Totally off the wall, but perhaps here's the best place for this since it does have to do with Photons.

Ok, so perhaps this should be posted at WebMD or the Mayo Clinic, but I was curious if any of you in the far north (or south in June) have ever tried using your LED light boxes to treat SAD instead of buying something cheesy like this: Amazon.com: The Litebook Elite Full Spectrum Therapeutic Lamp: Health & Personal Care


Those of you in Canada, Iceland, upper USA, etc. know what I'm talking about. You guys in SoCal and Texas might not, but due to lack of winter sunlight people use light therapy to make up for it so they don't go totally crazy.

They are using LEDs now in these units and I thought my Coolights might be better yet... Haha! Then again it might blow my eyes out (although you don't stare at the light, but set it off to the side). Seems the biggest concern people have is the UV rays they emit. Not sure if LEDs have that problem. Maybe Richard can chime in if he's around.

I'm going to give it a go tomorrow. If I don't post back for a while with a report, you'll know that I'm blind and it wasn't a good idea.

I hope no one is asking people to stare into it. Definitely a bad idea. From the side, ok.

Also I sincerely doubt the unit in the link is really full spectrum. No one LED is going to be able to cover the same spectrum that real daylight (or tungsten or carbon arc which are the only real full spectrum sources available). LEDs aren't full spectrum (at this point). And that's probably not all a bad thing. Full spectrum (if its really full spectrum) would also bring unwanted things with it like too much UV and infrared as well. Those aren't things we appreciate in "cool" studio lighting. Is it possible that those components add something to the light even if not readily visible that makes it more "full" and gives better color rendering? Yes but we use other sources like fluorescent which aren't full spectrum and they work well. I know that some say they have a "full spectrum" tube but I don't think so. You'll also notice they don't provide a photo-spectral analysis in most cases too. So you can see the supposed comparison to daylight.

We have some tricks we can do to make up for that lack of spectrum, like the bi-color fixture idea but its all an approximation which at least brings the parts of spectrum in (particularly more red) to give us higher CRI in the output.

To make a SAD fixture, maybe a combination of high color temp, low color temp (whereas the mixture of light from the two would give around 5000 to 6000K color temperature) and UV emitting LEDs for example would get you closer to real sunlight's spectrum but even then I'm not sure about it. So it would probably take 3 different kinds of LEDs, mixed together in the fixture, to make that SAD type fixture. You can experiment with the single color daylight fixtures like ours to see if it does any good, but I'm betting its hard to really replace sunlight with a man-made fixture.

i think part of the solution is the intensity of light hitting the eye and skin to mimic sun.
You can probably have the same power with bulbs and leds but it would cost the hell, since high power with led is difficult to reach for cheap.
For sure the Mayo clinic does not have this kind of concern.....

...perhaps this should be posted at WebMD or the Mayo Clinic, but I was curious if any of you in the far north (or south in June) have ever tried using your LED light boxes to treat SAD...

Part of the point of light boxes to treat SAD is UVB. It's the UVB light that triggers production of vitamin D in the skin. Most LED light sources don't produce any significant UV light at all. Indeed, since UV light is in most cases undesirable, some effort is usually taken to insure that LED light sources produce minimal UV.

But... you can always try it and see.

Just my two cents:

Blue light (460-480nm) is most effective at inhibiting melatonin production by the pineal gland via the visual pathway; you don't need full spectrum light. It shouldn't be a glaring light in your face (moderate intensity in your peripheral vision is what we do) and of course whatever device you use should not emit UV. Blue light is used for SAD and circadian shifting.

Since my alma mater, the Mayo Clinic, was mentioned...here is a brief SAD article from that esteemed institution:
Light therapy - MayoClinic.com (http://www.mayoclinic.com/health/light-therapy/MY00195)

FWIW, in the professional practice I'm a part of, we deal extensively with shift work and jet lag. Our experts recommend this Philips light for our shift workers and travelers: http://download.p4c.philips.com/files/h/hf3331_60/hf3331_60_dfu_aen.pdf

Not at all saying it is the only one that works, just that our team evaluated and chose this one. Unless you have particular expertise in both engineering and light therapy, it is probably wiser to use a device that's purpose built by a reputable manufacturer than DIY.

HMI bare bulbs emit a lot of UV.

But the cheapest solution is to buy a plane ticket to Miami. :)

Part of the point of light boxes to treat SAD is UVB. It's the UVB light that triggers production of vitamin D in the skin. Most LED light sources don't produce any significant UV light at all. Indeed, since UV light is in most cases undesirable, some effort is usually taken to insure that LED light sources produce minimal UV.

But... you can always try it and see.Agree, deliberate self-treatment with UV is not a good idea. Vitamin D production by the skin is really a separate issue and not part of light therapy for either Seasonal Affective Disorder or Circadian Desynchrony. I wouldn't argue too vigorously against small amounts of careful exposure to sunlight but I'd much rather have folks get adequate Vit D through proper diet and if necessary D3 supplements made by a reputable pharmaceutical company than self-treating with UV light sources.

Again, don't DIY treatment devices!

To keep myself from getting depressed (in winter or any time of the year) I don't use any fluorescent "energy saving" bulbs or LEDs.
There's only tungsten and halogen lights in my apartment for the reason that looking at the light of an "energy saving" fluorescent (no matter what color temperature) makes me go crazy in less than a minute. They all have a certain color hue (some green, some magenta) and they all lack a lot of frequencies in the light spectrum. With LED's it's the same, although not as bad as with household fluorescents.

Unfortunately, the EU wants to force us to use "energy saving" bulbs and started banning tungsten lamps, step by step. I already stock-piled tungsten bulbs so I can live happily for at least a few years, and then I hope they realize the "energy saving" fluorescents were a really bad choice for public health!

Professional Fluorescents and LEDs are better, they usually have a higher CRI for better color reproduction, but they still can't beat a halogen bulb!
This is purely subjective, based on what I see and how I feel when I see it. Professional fluorescents and LEDs are really fine tools for lighting video, no doubt about that - but that is somewhat different from how the light affects your mood in real life.