Tint, Binning, and CRI Explained (For XM-L LEDs)

I was comparing 2 lights on white ceiling last night, a Spark SL6 with a T5 (probably 3C) emitter, and an IOS T4 5B1 P60 drop in in a Solarforce P1 host. I noticed I could not really differentiate much difference in the tint between the two of them. So that made me try to understand a bit better what I’m seeing and why, so I’ve been reading various threads for the last few hours. If anything the more I learn the more confused I seem to get. Some of the questions I was trying to figure out:

-I assume I am getting more lumens from the T5 than the T4.
-Accordingly, I assume I get a higher CRI from the T4?
-So what puzzles me, why do the 3C and 5B1 tints look roughly similar to me, is it because the surface I was using did not have any bearing on CRI and the difference would be more apparent to me if I was outside looking at foliage and flowers?

When I look at some of the XM-L2 emitters currently on offer at IOS I see some T3 6A1 and T4 5D2, but no T5’s of any sort listed. I’ve been trying to figure out if I should wait for some XM-L2 T5’s to show up, or go with a T3 or T4?

This also has me wondering if it would be more sensible to use SMO reflectors for the T6 and T5 bins, and perhaps OP reflectors for the T4 and T3 bins?

There are several NW XM-L2s with T5 bin. Some can be found in the LED database.

Im not familiar with the Spark, but you assume its using 3C tint, but then you say its very similar to the T4 5B1. Assuming things does not make a comparison between two emitter that easy. 3C tints are mostly T6 bin (yes lower bin exist). If its a T5, then its higher chance the emitter is warmer than a 3C.. Again, im doing assumptions too. Which really does not get us anywhere.

IMO, there is a quite large difference between 3C and 5B1 emitters. Large difference to me might be subtle to others... It depends on how you see things and what you consider a large difference.

You should be getting slightly more lumens from a T5 than a T4 at similar current. But you will probably not be able to tell by eye, especially if the lights are not at the exact same current, using the same reflector, and are side by side.

You are getting higher CRI from the T4 emitter from intl-outdoor. T4 does not always give you higher CRI though, but in this case it does. We are looking at 75-CRI Typical (for the T5) vs 80 CRI Minimum for the T4. There is no such thing as a T5 with 80+ CRI.

Thanks a lot for clarify that. I also wonder if I made an error on assuming the tint for that T5 that is in the Spark, I should have done more homework before I posted it from memory as a ‘3C’, I’m thinking now I probably got it wrong.

In order to get a better overview of what my current options are for getting some XM-L2 emitters I placed some sources that I may use on the chart. The difference between the sources for what I looked at are:

- Fasttech: Alu Base

- IOS: Noctigon copper base

  • Simon: require lots of 5 bare emitters and flow solder to base of your choice

I case this may help anyone else thought I may as well place it here:

I noticed the 5B1 is available as T5 or T4. Does that meant you’d get the same tint but more output from the T5 bin?

Thanks for sharing your fantastic tint chart. I have made a few in the past. But many emitters XM-L2s have arrived since I last made one. Yours seem to give a good picture of what is out there! :)

Yes, you get the same tint and more output, but you dont get as good color rendering. The T4 5B1 from IOS is the more special 80 CRI minimum version. :)

Personally, id sacrifice on step of brightness in order to get better color rendering.

I have just noticed, I seem to now have a lot more drivers and emitters than I have hosts to put them in. As well I also seem to have a few XM-L emitters on aluminum base that I’m not as keen on now that I have run across these comments. So now my dilemma is what to do with all the XM-L emitters. I’m thinking of putting them into affordable hosts, but then you have to give people 18650 batteries and chargers as well. Perhaps the only way to go is grab a bunch of the $5.00 host from FT that takes the CR123 primary cells, put the XM-L emitters into them, and then give them away.

Ive had the same issue. My solution to your problem.


Why bother with getting rid of a bunch of decent emitters in a bunch of different lights, when you can get rid of a bunch of emitters in one or few lights. There are several benefits.

1. You might actually like your new multi-emitter monster :bigsmile:

2. Instead of having a bunch of outdated lights, you only have one, or a few.

3. When you have several thousand lumens, mostly in flood. You don't really care that much if you are loosing out on that extra 20% of output.

4. If you decide to sell it, lots of outdated emitters gone! :)

Some might ask, what to do with all the stock emitters from the multi-emitter lights. Well, they are only CW T6. They are great for testing, playing with, frying, doing various de-doming experiments, having in bench setups when testing new driver circuits. Everyone should always have 3 in series, 3 in parallel, + 1 XM-L ready for testing new drivers.. :) Suddenly 7 emitters got a purpose! :)

If you have a bunch of emitters you don't like, you could always do an emitter giveaway here on BLF. If you don't have a decent purpose for them, there is probably someone else who have.

Good ideas, I’ll probably end up using all of them. Is that an actual head or optic than can be readily obtained in that picture? Maybe I can make a porch light or something.

Its an actual head..

Fandyfire 9 XM-L

Got it, comes with the emitters already I see. When I go to the site it has a pop-up telling me about the group buy for 18650, they must know I clicked through from BLF I guess. Thanks.

Thanks for the write up scaru!! Great reading material, lots of good info in a really easy way to understand!!

I really appreciate your time and effort scaru putting this thread together - and to the others who have commented and kept the discussion going. Lots to read for a know nothing flashlight junkie but I’m beginning to see the light :).

I keep buying lights for all the wrong reasons then get disappointed. Finally starting to ask some good questions in advance thanks to you folks here in BLF.

Something important about CRI, that isnt well known and popular
Actualy CRI measures only Pastel tones, not the core RGB ones, even not the earth tones, thus its a bit….pointless.

Even more, even top priced and quality emitters doesnt perform well in representing RGB colours, especialy red(r9) and blue(r12)

Dont get me wrong, they are exellent, the technology is advansing with every single day, but for now( end of 2014) rendering the red colour is a huge issue for all led emitters, actualy i have seen only once a real R9> 80, was a Nichia 219 chip

Yes, they DO claim they have R9 over even 90, like Cree claim, but thats not true
Here, from a fresh calibrated ASENSETEK LIGHTING PASSPORT ( 2 weeks from now)

The top of the line Cree 1304 SSL Y94 CRI 95+ matrix emitter( XML is way worst than this)




Indeed, great overall CRI, hell anice chrom. chit, yet……poor R9 performance

Subbed. I want to see what comes next on this discussion, and R9 has always seemed like an underdiscussed topic around here.

Well, for the flashlights it doesnt matter realy( r9), but the fact that CRI actualy represent nothing important isnt well known
Yet, R9 is important when we talk about interior lighting, red is the colour of your child face, the skin…the colour or the blood too- and in the real life it almost never reaches 80, regretably of course

One of the factors that is important to me has been recognizing body fluids (such as blood) on the snowpack at avalanche sites (can indicate the proximity of a buried victim for example), and capillary refill, cyanosis, etc., for patient assessment, particularly in winter in sub freeing temperatures.

Until now I thought that that depended on CRI, and have found that T4 emitters seem to have been best. I thought that was a result of CRI, appears I was mistaken. Is the quality of r9 better in a T4 emitter, or is that just my imagination?

Thanks for the head’s up, this is very interesting, and will change the way I view the best lights for Search and Rescue purposes.

Hi Scaru - here is a quote from page 1 - “Recently, (December 2012) cree released the XM-L2, which is approximately 20% more efficient than the original XM-L. This means that a XM-L2 T6 is approximately as efficient as a XM-L U3. Unless it is specified, the light does not contain a XM-L2.”

A newbie question for sure so as a newbie I ask - what does efficienct mean in this context of XM-L comparisons?

Hi Samlittle
The efficiency is about light output(measured in lumens) per watt.this thread has a lot of info about everything to do with flashlights,but specifically,near the top,it has luminous flux tables for various emitters including XM-L and XM-L2.The XM-L U3 has 220 to 240 lumens at 700mA,the XM-L2 T6 has 318 to 341 lumens at 700mA,same thing.The XM-L2(edited) U2 has 364 to 386 lumens at 700mA.There’s your higher efficiency,more light output from the same current input.Hope this helps.

Ah yeah - the light came on - Thanks Billy.