3 ms·

Curious if LEDs can really match the black-body that is our sun (and therefore incandescents). I would get/build such a thing for my mental health, but I worry

Curious if LEDs can really match the black-body that is our sun (and therefore incandescents). I would get/build such a thing for my mental health, but I worry the LED illumination will be counter-productive.

jedbrooke 9mo ago
I've found that a 250w incandescent bulb (can be had for ~$10) paired with a 4000 lumen LED produced decent results on a budget. Search for "reptile" or "chicken" lamps, they are usually red. You can feel the HEAT from a 250w light bulb. The only thing to watch out for is that the lamp base you're using can support the high wattage.
syncsynchalt 9mo ago
Look for the CRI rating of bulbs that you buy. It's a measurement of how close to a blackbody spectrum the bulb is putting out, the highest fidelity being 100. Note that this is not the temperature measurement, and you can have e.g. 2700K or 5000K bulbs with high CRI. Newer LED phosphors are typically 90+ CRI, and I commonly find 93 CRI bulbs available off the shelf. https://en.wikipedia.org/wiki/Color_rendering_index https://en.wikipedia.org/wiki/Color_rendering_index
- hollerith 9mo ago
  Sunlight diverges significantly from a black-body spectrum because the atmosphere absorbs so many wavelengths.
  - syncsynchalt 9mo ago
    I didn't want to mention that CRI is matched against the spectrum of _daylight_ because of the confusion that happens with color temperature when you mention the "daylight" word. You're right though, the CRI reference spectrum is matched against sunlight rather than a true blackbody.
- JKCalhoun 9mo ago
  Interesting. The Wikipedia entry mentions SPD and I think that is where I think LEDs fall down—having a skewed and/or incomplete spectrum. Even though it may make certain target colors look correct.
- hillac 9mo ago
  Even high cri lights have a huge blue spike that doesn't match the sun. I don't know what chip OP uses, but you need a full spectrum light if you actually want very sun-like light. This page has some details: https://optimizeyourbiology.com/best-natural-full-spectrum-lights https://optimizeyourbiology.com/best-natural-full-spectrum-l... No idea if there's any evidence or not of the blue spike actually mattering for human biology.
  - JKCalhoun 9mo ago
    Kind of what I worry about—the spectrum mismatch. Damn but incandescents sound pretty good for just this one application. I must be (am) getting old.
AngryData 9mo ago
I have seen a couple studies that show having/adding deep red is an important part of LED lighting because deep red penetrates your skin the deepest and is used as a signal to your body that it is receiving light/sun. Personally if I wanted "daylight" replicated by LEDs I would go for a higher quality white grow light that included deep red LEDs. Just be sure you don't get one that is also outputting in the UV range, although most don't.
pocksuppet 9mo ago
Any spectrum you want with the right phosphor mix, but are they commercially produced, or must you make your own?

jedbrooke 9mo ago

I've found that a 250w incandescent bulb (can be had for ~$10) paired with a 4000 lumen LED produced decent results on a budget. Search for "reptile" or "chicken" lamps, they are usually red. You can feel the HEAT from a 250w light bulb. The only thing to watch out for is that the lamp base you're using can support the high wattage.

syncsynchalt 9mo ago

Look for the CRI rating of bulbs that you buy. It's a measurement of how close to a blackbody spectrum the bulb is putting out, the highest fidelity being 100. Note that this is not the temperature measurement, and you can have e.g. 2700K or 5000K bulbs with high CRI. Newer LED phosphors are typically 90+ CRI, and I commonly find 93 CRI bulbs available off the shelf. https://en.wikipedia.org/wiki/Color_rendering_index https://en.wikipedia.org/wiki/Color_rendering_index

hollerith 9mo ago
Sunlight diverges significantly from a black-body spectrum because the atmosphere absorbs so many wavelengths.
- syncsynchalt 9mo ago
  I didn't want to mention that CRI is matched against the spectrum of _daylight_ because of the confusion that happens with color temperature when you mention the "daylight" word. You're right though, the CRI reference spectrum is matched against sunlight rather than a true blackbody.
JKCalhoun 9mo ago
Interesting. The Wikipedia entry mentions SPD and I think that is where I think LEDs fall down—having a skewed and/or incomplete spectrum. Even though it may make certain target colors look correct.
hillac 9mo ago
Even high cri lights have a huge blue spike that doesn't match the sun. I don't know what chip OP uses, but you need a full spectrum light if you actually want very sun-like light. This page has some details: https://optimizeyourbiology.com/best-natural-full-spectrum-lights https://optimizeyourbiology.com/best-natural-full-spectrum-l... No idea if there's any evidence or not of the blue spike actually mattering for human biology.
- JKCalhoun 9mo ago
  Kind of what I worry about—the spectrum mismatch. Damn but incandescents sound pretty good for just this one application. I must be (am) getting old.

AngryData 9mo ago

I have seen a couple studies that show having/adding deep red is an important part of LED lighting because deep red penetrates your skin the deepest and is used as a signal to your body that it is receiving light/sun. Personally if I wanted "daylight" replicated by LEDs I would go for a higher quality white grow light that included deep red LEDs. Just be sure you don't get one that is also outputting in the UV range, although most don't.

pocksuppet 9mo ago

Any spectrum you want with the right phosphor mix, but are they commercially produced, or must you make your own?