What is really the High CRI feature?

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Budgeteer
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What is really the High CRI feature?

All high CRI offerings include a CRI factor of 85 and above. It seems the emitters are just in the 2700K-5000K color temperature range more than anyhting. Is there more to it? Are they manufactured differently? I have some osram warm white that renders colors by a night and day difference compared to lets say a random cree Q5 displaying 6500K+ color temperature.

So in short is it high CRI some generic new marketing catchphrase only to tel lthe cusomer it will be from warm whaite toward neutral tint?

High CRI is also wanted in photography... many studio lights are rated 5100K color temp.

So it is all about the color temp range?

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Edited by: Budgeteer on 02/01/2012 - 15:35
ri chevy
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I was wondering the same thing.  Good thread.  Laughing

I know from reading here that it means High Color Rendition Index, but.....what exactly is it? 

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High CRI is not related to warm or cold light, but specifies that the light has improved color rendering.

It is very subtle and will often be difficult to see.

The reason for all the warm lights with high CRI is probably because it only requires a small adjustment to the phosphor

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Budgeteer
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So it must be made for that particular application althrough warmer tints have improved CRI by itself but the specifically engineered ones are even a tad better?

kragmutt wrote:

They're gonna send you a green redcat with a black LED.

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Mostly the CRI says something about color rendition of certain test colors. The binning like 3A (~5000K) on XM-L only mentions the (integral? ) peak value with the highest output at a certain power, but says nothing about the whole color curve. Many take the CR index given for flashlights and their emitters as outdated as it often doesn't even cover saturated red (test color 9).

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Budgeteer wrote:

So it must be made for that particular application althrough warmer tints have improved CRI by itself but the specifically engineered ones are even a tad better?

 

Yes, a CRI of 85 is good, but you can get light with 95 or better (100 is perfect). The definition of a perfect CRI is very close to a incandescent bulb or sunlight.

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Not quite, warm or neutral white doesn't mean it's high CRI, although it usually has slightly better CRI than ordinary cool white and are perceived to give better color reproduction much more than difference in CRI index would suggest. To produce high CRI light you need to use different phosphors which are more expensive and sadly more inefficient in light conversion thus producing lower light output for same power.

High CRI is definitely not marketing bull****

 

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These are on my shortlist to get. I would really love to test one one out but the shipping is prohibitive unless youre a German resident. Any interested Germans willing to offer a "groupbuy"?

It seems there is an option to get hem on 20mm star and 10mm stars (no picture how that would look like, quite vague) the 20mm star however is good looking... i wish it was 16mm instead but if they make a proper 10mm that is still ok till my hands starts shaking by age.

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Pretty inline with a XP-G R5 but with better CRI and being 5000K by default. Err, make it XM-L up to 1,5A.

kragmutt wrote:

They're gonna send you a green redcat with a black LED.

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Warmer tints don't necessarily have higher CRI. The orange tinted sodium-pressure street lights are very warm yet have almost 0 on the CRI index. Sunlight at midday on a cloudy day is often above 6500k but 100CRI.

 

LEDs tend to be warmer if they are high CRI as they naturally emit monochromatic blue light and this is corrected with phosphor over the base die. To be more efficient this usually takes the form of peaks at different parts of the colour spectrum, but this does not give high CRI. Higher CRI generally means a better, more even spread of light on the spectral distribution. As LEDs naturally make enough lower wavelength blue light this means they need to make up much more in the medium (green) and longer (red) wavelengths. This is why with LEDs higher CRI normally takes the form of a low CCT output on the whole.

 

If you want to take it a little further you can still be very skeptical of CRI as a measurement of colour at all. It is not as far as I know directly derived from spectral distributions but simply measured subjectively by people who judge the light according to a black-body at the same temperature as the CCT level of whatever light source it is. This is also why incandescent lights necessarily have 100 CRI as they are a black-body themselves so they will be the same as what they are being judged against.

 

More recent psychophysical studies have been suggesting alternate and supposedly better measurements of colour accuracy of light sources with naturally peaked spectral distributions such as a 'Colour Harmony Rendering Index' which supposedly give a better fit to perceived colour accuracy. However, for the moment CRI is still the industry standard so that is what is used.

 

Still, while it is somewhat correlated with CCT it is strictly independent of it.

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CRI has been around for a long time as a way to measure how well a light renders all visible colors, but I think Cree has started using it recently as another way to market and bin their LED's. 4Sevens picked up on it with their line of High CRI limited editions, but I don't know that Cree is changing the way they are making the LED's (edit: okay, maybe they are, but I'm still a little skeptical). It's almost a direct correlation between other ways of describing the lights, like 75 is neutral and 85 is warm. At least for LED's.

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brted wrote:

CRI has been around for a long time as a way to measure how well a light renders all visible colors, but I think Cree has started using it recently as another way to market and bin their LED's. 4Sevens picked up on it with their line of High CRI limited editions, but I don't know that Cree is changing the way they are making the LED's. It's almost a direct correlation between other ways of describing the lights, like 75 is neutral and 85 is warm. At least for LED's.

It's mostly the pastel colors that are tested on LED emitters (color 1-8, see wiki link above) not the full color range, that's why it is so controversial to use the pseudo CR index. I would expect a heavy CRI drop if the full color range was used, this might be the reason why there is some resistance to go that way. Nobody wants to give the impression that their emitter get "worse".

Some Nichias reach 95-98 CRI.

Color Curve XR-E

Source in German ( and the crude fish of babel translation) how the pseudo CRI is applied nowadays.

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brted wrote:

CRI has been around for a long time as a way to measure how well a light renders all visible colors, but I think Cree has started using it recently as another way to market and bin their LED's. 4Sevens picked up on it with their line of High CRI limited editions, but I don't know that Cree is changing the way they are making the LED's. It's almost a direct correlation between other ways of describing the lights, like 75 is neutral and 85 is warm. At least for LED's.

So there is a chance at least in cree labs for some happy circumstances turned to some genuine BS eventually. They don't specifically make them High CRI they just came out that way. Smile

Anyway, this one turned out a great and informative thread.

I suggest to sticky this thread somewhere as the info is getting really good.

Gotta love the veriety of users and knowledge that can be had on BLF! Smile (from led info to electronics, chemistry, metallurgy even cooking flashlights lately...)

I really love BLF.

kragmutt wrote:

They're gonna send you a green redcat with a black LED.

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The CRI also has meaning only as it relates to the color temperature of the light.

A light with a high CRI and a color temp of 3000 K may represent colors more accurately than a light with a low CRI and a color temp of 3000 K but it won't be more accurate than a light with an average CRI and a color temp of 5500K.

The 3000K is still going to appear yellow compared to the 5500K light. High CRI and a color temp around 5500 will appear more like the light of the sun which we would judge to be "natural".

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The thing is that the CCT of sunlight changes massively during the day from 6500k+ at noon on a cloudy day to even below 2000k at sunset. Our eyes easily adapt to the CCT of most light sources if there aren't other bright light sources around to bias it. However, it is much harder, basically impossible in fact, for our eyes to adjust to/compensate for lower CRI.

 

Cree certainly did not 'make high CRI LEDs by accident', it was a deliberate decision and involved quite a lot of thought, research and effort to accurately make high CRI LEDs. They rate their other LEDs from previously according to CRI as well and I don't think they ever went above 80 even with warm or neutral tints. High CRI are specifically engineered to give a broader colour spectrum with the trade-off of efficiency, made to compete with Nichia and SSC's previous offerings.

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I had found a list of high CRI emitters and the only ones I own are the 3D XPGs I got from Shiningbeam, they do appear to show colors better than my other tint XPGs.

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Those 3D XP-Gs from shiningbeam are a very good tint, but I don't think high CRI, I believe they are around 75 CRI still? Cree does not yet make truly High CRI XP-Gs 85 or 90+ (or any other LED) above 3700k right now as far as I'm aware.

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Some McGizmos had High CRI emitters with quite High CCT valua also, I think they were Nichias of some sort.

CCT was probably above 4000K-5000K?

High CRI is interesting - Low Kelvin value added to it, not really Flat Stare

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But doesn't it all pertain to LEDs used in housing and work environments, where people will be using/exposed to it on a daily basis for hours on end? I mean it's not really all that pertinent to flashlights, usless you happen to be using one for several non-stop hours a day. No?

I can see the need for the above mentioned purposes, but for flashlights CRI seems to be a mute point. Could a flashlight user really be able to tell 70CRI from 80CRI (at the same color temp) while bike riding or walking in the woods, or would they have to shine it on a color test panel to really know anything?

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On that note can someone take a photo of beamshots of a high  CRI flashlight and a neutral xm-l light place side by side or any regular neutral light you have.

As an analogy, is the perceived difference similar to an mp3 file 256 vs 384, 128 vs 256, or 64 vs 128 kbps?

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why don't they offer high cri, or tint options in budget class lights?

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I can't comment on the science and manufacturing techniques behind HCRI, but I can say that the tints they usually come in just don't do it for me.

For example, the 30000k XP-G HCRI emitter in the FourSevens HCRI lights is extremely red/rosy, and completely exaggerates those colors as a result.

For me, I've found that neutrals somewhere around 4500k (and maybe a tiny bit lower) is my sweet spot.

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 Terralux LightStar80

might be the one of the cheapest ways to get a High CRI light, with decent output

 

 

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Vectrex wrote:

 Terralux LightStar80

might be the one of the cheapest ways to get a High Cri light

 

 

I wonder what the color temperature is.  And it's probably using an XP-E...?

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Good question and I am  still on the fence about trying one out. There are some very mixed experiences out there (and here ) ... if you get a nice one it seems to do the job. If there would be a German seller where I could send it back in case I receive a lemon, then I would have already ordered one.

I find the cool white high CRI option on Nichias especially interesting, that is certainly a feature one doesn't get from CREE. The whole reason I buy neutral/warm tints is to get slightly better CRI... but if I could 95-98 get CRI 7000K XP-G/XM-L ... I wouldn't own a single neutral/warm white light.

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[quote=Old-Lumens]But doesn't it all pertain to LEDs used in housing and work environments, where people will be using/exposed to it on a daily basis for hours on end? I mean it's not really all that pertinent to flashlights, usless you happen to be using one for several non-stop hours a day. No?
I can see the need for the above mentioned purposes, but for flashlights CRI seems to be a mute point. Could a flashlight user really be able to tell 70CRI from 80CRI (at the same color temp) while bike riding or walking in the woods, or would they have to shine it on a color test panel to really know anything?
Just me wandering through again...[/quote]

You would know the difference. An incan is 100 CRI. If you walked through the woods with an incan driven well so that it was closer to white than to yellow and then did the same walk with a white LED you could tell the difference for sure.

There also is no real distinction between using a flashlight for some period of time and being exposed to indoor lighting for hours on end.

You may not notice that there is anything "wrong" with your lower CRI lights unless you compared them to a high CRI at the same time as our eyes adapt/adjust pretty well.

However, I haven't been interested in any of the higher CRI lights that are only available in the lower color temps as I prefer a neutral or white light.

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Any sources for those High CRI Nichia LEDs?
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Budgeteer wrote:

These are on my shortlist to get. I would really love to test one one out but the shipping is prohibitive unless youre a German resident. Any interested Germans willing to offer a "groupbuy"?

It seems there is an option to get hem on 20mm star and 10mm stars (no picture how that would look like, quite vague) the 20mm star however is good looking... i wish it was 16mm instead but if they make a proper 10mm that is still ok till my hands starts shaking by age.

DATASHEET:

Current175 mA350 mA1500 mA 
Voltage3,0 V3,3 V3,5 V 
light efficiency152 lm/W138 lm/W97 lm/W 
luminous flux80 lm160 lm512 lm

Pretty inline with a XP-G R5 but with better CRI and being 5000K by default. Err, make it XM-L up to 1,5A.

Is that thing really high CRI? 70 RA doesn't seem so high to me.... also the experiences aren't too promising as far as efficiency is concerned. (scroll to the end)

The warm white has 80 RA .