Ultimate LED Bulbs - Ultra High CRI - The Honorable Quest

I have no idea. I dared to try a Yuji 4000K remote phosfor bulb once in the house, and my girlfriend felt like she was in hospital instead of at home. So apparantly 4000K is not for us.

Did you also had the opportunity to test some Yuji's?

I never checked that bulb actually because I have had it long before I got my spectrometer. I could if you are interested.

In one, simple but effective, word : YES

In two, honest and heartwarming, words : YES, PLEASE

Which of Yuji's reference have you got on hand?

It must be YJ-BC-RP-6-40, it is a couple of years old already but it looks like that one.

Surfing Hyperikon's website I have found a better promising bulb, in the name of the "Hyperikon 212000401" an A21 17W 120v (sic) solution, still ranging from 2700 to 5000K and advertised at CRI 92.

However, searching detailled data/tests on it, the 4000K version seems to be tested at "17" for R9 (source, indiecinemaacademy)... Meeh ? And EnergyStar tests on the supposedly same (if HyperA2190-40, A21-40, and 212000401 are the same) 4000K version R9 at 63...While the 5000K should be at R9 90 and CRI 95.

Oh, well.

EDIT : browsing indiecinemaacademy pages, have found the Quasar Science S-LED bulbs (95+CRI). Unfortunately, I can't find detailled info or other tests yet. And well, 120v again.

Hyperikon are great. I should do a review of them, I have spectrometer data. fneuf, the R9 of the 4000k are all between the low 70’s and high 60’s on all of mine. CRI Ra was in the 90’s as promised. And they are cheaper than anything else similar.

That would be great for NA, CA and Japan members here Joshk!

Do you intend to say that every 4000ishK bulb will struggle with R9 ?

I hadn’t noticed the thread-starter was from France, but yes, many members are from NA/CA.
I’m not sure where you are going with the R9 generality, but I will post all the data.

I just might have over-interpreted your "the R9 of the 4000k are all between the low 70’s and high 60’s on all of mine" sentence.

By "all of mine" do you mean all your 4000K Hyperikon's or all your 4000K LED lights?

Yes, I was talking about the R9 of my 4000k Hyperikon.
My Cree, for example, cost $20 per bulb and have an R9 of about 15.

Hyperikon’s Amazon pages are filled with pictures of lights that fried themselves, I assume from overheating. I haven’t seen anywhere close to that many proven failures from any other brand and combined with the cheap price it makes me really wary.

I haven’t had any failures yet, but they are only 6 months old so far. So idk.

For a while there were Cree-branded light bulbs that were awful

Anyway, cool info. I didn’t know, is E27 standard in Europe? E26 is the standard size in the US.
All of my bulbs are sadly CRI80.

It looks like the test data from Indie Cinema Academy is not the high CRI bulb, but Hyperikon’s standard CRI version.

Are you looking specifically for 240V bulbs?

In the US, 120V is almost universally standard.

No, but warmer CCT’s do require a stronger red component to match their black body reference. This is difficult to achieve, especially without a hit to efficiency.

So even though a 4000K might have more red in its spectrum than a 5000K bulb, it could have a larger gap to its reference.

Same old story everywhere I believe : the fun with standards is there are many.

B22 (Swan's bayonet mount) had an original strong grip on UK (and Commonwealth) and France. But France always used both B22 (and a bit of B15) and E27 (and a bit of E14).

Now B22 mostly remain in usage in UK, India and Australia. France is "converting" (don't know of norms fixing that decision, seem to me it's a market general decision) to E27 since some years (decades), but you will still find some bayonet in old houses/rooms. The majority of Europe uses E27.

I don't have the full history of that, so it looks like a fully purposed mess. For instance I don't know why E26 and E27 both exists same time.

From their sole purpose (electric contact) they are mechanically interchangeables. So maybe it could have to deal with the 110 / 220v standard, because I think E26 is mostly in use in countries which adores 110v, whereas for E27 its 220v believers.Or could it be another cryptic example of metric vs imperial units (where 26mm would be the closest translation of some imperial measure). But this is pure speculation.

This could explain the really poor result at 17. Hyperikon's reference are not clear everywhere.

Well, well, well. Standards. Here we go again :)

Helpfully I have a map for that specific question:

Easy isn't it ? Well, we can still dig in and find more fun. More detailled map:

To each his own, standard, I guess :)

One of the great point of LEDs vs Incandescent or Halogens is that many manufacturers have cleverly took the opportunitu to build worldwide converters (90-250ish) in their bulbs. But not everyone of them.

Very interesting! I've also been recently presented an interesting article (sorry, it is in french) around the design choices of LED manufacturers to achiever High CRI in their chips

I had been trying to find a “smart” bulb that was also CRI 90+ only a month ago with not much luck

Just measured the Yuji bulb: CCT=4040, duv=–0.0014, CRI=96.2, R9=91.6
So it does live up to its specifications.

One of my Philips GU10 3000K ExpertColor bulbs: CCT=2982, duv=+0.0004, CRI=97.4, R9=87.8

One of my Philips GU10 2700K ExpertColor bulbs: CCT=2779, duv=+0.0009, CRI=97.7, R9=88.5

Thanks for the work djozz. All your candidates have very great Duv values, special mention to the negative value of the Yuji.

Do you have R12 and Rf measurements also?