High CRI lighting - What's available and where to get them?

[Brumby]

Due to a recent acquisition of test gear, I have the challenge of restructuring my work area.  This is a multi purpose zone of electronics bench, computer desk and photographic workstation.

To accommodate the equipment I have, to the degree which I would like has introduced some space restrictions for the photographic lighting.  In short, I have to fit a solution into a narrow space.  An LED option is the only strong front runner here.

I have come across a 99 CRI LED strip from Waveform Lighting (See Here) which I could likely make work - but it would be nice to see if the LED emitters used were available, so I could roll my own.  I'm looking for something in the 4000ºK to 5000ºK range, so the 5000ºK variant looks promising.

My current setup runs at about 5000 lumens using cool white compact fluorescents at 4100ºK - but these will be far too bulky for the new setup ... (plus, I would like to improve the CRI.)

I've checked out Digikey, Mouser, Element14, RS and Wagner - but have not found anything standing out.  Most of the parametric searches don't seem particularly helpful - but I'd love to be proven wrong.


Does anyone have suggestions that I can follow to achieve my goal?

(Yes, a CRI of 99 is "up there" - but if it's available and the price isn't extortionate, then why not?)

[Cubdriver]

I've no insight to offer, but am tagging this to follow it as I too am interested in setting up some decent lighting.  Currently have a giant quad fluorescent bowl type reflector light I got from Adorama about ten years ago, but as you mentioned, such things are big, bulky and get in the way.

-Pat

[deadlylover]

Look for horticulture lighting strips instead, head on over to Cutter in Australia to see what they have. I am very partial to the Nichia Optisolis 757 series linked here. Getting completed strips from Cutter is probably the way to go, because you won't be saving much money if any if you get the bare boards from them and the emitters from somewhere else.

I absolutely despise vendors who don't disclose the LED used, especially the tint and flux bin. A really general rule of thumb is that higher flux bins are to be avoided if you have the choice, these tend to be a bit above the black body locus and look disgusting (this is if you're rolling your own, usually there will be data on the strip from the vendor). You can also find special tint bins that are all below the BBL but that's very rare unless you order a reel of thousands.

In particular I prefer a rosy tint (below the black body locus, Duv will be negative). I think there was a study done that shows most people do prefer rosy over green, but of course it's all preference.

I've always wondered why we look back at positive things with rose tinted glasses...and when we're feeling down we're jaded (green). That's some food for thought. 

If you want high quality emitters you'll have order all the way from Indonesia at this store here, the usual component suppliers won't have "the good stuff". As far as I know this seller is one of the only places us mere mortals can get the emitters, the seller is also a nutso torch enthusiast like myself. Bloody COVID-19 means you'll have to get the more expensive shipping option though.

No affiliation with Cutter or Virence, I've just bought stuff from them myself. Cutter can take a while even though they're local in Australia and it might be a couple of weeks until they send the order out. I think my Virence order took about a month or so with normal registered post but this was before all the shipping delays/restrictions.

Attached is proof that I am a nutso, top left is my heavily modified torch for garage use. The bottom two are popular high CRI enthusiast flashlights. Once you go below the black body locus you don't go back. 

[julian1]

I found these a while ago when searching for high CRI leds. They appear to be sold by the retail arm of a dedicated/specialist manufacturer. They have different color-temp choices available, or you can mix it up/control drive for variable color-temp lighting,

  cri 98. 0.18W
    https://store.yujiintl.com/collections/high-cri-led-emitters/products/vtc-series-high-cri-led-smd-2835l-100-pcs

  cri 98. 0.4W
    https://store.yujiintl.com/collections/high-cri-led-emitters/products/vtc-series-smd-5730

I am a bit skeptical of the 99CRI figure. From what I can tell, nothing beats a 'black body' incandescent source for full spectrum output.

[knotlogic]

So I'm posting to follow this thread as well, but I was also going to suggest Yuji.

They've been around a few years at least, and I was under the impression they core/original business was making phosphors.  But whether or not that was the case, LEDs seem like a natural extension of that.  What will probably be of interest is that they have a BC series of LEDs featuring a CRI of 95+ and a VTC series claiming 98.  As I understand it, the BC series uses a blue LED, but the VTC uses a violet one.  I purchased one of their sample sets a while back but haven't gotten round to trying them out.

Another option is/might have been Sharp's Zenigata series.  I don't know if they still make those, but some 10 years ago they were already claiming high CRI via a double phosphor system.  I think I've lost the pdf catalog that had some interesting nuggets of information.  One of which was that when measuring CRI, there are a number of colour swatches that are evaluated to get the CRI number, but there seems to be no requirement to test all the swatches.  If I remember right, they claimed most manufacturers stop at the eighth(?) swatch, because "R9" is red and most lights perform very poorly there.  Some of the Zenigata products had a red phosphor specifically to alleviate that problem.

This is the only info I could find relating to their dual phosphors right now.  I think the "Tiger" design is a new take on their dual phosphors.

I also vaguely remember reading that CRI itself is flawed as it uses an incandescent source as the reference standard.  And that the industry has moved on to more modern standards, but I could be completely wrong on all that.  It would be interesting to hear from someone who's in the field.

I do wonder if Yuji also uses a double phosphor system for their LEDs.

I've also come across the Virence store deadlylover mentioned, but not tried them.  Allegedly Nichia sales channels only go to major customers, so that shop might be one of the only ways to purchase small quantities of Nichia's high CRI products.

[knotlogic]

PS:  If anyone has any advice on recovering files (like a Zenigata catalog) from a failing flash drive, I'd like to hear it... It's recognised by Windows, but Explorer shows random ASCII characters for filenames and dates.

[Brumby]

Just going over a few points, I know there is problem with how my camera renders some blues and purple/violet.  Perhaps I should be looking closer to the 6000ºK colour temp for a bit stronger representation in the blue part of the spectrum.

Opinions, anyone?

[deadlylover]

Daylight white balance is around the 5600k mark but it varies, you should be able to set it in camera. You will probably look into D50 and D65 sources which are 5000k and 6500k.

It's good to have a couple of strips in different colour temperatures so you can do a little mixing.

Tint tint tint I can't stress this enough (often described as the deviation from the black body locus).

To use a multimeter analogy, CRI is like accuracy and tint is more like response time/update rate. You'll come to a point where you'll happily sacrifice a little in terms of accuracy to get a much better continuity buzzer/range switching for example.

A LED bin of CRI Ra >90 with a R9 value of >80 is a pretty common bin value, Nichia calls it R9080 for some of their emitters so if you see that then make note of it.

Don't waste too much effort trying to compare LED emitter CRI Ra's of 99 vs 97. Focus on the tint bin, tint shift over current and angle, but perhaps most importantly focus on stuff that's actually available for purchase at a reasonable price.

[langet]

Does anyone know of a better forum to ask than here or budgetlightforum?

I am looking for some high quality LED lighting to replace failing kitchen florescent tubes. My research from ~a year ago pointed to trying Waveform or Yuji. I'm finally ready to buy something. It seems like those are still the answer to the question. I remember looking at American Green Lighting that youtuber Matthias Wandel had tried out as a free promotion, but IIRC the specs were not as good as the others.


The kitchen uses this recessed box style: 9x 4ft fixtures. Current output of ~21-23,000 lumens @ 85-90cri, 6500k mix of higher quality GE & Philips tubes.


Looking to get something of comparable or better brightness while maintaining or surpassing light quality. I'd like to keep it ~$300-750 but willing to expand that depending on quality.

I am also concerned about tint. I'm familiar with Virence & his work with e21a's & optisolis emitters. I'm not familiar with D50/D65 grades that I see Yuji using. I don't fully understand the bbl graph. I've seen Virence's e21a comparison of ~a dozen temperatures - I'm guessing I'll just need to buy something & demo it (or order samples from Waveform)



Is there any preference to choose t8 tubes vs strips? Half of the current florescent tubes are flickering, and I am guessing the ballasts are bad(?). I am guessing installing LED ballasts is as simple as removing the florescent fixtures & wiring in the new LED ballast(?). I don't really understand the different types of florescent fixtures/ballasts/compatibility; if it's easier to just buy new florescent fixtures that is fine. It seems to me like strips would offer more flexibility, and would be a better choice if all else is equal.

Is heat dissipation an issue with enclosed spaces like the box lighting? They'd need to run at 100% for 4-8 hours. I don't know if cheap aluminum LED channel is sufficient. I don't know if VHB tape would last for years if I taped them to something like 1"wide 1/8" thick aluminum flat stock


Here are some old links I had bookmarked. Some apparently lead to optisolis/nichia/osram/sunlike flex strips.
https://www.rollitup.org/t/waveform-leds-d50-99cri-strips.982099/
https://www.ledrise.eu/led-strips-modules/led-strips.html
https://www.holectron.com/products/?id=155

[EEVblog]

I found these a while ago when searching for high CRI leds. They appear to be sold by the retail arm of a dedicated/specialist manufacturer. They have different color-temp choices available, or you can mix it up/control drive for variable color-temp lighting,
  cri 98. 0.18W
    https://store.yujiintl.com/collections/high-cri-led-emitters/products/vtc-series-high-cri-led-smd-2835l-100-pcs
  cri 98. 0.4W
    https://store.yujiintl.com/collections/high-cri-led-emitters/products/vtc-series-smd-5730
I am a bit skeptical of the 99CRI figure. From what I can tell, nothing beats a 'black body' incandescent source for full spectrum output.

Yes, Yuji seem to be the go-to online place for high CRI LED lighting stuff.
I use their corn cob bulbs in my big studio lights

[floobydust]

Yuji stuff seems expensive. $0.47 for a 0.2W LED, and $399 for a 659lm LED desk light? Is it Fendi or Gucci? Yamada?

I think the high CRI LED technology is good, it's just the light fixtures that have not caught up. There's a huge gap - either horticultural/bay lighting or downlights or bulbs, and task lighting or something for the bench is ugly so far. Everything seems to be a dim rehash of the fluorescent light fixture.