You can see the archived poll results on the Wayback Machine:
https://web.archive.org/web/20221220093741/https://budgetlightforum.com/t/-/72937
This depends a lot on CCT for me. I like my warm whites to be pleasantly rosy, maybe –0.0060. At 4500K I prefer a more neutral Duv (sorry sw45k 
), and for cool white I don’t mind the slightly positive Duvs of the standard illuminants.
0,0033 at 5500K.
A lot of interesting threads about light quality lately.
It also depends on CCT for me, –0.002–0.005 for higher CCTs, –0.004–0.010 for lower CCTs.
What Bob says
I googled it, and couldn't figure it out.
What is Δuv (in plain English)?
Here is some explanation, it is delta u,v, and I must confess that I do not know what entities u and v exactly signify, but the source at least gives a calculation for it :partying_face:
Thanks you, djozz!
Anything below 0 is great or if above, very close to 0 is still good for me.
It is very rough. 0.005 it is more than 5 MacAdam step. I like light from 0.002 to –0.002 . white almost without greenish or reddish deviations.
What I noticed is that for warm white, the lower DUV makes whites appear whiter and cleaner compared to the same higher DUV at the same color temperature.
My favorite CCT is between 3500k and 4500k, in that range I like a -DUV, but it does not have to be excessively negative.
are you guys kidding with all this stuff?
a; i never heard of it and
b. i can;t see from that link, what it has to do with LEDs or flashlights
You’ve posted on BLF over two thousand times and you haven’t heard of above/below duv? That is very interesting
i’m full of surprises
plus in at least 100 of those posts, i have mentioned not being a tint snob or caring much beyond NW neutral white
wle
It seems to me that it’s only very recently (last 2 years…ish) that dUV has been discussed, I’m not that familiar and couldn’t tell you what any of my lights are, I can barely remember/identify the CCT!
In my mind, the ‘parameters of interest’ from enthusiasts has evolved, perhaps a timeline would be as follows:
2002? - 2014? : Raw output/lumens
2014?- 2019?: CCT with/without CRI
2019-Current: dUV
I suspect that this is due to the technological development of LED’s, initially light quantity was the priority, now we have (mostly) sufficient outputs, light quality is of higher concern.
The distaste for overly green tinted LEDs has been discussed for years, especially with the Cree ”Tint lottery” I remember plenty of discussions about this since the early 2010s on a local forum, true the Duv metric was not known.
I would recommend taking a quick look at this presentation regarding duv and saturation preferences, which cites a few studies. Basically in average people prefer negative duv and oversaturated colors.
@SKV89 : also cited is a study on perceived white point, and like you observed at lower CCTs it is perceived below the BBL.
Lately many manufacturers have started offering below the BBL LEDs : Luminus Hospitality, Nichia Rs075 , Lumiled Core Range PW.
Ah yes, you are quite correct, discussions regarding ‘puke green’ from several manufacturers (4sevens and Zebralight amongst others) have indeed been going on for some time. In that respect, my timeline is not completely accurate, there should be more overlap between the periods.
Nice PDF, I will enjoy reading that properly when I get the chance. Thanks!
My first led swap was in may 2012, posted on CPF because I did not know about BLF then. It was a noname 16340 light with XR-E Q5 led, and I swapped it with the brand new 90CRI Nichia 219A which was the rage on CPF back then. I bought it reflowed on a very unhandy thick but small 10mm board from illumination supply. It would still work well as my EDC, beautiful beam.
So CRI was hot in 2012 already.
Excellent read, thank you.
What I found particularly interesting was that people tended to prefer lighting that oversaturates reds and greens rather than lighting with objectively higher color fidelity.