Comment by wheels | Hacker News Reader

Comment by wheels | Hacker News Reader

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> I absolutely hate LEDs. I don't know why, but...

I'm really interested in the why. Most people don't seem to care. My in-laws have CFLs in their living room that just feel horrible to me, but they're none the wiser. I'm very curious as to what it is in the light spectrum that seems to matter to some (small) class of people, myself, and it sounds like you, included.

The word for "fire-like" light, used in my original comment, is "black-body radiation". Stars, fire and incandescent bulbs put out a similarly shaped spectrum.

A few years ago there were scientists working on a black-body (i.e. incandescent) light bulb that reflected infrared emission back to heat the filament and re-emit as visible light making for a theoretically efficient incandescent bulb. I check every year or so to see if the research has been commercialized, but have always been disappointed:

https://www.dezeen.com/2016/01/13/mit-energy-efficient-incan...

Edit: Another point on the blueness of LEDs is that they seem to amplify macular degeneration, which has made my grandmother mostly blind, and I know based on gene sequencing that I have a more than 50% chance of developing. While most of my rejection of LEDs is based on them not looking nice to me, I am also worried about hurrying the onset of blindness in old age for persons like myself who carry the genes for macular degeneration:

https://edition.cnn.com/2019/05/16/health/blue-light-led-hea...

Well, fire does not shine by black-body radiation. Lamps try to emulate a black-body because that's what color standards dictate and labs test against, but fire has a very bad color resolution. (By the way, daylight isn't also like black-body radiation, but it's much closer than fire.)

Personally, flickering makes me ill. I am used enough to 120Hz to survive it, but any other frequency is bad. Also, the 6400K LEDs look way too blue, much bluer than the Sun. That may be because I have a relatively rare kind of color blindness.

> Well, fire does not shine by black-body radiation

Flame, not entirely; embers, yes.

huh that's really interesting about fire's emission spectrum!

regarding 6400k - even assuming the sun's spectrum matched the black body spectrum of its surface temperature, its surface temperature is closer to 5770k. but even taking that into account, its spectrum doesn't quite match 5770k in space - and the atmosphere changes it even further. https://en.wikipedia.org/wiki/File:Solar_spectrum_en.svg

I really don't know how much of that change us humans can perceive, but my thinking is that 5000k is probably closer to the center, at least. it might be more of a saturated color, though, since the spectrum is more pointed vs the very flat but spikey spectrum in that plot.

> I'm really interested in the why. Most people don't seem to care. My in-laws have CFLs in their living room that just feel horrible to me, but they're none the wiser.

My first suspicion would be the spectrum of light emitted, which is mostly reflected in the CRI [1].

CFLs in particular "cheat" by having a couple really strong peaks of very specific wavelengths that to your eyes (or reflecting off a white surface) look like the right color, but when reflecting off anything they have reproduce colors inaccurately -- it's beyond my ability to explain this in detail, but you can see this in some spectrum charts [2].

LEDs vary greatly in this respect, so if you're concerned, you should really be paying close attention to the CRI (and note, as CRI goes up, so does cost).

[1] https://en.wikipedia.org/wiki/Color_rendering_index

[2] https://www.ledsmaster.com/color-rendering-index-cri-versus-...

psa: you can get this thing, which isn't the most precise ever, but lets you see this spectral information about lights for cheap: https://www.amazon.com/EISCO-Premium-Quantitative-Spectrosco... - I got one and WHEW CFLs' band lines are really obvious. Also, I feel kind of tickled that I saw the band gap on LED lights before seeing a description of what it is in the source for the spectrum plots in this article (the source being https://commons.wikimedia.org/wiki/File:White_LED.png ).

I'm a bit miffed it seems so hard to find lights that don't have this problem, though. maybe we can improve it by getting the word out that these cheap little diffraction devices can give you a pretty good approximate reading of the smoothness of the spectrum of a light source. Hmm, I just realized I have yet to take this to home depot...

I'm really curious about those MIT incandescent bulbs. If they worked well and haven't been brought to market, it's possible that contacting the people involved in creating them could have good results in making them happen. Perhaps they could be convinced to prioritize it if a case can be made that it can have a significant positive impact on the world?

I like CFLs but hate most LEDs because they flicker! It's at 120hz, but I can see it and it drives me crazy.

Another thing I hate is LEDs with such a sharp point source them make speckle patterns like a laser.

But I did find some good LEDs and I'm using them now, them seem as good as the CFLs they replaced. Had to return a bunch of bad ones though.

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