Visibility - Lumen - CRI

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ZoomieFan
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Visibility - Lumen - CRI

A] I’ve read if the lumens are doubled the human eye sees a 25% increase in brightness. Is that true?

B] I’ve seen a picture (on this forum I think) that compare 325 lumen low CRI with 170 lumen high CRI.
I don’t know the exact CRI ratings.
It’s not the difference in color rendering that amazes me most, but the fact that the 170 lumen light is nearly as bright as the 325 lumen light.

The high CRI leds are less efficient if generating the same amount of lumens. But are they less efficient when generating the same amount of visibility?

Picture

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Edited by: ZoomieFan on 07/30/2019 - 13:10
clemence
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To me it’s not. Light meter calibrated based on human vision perception, sensitivity peaked at around green wavelength. What the meter says x lumen should be very close to x lumen. Of course our eyes sensitivity differ from one person to another.
What makes seeing under high CRI easier to discern objects is that it’s easier for our brain to ‘guess” based on our memory sets.
It’s very similar to see black and white photos vs. color photos.
Our brains like to assume everything

[Clemence]

clemence
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(more complete) Color tell us more of the story and details. We processed everything faster in color. Unless you’ve lived your life without color/dull vision before.

————————————————————-

[Clemence]

ZoomieFan
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Hi Clemence,

I’m not sure which question you are answering.
Considering you post B/W and color photo’s I assume you are saying high CRI has better visibility that lower CRI because it’s richer in color?

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ZoomieFan wrote:
Hi Clemence,

I’m not sure which question you are answering.
Considering you post B/W and color photo’s I assume you are saying high CRI has better visibility that lower CRI because it’s richer in color?

Visibility and brightness are light dependent. No matter how good the color is, dimmer is dimmer. Butt..anything with color (or more colorful), contain more information for our brain. Even if it doesn’t, our brain will use the extra color information to its imagination based on certain memory sets recorded.
Higher CRI light doesn’t make for brighter lit object, it just makes it easier for us to judge whats there.

[Clemence]

ZoomieFan
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Visibility = Brightness + color rendering (+ how the brain handles that combination)

Click

The key question for now is simply what you see in that picture?
Compare the 325 lumen low CRI and the 170 high CRI and tell me if there is a huge difference in visibility.
(I’m not sure camera settings messed things up)

Chargers: 1xBasen BD01 5/5, 1x Gyrfalcon All-88 4/5, LiitoKala: 3x100 3/5, 2x202 3/5, 1x402 3/5., MiBoxer C4-12 3/5.
Flashlights: DQG Tiny III 26650 5/5, DQG Tiny III 18650 5/5
FiTorch MR35 3/5, Haikelite SC26 HD 3/5, Lumintop Tool AA/AAA 4/5, Nitecore LA10, Skillhunt H04FRC 4/5, Sofirn C01 BLF 3200k/5600k 2/5, Zebralight H600Fc 3/5.
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clemence
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ZoomieFan wrote:
Visibility = Brightness + color rendering (+ how the brain handles that combination)

Click

The key question for now is simply what you see in that picture?
Compare the 325 lumen low CRI and the 170 high CRI and tell me if there is a huge difference in visibility.
(I’m not sure camera settings messed things up)

Looks like the camera used “P” or automatic mode. 325lm vs 170lm is very significant for camera sensor. I see the hot spot also relatively the same size.

[Clemence]

ZoomieFan
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Yeah 325 vs 170 is extreme, but still explains what I my question is.

1- More lumens means higher visibility because eyes see more details in brightly lit objects.
2- Higher CRI means higher visibility because the brain can extract extra information from rich colors.

Numbers vary but….
If comparing two leds which are driven at the same watt, the high CRI version generates 20% less lumens. 20% less bright.
Would higher CRI make the things 20% easier to process by the brain?
And that way compensate for 20% less brightness.

In other words is 1000 lumen 70 CRI equally visible as 800 lumen 90 CRI?
Once again when I write visible I’m not talking about brightness or color rendering; I’m talking about them combined, a package deal.

If that’s true then a high CRI led is not less energy efficient if comparing visibility instead of lumens.

Chargers: 1xBasen BD01 5/5, 1x Gyrfalcon All-88 4/5, LiitoKala: 3x100 3/5, 2x202 3/5, 1x402 3/5., MiBoxer C4-12 3/5.
Flashlights: DQG Tiny III 26650 5/5, DQG Tiny III 18650 5/5
FiTorch MR35 3/5, Haikelite SC26 HD 3/5, Lumintop Tool AA/AAA 4/5, Nitecore LA10, Skillhunt H04FRC 4/5, Sofirn C01 BLF 3200k/5600k 2/5, Zebralight H600Fc 3/5.
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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??

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hasddie293 wrote:
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! Smile
They can give you accurate measurement with/without the yellow filter/lens.

[Clemence]

Tally-ho
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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.

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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
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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]

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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.

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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.

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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.

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SammysHP wrote:
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.

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SKV89 found disagree, LOL

SKV89 wrote:
The yellow shades will not increase CRI. It just blocks out the blue wavelengths.

Clemence found agree.. Shocked

clemence wrote:
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.

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clemence wrote:
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.

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hasddie293 wrote:

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….

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

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SKV89 wrote:
clemence wrote:
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.
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How about this one, welding… see it produce lights that so bright. I wonder how much lumens was that and what CCT level? ? Silly 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…

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clemence wrote:
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

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Wink
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SKV89 wrote:
I learn something new everyday. These minus green filters do increase CRI and R9. Wow!

Say whaaat!!! Party Thumbs Up

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koziy wrote:
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”. Wink

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).

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SKV89 wrote:
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
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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.

Unheard
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I see a huge difference between Sofirn C01 and Fenix E01 when it comes to recognition. They are extremes, of course. It doesn’t necessarily has to do with the difference in color rendering quality only, I also notice this outside when walking or running using CW vs. NW lights. Armyteks low CRI warm lights are still slightly better than CW headlamps like my old Black Diamond Storm. Beamshots can reproduce that. CW illuminated scenes usually look flat to me. Likely this ist due to the relevance of distinguish shades of green as opposed to shades of blue.

Spitzbube.

JaredM
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As Clemence has pointed out and experiments with Lee filters have shown, the proper amount of blue filtering can increase the CRI in low CRI, cold white emitters. Perceived brightness is a hard thing to debate here as there’s not a clear-cut way of measuring it. We have eyes that are effectively camera’s in ‘Full Auto’ – constantly adjusting white balance and exposure and focal length. I can see many sides of this topic/debate. For example, what one can say (and IMO be mostly correct) is that filters can’t ‘add’ anything and that – for certain – less light is reaching your ‘eyes’ while wearing the yellow lens glasses. However, what I don’t know is how the eyes respond to this reduction of blue-wavelengths in regards to pupil dilation. Will this decrease in lumens ‘at the front’ of the eye be offset by a larger pupil letting in more (basically the eyeball’s auto-exposure)? Thinking from this perspective, it’s possible that we could perceive in the right environment (think of a white room vs open field of dew covered grass) equal brightness with higher ‘CRI’. (CRI is in quotes because color fidelity is not equal to gamut and/or vividness)

Said another way, we would likely all agree that a beamshot comparison taken with a camera on Full Auto (with no read-out either Facepalm ) would be inconclusive.

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My experience and opinion for the blue-filtering (yellow lens) glasses is that they have certain applications that really do help visiblity. Driving at noon on a clear summer day is the best example from my experience. The effects are that the sky/horizon is darkened, and bright reflections and glare are reduced significantly, allowing you to open your eyes fully and also dilate the pupils. Objects on and alongside the road (heavy in red and green wavelengths) then seem ‘highlighted’ and you feel more ‘alert’.

Clemence (as always) provided some excellent examples with the photos in post #21. Let’s look at the last set of pictures – the ones of the bush against a bright, blue sky. The filtered image, even when viewed on a monitor, appears to ‘highlight’ the objects on the ground. In situations such as driving, this is beneficial. NOTE however these are taken with fixed exposure and WB. It’d be interesting to see them actually in AUTO.

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Lastly, my 2 cents about ‘HD’ vision with high CRI/Rf/Rg is that it’s valid to an extent. Of course there are many, many people on the internet who will exaggerate anything and everything. Another fact is that everyone’s eyes and color acuity are different. Someone who is completely color blind will likely not be raving about their high R9 emitters, though someone like this lady with tetrachromacy may have a completely different opinion. In my n=1 experience, ‘good tinted’ hiCRI emitters provide significantly better visibility and pleasure (subjective), especially in my favorite environments where foliage, earth, and human skin are the main targets of illumination. As a result, I choose to spend my money nearly exclusively on hiCRI lighting products.

As an example of colors effect on visibility, I’ll once again refer to the images that Clemence posted of color vs grey-scale (post #3). The point of this comparison can be measured by the amount of time you have to look at the image to ‘feel’ like you mostly understand the environment. For me, it was 5+ seconds for grey images and probably about half for colored.

-Jared

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