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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."
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.
Hyperbole is the worst thing ever.
Full spectrum refers to fluorescents. Most cheap fluorescents have light that spectrally has a few peaks on visible wavelengths, and minimal or no light on others, though the light sill looks white to the eye. Full spectrum fluorescents have a mix of phosphors in them so that light from across the spectrum is emitted by the bulb to some degree - though there are still some peaks and lows nothing is skipped altogether.
Hyperbole is the worst thing ever.
Actually, there are incandescent bulbs (i.e., normal screw-in bulbs with filaments) that purport to offer "Full Spectrum" lighting. I think the issue isn't whether they're fluorescent or not; it has to do with the wavelenghts of light given off.
Karma: Chevy Kavalierma.
I guess should've have mentioned the fluorescents, it seems to have confused you (and probably other folks). The full-spectrum bulbs we have are not fluorescent.
Working toward a usable PDA environment in the spirit of Newton OS: Dynapad
Whether you buy a nice higher color temp incandescent bulb that is labeled 'full spectrum', or you get the cheapest incandescent bulb you can find, you will find that they are both full spectrum. The issue that causes typical fluorescents to only emit light in certain color bands does not affect incandescents. The bulbs labeled 'full spectrum' incandescents are just incandescents with a coating to give them a higher color temp, which just helps to confuse the meaning of the term. I do agree that higher color temp light is nicer.
Hyperbole is the worst thing ever.
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...
Please help metamoderate.