XM-L T6 3C vs 4C - I'm just learning that not all "neutrals" are equal.

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Ouchyfoot
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XM-L T6 3C vs 4C - I'm just learning that not all "neutrals" are equal.

  I was recently comparing a couple of different flashlights just to get an idea of tint differences.

First I was using a Balder SE-1 with a neutral XM-L T6 3C which is very nice while viewing brown leaves on green grass from my balcony. I decided to compare it to a Sunwayman M11R with a neutral XM-L T6 4C I had just acquired. The 4C really brought out the deep warm tones of the brown leaves compared to the 3C. Well, maybe not like night and day, but very noticeably to me.

  Does this mean that a 4C has a higher CRI than a 3C? Does the number before the C represent the CRI rating? The visual difference between the two is what made me look up which LED was in which light. Now I know when purchasing new lights that not all neutrals are equal, or some are more equal than others.
 
  What other common " neutral" LEDs might I be getting when I'm purchasing a light and they only state "neutral". I now know that I prefer the 4C over the 3C.
 
  Can two identical lights with identical LED's have slightly different tints. I have identical T6 4C M11R's and one seems slightly warmer than the other. On a white ceiling, one 4C has a whiter hot spot than the other. The other 4C's center is more yellow. Is this what they refer to as the tint lottery? This is all very clinical scrutinizing though. The 3C looks hot white in comparison to them, and a U2 makes the 3C look like a canary. 
 
Rod911
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Posted a tint comparison thread over here. Probably worth a look as I tested colour temperatures from 3000k to 6500k and included some high CRI lights into the mix.

Personally speaking I prefer anything between a 5A (4000k) to 4C (4500k) tint. Anything lower or higher, it’s simply too warm or too cool, respectively, for me.

edit: a 3C tint starts to go into 5000k territory which is has more blue to it, therefore, looks cooler (or “hot” as you put it) than a 4C tint.

Ouchyfoot
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Thanks Rod911. I’m going to have to start learning these tint temperatures and stop saying “hot” when I mean cool. This is getting interesting. Now I can’t wait for the I-Mini neutral XP-G R4 3B that’s in the mail so I can compare it to the others. It’s the real life visuals that are helping me to better understand this. I’m going to have to see if I can get the tint specs on all my neutrals and test them side by side.

nekdo12
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XM-L T6 4C? Where?

Dan
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Tints:

http://flashlightwiki.com/images/f/f6/Ansiwhite.jpg

These are (not quite) irrespective of CRI – in general a warmer tint will have a higher CRI value and a lower output, but that’s not necessarily true

higbvuyb
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The tint bin tells you what ‘colour’ the tint is:
http://romteb.free.fr/creexlampneutralwhite.jpg

The above picture isn’t perfect unless you have a calibrated monitor, but it illustrates the differences.
The line going down the middle is the ‘ideal’ colour of something if you heat it up to that temperature (in Kelvins) i.e. colour temperature of a black body radiator. A black body radiator is basically the ‘perfect’ white colour at its respective temperature.

Hence, the colour temperature is most ‘valid’ the closer you are to that middle line and your colour is closest to ‘perfect’ white the closer you are.

First thing is that ‘warm white’ actually means a lower colour temperature (i.e. colder) than cool white (but you already know that)

The difference between your 4C and 3C is that your 4C is a lower colour temperature i.e. closer to ‘warm white’. Both of them lie quite close to the line going down the middle, which is good.
The 4C has more ‘red’ in it so if you shine it on brownish objects they’ll stand out better just like you pointed out.

CRI is a bit more complicated.
http://www.olympusmicro.com/primer/lightandcolor/images/lightsourcesfigu...

If you look at the curve for the LED, you can see there’s a huge spike in the blue area, and a nasty gap in the deep reds. On the other hand, a light bulb or sunlight tends to be a more even spread without gaps. This is why sunlight and light bulbs have close to ‘perfect’ CRI scores wheras LEDs perform more poorly, the spikes and the missing bits mean that colours don’t show up as accurately.

In general, neutral/warm LEDs (i.e. lower colour temperature) have better CRI scores because they have more of the deep reds and less of the blue spike. In turn, they are less ‘efficient’ lumenwise. However, you can have two LEDs with the same colour temperature or same tint bin but one has a much better CRI score.

The maths is a bit more complicated, but you can think of colour temperature as the amount of red compared to the amount of blue, while CRI is how smooth the graph is over the different colours.

Rod911
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nekdo12 wrote:
XM-L T6 4C? Where?

You’re right. A T6 4C doesn’t exist. If you want a 4C tint, you’d need to go to a T5 bin. Well, that’s what Cree says on their data sheets.

Sunwayman, might have simply got their binning wrong when they put up their specs for their M11R neutral light or that they thought that people wouldn’t notice…

Ouchyfoot
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Thanks for all this good info.
Things are starting to make more sense to me now. I’ve seen those graphs before, but they were over my head. After your explanations and my visual comparison tests they are now very helpful to me. I filed them in my new LED file for easy reference.
I think I really want to become a “tint snob”

Ouchyfoot
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Rod911 wrote:
nekdo12 wrote:
XM-L T6 4C? Where?

You’re right. A T6 4C doesn’t exist. If you want a 4C tint, you’d need to go to a T5 bin. Well, that’s what Cree says on their data sheets.

Sunwayman, might have simply got their binning wrong when they put up their specs for their M11R neutral light or that they thought that people wouldn’t notice…

I leave that conundrum to the experts. Whatever the outcome, the tint is very appealing to me.

baterija
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Rod911 wrote:
nekdo12 wrote:
XM-L T6 4C? Where?
You’re right. A T6 4C doesn’t exist. If you want a 4C tint, you’d need to go to a T5 bin. Well, that’s what Cree says on their data sheets.

Cree also says “The information in this datasheet is subject to change without notice” at the bottom of every page. The current XM-L datasheet is revision 6. There’s no U3 bin either for the CW. Typically as higher flux bins become available the highest bin is not on the datasheet for a while.

cainn
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And given that U3’s are commonly available now (in 1C no less), a T6 4C is certainly a possibility.

texaspyro
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higbvuyb wrote:
you can think of colour temperature as the amount of red compared to the amount of blue

See: http://budgetlightforum.com/node/12296?page=3#comment-271443 for a pretty graph…

hank
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Update? I see XM-L2 T6-4Cs offered, like http://www.leddna.com/cree-xml-xm-l2-led-t6-4c-neutral-white-4250k-4500k-1/ just for example
(no idea if that’s a good deal or not)

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hank wrote:
Update? I see XM-L2 T6-4Cs offered, like http://www.leddna.com/cree-xml-xm-l2-led-t6-4c-neutral-white-4250k-4500k-1/ just for example
(no idea if that’s a good deal or not)

That’s not an amazing deal, but it’s decent.

Tint is all in the eyes of the beholder. As was demostrated with that White/Blue dress, we all see color differently, and even if we see the same thing some people will prefer a different tint. Usually I like warmer neutral tints outside and cooler neutrals inside. For me, 4c is too warm inside, but just about perfect outside.

My Favorite Modded Lights: X6R, S8 , X2R , M6, SP03

Major Projects:  Illuminated Tailcap, TripleDown/TripleStack Driver

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a bump just because

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things would be a lot more complicated than they already are.”
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