LED lighting undermines visual performance unless supplemented by wider spectra

https://www.nature.com/articles/s41598-026-35389-6

by bookofjoe • 6 months ago

212 208 6 months ago

Very interesting. I've always thought that there was something a bit "off" about LED torches and car headlamps; the brightness is there, but something about the light just doesn't seem to illuminate as well as an old dim incandescent or even fluorescent tube.

rpcope1• 6 months ago

I get that they're more efficient in some sense, but man the LED streetlights and other big lamps are so irritating and make things like like such ass compared to mercury vapor or even sodium lights.

VagabundoP• 6 months ago

Even a colour filter would help with the harshness.

skandinaff• 6 months ago

True. Yet, somehow more and more cities install them blindly because efficiency. I remember when I moved to Odense Denmark in 2013 - they had LED street lights all over the place. I thought - this is the future compared to my uderdeveloped post soviet Latvia. And yet, I remeber when I moved back, streets at night looked so yellow because the city still relied on sodium lights. And my eyes felt much more comfortable. At the time I wrote it off to nostalgia or something, and here we are.

orbital-decay4• 6 months ago

They're saying that the visual performance is indirectly affected by invisible wavelengths somehow. Not that you can see the difference between two types.

siffin• 6 months ago

They are saying that, and most real world LED lighting uses very cheap diodes, like, 99.9999% of them, which create very poor colour compared with incandescent bulbs, which create perfect colour representation.

It's a big thing and you can buy LEDs which produce a better colour range, but they're much more expensive and not as energy efficient, because creating bold reds costs hard energy that no diode trick will ever get around that.

schiffern6• 6 months ago

It's a poorly controlled experiment.

https://news.ycombinator.com/item?id=46764382

nicoburns4• 6 months ago

It's usually the Color Rendering Index (the spectrum of frequencies that the light puts out). Incandescent bulbs more of less mimic that of the Sun, they are "black body radiators". Cheap LEDs tend to be missing a lot of the red spectrum.

However, you can get LEDs that do this well. Look for one with a "CRI" of 95% or higher.

kuschku3• 6 months ago

There's a massive difference between the 2600K of regular incandescent bulbs, and the 6000K of sunlight. That's why hollywood used HMIs until they migrated to LED.

RivieraKid• 6 months ago

The CRI is an imperfect metric, I watch for both CRI and R9, both should be high.

Saris3• 6 months ago

Yes lots of them use cheap LEDs with poor CRI, high color temperature, and a huge blue spike in the spectrum. All of that leads to a very bright looking light that also doesn't let you see detail very well.

mjmas2• 6 months ago

Someone please tell the Australian government now that we've essentially banned other forms of lighting. (except fluorescent)

novok5• 6 months ago

You can't buy heat lamps? They are even more infrared and last longer.

Also LED lighting can have infrared, have a significantly more smoother spectrum curve and still last +20k hours without burnout. The cheaper bulb spectra that they show is a blue led + phosphor coating, but there are infrared LEDs, UV leds, and more. You can make quite the convincing sun simulation, even better than any incandescent bulb, but there is almost no demand for UV + Infrared super full spectrum lighting unfortunately. Only movie & theater lights come close.

krackers6• 6 months ago

LED lighting can have infrared, have a significantly more smoother spectrum curve and still last +20k hours without burnout

Do you have a link to a bulb that you can purchase meeting all these criteria? The only one I'm aware of was this obscure "StarLike" that was never actually sold in bulk. LEDs can be made good in theory sure, but in practice they are all terrible in light quality compared to a standard incandescent.

https://budgetlightforum.com/t/sunlike-vs-starlike/64155/7

u1hcw9nx2• 6 months ago

You can buy full spectrum LED lights (99 CRI, or grow lamps)

The article uses LED as synonym for typical LED lightning.

ale423• 6 months ago

How is "full spectrum" defined in this case? Visible spectrum is not the subject of the paper, as they care about infrared.

RobotToaster• 6 months ago

Call me when there's lights with a cri r9 of 99

dangus2• 6 months ago

Typical electricity rates in Australia are up to 40c/kWh or so.

Do you really think $5 AUD per month per bulb that you’re running 8 hours a day is worth it for better spectrum quality?

mjmas2• 6 months ago

Are we also going to ban powerful computers since they use lots of power?

noosphr5• 6 months ago

I have incandescent light bulbs at home I have to pretty much smuggle from China. It's amazing how we're replaying the asbestos playbook a century later. Only this time it's government mandated.

rrr_oh_man2• 6 months ago

It's amazing how we're replaying the asbestos playbook a century later

Can you elaborate?

wincy• 6 months ago

I’m guessing the Russian theory that asbestos is totally fine and isn’t harmful? The Russians still use asbestos and say it’s a plot by the west that we got rid of asbestos in our buildings. (Don’t shoot the messenger here, I have no dog in this fight and am not expressing an opinion)

sb0572• 6 months ago

There's a mostly-unsubstantiated-by-data belief that LED lighting can cause health problems by some combination of flickering and narrow color spectrum.

noosphr5• 6 months ago

Asbestos was pushed as a magical solution to problems of fire in homes without paying attention to the health effects. It took 80 years for the obvious to become law.

Leds are pushed as a solution to energy consumption by humans without paying any attention to the health effects. Hopefully it will be less than 80 years of cancers and metabolic disruption before the obvious is done.

But this time the regulation was captured pre-emptively, to the point that following best scientific advice for your health is illegal is most of the developed world.

cglouch• 6 months ago

where do you purchase yours out of curiosity? My incandescent light bulb dealer on Ebay stopped selling them...

AshamedCaptain2• 6 months ago

Why is it that right now there is still on the frontpage of an "article being found flawed after 6k citations " ( https://statmodeling.stat.columbia.edu/2026/01/22/aking/ ) but this random article coming out of nowhere makes the front page on the same day?

People really should get it and stop sharing newly published papers to the general public. The value of one single academic paper is exactly 0. Even a handful of such articles still has 0 value to the general public. This is only of interest to other academics (or labs, countries, etc.) who may have the power to reproduce it in a controlled environment.

Be very skeptical of correlations like this that have dubious or poorly understood causation. Be even more skeptical if they are about day-to-day stuff that would likely have large swaths of people able to reproduce something like it on huge scales yet they haven't. Extraordinary claims require extraordinary evidence.

novok5• 6 months ago

You can also look at all the papers it's citing too...

angry_octet2• 6 months ago

This article is not making an extraordinary claim, and your offence is hyperbolic. Analysis of research should not be restricted to the academe, but careful not to cherry puck research.

boxed2• 6 months ago

It seems like a pretty extraordinary claim to me.

Considering the percentage of live mitochondria that are exposed to external light in a human this seems like an enormous effect. The effect we'd expect from publication bias though is already pretty big. I'm going to go with the latter until we've got some replication, and a plausible mechanism (like.. why wouldn't whales be badly sick if this was a thing?).

HNisCIS3• 6 months ago

No mention of CRI which seems kind of odd. LEDs for lighting are increasingly graded by how natural their emission spectrum is. Older lights are quite bad, newer ones sacrifice a tiny bit of performance for more uniform spectrum.

novok5• 6 months ago

CRI is a pretty bad rating system. They are showing the full spectrum graphs which is what you'd want anyway. Spectral Similarity Index (SSI) is the better number

HNisCIS3• 6 months ago

Sure, but I don't see them mention what they're actually using for LEDs at all. They mention a "colour fidelity index" but I'd expect a manufacturer part number or something so I can pull the datasheet.

Funny enough, the best evidence for this study is that they should probably move somewhere with more sunlight if they can't spell "color" right... /s

hedora• 6 months ago

They use rf numbers, which is a newer standard, so that's probably good.

However, the experimental group (extra light sources) got rf 91 bulbs, and the control ("LED lighting") got rf 85 bulbs.

The two scales are not exactly comparable, but they both max out at 100. The only source I could find that discusses both says that > 90 CRI is "excellent" and just below that is "very good". It says > 85 rf is "very good", which tells me it's comparable to a mid-80's CRI bulb.

If I accidentally buy a mid-80 CRI bulb, I either return it to the store, or just throw it away.

So, I'd say this study's experimental setup doesn't support any useful conclusions. They showed that so-painfully-bad-California-won't-subsidize-them LEDs are worse than passable LEDs with supplementation from another light source.

The passable LEDs in the study are probably comparable to the cheap ones at our local hardware store, but worse than the ones that cost $10-20 on amazon ten years ago.

This would have been much more interesting if they'd compared high-end LEDs with and without supplementation, and found a difference. (And by "high-end", I mean "still much cheaper then the electricity they save")

sho_hn• 6 months ago

Out of curiosity:

a) How do Philips Hue bulbs stack up?

b) Did Philips update them generationally and assuming they are decent now, how recently?

wendy_kroy• 6 months ago

I think CRI is not important here as thats a measure in the visual spectrum. The paper talks about all the missing wavelength outside of the visual spectrum.

elric2• 6 months ago

What is the relationship between CRI and how broad (or narrow) the spectrum output by the LED is? Is CRI automatically better for broader-spectrum LEDs? Or is that too simplistic?

fragmede• 6 months ago

Slightly overly simplistic because the broader-spectrum LEDs could be broad-but-spikey for their output, resulting in light that is broad spectrum, but has a bad CRI (because it's eg really blue).

marcosdumay• 6 months ago

Just to point to anybody that comes here directly, the article has no relation at all with perceived illumination, color fidelity, or anything else people complain about leds.

It's an interesting niche topic that you may want your working place to notice if you work indoors.

herf• 6 months ago

There is a 15-30% difference between the groups at baseline (fig 8c-9c, 8d-9d), about the same magnitude as the claimed effect of the experimental condition.

I think the result would be much stronger if these baselines were comparable, so they show they have accounted for other variables like time of day and light history. I am also skeptical of any effect in the retina lasting 6 weeks, with no fading.

Consider that people are often exposed to much more infrared light outdoors, so "worked under a relatively dim incandescent lamp" is not a particularly novel stimulus. Imagine that any of these people spent time outdoors during the six weeks - thousands of times more infrared light there.

londons_explore• 6 months ago

Indeed - these study results are fairly substantial if they can be independently reproduced by more studies at bigger scales.

bob1029• 6 months ago

I've been using incandescent more often. All my vanity lights are 40w appliance bulbs now. The difference at night is remarkable. The LED is just too much even at 2700k. I still prefer LED for high power situations like br30/40 can lights.

PeterStuer2• 6 months ago

Was just discussing last week with a colleague how for the same 'lumen' there was such a dramatic difference between led and incandescent bulbs for ease of reading paper books.

Cthulhu_• 6 months ago

Which one of the two was better for it?

PeterStuer2• 6 months ago

Incandescent, by miles. Not even in the same ballpark. Even just candlelight beats led.

accidentallfact3• 6 months ago

I don't think that this is the reason.

Yes, there is something obviously wrong with most LED lights, but it isn't too much of short wavelength light, but on the contrary. It's the near absence of cyan light in most LEDs. Our eyes are by far the most sensitive to it, the majority of receptors in the eye are sensitive to it, and we may focus primarily on it (focus differs for different wavelengths). This is how you get the feeling of something being wrong with your vision as you for example walk into a mall, and so on.

If anything, higher temperature lights seem to make it better, not worse, but the problem will persist as long as the cyan hole stays there.

guenthert• 6 months ago

Sensitivity peak for humans is in cyan (~510nm) only for low-light conditions (night vision / rod cells). In daylight (cone cells) it's green-yellow (555nm). https://www.giangrandi.ch/optics/eye/eye.shtml

accidentallfact3• 6 months ago

The eye behaves differently in high or low light conditions: in daylight, for brightness levels above 3 cd/m2 the vision is mainly done by the centre of the retina, we can see colors and the maximum sensitivity is at 555 nm (in the green region). This type of vision is called photopic vision.

That's completely impossible, you would have severe tunnel vision in daylight, if it was true.

There has never been any real evidence that rods stop working in daylight.

accidentallfact3• 6 months ago

Here you can see that cones only extend to 2° from the center. I think it's illegal to drive with less than 20°FoV.

https://www.google.com/search?client=ms-android-samsung-rvo1...

adrian_b7• 6 months ago

It should be noted that even if we assume that the conclusion of this study is correct, i.e. that artificial lighting should have a wide spectrum including near-infrared light, that does not mean that returning to classic incandescent lamps is the right solution for this problem.

The incandescent lamps with tungsten filaments have a much lower temperature than the Sun, thus much more energy is radiated in infrared than needed.

There was about a year or two ago a discussion about a very interesting research paper that reported results from testing an improved kind of incandescent lamp, with energy efficiency and lifetime comparable to the LED lamps.

The high energy efficiency was achieved by enclosing the lamp in a reflecting surface, which prevented energy loss by radiation, except for a window that let light out, which was frequency-selective, so only visible light got out, while infrared stayed inside. The lamp used a carbon filament in an environment that prevented the evaporation of the filament.

With such a lamp, one can make a tradeoff between energy efficiency and the content of healthy near infrared light, by a judicious choice of the frequency cutoff for the window through which light exits the lamp.

Even with enough near-infrared light, the efficiency should be a few times higher than for classic incandescent lamps, though not as good as for LED lamps. Presumably, one could reach an efficiency similar to that of the compact fluorescent lamps (which was about half of that of LED lamps), for such an incandescent lamp that also provides near-infrared light.

lgeorget• 6 months ago

How does enclosing the lamp in reflective material help with the energy efficiency? Isn't the infrared radiation emitted anyway? Doesn't that make the lamp overheat?

adrian_b7• 6 months ago

If the reflective material is ideal, by definition no infrared or other radiation is emitted.

Perhaps I was not clear, but the reflective surface was the interior surface, so it reflected any light, visible or infrared, back towards the emitting filament, while the front window reflected only the infrared, while transmitting the visible light.

The lamp does not overheat, because the filament is kept at a constant temperature, the same as in a classic incandescent lamp. The difference is that you need a much lower electrical current through it for maintaining the temperature, because most of the heat is not lost away, like in a classic lamp. The fact that you need a much smaller electrical current for the same temperature is the source of the greater energy efficiency.

Only if you had used the same electrical current as in a classic lamp, the lamp would have overheated and the filament destroyed, but you have no reason to do that, like you also do not want to use in a classic lamp a current higher than nominal, which would overheat and destroy it.

wtcactus• 6 months ago

I found some interesting tidbit about this bigger issue. And I want to share how to more easily check it.

We many times see some people reporting that they clearly see lower quality LED light flicker and is really distracting to them and even causes them headaches.

Now, I didn't see this until recently (unless in failing lights) in the right conditions. If the light is very, very dim: For instance, only 1 light on in the night, and you are in a division far away from the light so that it's extremely dim. There, I could finally really see it flicker.

I've replaced that light for a better one and the effect went away.

schiffern6• 6 months ago

Scientific Reports is a junk journal fyi. Not conclusive, but indicative.

Despite saying the visible flux component is "small" and that the tungsten lamps "were not expected to [be used] as task lamps," Figure 6 (a) and (c) shows... desk lamps right at the work stations like task lamps! Not only is this experimentally unblinded, but the visible light immediately in front of the test subjects is noticeably brighter and warmer. The effect could simply be due to reduced eye strain.

What would James Randi do? "Extraordinary claims require extraordinary proof," and unfortunately this isn't it.

This would be more interesting if they add a visible light filter on the lamps so they only emit infrared radiation, and have an identical double-blind control with a 60 watt heater bulb so it emits no SWIR but the same radiant heat (which could confound and/or unblind).

zahirbmirza5• 6 months ago

The push toward LED seems to be primarily for emission target related reasons. It is very hard to buy incandescent bulbs in the UK; even for those of us that accept the cost implications. Also, many less expensive LEDs flicker at the rate of the frequency supply of the current (ie 240 or 120 Hz). This is very annoying and related to the instantaneous response of LED vs the averaging effect of the alternating current through an actual glowing hot filament. It is interesting to read on the development of blue and white LED technology.

oniony• 6 months ago

If I were able to see the flicker of mains supplied LED lighting (which I cannot), then I would be very tempted to install low-voltage DC LED lighting, which presumably does not flicker.

lightedman• 6 months ago

It only doesn't flicker if there's no power driving circuitry - eg just LEDs and a resistor.

Otherwise, if there is a power IC present, there is flicker, though fast enough for most humans to not perceive normally (you can still check it by waving your hand in front of the light and seeing the strobed afterimage.)

stubish3• 6 months ago

An AC/DC power converter works the same, either built into the bulb or in a separate unit. But yes, a separate power converter is almost certainly going to do a much better job of removing the 50/60Hz voltage drop. Not sure if it would be cheaper, given the economies of scale on AC bulb manufacture. Higher quality AC bulbs may come out ahead for flicker free lighting.

leoedin• 6 months ago

The push toward LED seems to be primarily for emission target related reasons

Is this true? I’ve got LEDs in my house because they cost vastly less to run, and because I rarely have to replace the bulbs.

Some cheap LEDs do flicker (at 50 or 60 Hz). But that’s fairly easily solved. I don’t think I’ve noticed the flicker since some cheap bulbs I bought in 2014 or so.

DeathArrow3• 6 months ago

Is this true? I’ve got LEDs in my house because they cost vastly less to run, and because I rarely have to replace the bulbs.

At least in EU is true. Citing from Wikipedia: "The 2005 Ecodesign directive covered energy-using products (EuP), which use, generate, transfer or measure energy, including consumer goods such as boilers, water heaters, computers, televisions, and industrial products such as transformers. The implementing measures focus on those products which have a high potential for reducing greenhouse gas emissions at low cost, through reduced energy demand."

https://en.wikipedia.org/wiki/Ecodesign_Directive

JKCalhoun• 6 months ago

"I don’t think I’ve noticed the flicker…"

Well… (Sorry, let me put my tinfoil hat on.) Yeah, well that noticed part is what is worrisome to me. I do worry that there is some effect on our brains even though we might not perceive the flicker.

As an analogy, I got into those supposedly audiophile "Class D" (or "Class T") amplifiers over a decade ago. Every day I turned on the music in my office and coded with the T-amp playing. I would have told you at the time that, indeed, it sounded amazing.

Some time later I built a tube amplifier (The Darling [2], in case anyone cares—I've since built perhaps a dozen more).

When I brought it into the office and swapped it out for the T-amp, the change was sublime but immediately noticeable. I hate to fall back on audiophile terminology but it's the best I have for the experience: I was suddenly aware of "listening fatigue" that had been a component of the T-amp. I hadn't even known it had been fatiguing until I heard the tube amp in its place for days on end.

With the loss of color fidelity and the flickering issue, I'm embarrassed to say that incandescent is starting to look good to me again.

I might, as an experiment, replace only those lights that we turn on in the evening when we are relaxing, reading.

[1] https://en.wikipedia.org/wiki/Class-T_amplifier

[2] https://www.diyaudio.com/community/threads/darling-1626-amp.... and https://imgur.com/gallery/oh-darling-tube-amplifier-Lq2Sx

zahirbmirza5• 6 months ago

It does seem an easy win for govts to easily conform.

I buy the ones that are suitable for dimmable switches (even tho I don't have dimmers) because there is discernible flicker with most other LED bulbs if you for eg wave your arm through the air or made a saccade. There is a certification (i think) for LED bulbs that are closer to sunlight in their emission spectrum

axus• 6 months ago

It costs less to run because less energy is used; I'm pretty sure incandescent bulbs aren't emitting anything by themself! "The push" is from the government, perhaps consumer demand is "the pull".

Sharlin• 6 months ago

LED bulbs, even though cheaper in the long term, used to habe high enough shelf prices enough that most houdeholds wouldn’t have switched without a government push. Incandescents are literally banned now for most uses, while the economies of scale have helped drive LED prices down.

SoftTalker2• 6 months ago

I have not found that LED bulbs last noticably longer than incandescents. I'm still replacing bulbs, and though I don't keep records it feels about the same.

LEDs are just terrible in every way except electrical consumption.

graemep3• 6 months ago

Is this true? I’ve got LEDs in my house because they cost vastly less to run, and because I rarely have to replace the bulbs.

its the same thing. If it uses less electricity it both reduces the cost to you and reduces emissions from generating electricity.

I think most people would have switched over gradually anyway, but effectively banning incandescents speeded it up.

wongarsu2• 6 months ago

In the EU this was indeed done for energy efficiency/emissions. Incandescent bulbs were gradually banned from normal sale, starting with the most energy hungry (diffused 100W) and gradually expanding until only low-wattage and special-purpose bulbs were left. Special-purpose bulbs cover a large variety for everything where switching didn't make sense, like machine shops or historic buildings. LEDs aren't mandated per se, but they are the most attractive alternative. And because this all happened before brexit the UK has the same rules, unless they revised any of them post-brexit

For the most part this was a very positive step. Prices for LED bulbs plunged when they went from the "premium" energy-efficient alternative to the default option. But you also get a lot of crap on the market, and stuffing LEDs in form factors designed for incandescent bulbs makes good electrical and thermal design challenging. Even for those brands that actually try

fundatus• 6 months ago

LEDs aren't mandated per se, but they are the most attractive alternative.

Yeah, basically what the EU did was to say: For X Watts of electricity at least X Lumen of light has to be produced. And this number was gradually increased. Since old school light bulbs are quite inefficient when it comes to producing light, they slowly had to be phased out.

palmotea• 6 months ago

The push toward LED seems to be primarily for emission target related reasons. It is very hard to buy incandescent bulbs in the UK; even for those of us that accept the cost implications.

Can you even buy them without buying new old stock? In the US they're banned and there's zero production.

I recall there was a guy in the EU who tried to get around the regulations by selling "heat bulbs" that were exactly the same as traditional incandescent bulbs but marketed as a heat source, but I think he was slapped down.

wongarsu2• 6 months ago

At least in Germany you can still fairly easily get 20W incandescent lamps. Sold as lamps for fridges and ovens, but they are available with standard sockets.

If you look around a bit you can also get 60W or 100W lamps, sold as "industrial lamps" or "extreme temperature lamps", labeled as unsuitable for household use. But those are specialty lamps that you won't find in your local supermarket. Not sure if those are new old stock or imported

nerdponx2• 6 months ago

Certain size/watt combos are still available for things like appliances and nightlights, but I think that includes 20W E26/A-something bulbs, and the bulbs for plug-in night lights. I can still find them on the Home Depot and some other places. No idea about quality but I still prefer how they look. There are so many other horrible energy efficiency problems with heating my home that the inefficiency of a few incandescents in key places doesn't bother me in comparison to the enjoyment I get from the nice light.

mark-r• 6 months ago

In the US they've even banned selling new old stock. I believe that was a recent change within the last few years.

NwtnsMthd• 6 months ago

The flickering is solely a result of cost cutting in the power supplies of these LED lights. The problem is totally solvable with a constant current switching power supply. But the filtering circuitry adds cost.

graemep3• 6 months ago

The problem is that consumers usually cannot know this about a particular light (or a lot more) at the point of purchase, so even if you are willing to pay a premium for this you cannot.

I would pay a premium for longer life, and at least in some cases (e.g. lights I read by) for better quality. How do I do so? I would love to be pointed at sources of better ones (in the UK).

fyrn_• 6 months ago

Wouldn't the supply usually be either 50hz or 60hz depending in the country?

stubish3• 6 months ago

Yes, OP incorrectly quoted voltage rather than frequency.

kalium-xyz• 6 months ago

This should also be true for TL lights. Which kinda contradicts common sense seeing that those are used all over the place in offices, kitchens, and hospitals, makes me think this paper is bogus.

DeathArrow3• 6 months ago

In EU, the ROHS directive forbids even more types of lightbulbs, beside incandescent:

Ban on all fluorescent tubes (T5 and T8 lamps) from August 24, 2023

Ban on all CFL lamps from February 24, 2023

Extension of the exemption granted to HPD lamps from 3 to 5 years

Extension of the exemption for special purpose lamps from 3 to 5 years

DeathArrow3• 6 months ago

There are some full spectrum led lights, they just cost over $100 a piece. And they might get banned in the future for not being energy efficient enough.

r_lee2• 6 months ago

I hate the LED street lamps so much. I can tell they've got a really spiky and unnatural spectrum, unlike the HPS lights, not to mention that they're white or bright yellow...

zahirbmirza5• 6 months ago

I miss the orange glow of sodium lamps that characterised cold dark and foggy english winter nights.

r_lee2• 6 months ago

Yup.

Even to this day when I'm on the bus on the highway it's so relaxing and comforting to ride through the orange lights.. then the bright white ones come through and it's almost like instant anxiety that kicks in

nrjames• 6 months ago

I’ve always been mildly bothered by the LED lighting in my home, as if it’s simultaneously bright but not illuminating. In simple consumer terms, if I wanted to shop for a variant that more closely replicated incandescent lighting, what exactly am I looking for on the packaging? Or does this not exist?

atopal2• 6 months ago

It’s called SSI, spectral similarity index. SSI is specified for a color temperature, eg 3200 or 5600. 100 is identical to tungsten or sunlight. Values above 85 are good.

yarekt• 6 months ago

In the UK I've not been able to find high wattage (10-20W) LED lightbulbs with high CRI, some don't even mention it in listings, let alone SSI, which I have never seen.

Where are you seeing these? Is this industrial/commercial suppliers?

johanvts5• 6 months ago

Ra value is (often) written on the package, go for 95+, it’s a bit hard to find but the difference is real. I Do not buy under 90.

Paianni• 6 months ago

What's available depends on the form factor, but there are some manufacturers that offer some choice in the 2700k 90+cri space nowadays.

SoftTalker2• 6 months ago

I buy the "warm" light LEDs, which look (to my eye) closer to incandescents.

Standard LEDs bulbs are bright white, almost bluish, and yes "bright but not illuminating" describes them well. I feel many modern car headlights have the same issue.

The human eye doesn't focus the blue end of the spectrum very well.

quickthrowman2• 6 months ago

There is no such thing as a “standard LED lamp”. LED lamps come in a huge variety of shapes, various bases, power usage/lumen output, color rendering index, and color temperature.

Lots of companies sell cheap crappy A19 E26 base 5000K lamps, that doesn’t make them the ‘standard’.

Saris3• 6 months ago

Bulbs that test well on spectrum and flicker tests, Phillips Ultra Definition is a good one I believe.

https://www.thesmarthomehookup.com/25-soft-white-led-light-b...

Nothing on the box really means anything, so many bulbs claim high CRI and everything but in reality have terrible spectrum. So you can only go off of actual real life testing from a third party.

ck2• 6 months ago

ever since they replaced streetlamps with led (like a decade ago?) I can't see anything anymore before dawn

there may be more light (photons) but their spectrum is too limited for my eyes to see like halogen, etc.

I still only use compact florescent in my home, led is useless to me

analog8374• 6 months ago

Also, LED strobes to dim. Which is unpleasant.

elric2• 6 months ago

In humans a single 3 min 670 nm exposure improves colour vision within 3 h, which is sustained for almost a week

That seems remarkable and almost too good to be true?

hnuser123456• 6 months ago

Seems like this is only relevant for people who don't go outside for weeks at a time? This article has a strangely "pro-long-wavelength" tone, yet sunlight also exposes you to UV frequencies that are so harmful according to this paper.

blacklion• 6 months ago

It was known among MTB riders who ride at night sometimes: typical XM-L T6 Chinese headlights were unusable in the forest when you move fast. Good diodes (like Nichia 219B) worked. And XM-L was dominant even in very expensive «brandnamed» lights for many years (you could buy Aliexpress headlight for $20, you could bu "Italian" lamp for $250, result is the same)

I'm not in this scene anymore for many years, but when I was, I built my one lamp from custom light engine (essentially round PCB with DC-DC current limiting schematics an LEDs) with 3x219B, Chinese body and CARCLO TIR Optics...

Good times.

mikkupikku3• 6 months ago

I have a theory that cheap LED lights with low quality drivers are bad for dogs. LEDs with low quality drivers very often have a high amplitude flicker at 50/60Hz, which is about the flicker fusion rate for humans so we don't perceive it (at least usually), but dogs are known to have a substantially higher flicker fusion rate and probably perceive the flicker. Probably worth considering, especially if you have a dog with epilepsy.

(Incandescents also flicker at 50/60Hz of course, but the thermal inertia of the filament makes this a lower amplitude flicker.)

buildbot• 6 months ago

If you are sensitive you can get really, really annoying blips of flicker even above 1khz - https://journals.sagepub.com/doi/10.1177/1477153512436367

They also flicker really badly if your power is not perfect, like you have a decent sized training rig on a different circut.

Incandescents are basically little light inductors and I would imagine the luminosity curve would be sinusoidal vs whatever hell a LED driver chip puts out.

countWSS• 6 months ago

(at least usually).

Nope. Lots of people see the strobing. Its causes headaches if you focus on the lights.

entropie3• 6 months ago

Besides the epilepsy, what do you mean with "bad for dogs?"

Sidenote: My partner and me both "feel" the difference of cheap LEDs. Its not something we can pinpoint down, but it got way better with hue lights.

We live with multiple dogs and iam really curious. One of the dogs that we often had around had severe epilepsy that very strong medication was needed and the dog died anyways way to early around the age of 2. She had less sizures than in her original home when she was with us which ofcourse might be unrelated to the lighting. But your thought is interesting.

mikkupikku3• 6 months ago

Besides the epilepsy, what do you mean with "bad for dogs?"

Psychological or physiological unease at least, I assume this from the way rapidly flickering dying florescent lights make me feel.

stubish3• 6 months ago

When you notice flicker, your iris is trying to expand and contract at that rate to compensate. It was one of the things people were pointing fingers at for sick office syndrome, back when fluorescent tube lighting was popular. People, and I assume dogs, have different thresholds when this problem kicks in and flicker becomes noticeable.

montjoy• 6 months ago

I tried Hue lights last year but 50% of them had problems. Did you run into that too?

Onavo2• 6 months ago

Why don't LED drivers just use plain continuous DC with no PWM?

ternus• 6 months ago

Dimming. And even without that, the "continuous DC" is usually provided by switch-mode power supplies that themselves have a PWM ripple. How much depends on the quality of the supply.

Saris3• 6 months ago

Cost.

rini17• 6 months ago

Since AC is pulsating you need to store some energy to get continuous DC, usually in a smoothing capacitor. And that capacitor is relatively big and when durable, then not cheap. And it requires some further complications (like avoid inrush current).

estimator72922• 6 months ago

Sibling comments have no clue what they're talking about. I actually engineer these things.

The short answer is cost and heat. What you're describing is a linear constant current driver, which are the gold standard for flicker-free operation. Drawback is a much more complex circuit and a transistor burning off a ton of waste heat.

A constant current driver requires sensing the current across the LED, which involves sensitive analog circuitry. A PWM drive requires essentially nothing more than a FET tied directly to your microcontroller.

There are switch-mode constant current drivers, best of both worlds. Essentially a buck-boost converter in current mode instead of voltage mode. These are slightly more expensive, so they don't appear in consumer lighting products.

All that aside, the reality is that if your PWM frequency is high enough, it doesn't matter. Above several KHz it's imperceptible. The reason that this still isn't done universally is that it's a third of a cent more expensive to use a controller that can switch above 1KHz. All hail the glorious race to the capitalistic bottom.

At work I just finished up a constant current driver circuit. At home I'm building a custom lighting system with bespoke driver circuits. Despite having a CC driver I can pull off the shelf, I still chose 10KHz PWM. It's easier and more efficient, and neither you or I could tell the difference in the quality of the output light.

nerdponx2• 6 months ago

I have a theory that they're bad for humans too. I think the same is true for computer screens too. Something about the flickering and the "unnatural" color spectrum messes with people's heads (anecdotal/subjective). Maybe our brains do extra processing work that detracts from other systems.

TheJoeMan• 6 months ago

The newer phosphor-coated "filament" LED's also have this "inertia" which is nice. And no other electronics to fail also since they are just series-connected LED's.

mikkupikku3• 6 months ago

The phosphors do have some inertia, but I'm not sure if it's really enough, since fluorescents have phosphor coatings too and those are notorious for noticeable flicker. Different kinds of coatings though, different thickness and quantities of phosphors, maybe different composition too. I don't know how comparable they really are.

aydyn• 6 months ago

Bad LEDs flicker at twice the power supply frequency, so 120 hz which is very perceptible by most humans.

But also note that not all LED lights flicker.

daveloyall• 6 months ago

The authors, bless their hearts, suggest that running halogen lamps at lower-than-rated voltages might be a good idea.

If this is done with a halogen bulb, which is a type of incandescent tungsten bulb, the filament lasts for a longer period as evaporated tungsten is redeposited on the filament rather than blackening the bulb glass. Hence, using a halogen bulb at lower voltage is a realistic alternative in terms of health and energy consumption.

Unfortunately, as I understand it, the redepositing action only occurs at high temperatures.. It's a chemistry thing. I have been led to believe that running halogens at low voltages will cause the bulb glass to blacken sooner. See https://en.wikipedia.org/wiki/Halogen_lamp#Effect_of_voltage...

pedrocr• 6 months ago

One of the authors of this paper did a pretty long podcast with Huberman about this topic:

https://www.hubermanlab.com/episode/red-light-to-improve-met...

The show notes have links to quite a few more papers. I have no idea if this is good science but this is not just a one off paper.

mikeyouse2• 6 months ago

It’s a shame that grift claims everything.. once upon a time, Huberman was a serious person but he’s now just Joe Rogan with an advanced degree - platforming all sorts of bullshit for a check. At least there are other sources listed though so thanks for those.

schiffern6• 6 months ago

It's junk science.

https://news.ycombinator.com/item?id=46764382

dwroberts• 6 months ago

I find it a little strange that there is no real discussion of limitations in this paper. They mention the limitations of something they cite, but nothing about the data they themselves collected or the conclusions they draw from it

schiffern6• 6 months ago

https://news.ycombinator.com/item?id=46764382

roughly• 6 months ago

You know, it's funny - there's a couple places where this kind of thing seems to have come up. There's research around crop nutrition levels that shows decreases in nutrient levels as yield per acre goes up, there's research on supplements and vitamins that shows synergistic effects between seemingly unrelated substances, we've seen surprising effects from adding or removing species from an ecosystem. One begins to suspect that the "reductive" method of science - the sort of physics- or mathematics-type "reduce the variables of the problem until we can isolate effects" approach - isn't particularly well-suited to dealing with biological systems. You see it in bioinformatics as well - we've sequenced the genomes for many organisms, and have learned a lot from doing so, but we're also learning the limits of that approach pretty strongly - the organism isn't defined just by its 'code', but its environment; the presence, distribution, and concentration of various chemicals; etc. I suspect as we move more towards the "biological" century here we're going to have to readjust how we approach things to start trying to find those synergistic effects earlier in the process, rather than pull everything down to its constituent parts and then experimenting pairwise with various combos. I get the difficulties in doing that, but I feel like we've repeatedly found the stuff we've discarded as irrelevant to the problem ("things that are not in the visual wavelength the eye perceives") in fact do wind up being relevant (wider full-spectrum light has effects outside the mere spatial perception of objects).

nazgul17• 6 months ago

Could it be the pendulum swinging hard before selling in the middle?

Once we learn from our mistakes we can find the frequencies that do yield the best outcome and at the same time consume (say) ¼ the energy of an incandescent bulb.

Or the minimum set of species yielding optimal outcomes, without the answer being "all of them"

BizarroLand• 6 months ago

Sounds like a holistics approach will be the next big swing of scientific endeavor.

That was the original point to begin with, right? Learn what makes things tick and then build on that. We've got enough of it down to the atomic level that maybe we should zoom back to the supermolecular.

schiffern6• 6 months ago

Complex system / ecosystem literacy is important, but this infrared thing is just junk science unfortunately.

https://news.ycombinator.com/item?id=46764382

bobbylarrybobby• 6 months ago

You are basically hitting on what has been referred to as high modernism, which promotes a level of confidence in science and technology that can only be maintained by eschewing all the inherent complexity of the world. The scientific method can really only study systems by modifying a handful of variables at a time and keeping the rest fixed, and isn't really capable of handling hundreds of interacting variables. Rather than acknowledge this limitation, high modernism embraces simplification even to the detriment of its products.

Further reading: https://en.wikipedia.org/wiki/Seeing_Like_a_State

fc417fc802• 6 months ago

The scientific method can really only study systems by modifying a handful of variables at a time and keeping the rest fixed

Not true. Statistical measures of large systems are a routine thing in the natural sciences. However that's higher effort and tends to make it more difficult to communicate the results to others so it's avoided whenever possible.

Also high dimensional models carry a distinct risk of overfitting.

iagorodriguez• 6 months ago

wouldn't this be a good thing? I prefer my circadian cycles not to be disturbed by artificial lights and if i am reading this right, it is what happens with led lights. this would be different of course if i had no access to natural lights. glad to be corrected :)

LED lighting undermines visual performance unless supplemented by wider spectra

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