Multiple scientific resources please. Otherwise, you’re free to your opinion.
No, definitely not to others or most. Higher CCT white lights with greater blue content will generate worse glare that people will falsely interpret as the light being “bright”, see Jim Benya’s take on the matter. Then there was also this research by UMTRI that showed that higher CCT LED headlights generated worse glare then lower CCT headlights.
terminology:
CCT = Corrected Color Temperature, expressed as Kelvin… eg…4000k, 5000k…
DUV = Tint, it plots the LED Tint in relation to the Neutral reference, aka bbl, Black Body Line
CRI = Color Rendering Index. measures the percent of a given spectrum output. Red Spectrum, aka R9 CRI. On High CRI LEDs, R9 is a positive number, on low CRI LEDs R9 is a negative number.
R9 is a CRI factor, it is not what we see as the Tint
Common usage of the word Tint, often is misapplied to mean CCT…
Daylight White Balance = 5600k
Incandescent White Balance = 2700k
White Balance of the brain is a primary factor affecting how warm or cool an LED “looks”, at the time.
For example
If I have a 3000K 219B, and I wake up in the dark, it does not look orange, nor “too warm”, at that time.
otoh, the same 3000k during the day, when my brain is Daylight White adapted, makes the 3000k look extra orange, and “too warm”.
Because white balance affects comparisons, I try to use a consistent daylight white balance for photos.
but in actual use at night, a 3000k light does not look as orange as it does during the day.
here is an example of three different Tints, CCT, and R9 CRI
the most apparent difference is the Tint, followed by Color Temperature.
The most subtle difference is R9 CRI. The above photo does not show R9 CRI at all. To see R9, the light must be illuminating a Red object…
Good observations Jon_Slider
This is why I wish there would be more variable color temp lights.
The optimum color temperature for looking at something in the daytime outside is quite a bit cooler than at night with dark adapted eyes. I think an Emisar D4 with variable tint like the Sofirm IF25, and running Anduril 2 would be lovely.
When choosing an LED for my lights I tend to consider the following in order of priority:
I agree 
my lumen requirements are at HDS levels… 2-300 lumens is seldom needed, for the way I use my lights at indoor distances and close range outdoors
Tint is a high priority to me, so is Color temperature
the conclusion Ive reached, is that even after all those criteria are met, I will choose the LED with the best CRI, and for me, the most limiting factor on CRI, is R9, Red Spectrum
so, I can agree with others who say lumens is their first priority, or tint, or CCT… but after the first priority, there are a few others that need to Also be part of the Total Package.
I want all of it, Output, and Tint, and CCT, And CRI :+1:
thanks all for the discussion and exploration
enjoy your choices!
Ah, yes I remember the first time I used 3000K during the day and thought “wtf is with this weird orange colour…?” I knew it was meant to be a warm temp but wasn’t expecting the funky colours it generated to my daytime eyes.
Which makes me wonder how much the brain can counter for all the variables. The pink BBQ chicken looks uncooked but if one were cooking using ONLY that light then our brain would adjust and the chicken would look more appetising. As indicated perception of light largely depends on environmental factors (other light sources at the time). So I still have a hard time understanding why “high CRI” generates so much interest. My guess is unless out camping or the like our eyes are adjusted to home lighting in the evenings and that’s the base point from where our brain makes the ‘balance’.
The brain is very good at adjusting its white balance to match the CCT of a single ambient light source.
The brain takes about 30 minutes to downregulate from daylight cool white, to incandescent warm white.
The brain definitely adjusts to make 3000k the “normal” white reference, IF that is the ambient CCT of the home lighting.
During the day, the brain is white balanced above 5000k… due to daylight.
in both cases, the ambient light, creates a setpoint for the brain’s white balance reference.
From there, turning on a second light source, an LED flashlight, will reveal any difference between the brain setpoint, and the LED.
IF the LED is warmer than the brain white balance at the time, the LED will look warm, or orange
this is the case when using a 3000k LED during the day.
otoh, a 5000k LED will not look cool or blueish, when the brain is adapted to daylight.
IF the LED is cooler than the brain setpoint,
for example, under incandescent house lights, a 5000k LED will look cool and blueish.
but the 3000k LED will not look very orange when the brain is adapted to warm light…
warm light is more relaxing
cool light is more stimulating
I use 3000k LEDs as a bathroom light, but I dont use them during the day. The warm (low blue content) light at night, helps keep me relaxed so I can go back to sleep easily.
I use 4500k-5000k LEDs as worklights, in the evening, and also during the day. The cooler light (more blue content) helps keep me awake and alert.
===
because of the complexity of dual white balance scenarios… iow warm white contrasted to cool white, I do not show photos set to warm white. I only show photos set to cool white. This most closely illustrates what an operator will see when they get a new light and turn it on during the day, which imo, is the most common scenario from which we make initial color and tint observations.
Tint is also affected by the two different white balance scenarios, because sunlight has a higher DUV than incandescent.
therefore, a light with green tint, may not look very noticeably green, during the day
otoh, that same light can look much greener when observed during the evening, when the brain is adapted to incandescent.
iow, sunlight is not only cooler than incan, it is also greener tinted.
you can see how people could report apparently different experiences of tint, depending whether they look at the light when their brain is daylight adapted, as opposed to when it is incandescent adapted.
Yes!
I took a deep dive into photography in the early 2000s, completing a two-year course at a community college. I probably spent somewhere between one and two thousand hours color-correcting/printing both analog and digital images. Along the way, I learned how to see color, shadow and light rather than objects/things. Truly, it was a journey into sight.
Most of the time, I like to print my pix without a color cast. That means somewhere around 5200K-5500K, which is a bit of a "cheat" compared to the 5600K that characterizes midday sunlight. The lower CCT warms things up just a bit, which can "improve" skin tones.
To that end, I look for four things in a flashlight used to illuminate the subject of a photograph. If any of these are absent, I can try to fix them up in post-production, but it's much easier to get things right in the camera.
My background in photography has thus led me to reject the 4000K (and warmer) emitters preferred by many members of BLF. Of course, there is no right and wrong. I just happen to prefer neutral CCT in the low 5000K range. Your mileage may vary.
An Easy Way To "See" High CRI
Shine your lights on some blonde-colored wood furniture or an oak door. High CRI should be an obvious improvement over low CRI.
Lots of eerie sounds in those woods at night
Several caveats to this. The sun is not set to 5000K throughout the day. Golden/morning hour could easily hit 3000K-3500K with later morning hours hitting 4000K and overcast days hitting 6000K or higher.
Ooh just another spanner to throw in the works :laughing:
I’ll go out on a limb and make some speculation here. If the brain is making adjustments then why do some people swear by having high cri? I guess it’s the persons who have no colour blindness who want high cri the most?? Are these persons with perfect colour sight most affected by poor colour rendition?? By contrast I have mild colour blindness (sorry if I’m repeating that) so my brain is used to making adjustments or allowances and i don’t really care which picture is better below for real world use.
If my speculation is close to the mark then i would better understand why there is so much talk about cri.
This is a nice way to look at choosing what light you prefer. The concern I have with the CRI discussion is that many who are new to the hobby get given the advice “Make sure you get high CRI, you’ll love it”. Unfortunately, they don’t get told to think about whether they look a warm or cool light, or what tint they prefer (most prefer rosy, some prefer neutral, some like yellow/green). If the first light they see says “90CRI” but is a 6500K light with a green tint then they’ll probably hate it. But they may not understand the CRI had nothing to do with why they hate it.
High CRI lights are great, and I love the ones I’ve got. But the main reason I like them is they have the CCT I like and the tint I prefer. The fact they are high CRI is the icing on a very sweet cake.
Our ladies knew that very well in the times of incandescent bulbs and fluorescent tubes: If you want to know what that dress really looks like, see it outside the clothes shop.
I do think the brain is very good at interpreting incomplete visual data, and with a single light source, it will adjust its white balance. I dont think it adjusts the CRI of the LED though…
as to why an old Hippy into natural foods, and organic farming would be interested in High CRI… I think it is me trying to use the most Organic Light, given the option…
In the above photo, the wood of the table is not actually green. It is the lack of R9 in the Low CRI LED, that omits the red spectrum content of the wood.
a more subtle example:
I know the flower on the left is a Rose, but given the choice, I get more excited looking at the one on the right (it is a Higher Fidelity, fuller spectrum image):
so true!
which is why I think it is important to note ambient adaptation, when making an observation about the color of an LED output.
The reason I recommend High CRI, is because I like the superior color rendering, tint, and CCT.
Lets use a real world example. Someone asks, which AAA Tool should I get, the CW that is brighter, or the High CRI, that has less lumens.
My first answer is always, get the High CRI.
I dont necessarily go into the details that the High CRI being offered is a Neutral White Nichia instead of a Cool White Cree.
and I dont necessarily go into the details about the CW having green tint, while the NW has pink tint… all of those CCT and DUV factors are included automatically in the recommendation to choose the Nichia.
I do post photos showing the difference in tint, and Im honest about the difference in lumens…
some people prioritize lumens over CRI, Tint, and Color temperature…
it is their choice
if they ask which Emissar D4 LED to choose, then the answer is more complex, because the LED option is more than just Nichia vs Cree. I still say get the High CRI, but now the buyer must also decide the CCT and Tint they prefer.
the answer is more or less detailed depending on the actual real world choices available… for a given model of light.
Just chiming in to say I wish there was more bin (tint) transparency on emitters. Seems like CCT and high cri choices have opened up a lot, but the specific bin you’re getting remains a crapshoot to some extent.
The low CRI leds showing the wood as green looks more to be a green tint issue than lack of R9 issue.
I think both factors play a role
I understand we can use a Lee minus green (pink plastic) filter, to reduce the green in the Low CRI light, but that also reduces output… and it wont make a light with low R9 into a light with 90+R9, so I would prefer a High R9 CRI LED either way.
maukka has an excellent post about using Lee filters… here is one example:
I dont want to add a plastic filter to my lights, if I can buy a High CRI LED to begin with.
whatever the reasons
the observation remains:
Low CRI makes the wood color Less Realistic
High CRI makes the wood color More Realistic
another example,
left is NW High CRI, middle is NW Low CRI, right is CW Low CRI:
the High CRI LED produces the most realistic wood color
This is just kind of how the semiconductor industry works. You have to pay a premium to narrow down a bin for whatever device you are purchasing because it involves more detailed testing and logistics. Usually you’ll only see that done when purchasing in bulk. If you reach out to Luminus and want to purchase ten reels of SST20, they’ll probably let you specify bins for tint, voltage, etc
If you take the color brown and remove the red, you are left with green.
A really good experiment would be comparing WW, NW, and KW all in HCRI. Let the cam do the WB.
Edit: No, I have no idea what can be seen then.
That’s not how the visible spectrum works. That’s how subtractive color works (ie pigments/paint). In nature, different surfaces have a reflective property that reflects only specific wavelengths back to our eyes, otherwise known as their color. Brown as it refers to the light spectrum, is low saturated oranges/yellows/reds. Theoretically, a neutral tinted LED of little deep red rendering (note— little deep red. leds with low R9 still produce red) will still show brown, just not as vibrant as it usually is. An led with a green tint to it will show brown as yellower or greener than what it should be. An led of magenta tint to it, will show brown as a more saturated red color than what it should be. This is why some people really like the SW45K tint bin, as it makes browns really pop. An ideally neutral light source should not make browns really pop and look rich, but neither should it make browns look green.
I did see your request to post some more picture regrading tint differences vs CRI differences on wood surfaces Jon. I’ll try to get some later, but it won’t be an ideal comparison, because the lights are slightly differing CCTs. What I can compare is a bunch of 65 CRI 5700k Osram CSLPMs at low output, (really green at low output, certainly negative R9) vs my 5000k Optisolis (slightly green, but very neutral by comparison, warmer, and amazing color rendering). Then, I can put some minus green over the Osram emitters, which should neutralize its tint and also warm it up a bit, but minimally affect CRI.
Actually, no. I think that is a CRI issue.
I see the same thing even when I compare XPL HI with Lee Minus Green filters to reduce the DUV to below the black body line to high CRI SST-20 or SW45K.
A good high CRI led with high R9 really does make woody colors look much better. That seems to be its primary advantage.