Do I have abnormal eyes ?

[paikeam]

Hello,

As you may have noticed I recently bought few lights (already more than needed) for warm white and high CRI but I also ordered an Astrolux S43 with Nichia 219C 5000K.

The thing is : the tint looks blue to my eyes, specially outdoor and when the light is not very intense.
But 5000K shouldn't be cool white.
It doesn't appears as blue as my previous Olight Seeker 2 of course, but clearly not very pleasant on the use.
The thing that surprise me is because I had an Olight Warrior X (Cree XHP35) which seems to be (as estimate on some reviews I've seen so far) around 5000K and the tint was greenish but absolutly not blue-ish (to my eyes).

Is it only me ? Why does it appears blue ? Do I have "bad" eyes ?

 

[archimedes]

5000K is a CCT rating, not a specific single tint

 

[LED Monkey]

The color temperature in the higher range are getting much better at color rendition , some leds which may be around 5000k, closer to neutral may appear to be somewhat bluer than an led with a somewhat higher color temp but has better cri.

Lastly maybe you have blue eyes? Sorry I just could not resist.

 

[Grijon]

It definitely seems everyone perceives color differently.

Speaking informally (please take my meaning):
5000K is to my eyes pure white, totally "tintless"
ANY over 5000K is blue to me and I will probably hate it
4000K is nice and a bit warm - my favorite
3000K is warm
Under 3000K is getting orange or yellow.

Those are my eyes. I see people all the time talking about their "pure white 6500K light" - and I want to scream ARGH that's BLUE not white!

But anyway, you don't have bad eyes, you just may very much prefer warmer lights (like me).

 

[LED Monkey]

I like the color temp to be around 4000~5000K it looks comfy white to me at least not blueish and like i've noticed the newer leds even above 5000k seem to be looking better these days. Bottom line is try to get the tint and temp that looks good to your eyes. 99.9% of people could care less but if you're here at CPF then you're not one of them.

 

[Grijon]

Sometimes my wife and I will compare our perception with each other by white wall hunting, LOL.

What I see as green she will see as blue or vice versa - while we're literally in the same room looking at the same beam on the same wall, you know what I'm saying?

And then on top of people perceiving color differently, they react to colors differently, too.

For example, I have a real problem with blue in my flashlight beam. I like incandescent-esqe yellow/orange. I am amused by purple and somewhat entertained by green. But blue generates almost an anger response in me - which it clearly does not in everyone. I have heard some people ridicule NW lights as being "yellow" or "orange" -really angrily said- and in the same review/post proclaim that the CW is "clean and pure" and so on. Then I get that NW light and it looks more green than anything.

It's all in the individual's eyes, neh?

OP, are you feeling better?

 

[paikeam]

For example, I have a real problem with blue in my flashlight beam. I like incandescent-esqe yellow/orange. I am amused by purple and somewhat entertained by green. But blue generates almost an anger response in me - which it clearly does not in everyone. I have heard some people ridicule NW lights as being "yellow" or "orange" -really angrily said- and in the same review/post proclaim that the CW is "clean and pure" and so on. Then I get that NW light and it looks more green than anything.

It's all in the individual's eyes, neh?

OP, are you feeling better?

That's almost the same for me, but I prefer magenta to green for warm white tint shift. If I'm feeling better ? Maybe but... I'm wondering :

At the time there were only incandescent lights, I've never seen no one complaining about those yellow-orange tint, was it because it was the only standard ?
I'm curious because I think, I'm pretty sure actually, if we had only cool white blue-ish, so I would have complained about it.

Anyway maybe the cool white for my eyes is more somewhere like 4000-4500K, or that's just a reason to buy other lights ^^

 

[WalkIntoTheLight]

You have normal eyes. 5000K might be considered neutral, but it's definitely on the cool/blue end of neutral. It's a lot better than 7000K or 8000K ugly blue, but it's still a bit blue when you compare it to other light sources you're likely to encounter at night. Try 4000K, you'll probably like it a lot better. But even 4000K will look cool, if you just come out of a room lit by incandescent light.

 

[Duster1671]

I don't know about others, but my perception of a color temperature seems to depend on the environment and how my eyes have adjusted. If I turn on a 5000K flashlight in the middle of a sunny day, it will look much warmer than if I turn it on at night in a room lit by 2700K lightbulbs.

Does the brain not do some kind of white balance?

 

[CREEXHP70LED]

I could go on, and on with this topic. Most of you guys/gals are very correct in the reasons 5000K or 4000K can all look different. The main variable is that everyone has variables in their eyes. Don't look at Kelvin only to make a light purchase you also need the tint. For many emitters out there you can easily find the charts. This means when looking at different Kelvin numbers to purchase a light, is just a guideline.

Without those variables, (Kelvin and Tint) everyone would see the exact tint AND the exact color. A 5000K light, in the exact Kelvin and tint given would look the same to everyone if everyones ones eyes were perfect.

Forget the CCT for a minute, because it is just a reference, albeit a pretty good one............ I have a 4000K light that that are 4000K but it has a VERY green beam. So in closing to the OP, You MIGHT HAVE A 5000K light, but your tint could be way off.

 

[jon_slider]

5000K shouldn't be cool white.

It can be to me, If I use it when I am adapted to the 3000k incandescent in my home.

I suggest you test your light during the day, and again at night. I think you will begin to learn that our brain changes its white balance based on the color temperature of the ambient light.

At first I found this very confusing, but now it makes sense to me. It has to do with the white balance of the brain.

my perception of a color temperature seems to depend on the environment and how my eyes have adjusted. If I turn on a 5000K flashlight in the middle of a sunny day, it will look much warmer than if I turn it on at night in a room lit by 2700K lightbulbs.

Does the brain not do some kind of white balance?

excellent post, I agree completely

here is my attempt to illustrate the effect of white balance on the perceived color:

===
these three images are unretouched, however the pair of lights in the 3rd image have changed color due to auto white balance from the iPhone

in this next image, with annotation, is also not modified for tint nor color temperature in post processing:

All above photos by iphone, auto white balance, at 2pm on a sunny blue sky day near San Francisco in July
imo the light sensor in the camera is choosing the coolest CCT in the image to reference its white balance setting

in this next image the bottom pair of lights have been edited to change the color temperature towards the 3000k source in post processing, making the 4500k source appear blue

imo my brain does the same thing, with a 30 minute lag time for the brain to change its ambient white reference. Iow, our brain has (slow) auto white balance.

because of the effect of white balance on color perception, I recommend using daylight white balance when comparing beam colors and tints, for consistency

since my iPhone has auto white balance, I always include a cool white light to make the auto white balance adjust to cool white, which is near the daylight white balance (5,600 kelvin) used in cameras.

 

[paikeam]

As I sayed in the first post the quad 5000K 219C of the Astrolux are looking bluer in outdoor conditions, I should be more precise, it looks even blue in the day time. Less indoor than outdoor but still blue.

I'm wondering because in my eyes, the sunlight never looks blue...

I remember few years ago speaking with some friends about one thing :
"In which color do you see the road ?" then it appears most part sayed grey, a very small part (including myself) sayed blue and only one sayed dark grey/black. {speaking about french road}

You might be right, the personal perception is different from one to an other, we don't all see exactly the same.

 

[idleprocess]

CCT or Color temperature is a thing, but in the world of LED it's a 1-dimensional measurement. Take a look at this (exaggerated) chart from the aforementioned article : generally, anything within the implied bounds of the blackbody line and the max/min of curve extrapolated out to the implied constant is white ... enough ... but even then that's just the dominant tint.

But to get the real story - insofar as instruments can tell it - you need to look at spectral power distributions. Take page 12 of the Cree XP-L data sheet as an example of how this shapes up for mass-production LEDs. The >5000K and >3700K- bins have 1.0 peaks of blue - to be expected of a blue-pumped light source with the 3700K exhibiting a broader ~0.5 plateau betyween 530 and 580nm falling off more gracefully to near IR. The >2600K bin is markedly different with a blue spike of ~0.37 but a broad distribution of light >0.50 distribution 530nm-655nm peaking with a relative 1.0 at ~605nm. If you want to go really into the deep end you'll overlay the human eye's peak responses for daylight and dark adaptation on those charts to get some idea of color rendition accuracy...

But back to color temperature ... the color temperature of noon sun on a clear day is 5500K - 6000K, which we generally perceive as a reasonably neutral light. Yet step into a building lit with the now fairly standard 4200K florescent fixtures and suddenly it seems like a much cooler temperature. A 6500K LCD screen seems to cast an acceptably neutral white. Use a 4000K LED in darkness and it seems cooler yet. Or conversely a borderline-conflagration bonfire at 2200K seems a warm shade of neutral yet a candle is so warm as to not even render green shades with fidelity. It's all about context, contrast, and how our eye is configured at that moment.

My understanding of how this works is that the sun makes what we understand to be a cool light source neutral through its overwhelming output causing our pupils to contract and forcing a relatively uniform level of illumination. At a more moderate level of intensity such as an office we tilt towards neutral output and not enough war lumens to overpower moderate obstructions resulting in shadow. Using a flashlight in the dark odds are you will not achieve an office level of illumination within the hotspot and will have darkness at the periphery thus your pupils will not constrict and you'll have big differentials in overall perceived illumination leading to the brain to really struggle with exposure as well as white balance.

I've personally started to transition my household lighting from 5000K/4000K (workspaces) and whatever mixture I can get from mixing 5000K + 2700K (living areas) to drive the CCT to <4000K to simply 3000K. A couple days of man that's really yellow has passed to acceptance.

 

[paikeam]

So if I understand well the problem appaers because mass LEDs are not good standards for spectral power distribution, as even for what should be neutral white there is a big peak on the blue spectrum.
I will search to have a look on how is this line for the Nichia's 219C 5000K and try to find a good one. Then maybe I will not have this problem of blue-ish tint, even at 5000K.

 

[WalkIntoTheLight]

So if I understand well the problem appaers because mass LEDs are not good standards for spectral power distribution, as even for what should be neutral white there is a big peak on the blue spectrum.
I will search to have a look on how is this line for the Nichia's 219C 5000K and try to find a good one. Then maybe I will not have this problem of blue-ish tint, even at 5000K.

Even high CRI emitters have a strong peak in the blue part of the spectrum. It's just compensated for with some peaks in the red and yellow parts of the spectrum. If you don't like the look of LED lighting, you'll have to stick with incandescent, which is the only light source that gives you a smooth natural spectrum.

 

[paikeam]

Even high CRI emitters have a strong peak in the blue part of the spectrum. It's just compensated for with some peaks in the red and yellow parts of the spectrum. If you don't like the look of LED lighting, you'll have to stick with incandescent, which is the only light source that gives you a smooth natural spectrum.

So there is no >4000K solution with a smooth natural spectrum ?

Here is the example of the Optisolis 5000K : https://www.nichia.co.jp/en/product/led_sp_optisolis.html
There is still a peak in the blue but it is clearly less than my 219C and the most difference is that the peak appears earlier on the spectrum, so it should be more purple with less intensity, isn't it ?

Does even exist better than this Optisolis ? Yuji ?

 

[jon_slider]

The white balance of a photo, will alter how blue a light looks.

The white balance of my brain does the same thing.

When I perceive a light as blue, it is because my brain has set its white balance to a lower color temperature.

in this example the Optisolis looks blue because the camera has set the white balance to the 5000k 219c

in this example the Optisolis looks blue because the camera has set the white balance to the average between the Optisolis and the e21a

in this example the Optisolis looks white, not blue, because the camera has set the white balance to the Optisolis

If I use the Optisolis when my brain is white balanced to daylight, the green tint of the optisolis is evident, but the blueness of the color temperature is reduced.

otoh, when I use the Optisolis at night, when my brain is adapted to white balance itself to my 3000k ambient house lights the Optisolis looks extremely blue.

So, my advice to you is,
look at your 5000k 219c during the day (when your brain is white balanced to sunlight), I expect it will not look blue.

then look at the 5000k when you wake up in full darkness (or your brain is adapted to 3000k incandescent) and you will see that the 5000k seems blue

 

[staticx57]

So there is no >4000K solution with a smooth natural spectrum ?

Here is the example of the Optisolis 5000K : https://www.nichia.co.jp/en/product/led_sp_optisolis.html
There is still a peak in the blue but it is clearly less than my 219C and the most difference is that the peak appears earlier on the spectrum, so it should be more purple with less intensity, isn't it ?

Does even exist better than this Optisolis ? Yuji ?

Theres the Seoul Semiconductors Sunlike, but they arent really flashlight formfactor

 

[paikeam]

So, my advice to you is,
look at your 5000k 219c during the day (when your brain is white balanced to sunlight), I expect it will not look blue.

then look at the 5000k when you wake up in full darkness (or your brain is adapted to 3000k incandescent) and you will see that the 5000k seems blue

Just tried it, it's 2PM here and weather is cloudy/rainy and lights indoor are not turned on of course.

Firstly outdoor it's difficult to see the light out of the lamp, I have to put it at the highest of the ramp (~1600 lumens) to see the beam.
I have to admit the green hue is the most perceptible, but there is still some blue-ish on the spill.
Then I tried inside my garage, with the flashlight as the only source of light of course, here the blue does clearly re-appears, almost exactly like I use to see it on indoor conditions.

I think the most important thing is not the CCT but the big peak in the blue on the spectrum scale. That's make sense for me.

So my question is : will the Optisolis 5000K just slightly better than the 219C ? Or really a lot better ?
I'm not speaking about 6500K which will have more blue even if it is extremely natural I suppose.

EDIT : We can experience the opposite : closing windows and turn on only incan lights and wait until you get used to. Then re-open windows, I'm pretty sure outside will not look blue.

 

[jon_slider]

I think the most important thing is not the CCT but the big peak in the blue on the spectrum scale. That's make sense for me.

I understand that would seem probable from your present perspective.
I respectfully disagree

I look forward to your further contributions of your impressions of different LEDs and CCTs for your use walking in the dark..

some of the LEDs we are discussing are not easily available in off the shelf commercial products..

a light I suggest you consider is an Emissar D4 with a 3000k SST, as far as off the shelf lights with high CRI options is concerned..

I think an AAA light is not suitable for your application. I believe you will be happier with the lumen levels and battery life from an 18650 light... but NOT in 5000k, way too blue