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> single-colour bulbs Incandescent light isn't single-color, it's all of them. Evidently that matters to some people. Things that don't matter to you might leg

by User23 3y ago

> single-colour bulbs Incandescent light isn't single-color, it's all of them. Evidently that matters to some people. Things that don't matter to you might legitimately matter to other people.

tivert 3y ago
https://en.wikipedia.org/wiki/Color_rendering_index https://en.wikipedia.org/wiki/Color_rendering_index: > A reference source, such as blackbody radiation, is defined as having a CRI of 100. This is why incandescent lamps have that rating, as they are, in effect, almost blackbody radiators.[24][25] The best possible faithfulness to a reference is specified by CRI = 100, while the very poorest is specified by a CRI below zero. I believe the best non-incandescent bulb I've seen had a CRI of 92, but (IIRC) most bulbs don't list a number (so can be assumed to be mediocre). I don't know if it's gotten better, because I haven't deep-dived into it for a few years.
- Syonyk 3y ago
  The big one to look at with CRI is the R9 index. That's the "pure red" rendering, and it's not included in the main CRI measurement. There are two types of bulbs: Those in which the R9 value is solid, and they report it, and those in which they don't report it, which means the value is crap. You can have a reasonably high CRI for the main 8 elements, and still have very little red, which is something humans are quite sensitive to in terms of perceived light quality. It's not hard to find R9 ratings of >90 in LEDs, but you're into high end LEDs that cost quite a bit more (some of the really high end ones are $30/bulb in small quantities), and the efficiency is somewhat less (lumens per watt), because putting energy into red is less effective than "putting it all in green" with how human eyes work.
dml2135 3y ago
I’m not sure what you mean by “all of them”. Are you saying that incandescent light is whiter than LED light? I’m pretty sure that’s not the case.
- itishappy 3y ago
  Yup. Incandescent uses thermal emission, which has a smooth spectrum peaking in the IR. LEDs use phosphors (usually a few different ones) targeting specific wavelengths, giving it a "spikier" spectrum. https://www.researchgate.net/figure/Emission-spectra-of-different-light-sources-a-incandescent-tungsten-light-bulb-b_fig1_312320039 https://www.researchgate.net/figure/Emission-spectra-of-diff...

by User23 3y ago

> single-colour bulbs Incandescent light isn't single-color, it's all of them. Evidently that matters to some people. Things that don't matter to you might legitimately matter to other people.

tivert 3y ago

https://en.wikipedia.org/wiki/Color_rendering_index https://en.wikipedia.org/wiki/Color_rendering_index: > A reference source, such as blackbody radiation, is defined as having a CRI of 100. This is why incandescent lamps have that rating, as they are, in effect, almost blackbody radiators.[24][25] The best possible faithfulness to a reference is specified by CRI = 100, while the very poorest is specified by a CRI below zero. I believe the best non-incandescent bulb I've seen had a CRI of 92, but (IIRC) most bulbs don't list a number (so can be assumed to be mediocre). I don't know if it's gotten better, because I haven't deep-dived into it for a few years.

Syonyk 3y ago
The big one to look at with CRI is the R9 index. That's the "pure red" rendering, and it's not included in the main CRI measurement. There are two types of bulbs: Those in which the R9 value is solid, and they report it, and those in which they don't report it, which means the value is crap. You can have a reasonably high CRI for the main 8 elements, and still have very little red, which is something humans are quite sensitive to in terms of perceived light quality. It's not hard to find R9 ratings of >90 in LEDs, but you're into high end LEDs that cost quite a bit more (some of the really high end ones are $30/bulb in small quantities), and the efficiency is somewhat less (lumens per watt), because putting energy into red is less effective than "putting it all in green" with how human eyes work.

dml2135 3y ago

I’m not sure what you mean by “all of them”. Are you saying that incandescent light is whiter than LED light? I’m pretty sure that’s not the case.

itishappy 3y ago
Yup. Incandescent uses thermal emission, which has a smooth spectrum peaking in the IR. LEDs use phosphors (usually a few different ones) targeting specific wavelengths, giving it a "spikier" spectrum. https://www.researchgate.net/figure/Emission-spectra-of-different-light-sources-a-incandescent-tungsten-light-bulb-b_fig1_312320039 https://www.researchgate.net/figure/Emission-spectra-of-diff...