Educate me on "warm" and/or "high CRI"

Mikeg23

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I don't really need to now how they work or why one is better than the other. I am curious what lights have these as an option.

I have a Quark tactical- low volage head -that is a limited run "warm" edition.
Running it with a 14500 lithium ion it looks like a brighter surefire E2e beam to me.
Are there other LEDs that have similar color to the Quark warm?
 

TyJo

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HDS is supposed to release a high CRI any day now, it should be out by 2012. Armytek Predator offers the XPG high CRI. I recommend both of those. I heard Peak can do custom orders, etc. but I have never bought anything from them. Unfortunately it seems that Fenix and 4sevens don't care about warm/neutral/highCRI tints anymore.
 
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tre

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Unfortunately it seems that Fenix and 4sevens don't care about warm/neutral/highCRI tints anymore.

FYI, Fenix has a neutral LD25 and LD40 and 4sevens has a batch of high CRI emitters on the way.

Zebralight also has some high CRI models (SC51c) and many neutrals (SC60w, SC31w, SC51w, etc). Malkoff has a high CRI M61 drop-in as well as fairly warm M31w and M61w drop-ins (3700K or so). The Thrunite Neutron "neutrals" are quite warm. Dereelight offers neutral and warm tints as does EagleTac. I'm sure there are others I'm missing.
 

whiteoakjoe

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I am not an expert on this but can give you my experience with a High (CRI) Color Rendering Index light, I purchased a Zebralight H51Fc high CRI light and what it does for me is make colors "POP". With the high CRI light the subtle hues of color are very noticable. When using this light as a headlamp colors don't wash out and details are more noticable, Everyones eyes are diffrent but for me, the high CRI light is one that I will always have if just for certian applications. At times I have to take detailed photos for my work and the High CRI lamp works better than the flash for giving a photo the true to life color your eyes pick up but the camera sometimes does not.
 

TyJo

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FYI, Fenix has a neutral LD25 and LD40 and 4sevens has a batch of high CRI emitters on the way.
I haven't heard anything about Fenix or 4sevens releasing any tints other then cool white, that is good news. Do you have any links to posts or other info about this?
 

tre

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TyJo

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Thanks tre. A high CRI from 4sevens sounds great, I was glad I was able to grab one of the few remaining warms at the end of last year.
 

B0wz3r

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I don't really need to now how they work or why one is better than the other. I am curious what lights have these as an option.

I have a Quark tactical- low volage head -that is a limited run "warm" edition.
Running it with a 14500 lithium ion it looks like a brighter surefire E2e beam to me.
Are there other LEDs that have similar color to the Quark warm?

Go read this.
 

Mikeg23

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Thanks for all tips guys... It's nice to hear that I may be able to but another warm quark soon.
B0wz3r thanks for the link I've only made it to page 2 but I'll read the rest this evening.

Another question I would guess that one conpanies warm is not the same as another companies. I see number like 4500k where would the quark warm fall in place so I know what kind of comparison I'm making.

I didn't know malkoff made a high CRI drop in, I may have to look at that!
 

Napalm

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"Warm high CRI LED" is a feeble attempt to replicate the tint of a 2xAA Maglite incandescent.

Nap.
 

Mikeg23

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"Warm high CRI LED" is a feeble attempt to replicate the tint of a 2xAA Maglite incandescent.

Nap.

So I take it you don't like them? I have carried a strion, a 6P, or an E2e for a long time and always disliked LEDs until I got this warm quark a year ago. To me it really seems like a brighter E2e beam with the addition of a low mode
 

Mikeg23

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Oh this I know as stated I have always disliked LED but they do have advantages over Incan. The biggest advantage for me is the ability to use a range of voltages for the purpose of using lithium ion and primary batteries without it having to be a 3 cell/9 volt light
 

GaAslamp

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I don't really need to now how they work or why one is better than the other.

Like that's going to stop us! :devil:

I am not an expert on this but can give you my experience with a High (CRI) Color Rendering Index light, I purchased a Zebralight H51Fc high CRI light and what it does for me is make colors "POP". With the high CRI light the subtle hues of color are very noticable. When using this light as a headlamp colors don't wash out and details are more noticable,

I just got the H51c, and have had the same experience. Not everybody is as sensitive to subtle variations in hue and saturation, but for me colors that have never looked right even under neutral white LEDs, much less cool white LEDs, appear as accurate (using their appearance under sunlight as my ideal reference) as I've ever seen under any artificial light source (and THE most accurate of any LED I've seen). Not only do colors show up ("pop") better, the overall level of contrast appears to be increased, allowing me to see better with less light, which in return reduces glare.

In addition, at least the example I have has a nice "creamy" tint that doesn't seem to overly emphasize yellow or any other particular color, considering the 4000K color temperature (CCT). While I'd prefer a higher CCT (about 5000K-6500K) with the same or better color rendering, thus far the emitter in this flashlight has the best combination of attributes I've seen in an LED. :rock:

Everyones eyes are diffrent

Absolutely, I can easily believe that some folks wouldn't benefit much from improved color rendering at all, since they wouldn't notice much of a difference (if you don't cringe every time you look at colors with a cool white LED like I do, then you probably wouldn't notice). To some this may seem dangerously like an "Emperor's New Clothes" type of thing :eek:, but there is no denying that everybody's eyes (and visual perception) are different.

but for me, the high CRI light is one that I will always have if just for certian applications. At times I have to take detailed photos for my work and the High CRI lamp works better than the flash for giving a photo the true to life color your eyes pick up but the camera sometimes does not.

The color accuracy of cameras is poor enough as it is, so any improvement in the light source should help some.

Another question I would guess that one conpanies warm is not the same as another companies. I see number like 4500k where would the quark warm fall in place so I know what kind of comparison I'm making.

Yes, the actual CCT varies between manufacturers (and individuals) with regard to vague terms such as warm, neutral, and cool white. For the most part, warm is around 3000K (similar to incandescent), neutral is around 4000K (similar to "cool" white fluorescent :rolleyes:), and cool is around 5000K and above (similar to "daylight" fluorescent), but not everybody uses the same definitions, and some have created new ones, such as Cree with "outdoor" white (around 4500K).

In addition, the proportion of green can vary quite at bit at any CCT, giving some white LEDs either greenish or purplish (less green) tints.

"Warm high CRI LED" is a feeble attempt to replicate the tint of a 2xAA Maglite incandescent.

I think there is definitely some truth to this, as snarky as it may seem. ;) Even though solid-filament-based incandescent lighting has a CRI of 100 (virtually), the manner in which it renders colors due to its necessarily low CCT is not all that accurate if we use sunlight as the standard (which makes the most sense since we evolved under this dominant natural light source). They emit far too much red, for one thing, making purples look overly reddish or pinkish, greens overly brownish, and yellows overly orangish--these colors would only look right if the Sun were a red dwarf star, but obviously it is not. Warm high-CRI LEDs can only hope to approximate the already inaccurate color rendering of incandescent lighting, and even with a 90 CRI frankly they don't necessarily do that good a job of it, either. This is because as deeply and thoroughly flawed as CRI is in quantifying color rendering accuracy, it's even less useful at low CCTs, as I showed (with specific examples and spectral graphs) in the following post from a different thread (the first half or so contains important background information, while the pertinent comparisons are in the second half):

http://www.candlepowerforums.com/vb/showthread.php?315546-Not-Gonna-Buy-Cool-White-Again!-Join-Club-Here&p=3720060&viewfull=1#post3720060
 
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GaAslamp

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Thank you for the link so apparently there's not a huge difference between neutral and warm?

There sure is to me! Under the particular camera white-balance setting that was used (which does majorly effect how the colors in photos turn out), the photo of the tree lit up by the warm white Quark looks positively orange, while right above the somewhat similar photo of the tree lit up by the neutral white HDS high-CRI Clicky at least shows some green.

Then again, much like CRI does NOT tell us a whole lot about the actual accuracy of color rendering in practice (especially with low CCTs, where CRIs are typically massively inflated), CCT doesn't tell us everything about the tint of an LED and how it affects all of the visible hues in various ways. The only way to really know is to use the flashlights, although we can get some idea, as well as analyze what we're seeing in a quasi-objective manner, by looking at the spectral power distribution curves of the LEDs in question, like I did in the big post that I referenced earlier. I had a lot of fun doing that, so let's do it some more! :D:duck:

I'll start by taking another critical look at the Luxeon Rebel LXM3-PW51 (4000K CCT, 85 CRI) LED used in my high-CRI ZebraLight H51c. Here is its emission spectrum:
lxm3pw51.png


Although its spectral curve is a noticeable improvement over those of typical low-CRI LEDs, it still has several flaws. The main ones are that although much improved it still has too little cyan, and it also has a bit too much yellow. Subjectively, to my eyes this is only slightly visible in the form of a mild cream-colored tint in the beam, and has little effect on color rendering once my eyes have adjusted to it. Otherwise, purples are spot on (excellent blue-red balance), greens and browns look right (excellent green-red balance), and blues and oranges are neither over- nor under-emphasized. If Lumileds could only trade the excess yellow for additional cyan (which is extremely difficult to accomplish, I would imagine), this LED's spectrum would be practically perfect (note that this would probably happen to raise its CCT to somewhere in the neighborhood of sunlight, which reinforces how right it gets everything else). Due to this LED's excellent overall performance in practice (to my eyes, compared with sunlight), as well as its verifiable flaws that match what we can see on the graph, I think that its spectrum would make a good baseline for comparison with other LEDs, including those with higher CRIs.

With that in mind, now let's look at the spectral curve of the LED used in the HDS high-CRI Clicky (HDS EDC-E1S-HighCri), which is the Seoul Semiconductor Z-Power P4 S42180 (4000K CCT, 93 CRI):
s42180.png


It looks rather similar to the 85 CRI Rebel's spectral curve at first glance, doesn't it? When we take a closer look, we can see that it is slightly improved in the cyan range, which is good because that seems to be difficult to achieve. However, since it has the same CCT, then something else has to give, right? Unfortunately, the relatively benign yellow peak (in practice) of the Rebel has been traded for an orange-red peak, which means of course lots of additional orange and red relative to everything else. :shakehead Whatever the reason for its CRI being substantially higher, its spectral curve looks worse to me. :thinking:

Now, I can't fairly judge the S42180 without using it myself--looking at real objects with its light using my own eyes--but in all of the photos I've seen (should be taken with a grain of salt because they're only photos), orange and red do appear to be noticeably and consistently emphasized. Some folks may prefer this "warm" tint (even though this LED measures as neutral white overall), and perceive its color rendering to be richer and more aesthetically pleasing as a result, but I suspect that in reality it's not quite as well balanced as the LXM3-PW51, and therefore not as accurate in color rendering relative to sunlight (the S42180's higher CRI notwithstanding--so much for CRI :ironic:).

Since there appears to be some traction in the area of accurate color rendering in flashlights these days (I hope! :bow:), let's examine the spectral curves of a couple of other likely candidates for high-CRI flashlights, starting with the Nichia NS6L183A-H1 (3500K CCT, 92 CRI):
ns6l183ah1.png


It looks very similar indeed to the spectral curve of the S42180, except that there is significantly less blue and cyan, which helps explain its lower CCT. So basically what is wrong (I think) about the S42180 is even more wrong about the NS6L183A-H1. :( While it may potentially garner accolades for its CRI of 92, this LED would seem to make everything look orangish. That's OK if that's what you prefer, but the high CRI in this case has little to do with color accuracy; I guess it's probably better than other warm white LEDs that have lower CRIs, so there's that. As I've said before, CRI is inflated when dealing with low CCTs.

The real "Holy Grail" for those who consider sunlight the ideal light source for color rendering (like I do) is a high-CRI (not that CRI means much--let's say well-balanced instead) cool white (5000K CCT or a bit higher) LED. Well, what do you know? The Nichia NS6W183A-H1 happens to have a CCT of about 5000K (according to its chromaticity coordinates) and a CRI of 92. :eek:oo::twothumbs Could it be? Ultra-pure white light with accurate color rendering?! :drool: Let's find out--here is its spectral curve:
ns6w183ah1.png


Wow, look at that practically flat portion from green to orange-red! :eek: Not that the spectral curve of sunlight itself is flat (it actually peaks at shorter wavelengths), but at least this portion mirrors sunlight's corresponding slope pretty well--that's the good news. The bad news, unfortunately, is that there is too much blue! If more of that blue could be turned into cyan, then this might be the practically perfect LED, much like the example I gave earlier of trading some of the LXM3-PW51's yellow for cyan. In this light (so to speak ;)), comparing these two LEDs to each other, the NS6W183A-H1 should have a more accurate white and grayscale (relative to sunlight), while the LXM3-PW51 probably renders some colors more accurately due to its better blue-red balance, which brings us back to a point I made in my big post in the other thread--that 4000K CCT is where the most accurate overall color rendering can be achieved with today's LED technology (everything is still a compromise).

But regardless, what Nichia has been able to accomplish with the NS6W183A-H1 is very interesting (although I think that I still prefer the LXM3-PW51 overall...maybe :thinking:), and bodes well for what can be accomplished in the near future. :thumbsup: I'd seriously consider buying any flashlight that uses it--who knows, it may end up being my favorite LED, but I'd have to use it for a while first to really know.
 
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GaAslamp

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I don't know whether anybody would be interested at all, but yesterday I tried to take some photographs of various colored objects using various light sources in order to show what I'm seeing and have been discussing with regard to spectral curves. Well, it was quite frustrating, to be honest, and the limitations of my sad little point & shoot camera as well as my relative inexperience at taking photos didn't help. Rarely have I seen such photos that were useful in drawing any conclusions, and now I understand why. :hairpull: Usually the photos don't quite match what people actually see, and comparatively many colors that look different to the human eye can look the same in photos.

Infantile whinging aside :whistle:, I finally did manage to come up with a set of photos of one particular object that fairly accurately shows what I've been talking about--Johnson & Johnson's Baby Shampoo, which apparently is purple these days (it was always orange when I was a child). Most of the following photos have a couple of other colorful fluids to either side, but one doesn't look as different between various light sources in the photos as it does to my eyes, and the other just doesn't look accurate in general, so ignore them. The photos were not retouched with regard to color, although I did make in-camera adjustments to the white balance when necessary in order to make them come out as accurate (to my eyes) as possible--while using a fixed white balance would seem to be ideal in theory, it seems to accomplish very little in practice. Oh, and one more thing--the photos should look alright on computer monitors set to a 6500K white reference, so use that if you can (otherwise they will look too bluish, although that's probably OK for doing comparisons).

First, here is the photo of the baby shampoo under noonish sunlight and a clear blue sky (an ideal reference). It's maybe a tad more reddish in the photo than it appeared to my eyes, but it's fairly true-to-life.
cri0101sunlight.jpg


Here is the same bottle (in the middle, obviously) under incandescent fixed lighting (65W BR30 bulbs), just to provide another common baseline for comparison. The color of the shampoo seemed a tad more saturated than the photo shows, but it was rather pinkish, as shown. What happened to the purple? This light has too much red and not enough blue, I guess.
cri0102incandescent.jpg


Here is the photo I took under a warm white (2700K CCT) CFL bulb. :sick2: Nearly everything has an orangish and also a greenish tint under this thing, probably due to the gigantic spikes in its spectral curve (tons of orange, but not much actual red). Instead of purple, the shampoo looked sort of grayish-violet under this light source, and the photo did a decent job of capturing it.
cri0103fluorescentw.jpg


Now let's try the "cool white" fluorescent tubes (Philips Alto 4100K CCT, 62 CRI) under my kitchen cabinets. The photo came out a bit yellower than the real light looks, but the color rendering of the shampoo is close enough. It's only a slight improvement over the warm white CFL, despite the neutral white (in LED terminology) CCT.
cri0108fluorescentc.jpg


For kicks, here is the photo I took under a not-so-bright old "daylight" (not even close, and not one of the specialized type) fluorescent task lamp (CCT looks to be over 9000K). The purple shampoo actually looked quite rich in color, surprisingly, but there was far too much blue and not enough red in comparison to sunlight.
cri0104fluorescentd.jpg


Here is the photo I took under an incandescent flashlight--this is what high-CRI warm white LEDs strive for. The colors look nice, as expected, but obviously there is far too much red, so the color rendering is nonetheless inaccurate in spite of the light's 100 CRI.
cri0105incandescent.jpg


The photo I took under a typical cool white LED shows, unsurprisingly, that it lacks sufficient red, although it should be noted that these LEDs perform better than any of the fluorescent lamps I used.
cri0106ledc.jpg


And finally here is the photo I took under the ZebraLight H51c with its 85 CRI neutral white (4000K) Rebel LED. The purple looks pretty close to how it does in the photo taken under sunlight, which demonstrates the excellent blue-red balance that I had mentioned in previous posts. The tint of the beam is just a touch more yellowish and just a smidge more pinkish than it appears here (what I believe people often describe as "creamy"), but the purple looks fairly true-to-life (actually slightly more reddish than it appears in person, but the same is true for the photo taken under sunlight, so the comparison is valid).
cri0107ledrebelhicri.jpg


Unfortunately, I do not currently have any other neutral white (with a normal CRI) LED flashlights to use in this comparison. I used to have one, though (I was more concerned with beam whiteness than color accuracy back then :eek:), and from what I remember its beam was a bit more greenish-yellow in tint and it was somewhat lackluster on red hues. I wasn't nearly as impressed with it as I am with my H51c. Since I can't provide a photo myself for comparison at the moment, I went searching for such a comparison and found this:

http://www.candlepowerforums.com/vb...-CRI-Release&p=3651029&viewfull=1#post3651029

Save the second (ZebraLight SC51c H1) and the fifth (ZebraLight SC60w M1) on your local drive, and flip back & forth between them (their overall brightness is similar, which makes the comparison fair). See how the colors "pop" more in the SC51c photo, especially the red tones? It just looks more accurate and "natural" to my eyes in person, although these photos are able to capture some aspects of the difference. The color of the beam itself is also rendered fairly well in this photo, by the way.

Now look at the photo taken with the McGizmo Sundrop. I've never used one personally, so any observations I make based on photos alone therefore carry limited weight, but doesn't this photo look rather too reddish? :thinking: The spectral curve of the high-CRI Nichia 083 LED that it uses is even flatter than that of the SSC S42180 that I critiqued in a previous post, but it seems to have a similar problem with too much red. Actually, the S42180 has an overabundance of orange that makes its light somewhat resemble that of an incandescent bulb, while the 083 appears (in this photo as well as others I've seen) to be plain reddish, just as its spectral curve would appear to indicate. Another example (more subtle) can be found in this post (by McGizmo himself):

http://www.candlepowerforums.com/vb...significance&p=2501298&viewfull=1#post2501298

The color rendering looks nice, but in terms of accuracy the purple is too reddish, at least in the photo. Based on my experience thus far (I've tested many purple hues), I bet that the H51c/SC51c would render it more accurately (if not quite as colorfully, due to its slightly yellowish tint), despite the lower CRI of its emitter. Perhaps the Nichia 083 has its own advantages in other areas (it has more cyan, for one thing), although at present I couldn't say what they are in practical terms.
 

Mikeg23

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Ok I think I want to get my hands on a Malkoff M61HCRI. This is different from the M61W correct?
 
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