectrum guys, especially for reading and similar activities.

Siiigh. Okay, let me put my theatrical lighting designer hat on.

Your brain has a sort of biological "automatic white balance". It gets 'used to' different lighting so you 'see' the same colors.

This is both exploited by, and an annoyance for, lighting designers- if you have a very 'cool' scene, the next that follows will appear much warmer than it would to someone, say, walking in off the street.

The problem here is that you're used to the flourescent bulbs(which have a very high color temperature, ie, they're "cool" light- yes, it's odd). When you walk into a room with a regular incandescent bulb, your brain is 'calibrated' for the floursecent bulb and the light seems very warm. In the theater industry, there are specifically designed correction 'gels'(filters that look like they're plastic, but they're not- plastic would melt) for flourescent, HID and incandescent bulbs to make them 'look' like other light sources, or at least get them to a common baseline to then further color them with another gel.

This effect works in other ways- headlights look yellowish during the day but bright white at night. People driving cars with HID lights see 'normal' headlights as looking very yellowy; we see the HID lights as looking very blue.

If you want to see the effect yourself, find some lightly colored plastic, preferably light blue or light orange. Hold it over one eye, with the other closed, and after a minute or two, remove the plastic and note how the room looks different lighting-wise...