Visibility - Lumen - CRI

clemence · 2019-07-31T09:22:13.000Z

hasddie293:

I have a question that I need an answer from CRI expert like you Clemence. Here I will try to explain, I found that our eyes are very sensitive to blue light and this also had most to do with our 6500k temperature flashlight. Also sitting front of monitor/laptop even mobile for long time will eventually led to eyes strain.(due to blueish light). So, accidentally I had come across with anti blue glass which form of yellowish lens like picture below.

What happen next was surprised me… I was able to see thing in high CRI environment. It seem like I able to manipulating my sight. You guys should had try this. I’ve got 6500k light and produce 4000lumens xhp70.2. when light up, I think that the beam had appeared like 3000k version!! plus, you will won’t feel any eyes strains the next day as this yellowish glass block blueish light from entering our eyes. Till then, I used it everyday… On turbo, it feel so comfortable.

So, this my question… Do I actually see thing/object at High CRI level when I used this yellow lens? Would likely to hear whats your thought Clemence??

I have my own opinion about this but I can’t give any valid data about it. It’s better if those with Spectrophotometer chime in. Hey, Djozz, Maukka, Bob, and SKV89 please come on in!
They can give you accurate measurement with/without the yellow filter/lens.

[Clemence]

Tally-ho · 2019-07-31T17:35:27.000Z

With this yellow anti blue glass (that probably only removing parts of the blue light) you are removing blue, then modifying magenta (made of red+blue), modifying cyan (made of green+blue) modifying white (made of red+green+blue) and enhancing colors with green and red (yellow is made of red and green). You probably have lot of hue shifts.

See how colors looks like with your 6500K lights. If it is CRI70, red shades are probably very poor, with glass they probably will have deeper orange shades but still not completely red.
Blue colors will tend to shit to darker green, cyan will shift to brighter green, magenta will shit to red, white to yellow, etc.

Very high CRI 3000K flashlight has less blue and more red than 6500K, logically by removing blue and adding a bit of red to your 6500K low CRI LED it will be a tiny bit closer to a 3000K but this definitely needs to be tested with a spectrometer like Clemence said to know exactly how the spectral distribution is modified.

Just wild guessing, sorry if i’m wrong.

SKV89 · 2019-07-31T21:06:04.000Z

The yellow shades will not increase CRI. It just blocks out the blue wavelengths. Actually I found that blue wavelengths get blocked the easiest. Using any diffuser will lower proportion of blue wavelength a good amount.

For me, I have the whites on my monitor calibrated to 3000K with DUV = 0.000 using Windows night light settings and my monitor’s color settings. I measured a very significant drop in blue wavelength output setting it to 3000K. When night light settings first come on, the screen looks unbearably yellow and it takes about 10-20 minutes for my eyes to adapt and no longer find it yellow. What I find helps my eyes adapt faster is by using bias lighting behind the monitor. If you use a bias lighting warmer than your monitor’s cct, your monitor will not look yellowish. For example, if you use a 2000K bias lighting, a 3000K monitor setting will look almost cool white. Bias lighting on its own also benefits your eyes because it increases lighting in your peripheral vision, which causes your pupil to constrict so less blue light enters your pupils. This is the reason why people say it’s bad for your eyes to play on the phone in a dark room.

I find the best bias lighting to use is the Auxma 5050 2400K 95CRI after testing many different LED strips due to its close to the BBL tint (too far from the BBL will cause your monitor to look pinkish or greenish) and one of the lowest blue light output I’ve seen in this color temp. You can buy a cheap usb bias lighting from Aliexpress and cut out the led strip and connect the Auxma strip to it.

This is what I tested for the Auxma led strip

Auxma 5050 2400K DC12V CRI 95
CCT: 2329K
DUV: –0.0015
CRI (Ra): 95.7
R9: 94.5
Rf: 95
Rg: 103
Blue Peak: 18% of max

If you want to use a flashlight for bias lighting or as a bedside light, nothing beats the E21A 2000K, which has a neutral DUV of 0.0000 and the lowest blue light output I’ve ever seen in any LED or any lighting for that matter. It produces even less blue light than incadescent and halogen bulbs.

clemence · 2019-07-31T22:00:20.000Z

Based on Maukka and Djozz measurements. Color filter including your eye glasses, can increase or decrease CRI. The easiest example is the minus green filter. It even out the greeness to make the rest of the spectrums (if any) stands out more. CCT and CRI are the result of spectrum balance.
In your case, it’s blue filter. I haven’t seen any test result about it. To my understanding, filter can only reduce but won’t add anything that isn’t there in the first place.
@SKV89, could you help us to measure filtered low CRI 6500K lights you have? Thanks.

[Clemence]

koziy · 2019-08-01T03:40:58.000Z

I don’t agree with the common BLF dogma that says high CRI makes things easier to perceive or recognize. For decades, people watched movies on low resolution televisions with literally no colors and they were able to recognize everything on the screen. With flashlights, I have literally never found myself actually unable to recognize or taking even a millisecond longer to recognize any single object in the world because the flashlight used to illuminate it was “low CRI.” OK, so reds are a little dimmer in low CRI light, it’s just something you get used to. The color of sunlight changes throughout the day and is different still when it’s cloudy, and humans have evolved to continue to recognize items in the world even with these slight changes, so it’s not clear to me how messing with the colors to such a small degree is supposed to affect cognition.

That said, high CRI LEDs are absolutely better than low CRI LEDs. On knife forums, enthusiasts talk a lot about their high carbon steels or ultra hard stainless steels. Well, high CRI is kind of like that. It tends to be a desirable feature because, even though the difference doesn’t have a huge amount of practical repercussions over something more basic (or rather, there are benefits, but they tend to be diminishing returns), it’s still more pleasant to use high CRI flashlights. The color of light tends to affect our mood, and the technical accomplishment of formulating an LED that approximates sunlight so well is cool in itself. There are certain practical advantages, like in medical use, although not everyone will really care about the actual advantages like that. Mostly, it’s just that a good high CRI emitter tends to produce light that “looks better”than an inferior product.

The same goes for brightness. Even though a 300 lumen flashlight is about as bright as the average handheld user will ever practically need, we still want the ability to shine 3000 lumens, 30,000 lumens or, someday, 300,000 lumens, if only because it’s a technical accomplishment and it’s cool. It doesn’t matter that the human eye doesn’t perceive light linearly, it’s still something that enthusiasts want because it’s “bigger and better” than what was available last year.

Joshk · 2019-08-01T04:16:06.000Z

In the early days of TV, people on TV wore clown-like makeup to exaggerate skin tones so they looked “correct” on an early TV.
Heck, Nixon is agreed to have lost a 1960 debate because he refused to wear makeup when offered and therefore looked “unhealthy” compared to Kennedy, who wore makeup.

SammysHP · 2019-08-01T04:36:24.000Z

In some situations low CRI lights are like color blindness. Walking through a forest and everything looks like the same gray/green/brown isn’t fun.

koziy · 2019-08-01T05:02:53.000Z

SammysHP:

In some situations low CRI lights are like color blindness. Walking through a forest and everything looks like the same gray/green/brown isn’t fun.

Gray, green and brown are the primary colors found in forests, though. Human low light vision is like color blindness for sure, since our most sensitive light receptors in our eyes are not that good with colors, but if you’ve got a flashlight, you are not experiencing color blindness. Like….at all. These kinds of exaggerations just have the effect of encouraging people new to the hobby to spend lots of money to finally find out what “HD vision” is like, since so many people on this forum use that term and supposedly experience it.

hasddie293 · 2019-08-01T05:05:57.000Z

SKV89 found disagree, :laughing:

SKV89:

The yellow shades will not increase CRI. It just blocks out the blue wavelengths.

Clemence found agree…

clemence:

Based on Maukka and Djozz measurements. Color filter including your eye glasses, can increase or decrease CRI.

until then, what benefit most of using yellow lens/shades is that, it can reduce eye fatigue or itchiness base of what I’ve been experience. Also on my own thought, lumens in 6500k is higher than 3000k which absent of blues, but with shades lumens stays the same. Yeah this is my own opinion, try your own and I’m sure out there someone own 6000lumen. TRY wear yellow glass and lights up your flashlight on turbo! see if you know what i mean…

The only disadvantage of using Glass/shades is during rains. glass often get wet and block.

SKV89 · 2019-08-01T05:26:23.000Z

clemence:

Based on Maukka and Djozz measurements. Color filter including your eye glasses, can increase or decrease CRI. The easiest example is the minus green filter. It even out the greeness to make the rest of the spectrums (if any) stands out more. CCT and CRI are the result of spectrum balance.
In your case, it’s blue filter. I haven’t seen any test result about it. To my understanding, filter can only reduce but won’t add anything that isn’t there in the first place.
@SKV89, could you help us to measure filtered low CRI 6500K lights you have? Thanks.

[Clemence]

I’ll find a green filter and test it and post the results.

ZoomieFan · 2019-08-01T07:25:11.000Z

hasddie293:

Also on my own thought, lumens in 6500k is higher than 3000k which absent of blues, but with shades lumens stays the same.

Colored shades filter or not.
If light get’s filtered it get’s less bright.
Say you have an RGB light that draws 10 amps. Then you filter away the RG. The light still draws 10 amps but the RG light is gone.

Those yellow glasses are interesting. I’ve seen them advertised as being able to look better through fog.
I use them for fishing and the can make a huge difference.
A while back a clear river, about 10 feet deep. A dozen catfish on the bottom. A sunny day but the reflection of the water wasn’t bad.
With the glasses on I could see the catfish at least 3x better.
I have no idea why but it makes a real difference. Not just something that can only be measured in lab.

And that’s why I posted my original question.
The thing with YouTube reviews and pictures is always that camera settings may mess up the results.
Below the Convoy BD04 at differnt color temps. Not an high CRI led. But study the details.
The 3000K looks like having the most contrast on the leaves. The 7000K washes out colors.
Does that make the 3000K light always better? I think it depends on what colors the scenery has.
In this case mainly green. How different would it be if the it were not green bushes but red roses?

The bench has superior contrast at 6500K, but is totally white.

Maybe “the best” depends on what you use the light for.
I’ve read that those mountainbikers that race from a hill in the dark prefer lower K because the eye responds quicker to it.
A guard may prefer 6000K because all he wants is max brightness to see if someone is on his turf.

Anyway if color temps make a diff in contrast and brightness, then CRI may add to that mix too.
I would be suprised if it doesn’t….

clemence · 2019-08-01T08:42:16.000Z

All pictures below taken with Manual mode and used same WB. speed, and aperture
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[Clemence]

Tally-ho · 2019-08-01T16:42:56.000Z

SKV89:

clemence:

Based on Maukka and Djozz measurements. Color filter including your eye glasses, can increase or decrease CRI. The easiest example is the minus green filter. It even out the greeness to make the rest of the spectrums (if any) stands out more. CCT and CRI are the result of spectrum balance.
In your case, it’s blue filter. I haven’t seen any test result about it. To my understanding, filter can only reduce but won’t add anything that isn’t there in the first place.
@SKV89, could you help us to measure filtered low CRI 6500K lights you have? Thanks.

[Clemence]

I’ll find a green filter and test it and post the results.

Clemence was not mentionning a green filter but a minus green filter. The denser Lee minus green filter approximates a CC30 magenta camera filter.

hasddie293 · 2019-08-03T06:07:00.000Z

How about this one, welding… see it produce lights that so bright. I wonder how much lumens was that and what CCT level? ? From my bare eyes observation, that looks like, my guess 6000lumens or more with 6500k… I do recall a flashlight that can burn paper, acebeam??

but, the key things here is, that guy is using black shades to cover his eyes from looking direct EXCESSIVE amounts of lights that going to cause blindness. 2nd he used shades so that his eyes can filter trough a Ultrahigh brightness situation which make him able to see thus manage his task which is to welding…barely see though

Now, isnt’t that ultra high brightness flashlight can be dangerous? would love to hear from you all…

SKV89 · 2019-08-03T06:43:47.000Z

clemence:

Based on Maukka and Djozz measurements. Color filter including your eye glasses, can increase or decrease CRI. The easiest example is the minus green filter. It even out the greeness to make the rest of the spectrums (if any) stands out more. CCT and CRI are the result of spectrum balance.
In your case, it’s blue filter. I haven’t seen any test result about it. To my understanding, filter can only reduce but won’t add anything that isn’t there in the first place.
@SKV89, could you help us to measure filtered low CRI 6500K lights you have? Thanks.

[Clemence]

I learn something new everyday. These minus green filters do increase CRI and R9. Wow!

Acebeam TK16 w/ Oslon White Flat emitters
CCT: 6180K
DUV: 0.0038
Ra (CRI): 67.1
R1: 67.1
R2: 69.1
R3: 69.0
R4: 69.5
R5: 68.5
R6: 59.7
R7: 74.4
R8: 59.1
R9: –34.1
R10: 25.7
R11: 69.4
R12: 36.1
R13: 65.9
R14: 82.3
R15: 60.7
Rf: 63
Rg: 96

Acebeam TK16 w/ Oslon White Flat emitters and Lee 248 Half Minus Green Filter (Y=72%)
CCT: 5774K
DUV: –0.0129
Ra (CRI): 77.2
R1: 83.8
R2: 79.0
R3: 72.1
R4: 78.7
R5: 83.5
R6: 71.5
R7: 77.1
R8: 71.5
R9: 14.0
R10: 47.4
R11: 83.1
R12: 53.4
R13: 80.7
R14: 83.4
R15: 79.5
Rf: 66
Rg: 103

clemence · 2019-08-03T06:44:54.000Z

hasddie293 · 2019-08-03T07:06:17.000Z

SKV89:

I learn something new everyday. These minus green filters do increase CRI and R9. Wow!

Say whaaat!!! :partying_face: :+1:

Tally-ho · 2019-08-23T18:59:38.000Z

koziy:

These kinds of exaggerations just have the effect of encouraging people new to the hobby to spend lots of money to finally find out what “HD vision” is like, since so many people on this forum use that term and supposedly experience it.

Let’s take the FireFlies E07 as an example. The high-cri version with SST20 4000K CRI95 cost 20 dollars less than the one with XPL Hi V2 5A 4000K and lower CRI.
You don’t need to spend lots of money for “HD vision”.

On a side note : “Taken together, the present results indicate that a wider spectral bandwidth of illumination allows the visual system to focus more accurately. From an ecological standpoint this does not come as a surprise because natural objects possess broad spectral reflectance functions, and the eye is seldom confronted with narrow-band light. Even the spectral distributions of colorful objects can be relatively broadband. When sunlight reflects diffusely from these objects, the retinal image is composed of light of a spectrum of wavelengths. Thus it seems reasonable to speculate that the visual system might have evolved focusing mechanisms that operate best in the presence of broadband illumination”.
(Source : Spectral bandwidth and ocular accommodation (pdf)).

maukka · 2019-08-24T05:20:28.000Z

SKV89:

Acebeam TK16 w/ Oslon White Flat emitters and Lee 248 Half Minus Green Filter (Y=72%)
CCT: 5774K
DUV: –0.0129
Ra (CRI): 77.2

CRI isn’t really valid for this light source. The duv of –0.0129 from the BBL isn’t white as per the CRI standard (CIE 13.3:1995). Duv of +–0.0054 is required and that’s why some software have a warning regarding CRI measurements if the duv is too large.

But yes, theoretically CRI has improved.

zerodish · 2019-08-24T12:56:47.000Z

I worked in a photo lab for a while. I took some blue block filters taped them to my glasses and wore them around all day. For a while every think that was white looked yellow. Eventually my brain adjusted and every thing that was white looked white. Every thing that was blue looked black.