You can buy full spectrum LED lights (99 CRI, or grow lamps)
The article uses LED as synonym for typical LED lightning.
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How is "full spectrum" defined in this case? Visible spectrum is not the subject of the paper, as they care about infrared.
Also even limited to visible spectrum, I have not seen any 99 CRI bulbs. The highest one I have ever found are the 98 CRI by YujiLED, but you pay around $35 for a single bulb. It is absolutely not "easy" to get flicker-free high CRI bulbs, let alone ones that cover the infrared range.
Phillips, GE, Cree, and others sell high-CRI bulbs.
10 years ago you had to work to find high CRI bulbs but could still find Cree bulbs pretty easily. Now you can get high CRI bulbs at the grocery store.
High CRI bulbs generally have low or no flicker because high CRI is toward the premium end of the market.
IR emission is not a "feature", it's a bug.
Almost all of the bulbs you can find at a hardware store (let alone grocery store) exhibit terrible 120hz flicker. I know because I've literally tried every single one. Also it's not hard to get "high" (~90-94) CRI while nonetheless having terrible deep reds.
Out of the manufacturers you listed, only Philips Ultra Definition (95 CRI, R9 90) have low flicker and good R9. Unfortunately they are poorly made and I have to keep buying new packs each year but it's more cost effective than Yuji for lesser used areas.
Also the claim from TFA is that NIR component improves visual performance (and I've read elsewhere that NIR also has health benefits).
How about Phillips flicker-free "warm glow" bulbs? I honestly have a hard time believing that they flicker because I can literally unscrew the bulb and watch it dim gradually over the course of a second. Which indicates to me that there's a capacitor in front of the LED drivers smoothing the current out. (Which I guess is required to be compatible with triac dimmers anyway.)
Never tried those, but speaking about flicker, some LED lamps flicker not because of the mains frequency (50/60 Hz depending on where you live) but because of their internal switching power supplies.
It's mostly a crapshoot even within the same model line. Even under "Philips UltraDefinition" some styles have high flicker while others don't. I'm not sure being dimmable is any guarantee of smoothing quality, in fact dimming is usually implemented with PWM as I understand so the easy solution to avoid flicker of chucking a smoothing capacitor on there might make it harder to implement dimming. (To dim properly without noticeable I think you'd have to PWM in the kHz range. Even cheap CFLs necessarily had the technology to operate on this frequency, for some reason it seems rare for LEDs to do it.)
Huh, through experience with (mostly non-premium) LED bulbs, I've learned to interpret "gradually dims over the course of a second" an an early indicator of imminent bulb failure.
Have you tried LEDVance?
> IR emission is not a "feature", it's a bug.
If you look at energy efficiency, it totally is. But the whole point in the discussion is that IR _might_ (according to the paper) have biological relevance.
Specialized stores or online. If enough people start buying them, they become popular and cheaper.
https://www.waveformlighting.com/ sell 99 CRI LEDs. They're in strip form not bulb form, and they're definitely expensive, but they are available.
Call me when there's lights with a cri r9 of 99