# Puny LED flashlights (Not!) + COLOR RENDITION Comparison



## UnknownVT (Dec 18, 2007)

_*EDIT to ADD*_ -
This thread has also evolved into a discussion of 
Color Rendtion comparsion between LEDs and incandescents - starting at Post #*28* (link) using a Map

Using Tungsten and Auto white balance to approximate to the way the brain would adjust/compensate to incandescent lighting - 
and also using a standard Macbeth color (patch) rendering chart - see Post #*52* (link).

Experiment with color removal/desaturation to compare the luminance/brightness in patches Post #*59*

Experiment with adding orange LEDs and using vision enhancing sunglasses as filter - Post #*69* 

Socks - differentiating between navy and black - Post #*82* 

Sunlight pics of Macbeth chart Post #*105* 

Better Sunlight pics of Macbeth and Map - Post #*112* 

Summary of position/opinion so far - Post #*73* 

Warmer tints and Kruithof curve - Post #*123*
-------------------------------------------------------------------

Not so long ago LED flashlights were regarded as efficient and frugal on batteries, but only "bright for what they were" and used only for close tasks and emergencies.

Since the advent of the Cree 7090 XR-E - LED flashlights have surpassed the brightness of the typical 2x lithium CR123A xenon light - like the fabulous SureFure 6P, G2 and Streamlight Scorpion (the one used most in CSI).

In fact even the single AA Fenix L1D-CE is rated brighter than these 2x CR123A xenons - this is simply incredible and unheard of just a few years ago.

These comparison beamshots have had the color removed by deSaturation leaving only the luminance/brightness information - to remove any color bias/influence -








remember this is single AA battery light compared to a 2x CR123A lithium xenon light 
- which is already brighter than a typical 3x D battery Kypton flashlight....





With the more premium Q-series Crees and LumiLEDs Rebels - and using more than 3 volts - we have now surpassed even the typical 3x lithium CR123A xenon lights - at one time regarded as the tops and "ridiculously" bright.

Of course one can see that just from the specs - the now legendary SureFire 9P (3x CR123 xenon) is rated at 105 lumens - the new Fenix T1 is rated at 225 lumens, that's a factor of 214% - so should easily be brighter, even allowing for inflated specs. 

Even on the P91 ultra High Output lamp the SureFire 9P reaches 200 lumens - BUT runs for all of 20 minutes on 3x CR123 - 
compared to the Fenix T1's 225 lumens, rated to run for 1.5 hours - similar brightness - 
but 4.5x the runtime on 2/3 the batteries.......

In fact the specs of the Fenix P3D's are - 
Q5 - 215 lumens 1.8 hrs; 
Rebel100 200 lumens 1.8 hrs

Just to put matters to rest -

Fenix T1 vs. SureFire 9P (3x CR123 xenon - P90 standard lamp)








Still not convinced?

Practical stairway shots -
Color deSaturated -














That last shot is from a single AAA light - but using an AAA sized 3.7V Li-Ion rechargeable 10440 battery.

I think these shots speak volumes.....


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## blademan (Dec 18, 2007)

*Re: Puny LED flashlights (Not!)*

I got rid of my incans before and now LED's are even outhrowing incans. These are great pictures!! LED's provide better more even illumination for my needs also.


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## afraidofdark (Dec 18, 2007)

*Re: Puny LED flashlights (Not!)*

Unknown, of all the beamshots on CPF, your "stairway shots" are my favorites :thumbsup:

(It never ceases to amaze me what an L0D on a 10440 cell can do)


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## tebore (Dec 18, 2007)

*Re: Puny LED flashlights (Not!)*

What I love most is that with LED lights you can (with some skill with a soldering iron) upgrade them as LEDs get brighter. 

A simple emitter swap doubled the brightness in my HDS lights. I'm loving the LED trend.


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## Federal LG (Dec 18, 2007)

*Re: Puny LED flashlights (Not!)*

Nice shots VT !! :thumbsup:


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## p1fiend (Dec 18, 2007)

*Re: Puny LED flashlights (Not!)*



UnknownVT said:


> In fact even the single AA Fenix L1D-CE is rated brighter than these 2x CR123A xenons - this is simply incredible and unheard of just a few years ago.
> 
> These comparison beamshots have had the color removed by deSaturation leaving only the luminance/brightness information - to remove any color bias/influence -
> 
> ...


 
I'm no rocket scientist, but if I had to place those three pictures in order of brightest to dimmest, in regards to the central hotspot, then it would be:

Mag3D
Scorpion
Fenix L1D-CE

The Fenix may have more spill, but looking at those 3 pictures, it has the dimmest hotspot. It is still quite impressive and you make a good point about the brightness of LEDs.


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## adirondackdestroyer (Dec 18, 2007)

*Re: Puny LED flashlights (Not!)*

Good thread Unknownvt! Hard to argue with the pics. Incans are dead with the exception of Hot Wires. There is no reason to buy a 2x123 or 3x123 cell Incan unless you are obsessed with Surefires.


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## easilyled (Dec 18, 2007)

*Re: Puny LED flashlights (Not!)*



p1fiend said:


> I'm no rocket scientist, but if I had to place those three pictures in order of brightest to dimmest, in regards to the central hotspot, then it would be:
> 
> Mag3D
> Scorpion
> ...



Yes this is hardly surprising because throw is mainly related to the size
of the optic. Hardly a fair comparison between the Mag3D and the Fenix L1D-CE!

Try comparing the Mag3D to a Mag with a Seoul/Cree-XRE for throw
if you want to be objective.


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## Crenshaw (Dec 18, 2007)

*Re: Puny LED flashlights (Not!)*

yes but incans will always have a special place in any flashaholic's heart, i mean, WHO is going to throw an M6 into the bin? any surefire for that matter

Crenshaw


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## flashy bazook (Dec 18, 2007)

*Re: Puny LED flashlights (Not!)*

we should bookmark this thread and have a macro to insert a link to it whenever we hear about how incans are great!:laughing:

But probably there is little reason, there seem to be fewer and fewer "pro incan" threads or opinions these days. Those who like incans have learned to make their point by supporting specific lights, that are incans but without actually mentioning that little fact, and adding other features into the mix (like a supposed "reliability" of the flashlight, which of course never includes the far superior reliability of the LED in the equation as considered against that of the incan bulb!).

Good post and very powerful pics.


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## Schuey2002 (Dec 18, 2007)

*Re: Puny LED flashlights (Not!)*

Woah!  I think that I be needin' a Fenix L0D-RB80...


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## daveman (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*

Nice beamshots, VT. It's true that Incans do offer slightly to moderately superior color rendition than LEDs, BUT that edge in color rendition can only cover so narrow a gap in lumen output. When LED lights are producing 2x as many lumens as as Incans, they will simply appear brighter, in accordance to being brighter.


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## woodrow (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*



p1fiend said:


> I'm no rocket scientist, but if I had to place those three pictures in order of brightest to dimmest, in regards to the central hotspot, then it would be:
> 
> Mag3D
> Scorpion
> ...


 
UnknownVT,
I could not agree with you more. Please let me know if you would like to remove these beamshots. I post them only to reply to the above post.

p1fiend, Here is a picture of a Mag 4d on pretty fresh batteries and then a Fenix T1 below it. Both lights are running on 6 volts and camera settings are the same.











The mag will *slightly* outthrow the Fenix T1...both indoors and out, but it illuminates so little. Yes, the P3D is not the greatest throw light in the world, but it has a reflector no bigger than a dime. Make the light a led thrower, and their is no contest.

The new leds are great, and only getting brighter.


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## Tsarli (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*

Nice comparison pics! Thanks to LEDs now is a *good time* to be a flashoholic.

A *bad time* guaranteed for the wallet though, as I am now finding out.


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## woodrow (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*



Tsarli said:


> Nice comparison pics! Thanks to LEDs now is a *good time* to be a flashoholic.
> 
> A *bad time* guaranteed for the wallet though, as I am now finding out.


 
Actually it is a VERY good time for the wallet. To get a T1's output, you used to have to buy a SF M3 at about $250 or so. Then you had to put the high output bulb in it. That lasted about 20 or so minutes, so you bought A LOT of 123a batteries, because you changed them out every few days.

Now for $50-$80 you can have a pretty bright light that is effecient and can run on rechargables. (of course I say this as I am ready to spend $168 for a MRV SE digital) OK, its still expensive, but it is a VERY good time to be a flashaholic!



:mecry:


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## LightInTheWallet (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*

Maybe a moderator could be so kind to post this thread in the general flashlight column. ( posting in the LED column is preaching to the choir ) IMHO and I fully agree with your post. :thumbsup: Thank you.


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## L.E.D. (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*

It's fun to watch a SSC P4 modded Streamlight Propoly 4AA destroy a 4D Mag in overall output AND throw. Streamlight did awesome work with this light, and especially this reflector.


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## UnknownVT (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*

Here are some size comparisons -
















see -

Fenix T1 Comparison Review


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## wishywashy7 (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*



Crenshaw said:


> yes but incans will always have a special place in any flashaholic's heart, i mean, WHO is going to throw an M6 into the bin? any surefire for that matter
> 
> Crenshaw



we won't throw them away, we just replace the heads and light assemblies


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## garence (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*

Thanks for this really informative comparison, VT. Wow, I had no idea that incandescents have been caught up to and surpassed by a number of not-so-overpriced LEDs. Even if you don't want to fork out the expense, you can always go the cheap route of either buying an inexpensive body to use with a drop-in or as wishywashy said, cannibalize the incan bodies. 

The only economic advantage I'd say incandescents still have is underwater. I used a Xenon UK D8 on my last diving trip and it seemed to hold its own against a Princeton Tec LED of similar design being used by my dive buddy (the Princeton Tec LED is 2x expensive).


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## jefflrrp (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*

HUMPHHH ! ! I still love my G3, even with its puny 105 lumen lamp and only 25 hour lamp life. :candle: And Im about to buy a 6PD w/ extra P61 la. (although truthfully if I could afford it I'd by a P60L and put that in the 6PD)

*Note to JeffLrrp: You still like your 6PL more*

Darn :thinking:

If only Surefire would make brighter LEDs. THen I'd have no more money for food.


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## jefflrrp (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*

Although truthfully, I do like incans better for color rendition. To my eyes at least, I can pick out things clearer in yellowish-white better than bluish white. 

But nothing can beat LEDs for reliability


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## UnknownVT (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*



jefflrrp said:


> Although truthfully, I do like incans better for color rendition. To my eyes at least, I can pick out things clearer in yellowish-white better than bluish white.


 
I'd agree in some ways - afterall one of my EDC lights is a Yellow Photon -which I've carried since the Mk 1 before Photon 2 were available (it's now a Yellow Photon 2).

Thank you all for your responses and to woodrow for the additional beamshots - although the original contention was that the single AA Fenix L1D-CE was not as bright as the Mag 3D or Streamlight Scorpion - 

Both those incands have better throw having much larger reflectors - especially the Mag - they are famous for throw. However the simplest question is with which of those 3 lights do you see more/better?

Anyway getting back to color rendition - here are the full color stairway shots -
The BIG guns -
















Fenix L1D-CE vs. Streamlight Scorpion vs. Mag 3D


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## jefflrrp (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*

Dang you, sir.

I stand corrected


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## UnknownVT (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*



jefflrrp said:


> Dang you, sir.
> 
> I stand corrected


 
You weren't being corrected - 
my eyes also see "better" under yellower light like incands

Although we've been told the "camera never lies" - 
they are a bit limited in showing only one version of the rendition -
our brains compensate for the scene we are seeing -
most of us use simple incandescent light bulbs at home (some also use the more energy efficient fluorescent bulbs) - 
we tend to think things seen under these lights as quite natural - 
but the most popular and used type is "soft white" - which is _VERY_ yellow.

Look at the stairway shot under my house lighting




the shot was supplemented with flash (more daylight'ish) but the top of the stairs - where the door and "target" is, is much more like the way the camera sees our house lighting - very yellow.

I think at lower light levels my eyes sees better with yellower light - so in the real early puny LED days we could have done more with LEDs that were more yellow biassed - 
but now that they've surpassed most hand-held compact incands - the whiter/bluer tint is kind of OK - although I still favor warmer white tints


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## easilyled (Dec 19, 2007)

*Re: Puny LED flashlights (Not!)*



garence said:


> Thanks for this really informative comparison, VT. Wow, I had no idea that incandescents have been caught up to and surpassed by a number of not-so-overpriced LEDs. Even if you don't want to fork out the expense, you can always go the cheap route of either buying an inexpensive body to use with a drop-in or as wishywashy said, cannibalize the incan bodies.
> 
> The only economic advantage I'd say incandescents still have is underwater. I used a Xenon UK D8 on my last diving trip and it seemed to hold its own against a Princeton Tec LED of similar design being used by my dive buddy (the Princeton Tec LED is 2x expensive).



Ah, but is the Princeton Tec LED using the Cree-XRE's that 
are used in the Fenix T1 and are twice as efficient as the luxeons,
or is it still using the now outdated luxeons?


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## UnknownVT (Dec 20, 2007)

*Re: Puny LED flashlights (Not!)*

For any still dubious -now here's a REAL challenge -





Yes, a *1,000,000 candle power spotlight*!!!! - 

At one time this would have been considered a silly/crazy comparison -
but look and judge for yourself -
















Color removed/DeSaturated -


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## UnknownVT (Dec 25, 2007)

*Re: Puny LED flashlights (Not!)*

I have been intrigued by the CRI (Color-Rendering Index) given for incandescent lights as close to 100 (perfect) - 
yet I know I often have problems seeing yellow on white and distinguishing shades of colors like blue under incand lighting - which I don't have with white LEDs.

Yet white LEDs have much lower CRI in the range of 60-70 - so what gives?

Fortunately I found the GE lighting web page - About Light: Color Rendering

"_An incandescent lamp, virtually by definition, has a Color Rendering Index (CRI) close to 100. This does not mean that an incandescent lamp is a perfect color rendering light source. It is not. It is very weak in blue, as anyone who has tried to sort out navy blues, royal blues and black under low levels of incandescent lighting. On the other hand, outdoor north sky daylight at 7500K is weak in red, so it isn't a "perfect" color rendering source either. Yet, it also has a CRI of 100 by definition._
_..._
_Technically, CRI's can only be compared for sources that have the same Color Temperatures._"

This made more sense - but the reliance on CRI is still somewhat of a mystery to me - 

So I thought I'd do my own ad-hoc experiment - to compare LED with xenon based lights using a common but fairly demanding "target" - a Rand McNally map - which most people have easy access to - (I used Gainesville, Florida area from the 1991 edition) - camera set on fixed daylight white balance.

First, reference lighting conditions -

White Reference .................................................. ................ Tungsten Room lighting








LED and Xenon Lights -



















The white reference shot (which was a scan) probably has the best color balance and rendition - followed by the LEDs - they are close - but if I had to rank them, my preference was - Rebel 100, Luxeon III, then the Cree Q5 - but like I said they are close and in any real use where there is no direct side-by-side comparison they would be more or less equal.

The xenons were better than the regular tungsten room lighting - (2x 60 watt "soft-white" bulbs) - with the SureFire 9P a bit better than the Scorpion (the SF 9P using 3x CR123 - 9 volts would be burning the xenon a bit hotter - therefore "whiter") but all the incandescent lights had the problem differentiating yellows against the white of the map - eg: look at the background under Fairbanks (top left of map) on any of the incand lights - is that yellow? (no, actually it's plain white background), also look at the interstate 75 - that's a yellow background can that really be made out under the incands - and is that line really blue - if one didn't know it beforehand?

The LEDs do show weakness in rendering reds - but for map reading this is not really a big problem.

So despite much lower CRI - LEDs seem to "render" the simple colors on a map quite a bit better to my eyes than incandescent xenon lights.


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## Culhain (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

Fascinating thread.

I have a question that I'm a bit embarrassed to ask, but will do so for the sake of science.

I own only two colors of socks: dark navy blue and black. Under sunlight they are easy to match. Mostly, I neglect to sort them until I'm getting dressed in the dark. I find that LED lights (from 5mm to M60 Malkoff) are of no help in sorting the blues from the blacks. My SF E2O is my preferred sock matching light as it clearly shows the difference between blue and black.

So, is my color vision faulty or is the incan really better in this case?


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## Sgt. LED (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

:shrug: I know my color vision is faulty! My lady does those sorts of matching for me, and tells me when things I pick out don't work.


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## sabre7 (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

Great Scot man get a grip!! Just how much $$candlepower$$ do you need to find that doorknob anyway? Looks like they are ALL more than adequate. Maybe you could fit a couple dozen kleig lights into that stairway for comparison too? Kinda just boils down to a pissin' contest now don't it?


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## easilyled (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*



UnknownVT said:


> I have been intrigued by the CRI (Color-Rendering Index) given for incandescent lights as close to 100 (perfect) -
> yet I know I often have problems seeing yellow on white and distinguishing shades of colors like blue under incand lighting - which I don't have with white LEDs.
> 
> Yet white LEDs have much lower CRI in the range of 60-70 - so what gives?
> ...



There has been much debate about CRI in these halls.

If you do a search you should find many threads on the subject.

I was vigorously arguing precisely the points you have made yourself
re color rendering being a lot better for leds than the current definitions
seem to indicate.

You might be interested to know that according to Wikipedia, the CRI
definition is being changed to take into account the fact that
led and fluorescent lighting seem to give much higher relative values than
the figures derived from the current definitions.

The most common argument used in favor of incandescents in relation
to CRI, is that the spectrum is complete for incandescent light and incomplete
for led light.

This is an oversimplification. The spectrum for led lights has a high blue
spike and blue and green wavelengths are more represented than red
and orange. However the red and orange wavelengths are still present
and now that the overall lumens (output) of led lights is so much more
impressive, all the different wavelengths are adequately represented
even if there is a blue bias.

I am sure that there is a strong red bias in the incandescent spectrum.

In my opinion, it depends what you want to use the lights for.

Like you said for map-reading, leds are probably superior.

For spotting a deer in the outdoors, maybe incandescents have the
edge.


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## cv3po (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

[
For spotting a deer in the outdoors, maybe incandescents have the
edge.[/quote]

I've heard this said the most. That for outdoor work most folks just "like" the look of incans better and that led's make things look "washed out". I've even noticed it a tad bit outdoors, just a kind of bias towards incans. But when you think about it, the human eye evolved outdoors in sunlight  which is closer to a good incan. So especially outdoors led's just don't look "right".:thinking: Then you use them more and realize nope............led's are better at most things. As far as the deer, the brown fur does pick up on the led's weakness in the red end of the spectrum. Just my 2c


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## Saiga (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

(quote) "Unknown, of all the beamshots on CPF, your "stairway shots" are my favorites :thumbsup:" 

I totally agree, these shots did a better job of contrasting and comparing lights and beams than any others IMO.Other reveiwers might should consider "borrowing" your technique.Great post !


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## Thujone (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

Wonderful thread... I think the tide has truly turned.


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## UnknownVT (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*



cv3po said:


> But when you think about it, the human eye evolved outdoors in sunlight  which is closer to a good incan. So especially outdoors led's just don't look "right".:thinking: Then you use them more and realize nope............led's are better at most things. As far as the deer, the brown fur does pick up on the led's weakness in the red end of the spectrum. Just my 2c


 
First I am a believer in being able to see well under yellow biassed lights - I actually carry a _YELLOW_ photon 2 as my EDC for well over 10 years now.

However white LEDs - esp the high powered ones like the Cree, Rebels and Luxeons are much closer to sunlight than any incand.

My ad-hoc map shots were taken with fixed Daylight white balance - and the incands all are distinctly yellow.

The all important color temperature for noon day sunlight is about 5500-6500K - incands are much more like 2800K - which is way lower - white LEDs despite discontinouous and possibly unbalanced spectrum average out closer to 6500K - which is (obviously) much closer to sunlight.

Our conditioning/evolution is due to using fire/candles as light sources at night - hence our adaptation/bias to being able to see well using yellow-biassed lights, our brains also compensate and adapt - that's why most of the time we think tungsten and incand lighting is "white".


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## tebore (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

I don't think conditioning and evolution has much to do with why when we see things with LED's they look washed out. 

While LEDs is 6000-6500K and supposedly closer to sunlight. It's in that LEDs lack a lot of red in the spectrum and you need pretty much a full spectrum to get good color rendition.


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## UnknownVT (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*



tebore said:


> I don't think conditioning and evolution has much to do with why when we see things with LED's they look washed out.
> While LEDs is 6000-6500K and supposedly closer to sunlight. It's in that LEDs lack a lot of red in the spectrum and you need pretty much a full spectrum to get good color rendition.


 
I'd agree with this - it is the lack (but not an absence) of red that makes white LEDs look less warm and therefore less rich in color - I explicitly talked about the weakness in red in my comparisons.

Again I agree with incands being better for spotting deer in the woods at night - BUT it is the strong red and yellow bias of incands that makes the contrast.

Although this is a common use - it is still a special case - 
let me give another example - the "invisible" fluorescent marks on currency bills are revealed by UV light - therefore UV lights are (obviously) better for seeing those marks - but does anyone regard UV lights as a good general purpose light?

So incands are superior for outdoors use among woods - 
but are they really better at color rendition? 
(Please go back and look at the maps - 
and remember Rand McNally have years of experience and specifically designed their maps to be legible under incand lighting - 
eg: that's why yellow roads have a red outline)


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## easilyled (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*



tebore said:


> I don't think conditioning and evolution has much to do with why when we see things with LED's they look washed out.
> 
> While LEDs is 6000-6500K and supposedly closer to sunlight. It's in that LEDs lack a lot of red in the spectrum and you need pretty much a full spectrum to get good color rendition.



You can argue this both ways.

Just as you say leds lack red compared to blue, you can also say that
incandescents lack blue compared to red in their spectrum.

Neither spectrum is perfect by any means.

This is clearly illustrated by UnknownVT's maps.

As I said earlier, because of the increased overall output, there is more
red and orange been given off then before for the newer generation of
leds even though the proportion (ie. spectrum) remains unchanged.


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## cv3po (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

I've never agreed with the whole 6500k sunlight thing. These readings are taken at high noon when the sunlight is going through the thinnest part of the atmosphere. For MOST of the day it is angling through (for ALL of the day if you live a fair distance from the equator) alot of air which as we all know filters out the blue part of the spectrum (the sky is blue because the blue part gets refracted or bounced around) To take the measurement during perfect high noon (when alot of animals are taking a siesta) you kind of skew the truth a bit. Ever wonder why the sky is red/orange during a sunrise/sunset? Anyway, I'm sorry for helping get the thread off track, LOL, and I do LOVE the stairway shots. It makes me get all warm and fuzzy and want to hug my LOD-Q4  When I think about just 5-7 years ago, imagine what we would have paid for this light $$$!!!! Not to mention my current photon II DS which on a single 2032 is brighter than my first 5600 nichia photon was on 2-2016's. 5mm's are coming along too, although at a SLIGHTLY slower pace.

BTW, that candle/fire thing is a good point also. That never even occured to me.....................DOH!


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## RichS (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

All but one of my lights are LED (w/ more LED lights on the way), but a couple of months ago I bought a Streamlight TL-3 and took it outdoors with my DBS, Fenix and other LED lights to compare. I was extremely impressed how it performed next to my high power LED lights.

When I lit up a tree with the DBS it looked bright as day, but when I lit it with the TL-3, I suddenly noticed all the brown, yellow, and various shades of green leaves on the tree where with the DBS it all looked pretty much various shades of green. Also, I shined the DBS in a large field and it again was amazing how it's spill lit it up the area, but when I shined the TL-3 in the field I saw it was covered in brown and yellow leaves which I didn't even notice were there with the DBS. This was sort of strange because the DBS lit it up like it was day. The last thing I noticed, when pointing the lights at targets far in the distance, of course the DBS lit it up way brighter. But at a reasonable distance, even though the DBS lit it up more (outside shining the lights inside of a barn for instance), I could make out the objects just as easy with what seemed like less light with the TL-3. I just assumed that this was because if the incandescent color-rendering. The pure white LED light just seemed to wash things out a little bit, where the incandescent made objects that were lit up by it stand out in comparison.

With this experience it makes sense to me that it would be much more difficult to spot a deer lying down in a field for instance with an LED compared to an incandescent. It also seems to me that if you were looking to spot any animal, or even humans wearing earth tone colors, it might be a much easier task than with an LED light. I don't think they necessarily give more contrast, but they do seem to separate specific colors in the spectrum as mentioned above which definitely helps with recognition. I wish LEDs were better at this because I much prefer the clean, white light of my DBS/CL1H over the yellow tint of my TL-3.

That being said, I have found that my Fenix Rebel 100 has a warmer tint, and gets a little closer to providing the color separation of an incandescent, but it's still much closer to the typical LED rendering side. 

I still much prefer LEDs for the crazy bright output, nice white light, runtime, 50,000 hr longevity.... but, I will always have a very good incandescent available if needed for something like an outdoor search in a field/woods, etc. because I've seen the difference. And if needed, I know my (now hotwired - thanks Lebox!) TL-3 will be up to the task.


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## davidra (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

Actually, for my specific usage incans have proven to be better. I need a thrower for spotting channel markers in the dark on the water (actually, I live in Gainesville so I appreciate the map choice). I purchased a WF-600 to get a feel for what this was all about, as it was inexpensive and had a great review as a throw king. It will work fine on the water as long as there is no mist or fog. Simple haze makes the beam scatter much more than my TL-3, which I've used for years for this purpose. In perfect conditions, the LED will outthrow the incan, but most of the time I"m not in perfect conditions and the beam of the incan cuts through the mist without scattering much beeter than the LED. Not that I don't like LED's; I bought a T1 as well, hoping it would have a smooth reflector but it didn't. The LED still has an amazing wow factor in good weather, but next time you've got some fog around compare it to any incan, even one with just two cells like a 6P and you'll see what I mean.


----------



## Gunner12 (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*

Shorter wavelength light does scatter more in fog(that is also the reason I want to build a Mag 85, well beside sheer output).

Thanks UnknownVT for the comparison, LEDs have come a long way from the little indicator lights.


----------



## UnknownVT (Dec 26, 2007)

*Re: Puny LED flashlights (Not!)*



davidra said:


> next time you've got some fog around compare it to any incan, even one with just two cells like a 6P and you'll see what I mean.





Gunner12 said:


> Higher wavelength light do scatter more in fog




FWIW - For a long time car fog lights were yellow and one could even buy yellow/amber filters to cover the headlights in fog.

I have also heard this was supposed to be a myth.

But like others I think not only is yellow/amber easier to see in fog - 
they also seem to cut through better and scatter less.

The shorter wavelengths (higher frequency) are scattered more - the one time frequent ads for "BluBlocker" sunglasses made that well known - 
and glasses that enhance vision (eg: shooting glasses) were yellow/amber or even orange.


----------



## woodrow (Dec 27, 2007)

*Re: Puny LED flashlights (Not!)*



cv3po said:


> [
> For spotting a deer in the outdoors, maybe incandescents have the
> edge.


 
I've heard this said the most. That for outdoor work most folks just "like" the look of incans better and that led's make things look "washed out". I've even noticed it a tad bit outdoors, just a kind of bias towards incans. But when you think about it, the human eye evolved outdoors in sunlight  which is closer to a good incan. So especially outdoors led's just don't look "right".:thinking: Then you use them more and realize nope............led's are better at most things. As far as the deer, the brown fur does pick up on the led's weakness in the red end of the spectrum. Just my 2c[/quote]

Having lived in Nebraska and Kansas for a number of years, and having TKO'd one deer and nearly missed many others, I think the limitation of lighting is not color spectrum, but amount of light. I would rather drive a car with hid beams on high, though the beam is a very cool white, than my car with the best regular incan headlights I can buy.

(but I hate driving toward one of those stupid hid equipped cars at night, on a blacktop road...in the rain!)


----------



## Norm (Dec 27, 2007)

*Re: Puny LED flashlights (Not!)*



UnknownVT said:


> First, reference lighting conditions -
> 
> White Reference .................................................. ................ Tungsten Room lighting
> 
> ...


As someone on TV once said Verrrry interesting.
Love the map shots, kinda put a damper on the colour rendering issue.
Norm


----------



## yaesumofo (Dec 27, 2007)

*Re: Puny LED flashlights (Not!)*

I would like to see the T1 next to a 6P.
Can you do that?
Yaesumofo



UnknownVT said:


> Here are some size comparisons -
> 
> 
> 
> ...


----------



## EV_007 (Dec 27, 2007)

*Re: Puny LED flashlights (Not!)*

Excellent illustration of the performance of the LEDs, however, I have a few observations to make:

Since the incans are warmer light sources, would not a color balance on your camera set to tungsten reveal more accurate colors in your map shots since the human eye automatically corrects for this. I highly doubt the maps look that orange to your eye in person. Daylight balance even set to auto white balance biases warmer illumination and renders it yellow/orangish on the final image. 

I am not arguing the efficiency and advances in LED technology which is not limited to one flashlight manufacturer, but would not an outdoor beamshot reveal the true performance of incan vs. LED debate. 

The P91 vs. the Fenix T1 may look close in the white wall hallway shots, but how would it perform under outdoor conditions, especially with some atmospheric haze and beyond 10 feet?

Again, I own both LED and Incans and some are even from Fenix, however, in the end each to their own. I don't think incans are dead nor do I think LEDs are puny. 

These are apples to oranges comparisons and characteristics of each should be considered when comparing the two very different light sources.

No one is denying that leaps are being made in LED advancement compared to incans. I wouldn't throw in the incan towel just yet. Not until the output and beam profile of my Surefire 9P+A19 running on 2x17670s powering the Lumens Factory EO-9 or even the P91 for all that matter is surpassed by an LED. Guilt-Free color rendering lumens.


----------



## UnknownVT (Dec 27, 2007)

*Re: Puny LED flashlights (Not!)*



yaesumofo said:


> I would like to see the T1 next to a 6P.
> Can you do that?


 
Don't have a 6P - will a Streamlight Scorpion do?


----------



## soffiler (Dec 27, 2007)

*Re: Puny LED flashlights (Not!)*



EV_007 said:


> ...Since the incans are warmer light sources, would not a color balance on your camera set to tungsten reveal more accurate colors in your map shots since the human eye automatically corrects for this. I highly doubt the maps look that orange to your eye in person...


 

+1


----------



## garence (Dec 27, 2007)

*Re: Puny LED flashlights (Not!)*



UnknownVT said:


> I have been intrigued by the CRI (Color-Rendering Index) given for incandescent lights as close to 100 (perfect) -
> yet I know I often have problems seeing yellow on white and distinguishing shades of colors like blue under incand lighting - which I don't have with white LEDs.
> 
> Yet white LEDs have much lower CRI in the range of 60-70 - so what gives?
> ...


Very cool, UnknownVT -- thanks a lot for posting this insightful information.


----------



## UnknownVT (Dec 27, 2007)

*Re: Puny LED flashlights (Not!)*



EV_007 said:


> Since the incans are warmer light sources, would not a color balance on your camera set to tungsten reveal more accurate colors in your map shots since the human eye automatically corrects for this. I highly doubt the maps look that orange to your eye in person. Daylight balance even set to auto white balance biases warmer illumination and renders it yellow/orangish on the final image.


 
Digital camera's Tungsten white balance - and for that matter the AWB (Auto-White Balance) do very well 
(at least on the digicam I use - Canon A610 for these shots) - 
possibly even a bit better than the human/eye combination - 
but then everyone's different, and obviously YMMV.

As requested -

White Reference from previously -







Reference Room lighting (2x 60 watt soft-white bulbs)







Scorpion - xenon 2x CR123








As one can see the Scorpion using Tungsten White balance is really good 
- but in reality the Scorpion AWB (Auto-White Balance) shot probably is closer to the way I see it.....

However I have to *stress a very important point* here - Rand McNally maps have years of experience, and have designed their maps specifically to be seen well under incand lighting 
- so the "target" here does favor the incands, once the white balance has been adjusted - look how well the reds are shown - it's better than real life........

*Hold on....*
*we're not done yet -*
since we were talking about Color Rendition - 

I found on the web a copy of the Macbeth color chart -
probably the most famous and used color rendering chart in photography.

I don't have the real thing - but I printed out the file to the best accuracy I could -

References -
scan of my Printed target




Daylight White Balance -















Auto White Balance -















Tungsten White Balance -













*Comments* -
On the printed target the colors seem more muted in the scan than the original file - 




this is more or less normal/as expected - it is just a matter of saturation - I think there is very little, if any, hue shift - in other words the actual colors are pretty accurate.

_*EDIT to ADD*_ -

Added photos of Macbeth chart under sunlight (~3:30pm Georgia, USA) - for comparison (shots taken for control ref comparison see post #*112* )

Comparisons -

Daylight White Balance - obviously the incand lighting are going to be very yellow - the LED (Rebel 100) does very well here.

Auto White Balance - again the incands show up as very yellow biassed - the AWB on the digicam sees all those color patches without a white reference - so does not do such a good job as it did in the map shots which has a lot of white background. The LED (RB100) looks very good.

Tungsten White Balance - obviously both the incands do pretty well balancing out the huge yellow bias seen in the shots above. The LED on Daylight WB does very well and I think is still more accurate than either of the incand shots (look specially at the neutral tones in the last row of white/greys/black - it has the least color cast).

JFYI - notice in the photos of the target the colors are more vibrant - saturated - this is due to the Canon A610 I used - it is a simple point & shoot consumer digicam and Canon boosts the staturation in reds and blues to make the colors more appealing - and they succeed - 
that's why the white corrected/balanced shots look closer to the original file - 
we really should be comparing to the (scan) print target - as that's what I was shooting as the target.


----------



## easilyled (Dec 27, 2007)

*Re: Puny LED flashlights (Not!)*

Excellent work. Love the colour charts.
This really dispels a lot of myths. :thumbsup:


----------



## daveman (Dec 27, 2007)

*Re: Puny LED flashlights (Not!)*

Well done, UnknowVT.


----------



## GarageBoy (Dec 28, 2007)

*Re: Puny LED flashlights (Not!)*

How about something like an A2? REALLY damn white incan


----------



## UnknownVT (Dec 29, 2007)

*Re: Puny LED flashlights (Not!)*



GarageBoy said:


> How about something like an A2? REALLY damn white incan


 
I can still see a lot of yellow even in a hotter burning xenon light like the SureFire 9P - 9volt (3x lithium CR123). 

I would expect the 2x CR123 (6volt) A2 (50 lumens) to burn less hot - 
therefore actually be more yellow than the 9P? 
The A2 may be closer to the 6P, G2, and Scorpions (all 2x CR123 xenon and ~60lumens) of this world......

Xenon flashlight bulbs have a color temperature around 3000-3200K - 
compared to 5500K for sunlight and 6500 for "daylight" 
so they are still very yellow (with strong red component - that's why photos taken with daylight balance will show more orange, rather than just yellow)

Incand lights cannot exceed 3400K in color temperature (this is still very low/yellow compared to even warmer sunlight's 5500K) -

from this Underwater Kinentics page
_"COLOR TEMPERATURE (whiteness):_
_Color temperature is expressed in degrees on the Kelvin temperature scale (1°K = 1°C - 273). This temperature is close to the temperature of the actual filament in the lamp. As the filament gets hotter the light coming from the filament becomes more white. Near 3400° K the filament melts and the light burns out."_
_and_
_"Lamps used in UK lights are designed to operate at the highest color temperature without getting too close to the burnout temperature (3000° - 3200° K.) They are filled with xenon gas to retard filament evaporation and when necessary, some have small amounts of halogen gas added."_


----------



## GarageBoy (Dec 30, 2007)

*Re: Puny LED flashlights (Not!)*

The A2 is a 3.7V bulb, so I'm not sure how hot it is, but its whiter than a fresh pair of CR123s in a P60


----------



## UnknownVT (Dec 30, 2007)

*Re: Puny LED flashlights (Not!)*



GarageBoy said:


> The A2 is a 3.7V bulb, so I'm not sure how hot it is, but its whiter than a fresh pair of CR123s in a P60


 
That may be the case - and you would know much better than me, since I do not have an A2 -

_BUT_ the A2 cannot possibly be "whiter" than 3400K - the filament would have vaporized - xenon incands are probably not much whiter than 3200K.

Do you really think an A2 would be whiter than a SureFire 9P (3x CR123 - 9volts)? 

Like I said even if it does manage 3400K - that is only very marginally whiter than 3200K - the SF 9P -
and that is still _way_ lower than 5500K for sunlight and 6500K for daylight - so will still be distinctly yellow/orange ..... sorry.


----------



## UnknownVT (Dec 30, 2007)

*Re: Puny LED flashlights (Not!)*

Most know that LEDs are supposed to be more biassed toward blue, and that incands are richer in yellow and reds - 
there are ways of quantifying this -eg: The_LED_Museum threads in the Reviews section -
Spectrographic charts and Spectrographic analyses, pg. 2

But I still find this hard to visualize.

I tried this with photographing a Macbeth color rendition chart and Luminescent has also started another thread LED light color rendering also with photos of a color chart.

But these photos only go to show one aspect of how the incands are very yellow/orange with daylight balance - but can start to look more realistic using tungsten balance (somewhat like how our brains would compensate/adjust).

I thought of being able to compare the specifically the blue and yellow responses visually between incands and LEDs -

_*CAVEAT*_ - I am just experimenting - and am not too sure how valid this might be.

I thought of removing (by desaturation) the colors, and comparing the luminance information in those color patches - 
to see if this makes some sense -

First the reference white (scan) of the Macbeth chart print that I used as a target - but I've added grid references to the patches -




then removed/desaturated the colors -
















I used the grey (color neutral) bottom row D to try to make the brightness roughly the same - the contrast difference makes this approximate only - the one shot that I had to adjust was the Scorpion Daylight balanced shot - it need some brightening to get the levels about the same as the rest (I've noted that on the photo).

Then I looked for deviations from the reference chart. Some were as expected - others weren't -

Comments:

C1 (dark blue) - notice on the both the incand (Scorpion) shots how dark this patch is compared to the reference chart - the LED is much closer - this is not surprising since incands are very weak in blue - and despite using the Tungsten balance to boost the blue - on a color removed/desaturated shot that patch is dark - compare on the same chart C1 vs. D6 - the dead black patch......

C4 (mid-yellow) again not surprisingly the LED's rendition is darker than the reference and either of the Scorpion shots - but what surprised me was how close the incand shots are to the reference - I was expecting them to be lighter/brighter.

C3 (red) - now this was a surprise I was expecting the LED to show this as darker - but it didn't - it is similar to the incands and reference chart. Why?

A4 (drab green) & B4 (purple) - the LED shows A4 as darker than B4 this is reversed compared to the reference chart - but the daylight balanced shot for the Scorpion did the same - whereas the Tungsten balanced shot makes them about equal....... I was a bit surprised - since we complain a lot about green tints on LEDs - but this shows that they are somewhat weak in greens..... I can't explain why the daylight balanced incand shot also showed weaken green and required boosting the blue in the Tungsten balanced shot to make the patches equal.

A1 (brown) - not surprising the LED was weak in this patch showing it dark - but what surprised me was although the Scorpion shots were lighter - they were also dark too - I would have thought they should have been lighter.

This is my first blush at this - I hope other eyes and opinions will help and see if this is a worthwhile method of seeing color balance (by stripping out colors!!)


----------



## GarageBoy (Dec 31, 2007)

*Re: Puny LED flashlights (Not!)*

Thanks for th MacBeth charts


----------



## UnknownVT (Jan 1, 2008)

*Re: Puny LED flashlights (Not!)*



GarageBoy said:


> Thanks for th MacBeth charts


 
Thanks for the response GarageBoy - Happy New Year to you - 
and to everyone on CPF!

I wasn't too sure how valid or understandable doing the color removal/desaturation of the Macbeth color rendition chart was - 
it made sense to me - 
but whether I managed to convey what I was thinking - 
and if it made sense to anyone else is another matter.

For example there may well be a problem of sorts - at least in my flashlight shots on the Macbeth - the corners may be slightly darker because they were near the edge of the hotspot - if one looks at patch A1 - brown - that I commented on - one can just see some difference in shade between the far upper left corner and the lower bottom right corner of that patch A1 in the flashlight shots, which is not present in the scanned reference image (of course this could also be vignetting/corner darkening of the camera lens, or a combination) - so my comments were based on using the lower/inner half of the patch.

I would really appreciate comments/feedback/suggestions on what I attempted - 
and/or how to improve or clarify the method.


----------



## MrMom (Jan 1, 2008)

*Re: Puny LED flashlights (Not!)*

Great work unknownVT. The de-saturated shots bring in additional data. Have you tried smoothing out the beam by firing through a thin sheet of white tissue paper? It works well to smooth out the large intensity gradient for close up shots without changing color.

There have been some great follow up post in which I concur based on extensive flashlight use in the woods and on and near the water (mist). Thick woods, fog and over the water scenes present very similar lighting challenges. I call these complex environments.

The canopy of thick woods holds evaporating soil moisture creating a high humidity misty/light fog challenge to reflect back and scatter. Thick brush will reflect back and scatter in a similar fashion. Fog/mist on the water reflects back.

Incans do well here because of the typical large reflector and pencil thin beam. IE more light makes it down range. LED's can work well in complex environments too. 

The old style SF L1 with its pencil beam and lack of side spill performs in complex environments. The trick is to get the light down range (SIDESPILL HURTS HERE) without the side spill reflecting off thick brush, fog and mist back into your eyes. Now that the newer dies emphasize throw over spill, I expect longer range visibility in complex environments. I still prefer a L4 beam for close to mid range needs, beyond that, spill hurts in those environments. 

I find that color, incan/LED/amber has little to do with scatter performance. 
Incans, however, keep the three dimensional feel to the scene, with LED’s it looks flat.

I have done several experiments using various lights in complex environments. In all cases, I can pick out objects at a greater distance with a pencil beam even when going up against much much brighter lights with spill. 

LED's do present a one dimension feel in the woods, the full moon lighting effect. Nearly all bark appears grey. Browns and subtle reds and oranges are lost. Because I spend so much time camping/hiking/geocaching and color rending is important, last spring/early summer I began communicating with Milky regarding a build. I spent time studying spectral graphs from various LED's and compared them against human eye response charts. I came up with a combination to try. Milky built the “Mother Nature” in a SF turbo head with 6-SSC-P4’s and a Red-Orange Luxeon in the center. He had one similar build a year back using all Luxeons. The “Mother Nature” was the first mixed color LED light using the newer breed of emitters.

The Mother Natures white wall beam shots are scary boasting a pronounced pink hot spot but when used for its intended purpose, it excels. All of a sudden the woods jump to life in three dimensional color. Other campers (untrained) have noticed immediately and commented on the 3-D rendering. Reds and oranges stand out. Subtle differences in browns and greens, lost with conventional LED’s, are now distinguishable. The woods come to life. I will bring this to the shootout at SHOT. It would be interested to see the color rendering in the Nevada desert with the rust colored soils. Remember, up close, the beam is not pretty but it excels at its intended task.

The challenge in building a PERFECT light source for color rendering using mixed color Led’s would be in matching luminous intensities and dispersion for an accurate spectral rendering. A RO Lux is small and presents a point source to the reflector while the larger SSC interacts in a deferent manner within the reflectors parabola curve. In my light, the red-orange tends to throw while the white tends to spill.

Keep up the excellent research!

Shine on


----------



## UnknownVT (Jan 2, 2008)

*Re: Puny LED flashlights (Not!)*



MrMom said:


> Milky built the “Mother Nature” in a SF turbo head with 6-SSC-P4’s and a Red-Orange Luxeon in the center. He had one similar build a year back using all Luxeons. The “Mother Nature” was the first mixed color LED light using the newer breed of emitters.


 
Thank you so much for your interesting input - 

I was particularly taken with the mixing of a red/orange emitter. I "played" with doing something like that - as I have a Red/White eternaLight ergo 3 - and liked the effect of having the the white and red LEDs on - this was mainly to compensate for the overly blue 5mm white LEDs used, but crude as that mixing was, the combined light seemed to me to give slightly better rendition/realism.

Perhaps I'll play around with adding red and amber LED light to the LED beams to see if they improve color rendering......

Going back to the color removed/desaturated Macbeth charts - noticed the difference between C4 (mid-yellow) and C5 (pink-magenta ?) - 
all the flashlight shots show C4 darker than C5 -
the opposite to the reference white image. 
This was expected for the LED shot - 
but shouldn't the incand shot(s) show the correct way since they are supposed to be stronger in yellow than the pink-magenta of C5? 
Or does the red element in C5 out weigh the yellow in C4?


----------



## soffiler (Jan 2, 2008)

*Re: Puny LED flashlights (Not!)*

Vincent: very interesting work you're doing! Quick comment on the red-mixed LED as mentioned by MrMom: Coast makes a dual-color flashlight (p/n TT7736DCP) with 5x5mm white Nichia's plus a red in the center. They are on individual switches so you can run them both at the same time if you want. I noticed immediately that the beam is distinctly pink when you do this, and not mixed particularly well, but I prefer to run it this way because of the effect on color rendering. It's too much red, to be perfectly honest, exaggerating the reds and browns rather than rendering them accurately. The nice thing is that this flashlight is relatively inexpensive and readily available (I got mine at Lowe's) so you might consider picking one up just to do some experimentation.


----------



## UnknownVT (Jan 2, 2008)

*Re: Puny LED flashlights (Not!)*



soffiler said:


> Coast makes a dual-color flashlight (p/n TT7736DCP) with 5x5mm white Nichia's plus a red in the center. They are on individual switches so you can run them both at the same time if you want. I noticed immediately that the beam is distinctly pink when you do this, and not mixed particularly well


 
Thanks so much for your comments and the info about the Coast flashlight - looks interesting.

Doesn't the LRI Proton also have white and red LEDs, but running on a single AA? Can they be turned on togther?

In the meantime I'll see if just using red or amber LED Photons or clones mixing in with the Cree, Rebel, and Luxeons work.

Thank you for the feedback.


----------



## easilyled (Jan 3, 2008)

UnknownVT, I would be very interested to see the result of using an led with a
warm tint on your color charts.

I have 2 lights with WG Crees which are noticably warmer than my
other led lights.

The spectrum for these leds should be shifted towards the higher wavelengths
and contain more yellow, orange and red.

This might be a better balance than an incandescent light which is very
weak in the lower wavelengths, a fact which so many seem to disregard.


----------



## UnknownVT (Jan 3, 2008)

easilyled said:


> I would be very interested to see the result of using an led with a warm tint on your color charts.
> I have 2 lights with WG Crees which are noticably warmer than my other led lights.
> The spectrum for these leds should be shifted towards the higher wavelengths and contain more yellow, orange and red.


 
I would be *very* interested in trying a warm white LED -
unfortunately I don't have a flashlight with one.

If someone cares to donate or loan me a flashlight with a warm white LED - 
I'd be happy to take color chart shots with it.

Thanks


----------



## D MacAlpine (Jan 3, 2008)

I've only just found this thread and the information on relative colour rendition is highly informative. Definitely one to follow.

To add my own 2p worth;

A few months ago I started using a pretty powerful led light made for me by Milkyspit (550 emitter lumens, based on manufacturer's specs) at work. In urban London this generally means competing with high levels of background sodium lighting.
What I have found is that, next to any incandescent handheld light, the leds are always brighter and (full-spectrum) whiter. There is no noticeable "flattening" or washing out of colours in comparison to filament illumination. I have used the Milkyspit light side by side against Surefire p60s, assorted 100ish lumen rechargeables and even a couple of rechargeable hand lanterns. Whilst these usually had a more intense hotspot, this just looked like a tiny patch of yellow. Playing one beam over the other did not produce any increase in colour depth etc.

At this point I imagine there will be a few cries of "foul", the led light is much brighter than the incands. I compared it to a brighter incand source (twin 55w headlights on my car) on some foliage and branches. With the bias in the other direction the led light really did seem to wash out colours. The car headlights still looked quite yellow in comparison though. Interestingly there didn't seem to be much difference in how bright things looked between headlights and the torch.

I think that this bears out what has been said earlier in this thread, a "white" led does render reds and greens. If you produce significantly more lumens from an led than an incand it will light everything up better.
The car headlight comparison and builds like MrMom's "mother nature" demonstrate that you can still improve on led lights for overall colour reproduction.

Those are just my observations, many thanks to Vincent for his somewhat more scientific efforts to getting to the truth of the matter.


----------



## UnknownVT (Jan 3, 2008)

D MacAlpine said:


> I think that this bears out what has been said earlier in this thread, a "white" led does render reds and greens. If you produce significantly more lumens from an led than an incand it will light everything up better.
> The car headlight comparison and builds like MrMom's "mother nature" demonstrate that you can still improve on led lights for overall colour reproduction.


 
I think yellow/orange bias enhances vision - I've long been a supporter of this - as evidenced by my EDC for over 10 years of a Yellow Photon (2) - other evidence is the hype and popularity of the notorious BluBlocker sunglasses - there are a lot better sunglasses - like the stunning Serengeti Drivers - but bascially these block blue with a yellow/amber/orange bias. The Serengeti Drivers are a very good case in point - in a bright sunny day - reds fairly jump out at you, and things seem more defined and 3-D - this is confirming the input that incands seem to make things more 3-D outdoors in nature.

This is NOT to take anything away from LED lights that are now bright enough so the yellow enhancing bias of incands no longer show that much advantage.

I was very interested in the addition of red/orange LEDs to enhance outdoors use of white LEDs - so I thought I'd experiment (read "play") more on this aspect -

The Players -






Macbeth rendering using 2x Orange LEDs with a Rebel 100 in order of High, Medium and Low -



















I think that the orange LEDs do not exactly make color rendition more accurate - but the yellows and reds do look a bit closer to the reference white shot, and the colors do seem more vibrant than the RB100 daylight balanced shot?

*Important* - Remember Orange LEDs are actually monochromatic - in other words the orange is a peaked at a single wavelength - whereas we normnally see "colors" as a combination of the primary colors in the spectrum (eg: yellow is made up of green and red etc. orange would have more red component - but there is still components of green - whereas the orange LED does NOT have these components - it is just orange)

2x Orange Fauxton LEDs rendering -





Comparing relative brightness of the Orange LEDs -















WTF are those sunglasses doing in the group?
Well, I talked about the Serengeti Driver Sunglasses enhancing vision - 
how about a good tinted LED through these sunglasses?
Rebel 100 in Fenix L1D - through Serengeti Driver Sunglasses - in order High, Medium, Low















Not very realistic using fixed Daylight balance - BUT guess what?
Not exactly - but doesn't this kind of approximate to a typical xenon incand like the Streamlight Scorpion? 









Interesting huh?


----------



## D MacAlpine (Jan 4, 2008)

Now there's a thing. I've been using Serengeti Drivers for years and it never occured to me to try shining a torch through them!

More seriously, isn't the reason that these brown tints are so good for driving that they filter out the shorter wavelength end of the spectrum?
As I understand it (barely!) these wavelengths of light are more energetic and irritating to the eye. As previously stated they also scatter more in rain or fog - thus this tint enhances vision in these conditions.

I seem to recall reading a RayBan advert which mentioned brown tints for driving and darker grey tints for aviation, to preserve colour rendition.


----------



## easilyled (Jan 4, 2008)

D MacAlpine said:


> Now there's a thing. I've been using Serengeti Drivers for years and it never occured to me to try shining a torch through them!
> 
> More seriously, isn't the reason that these brown tints are so good for driving that they filter out the shorter wavelength end of the spectrum?
> As I understand it (barely!) these wavelengths of light are more energetic and irritating to the eye. As previously stated they also scatter more in rain or fog - thus this tint enhances vision in these conditions.
> ...



Surely filtering out purples, blues and to a lesser extent greens is not
the aim of providing great color rendition?

My understanding of good color rendition is to have a spectrum that
is complete and evenly balanced in all wavelengths of visible light,
which is something that neither incandescent lights nor led lights 
have at the moment.


----------



## D MacAlpine (Jan 4, 2008)

easilyled said:


> Surely filtering out purples, blues and to a lesser extent greens is not
> the aim of providing great color rendition?


 
The brown tint on lenses like the Drivers isn't designed to provide accurate colour rendition. It concentrates on filtering out the blue end of the spectrum, which eases the tiring effect of glare without needing too dark a tint (so you can wear them in fog). Coincidentally it also makes greens appear much richer - but I do not believe that is the intent in this application.
The grey/black tint is the one which preserves colour rendition - but it cuts out more light overall and thus you end up with "darker" glasses.


----------



## UnknownVT (Jan 4, 2008)

Many thanks to both D MacAlpine and easilyled for your inputs and for keeping this interesting discussion going - both from the UK/London area...



easilyled said:


> Surely filtering out purples, blues and to a lesser extent greens is not the aim of providing great color rendition?
> My understanding of good color rendition is to have a spectrum that
> is complete and evenly balanced in all wavelengths of visible light,
> which is something that neither incandescent lights nor led lights
> have at the moment.


 
Correct.

Let me try to put things into context - 
and maybe attempt to explain some of the confusion.

*Color Rendering* - this seems a pretty loose term - 
I tend to use it for how accurately colors are perceived and/or reproduced. This seems simple enough..... but hold on -
but color perception (ie: what we see) and reproduction eg: photo or print etc - may _*not*_ necessarily be synonymous - 
case in point - we manage to see colors pretty well under most good incandescent lighting. Yet taken as a daylight white balanced photo - incandescents produce distinctly yellow/orange biassed photos.
But adding to the complexity we see colors well under incands due to our brains adjusting/compensating - so we can also take the photo with Tungsten white balance and reproduce a photo that's pretty close to "daylight" conditions.

*CRI - Color Rendering Index* - this is not well understood (at least by me) - there is a scientific definition and formula for calculating the CRI - BUT incandescent lights usually rate close to 100 (perfect) by definition - yet most people know that incands are yellow/orange biassed and weak in blues (upper/shorter wavelengths of the spectrum) - so practically incands are far from perfect for "color rendition" - but it rates nearly 100 CRI - 
yet a typical Luxeon type LED rates CRI of between 60-70. Clearly there is something amiss - if we take CRI as how accurately colors are "shown".

Also often in discussion of LED and incand - CRI is quoted to show incands are better at color rendering (cough!)

What I originally set out to do was to show this discreprancy between CRI and in color perception.

I do understand that "white" LEDs have peaks and troughs in their spectrum - and perhaps that is why the CRI is so low - but at least in photos and most practical situations they are "better" for color differentiation and identification over incands - at least for my eyes.

The discussion also had people saying they saw better with incands outdoors - eg: seeing brown deer among trees - and that incands seem to be more 3-D whereas LEDs seem to flatten the scene.

I attempted to address this - by using the vision enhancing Serengeti Drivers sunglasses - which filters/suppresses blues and violets, and enhances yellows/orange/reds....

Lo-and-behold filtered through Serengeti Drivers suglasses the LED spectrum looks pretty similar to that of the incand Streamlight Scorpion (xenon 2x CR123)......

So perhaps we see better with incands outdoors - 
_*NOT*_ necessarily because it is more color accurate - 
but because its spectrum actually enhances our vision.

ie: seeing better does not necessarily mean more accurate colors - 
hence perhaps some of the confusion?

....of course someone's going to comeback with incands have better CRI (Color Rendering Index).... and we'll go round again...... :nana:


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## easilyled (Jan 4, 2008)

UnknownVT, thank *you* very much for all the effort you've made
to uncover all the different nuances of this complex subject.

I think your summary is excellent. :bow:

Maybe this should become a sticky thread? :shrug:

I would just like to add the following spectra (courtesy of Newbie from
a thread on spectrographic analysis)

I find this a superb visual aid as it
shows the colors corresponding to the wavelengths.

Therefore looking at the area of the different colors under the straight
or spikey lines gives a very good idea of the proportions of the different
colors in these spectra immediately.

Incandescent spectrum:-






Spectrum of a luxeon III UX1J:-


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## Blinding (Jan 4, 2008)

Why are the manufacturers not adding more red phosphor to the LEDs to balance out the spectrum? Does it reduce the measured lumens they quote? Is that what is done in warm white LEDs?

I have some warm white and they are nice but not bright enough. Given a choice I will pick the brighter LED so maybe the LED makers are doing the right thing.

I have a Coast light that has red, green and blue LEDs in addition to the white. Turning the red on with the white does improve the color rendering. The down side is the output does not mix evenly as I think everyone trying to mix separate RGB sources to get white has found out.


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## UnknownVT (Jan 5, 2008)

Blinding said:


> Why are the manufacturers not adding more red phosphor to the LEDs to balance out the spectrum? Does it reduce the measured lumens they quote? Is that what is done in warm white LEDs?
> I have some warm white and they are nice but not bright enough. Given a choice I will pick the brighter LED so maybe the LED makers are doing the right thing..


 
I'm not too sure what they do - but by the sounds of it - probably use the correct material to re-irradiate on the longer wavelenths (eg: red) and possibly attenuate some of the blue - hence the lower brightness levels.



Blinding said:


> I have a Coast light that has red, green and blue LEDs in addition to the white. Turning the red on with the white does improve the color rendering. The down side is the output does not mix evenly as I think everyone trying to mix separate RGB sources to get white has found out.


 
I am not too sure whether adding red LED into a white LED mix actually makes colors more accurate (as my experiments of adding Orange LEDs to the mix above in post #*69* showed) - but it does help enhance the vision somewhat - and it's more pleasent (if your prefer warmer tints)

For myself, I am beginning to feel -

CRI (Color Rendering Index) does NOT (necessarily) = Color (rendition) Accuracy does NOT (necessaily) = Better Vision


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## Phaserburn (Jan 5, 2008)

*Re: Puny LED flashlights (Not!)*



Culhain said:


> I own only two colors of socks: dark navy blue and black. Under sunlight they are easy to match. Mostly, I neglect to sort them until I'm getting dressed in the dark. I find that LED lights (from 5mm to M60 Malkoff) are of no help in sorting the blues from the blacks. My SF E2O is my preferred sock matching light as it clearly shows the difference between blue and black.


 
I keep an incan in my dressing area for just this reason. Navy/black differentiation. I find that I also get better feedback on color shades, like tans, with the incan then the brighter, more efficient led light sitting next to it. Not sure why this is, but I'm quite sure it's true.


----------



## UnknownVT (Jan 5, 2008)

*Re: Puny LED flashlights (Not!)*



Phaserburn said:


> I keep an incan in my dressing area for just this reason. Navy/black differentiation. I find that I also get better feedback on color shades, like tans, with the incan then the brighter, more efficient led light sitting next to it. Not sure why this is, but I'm quite sure it's true.


 
The tans differentiation stands to reason - since incands are stronger in longer wavelengths (yellows through reds) - that's why people see deer better against trees with incands. Differentiation between pale yellow and white (eg: yellow lines on white paper) is extremely difficult for exactly the same reason - as there is too much yellow bias in the incands which over illuminates the yellow and at the same time shows the white as yellow - therefore hard to differentiate.

However the bit about navy blue and black surprises me - since LEDs tend to be strong in blue therefore should show navy blue quite a bit differently from black - and this is exactly the example used for difficulties using incands - see GE lighting web page - About Light: Color Rendering
"_An incandescent lamp, virtually by definition, has a Color Rendering Index (CRI) close to 100. This does not mean that an incandescent lamp is a perfect color rendering light source. It is not. It is very weak in blue, as anyone who has tried to sort out navy blues, royal blues and black under low levels of incandescent lighting. "_

I am not doubting either of you about this - maybe the operative phrase above is "_low levels_" - which would also seem to be confirmed that with brighter/more adequate levels of light LEDs seem to allow us to see better too.

Another slight chance might be the dyes/pigments used for the socks/clothing - some have color metamerism - ie: appear as different colors under different lighting conditions - 
eg: some blacks in daylight may appear to be green (or some are red) under artificial lights.

However we come back to 
being able to see well does NOT necessarily = accurate colors.

It is pretty obvious incands have a very yellow/orange bias - even if our brains compensate/adjust - 
but we do see well with incands - 
but they do not illuminate colors accurately.

Also superiority in one area/part of the spectrum does not necessarily mean superiority over the entire visible spectrum.

I'll come back to my stupid example -
the "invisible" fluorescent marks on currency bills are revealed by UV light - therefore UV lights are (obviously) superior for seeing those marks - but does anyone regard UV lights as a good general purpose light?


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## soffiler (Jan 8, 2008)

*Re: Puny LED flashlights (Not!)*



Culhain said:


> ...I own only two colors of socks: dark navy blue and black. Under sunlight they are easy to match. Mostly, I neglect to sort them until I'm getting dressed in the dark. I find that LED lights (from 5mm to M60 Malkoff) are of no help in sorting the blues from the blacks. My SF E2O is my preferred sock matching light as it clearly shows the difference between blue and black...


 
Fascinating. I just had to try this last night. Since I don't have a handy incan flashlight, I just used the 60W bulb in the bedside table lamp as the incan source, and my SureFire G2L as the LED source. I chose some black socks, some very dark navy blue socks, and a couple of slightly lighter shades of navy blue.

Incan: I was certain only that the lightest of the four shades of blue was in fact blue. The rest appeared black or nearly so to my eyes. 60W incan has plenty of lumens (very warm tint) and I held the socks within about 6" of the bulb.

LED: Using just the spillbeam, the black and the very dark navy blue were a bit difficult but I was still able to tell them apart. The other two shades were trivially easy.

My bottom line: LED did a far better job.


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## easilyled (Jan 8, 2008)

*Re: Puny LED flashlights (Not!)*



soffiler said:


> Fascinating. I just had to try this last night. Since I don't have a handy incan flashlight, I just used the 60W bulb in the bedside table lamp as the incan source, and my SureFire G2L as the LED source. I chose some black socks, some very dark navy blue socks, and a couple of slightly lighter shades of navy blue.
> 
> Incan: I was certain only that the lightest of the four shades of blue was in fact blue. The rest appeared black or nearly so to my eyes. 60W incan has plenty of lumens (very warm tint) and I held the socks within about 6" of the bulb.
> 
> ...



Its even more fascinating that 2 different people see things
oppositely.

However as UnknownVT said, I would have expected the LED lighting to prevail
for this scenario, so I'm pleased that you confirmed that.


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## GuyZero (Jan 8, 2008)

This thread is the most interesting thing I've read all week! *THANKS* VT for all your work in this area! I wish so much that I had something factual/useful to add.

I'm especially curious about the ideas expressed in this thread about seeing better in 3-D in the woods with warmer tints, and about mixing red/orange LEDs with whites to improve 3-D rendering.

And so I'm curious, does anyone have two Fenix lights with identical reflectors and one of those Fenix red filter attachments? I wonder if you held the two lights side by side, one with the red filter, and played with the brightness settings of the two lights... Since the reflectors are identical (same pattern of light) and small (so they can be very close together) would this render an outdoor woodland scene with better 3-D accuracy, with out the red/white divergence being too distracting? Or would you ideally have one of them have an orange/amber filter? Or does the filter need to be a special "blue blocking" type? (I don't fully understand how the blue blocking lenses work).

The reason I ask is that I like to mountain bike at night, and I've been using a Fenix L2D RB100 on my helmet with great enthusiasm, but I have noticed the flattening effect in the woods. It's still an excellent bike light, but when you are moving fast through the woods on uneven terrain every advantage helps! After reading this thread I have visions of two L2D's on my head, one set on medium or low with a red filter, and having better 3-D vision.

Is this a viable idea, or am I just looking for excuses to buy more flashlights?

[Or, preferably both...  ]


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## UnknownVT (Jan 8, 2008)

I am not too sure how valid this is, as our eye/brain combination is a lot more flexible than a camera and can compensate for a lot of conditions - but FWIW -

*The Socks Problem -*

I used the two different kinds of navy blue sock, two different kinds of black sock, and a pair of grey socks to do this - 
Daylight Control shot literally out in the daylight - in direct sunlight about 1:30PM Atlanta, GA, USA -





as one can see even under direct sunlight it's kind of hard for the camera to distinguish between the navy and black - of course it's too high contrast (background is white) and the camera has limited dynamic range - as most of us know this should not be a problem for our eyes.

So I cropped the photos to show mainly the socks - 
then adjusted only the brightness and contrast - to get the balance that best shows any difference - 
so each of the following shots has been adjusted differently just to optimize any difference that can be seen - 
ie: this is the best difference the camera can show.

Fixed Daylight Balance -















AWB (Auto White Balance) -















Tungsten White Balance for the incand lights -












The LED (a particularly well tinted Rebel 100) seems to differentiate the middle pair of navy blue socks best from the black socks either side of it (even better than direct sunlight) - the right-most navy pair still in the bundle does not show as well - but I think that's just the angle of the lighting - this is for both Fixed Daylight and AWB.

The incands Xenon (in Streamlight Scorpion), and room lighting - obviously do terrible using the Fixed Daylight White Balance as would be expected - not only is there a huge yellow orange cast but the all the socks kind of look gray - with some color cast. But using either AWB or Tungsten balance - the Xenon does slightly better using the Tungsten balance over the AWB - 
enough to be able to see the difference between navy and black which is what I do see in real-life - 

But notice the room lighting (not as intense or "white" as the Xenon) - even with the best I could adjust the brightness/contrast the navy sock never attain any blue and just looks like a shade of gray......

Please let me know what you think?


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## soffiler (Jan 8, 2008)

GuyZero said:


> ...I'm especially curious about the ideas expressed in this thread about seeing better in 3-D in the woods with warmer tints, and about mixing red/orange LEDs with whites to improve 3-D rendering...
> 
> The reason I ask is that I like to mountain bike at night, and I've been using a Fenix L2D RB100 on my helmet with great enthusiasm, but I have noticed the flattening effect in the woods. It's still an excellent bike light, but when you are moving fast through the woods on uneven terrain every advantage helps! After reading this thread I have visions of two L2D's on my head, one set on medium or low with a red filter, and having better 3-D vision....


 
I am also an enthusiastic mountain biker, and I do a lot of night-riding. I use a helmet-mount HID with 450 lumens, and a handlebar-mount Coast Focusing Lenser modded with a Seoul P4 that does better than 150 lumens out-the-front. _And I still want more light_. I ride with a fast group of guys and the thick forested terrain here in New England seems to suck up whatever light you throw at it.

I think the red idea is kind of interesting, but, if I were you and I was going to add a second L2D on my helmet, I'd say: Give me MORE LIGHT! Run them both on high and screw the red filter. Doubling your light will have a much larger effect on your ability to see the terrain than a bit of red will do to mitigate the flattening effect (which I agree does exist).


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## soffiler (Jan 8, 2008)

Vincent:

The "Daylight control/Daylight balance" and "Daylight control/AWB" images both clearly show the rightmost pair of socks in the bundle is blue. But on the other hand, they do a poor job of showing the middle pair is blue.

The "Rebel 100/Daylight" and "Rebel 100/AWB" do just the opposite: the middle pair of socks is obviously blue, but now the rightmost pair in the bundle looks black.

I don't see much in the way of blue in any of the incan shots regardless of camera balance. You've made it clear, and I totally agree, that the camera doesn't necessarily see what our eyes see but I still think your results support the idea that LED lighting (or natural daylight) is superior at the task of differentiating dark blue from black.


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## meuge (Jan 8, 2008)

soffiler said:


> I am also an enthusiastic mountain biker, and I do a lot of night-riding. I use a helmet-mount HID with 450 lumens, and a handlebar-mount Coast Focusing Lenser modded with a Seoul P4 that does better than 150 lumens out-the-front. _And I still want more light_. I ride with a fast group of guys and the thick forested terrain here in New England seems to suck up whatever light you throw at it.
> 
> I think the red idea is kind of interesting, but, if I were you and I was going to add a second L2D on my helmet, I'd say: Give me MORE LIGHT! Run them both on high and screw the red filter. Doubling your light will have a much larger effect on your ability to see the terrain than a bit of red will do to mitigate the flattening effect (which I agree does exist).


Actually, I think he'd be much better off if he mounted 2 L2Ds on his handlebars, as far from each other as possible, then aimed them to cross beams at 10-20 meters. 

I think a lot of the "flattening" has to do more with single-source shadowing than anything else.


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## soffiler (Jan 8, 2008)

meuge said:


> Actually, I think he'd be much better off if he mounted 2 L2Ds on his handlebars, as far from each other as possible, then aimed them to cross beams at 10-20 meters.
> 
> I think a lot of the "flattening" has to do more with single-source shadowing than anything else.


 
Cool idea! Now you've got me thinking... I might just have to try something like this. I don't have even one L2D, never mind two, but I have two lights with remarkably similar beam patterns: SF G2L plus an older Pelican M1 modded w/ Cree. Both use OP reflectors. Tint is different, and G2L has a wider sidespill, but otherwise they are amazingly similar in a whitewall comparison.

Although, I really can't get them very far apart on my bars given the placement of the shifters and brake levers. By the time you get 10-20 meters away, I think they'd look like a single-source again. Still very much worth a try. I might be riding Thursday night if we get some colder weather back thru here and the mud from the January thaw stiffens up...


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## UnknownVT (Jan 8, 2008)

soffiler said:


> The "Daylight control/Daylight balance" and "Daylight control/AWB" images both clearly show the rightmost pair of socks in the bundle is blue. But on the other hand, they do a poor job of showing the middle pair is blue.
> The "Rebel 100/Daylight" and "Rebel 100/AWB" do just the opposite: the middle pair of socks is obviously blue, but now the rightmost pair in the bundle looks black.
> I don't see much in the way of blue in any of the incan shots regardless of camera balance.


 
Right - I originally thought it was a simple matter of lighting angle - since the sunlit shots had what I'd consider optimum angle of lighting 3/4 up/down as well as side/side. Whereas the flashlights were mainly straight on.

But the colors in the daylight shots are much closer to the way I actually see them in sunlight - the LED shots seem to emphasize the middle blue pair - might be the dyes/pigments used that respond to a particular wavelength the Rebel is rich in or maybe it's a simple lighting level - the outer pair probably was not as well lit as the center of the hotspot?

I also have direct flash shots that "imitiate" daylight - these have more or less the same angle lighting as the flashlights - these are closer to the daylight shots as one would/should expect.......









As one can see from either the daylight or the flash shots that middle navy pair is particularly difficult to differentiate from black in the photos - our eyes/brain do manage better - but it is still quite difficult - different angled and good lighting is needed 
- the LED actually enhanced the difference......


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## GuyZero (Jan 8, 2008)

meuge said:


> Actually, I think he'd be much better off if he mounted 2 L2Ds on his handlebars, as far from each other as possible, then aimed them to cross beams at 10-20 meters.
> 
> I think a lot of the "flattening" has to do more with single-source shadowing than anything else.



I've considered this as possibly part of the problem, but I'm not likely to switch to dual handlebar mounts, and here's why:

I ride with two lights - one of my helmet and one on my bars. The one on the bars is nice because it always aims at what's directly in front of the wheel so you can quickly glance down with out swiveling your head. But the Helmet mounted light is far superior for mountain biking, flattening effects notwithstanding, because it always points where you are looking. When you are in the woods in the dark, and you are about to come around a sharp corner, your bar mounted light doesn't look around the corner until you're already into it. You end up continually turning into darkness. This can be done (lots of people do it all the time) but once you've experienced the advantage of being able to aim your light around a corner before you get there you're very unlikely to go back to just bar lights.

But everyone is different, and I can respect a difference in opinion here. I suppose if you had close to 500 lumens coming off your bars in a good spread this might not matter so much.

But might question was about getting the best of both worlds - if putting a red and white light together on your head would give you a directional light with better 3D rendering capability...?

I have several Streamlight PPL's (this is what I use on the handlebars) and a sampler pack of colored lighting filters. If I can get out into the woods to night I might take a walk with them (one red, one white) and see what it looks like.

The only problem is that the SLPPL's have only one brightness setting, and they are very throw oriented. I feel like two Fenix's would be better to test with. Maybe I'll ask my boss if I can borrow his for an evening...

If it works out I'll report back!

Does anyone know, are the blue blocking lenses just brown/orange filtered, or is there some other special magic to them? For instance, do they just filter out everything outside of the brown spectrum (I'm not sure that's really part of the spectrum) or do they allow certain parts of the spectrum through in some special combination?


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## GuyZero (Jan 8, 2008)

UnknownVT said:


> *The Socks Problem -*



Fascinating! 

I don't know much about spectral reanalysis, but I do know a little about photography and white balance that might help in your quest...

Have you ever used a "grey card"? It's a photographic tool that's basically just a neutral grey card with no color tint that you can set your custom white balance too. This might help you simulate the brain's ability to adjust to different types of lighting.

With a Canon, basically how it works is you hold the grey card up in the area where your photography subject will be so it's in the same lighting. Then you fill the frame of your camera with the grey card and set your custom white balance with it. What the camera does is assume that what ever it's looking at should have no color tint and it customizes the filtering system to compensate for any tint that actually exists. It's far more accurate then the white balance presets that are built into the camera if accuracy counts.

You can also do this with a truly white sheet of paper, but a grey card is more accurate.

It seems that you're using tungston and AWB settings to try and approximate for the tint of the various lights. If you can get a hold of a grey card you can set a custom balance that would be nearly perfect for each light source. This may seem trivial, but in these tests we're specifically looking at how small differences in in the spectrum affect out ability to detect colors, so it could make a big difference.

A good photography shop should have grey cards, and some photography books will make their inside covers a neutral grey color for this purpose, if you have one of those. (My National Geographic Photography Field Guide has this feature).

Again, I'm fascinated by your "Blue Socks" tests, and by this whole thread in general! You are a true scientist! Keep asking questions!

-GZ


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## Daekar (Jan 8, 2008)

I have two things to add to this discussion which will hopefully be helpful. First, I noticed this single-source flattening problem a good while ago, and as far as I can tell walking in the woods, two lights of whatever brightness or tint is definitely better than one. This flattening effect seems to be worse for me the closer the light is held to my eyes, meaning that headlamps seem to suffer this problem the worst unless they are multi-emitter like the 5mms on the PT Apex, which is OK but not great.​ 
Second, I feel that the ability for our eyes to "white balance" according to the prevailing light conditions may not have been given proper attention. It is my experience that the only way to accurately compare lights under realistic usage conditions is... to use them. What I mean by this is that each user must evaluate each light in such conditions that their eyes have time to adjust to it. As I experimented with my lights (see sig pic), I found that if my eyes adjusted to good-quality LED-sourced light (or the light from my Boxer24W) the colors and details were quite good and that my ROP/P60 seemed very orange/yellow/brown. However, if my eyes were adjusted to the light from my ROP/P60 the colors were good as well, and the LED/HID light seemed ghostly/blue/green. ​ 
The question to me, then is not "which is whiter," or "what has the most complete spectrum," but "which shows the most detail and accurate color after my eyes have adjusted?" For me, the answer was unexpected, raving LED fanatic that I am. As far as I can tell, with appropriately adjusted eyes, in any environment, inside or outside, regardless of season (leaves on trees or not), I can see more detail and color with my ROP than with even my Boxer24W, which came as a surprise, believe me. I suspected this after having the lights for a relatively short time but refused to believe the evidence of my eyes until I passed over a skunk in a field with the HID and suddenly saw it with the ROP - how could I have missed a blank and white lump the size of a small dog in the middle of a green field? It was the last straw of proof for me, you might say. Does this mean I'm going to abandon my LEDs? Heavens no! The other pro-LED arguments still stand as valid and I will remain interested in improving my collection as technology evolves - but it also means I'm seriously considering getting an N30 to supplement my collection, hopefully the 4200K bulb will help. This does mean, however, that for tactical operations with a weapon-light, I would still recommend an incan to those I love, with their safety in mind - picking out colors might not be important for my torches (I don't tend to pick out drapes or furniture by EDC-light) but in time-critical life-threatening situations, I'd personally choose an incan with adjusted eyes over LED with adjusted eyes. Of course, I'd make darn sure that my loved-ones had a good LED light too, so they wouldn't need to use the battery-sucking incan for mundane tasks - or if the incan failed/ran out of juice.​


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## dulridge (Jan 8, 2008)

meuge said:


> Actually, I think he'd be much better off if he mounted 2 L2Ds on his handlebars, as far from each other as possible, then aimed them to cross beams at 10-20 meters.
> 
> I think a lot of the "flattening" has to do more with single-source shadowing than anything else.



I'm not convinced about this. Using LED and incan lights, I will have better depth perception with the incans than the LEDs. Both single sources, and more than one pair of eyes testing this. I'm not good at distance estimation in ANY light, but I'm marginally less bad with incans of comparable output to LEDs. And this is not just my eyes though the pairs of eyes I've checked this against are all within a few years of my age (i.e., 40-55). LED lights seem to give a sort of 2D representation of the landscape, whereas the 2 incans I own (as opposed to 50 or so LEDs) seem to make the landscape more 3D.

Given that I'd rather buy LED lights than incans, this is odd.

Colour is not an issue for me - I used to make a living making colour photographic prints and got used to colour matching under monochromatic sodium light which is not easy. I am very good at this, regardless of the light source as I have become used to doing it. I do not find incan vs. LED colour rendition issues to be a problem - I do find 3D to be an issue, but then 3D is rarely an issue in a darkroom where I learned colour rendition and matching.


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## cdosrun (Jan 8, 2008)

Unknown, thank you for all your work on this topic, I have been following the topic for since you started it and I think airing your dirty laundry was a fantastic start to the New Year 

I think that the eye's ability to focus blue light has a bearing on the topic of depth perception with LED lights. I can't make a comment based on as much experience as many because my incandescent lights (Mag85R and ROP-Hi) are far more powerful than my brightest LEDs (Dereelight DBS/CL1H etc.) but even though I prefer the LEDs, I find the incandescent lights easier on the eye outside at night. As the eye is better at focusing red lights onto the retina (for proof of this, try to look at the a 'blacklight', the violet output always looks fuzzy; well to me at least) I think the depth perception is easier.

http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&uid=3364521&cmd=showdetailview&indexed=google

I am not sure if one can extrapolate from the linked abstract to a paper on chromatic aberration of the Human eye, but from the scant details available it appears that the eye is focused on blue wavelengths at shorter distances 0.4m) and progressing to green at the 3m ranges tested; if the 'trend' (insufficient data to call it that but, poetic licence) continued it could explain why it is easier to see at a distance with a longer wavelength light source.

As to colour rendition, I really think this is a more complicated issue because it is so difficult to incorporate the Human element into a test we are, by our own nature, a big variable.

I think Unknown has done a tremendous job of showing fallibilities in Human vision and perception. This could be akin to hearing though, at low volumes, it is common to boost the bass and treble (loudness control) to bring the sound back into line with what is heard at normal volumes due to the ear's non-linear response to SPL, is there a similar effect with vision?

Andrew


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## UnknownVT (Jan 9, 2008)

cdosrun said:


> and I think airing your dirty laundry was a fantastic start to the New Year


 
Yes I sacrifice comfort to serve CPF - 
do you know cold my feet got without socks on? 



cdosrun said:


> I think that the eye's ability to focus blue light has a bearing on the topic of depth perception with LED lights.
> ....
> As the eye is better at focusing red lights onto the retina (for proof of this, try to look at the a 'blacklight', the violet output always looks fuzzy; well to me at least) I think the depth perception is easier.


 
No, sorry the eye does _NOT_ focus red well either - hence the problem a lot of people have seeing well under red light.

Well, there used to be a authorative paper on-line -

USAF Flight Surgeon's Guide Chapter 8
http://wwwsam.brooks.af.mil/af/files/fsguide/HTML/Chapter_08.html
this link is now broken and I can't find the paper on the web.

Anyway I have a saved copy - and from that - on *Visual Acuity* -

"_Also, the refractive characteristics of the eye causes blue light to focus in front of the retina and red light to focus behind the retina, when compared to yellow light that is focused on the retina. In other words, when the eye is emmetropic for yellow light, it is myopic for blue light and hyperopic for red light. This difference in color refraction, known as the chromatic interval, causes some distortion of the image on the retina. On theoretical grounds, then, the elimination of the short wavelengths by a filter should increase the sharpness of an image. This would seem to be confirmed by the use of yellow filters in photographing distant scenes. Such filters absorb the short wavelengths and allow the long ones to pass. They do give sharper photographs of distant scenes._ "

Surprise - for years I have been an advocate of using yellow light for dim situations (that's low light, not stupid ) as I said I've EDC'd a yellow Photon for over 10 years now......


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## kosPap (Jan 9, 2008)

UnknownVT 

You have started a good thing and we must be thankful for your contribution. But somehow and influenced by my photographic knowledge i am kinda lost...

There is one thing I disagree with regarding your B&W conversion method. Desaturating is not 100% accurate. You need to go another route. Converting to Lab color.

Assuming you use Photoshop here are the steps:

Image>Mode>Lab Color>
View>channels> unclick all the layers in the pop up window except the one that says lightness

Briefly put *L,a,b* color is the best color coding method. All colors are ploted IN a sphere. a & b are the latitude/longitute coordinates and L is the distance from the core and demonstrates lightness.

Now if you appply that method to the Mcbeth charts you will see a small difference in the output. I tried it myself

There are some more issues. One is the use of the various camera white balance settings...Hmmm to many calculations, too many variables & biases.

The second is that you are messing with color coding profiles. I forgot to check, but if your jpegs have a sRGB profile loaded things are a bit worst. sRGB is a compressed color palette narrower than others (Adobe RGB) which categorize colors with different methods....Usually converting to sRGB creates unequal shift in hue and saturation between colors!!!

Could you run another test? Dawn/morning rise light (yellow at about 3200K), noon light (at about 5000?), tungsteen interior light (around 2800K), LED light of a known bin and a Xenon source. Then photograph the McBeth in raw format and "flash white balance", open the image in PS and extract the lightness channel (this way you remove all color-reading bias).

keep up the good work, Kostas


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## soffiler (Jan 9, 2008)

GuyZero said:


> I ride with two lights - one of my helmet and one on my bars. The one on the bars is nice because it always aims at what's directly in front of the wheel so you can quickly glance down with out swiveling your head. But the Helmet mounted light is far superior for mountain biking, flattening effects notwithstanding, because it always points where you are looking...


 
Ditto that!

I ride with a helmet-mount 450-lumen HID, and a bar-mount 150-lumen LED. Before I added the bar-mount LED, I was running just the HID on the helmet (and before that, it was a 20-watt ~300 lumen incan on the helmet). Most night-riders I know use a helmet mount only, and the rest use both as I do. NOBODY I know rides offroad using a bar-mount only. You run into many situations where your bar-mount is not illuminating where you need to see. You mention corners, a good example. My favorite example is riding over fallen logs across the trail. As soon as you loft the front wheel over the log, your bar-mount light is illuminating nothing but the trees above, and there's a black hole on the other side of the log that you're about to drop your front wheel into.

BTW, I added the bar-mount light right after an epic crash. Leading a group-ride at night, I was swivelling my head to the side, looking for a trail junction I wanted to take. Moving at a decent clip, I ran headlong into an obstacle in the trail directly in front of me. Had I been using a bar-mount "low beam" it would have been obvious in my peripheral vision.



> ...But might question was about getting the best of both worlds - if putting a red and white light together on your head would give you a directional light with better 3D rendering capability...?


 
I am unconvinced that the mere addition of some red light will suddenly change the whole world from 2D to 3D. I tend to agree that incan looks somehow "better" and more 3D where LED (and HID) create that 2D "flattening" effect, but I feel it's a fairly subtle effect, not a night-and-day difference. Just my opinion. I also feel that doubling your light by using two where you've only got one right now (helmet) will have a greater impact on your overall ability to see (i.e. safely and comfortably navigate difficult terrain at speed) than adding some red. I feel, just my opinion, that throwing a LOT more lumens out has the effect of creating more reflections from marginally reflective surfaces (rocks, dirt, tree bark...) and it is that reflected light that actually enhances 3D. It's also why I prefer my HID over my incan...

... although I must admit this thread has got me thinking I might bring both incan and HID on my next night-ride and try to compare them. Happily, both lampheads are the same brand, using the same helmet-mount mechanism and power cord, so I can change them out on the trail very easily.



> Does anyone know, are the blue blocking lenses just brown/orange filtered, or is there some other special magic to them? For instance, do they just filter out everything outside of the brown spectrum (I'm not sure that's really part of the spectrum) or do they allow certain parts of the spectrum through in some special combination?


 
I don't know for sure but believe the blu-blocking sunglasses are simply yellowish-orange filters that take out the blue part of the spectrum. No magic to it.


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## GuyZero (Jan 9, 2008)

So I went out with my boss and his L2D and some colored filters last night to do some testing regarding adding red or yellow light together with the white RB100. The results were interesting...

I didn't have a whole lot of time so I only chose two colors of filter to play with. I have an old kit that I got years ago for my Mini Mag that included a red and an amber filter. I figured those must be good choices since Mag picked them.

I wrapped a strip of rolled over duck tape around the head of one of the Fenixes and left a little over hanging the end so I could easily, temporarily, stick the filters onto the end.

We walked out into the woods and did a few tests. There weren't many green leaves around, just some sticker bushes, but we did have some grass, some dirt, and some evergreen trees to shoot at.

First we tried the red filter and played with various intensity settings on the two lights. It wasn't that impressive, to tell the truth. It made the scene a little brighter, but not particularly more 3D.

Then we tried the amber filter and found that our favorite setting was full power on the amber light and medium power on the white light. This did produce a more 3D image to our eyes, but I would not call it dramatic. The biggest difference was how it seemed to make everything sharper, easier to focus on, and a little higher contrast. Leaves and evergreen bows stood out from the brown tree trunks. Dry grass suddenly showed a lot more detail, and the scene was also brighter, as you'd expect. 

Using only the Yellow light also produced high contrast, but it was much dimmer and color rendition was very difficult. It was not very pleasing and I would not want to mountain bike with only yellow filtered light.

We also tried just using two white lights on full power, and that did create a lot of light, but it was still somewhat washed out looking. We preferred the white/yellow combination. 

Also interesting to note is that the Fenix with the yellow filter on high appeared roughly the same intensity of light as the white Fenix on medium. I assume this is because much of the strongest part of the LED's spectrum 
(the blue) was being cut out. So in a sense, what found to be the best combination was an even mix of white and amber lights of the same apparent intensity.

I find it interesting having just read VT's post quoting that yellow light provides the best focus for the human eye. That's exactly what We experienced when we added the yellow light to the mix: colors could still be distinguished but everything just seemed to snap into better focus.

This also makes me think that the inherently yellower light of an incan probably is the superior light for seeing things outside at any given intensity for the same reasons. But for biking you have to take into account the big, heavy, short lived battery packs that go with them.

I would like to actually do a test on a bike in the woods with both lights on my helmet, but from last nights tests I would say that an amber filtered light plus a slightly dimmer LED would make a great combination. I'm not sure if it's worth strapping two 2AA flashlights to your head though. I used to use a Streamlight PPL on my helmet, which was very heavy, and it worked fine, but it was sure nice when I switched to the MUCH lighter Fenix.

Maybe what I REALLY need to do is buy 2 1AA Fenix L1Ds for this... (My wife will be thrilled with me!)

Cheers,
-GZ


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## UnknownVT (Jan 10, 2008)

kosPap said:


> There is one thing I disagree with regarding your B&W conversion method. Desaturating is not 100% accurate. You need to go another route. Converting to Lab color.
> Assuming you use Photoshop here are the steps:
> Now if you appply that method to the Mcbeth charts you will see a small difference in the output. I tried it myself
> There are some more issues. One is the use of the various camera white balance settings...Hmmm to many calculations, too many variables & biases.
> The second is that you are messing with color coding profiles. I forgot to check, but if your jpegs have a sRGB profile loaded things are a bit worst. sRGB is a compressed color palette narrower than others (Adobe RGB) which categorize colors with different methods....Usually converting to sRGB creates unequal shift in hue and saturation between colors!!


 
Many thank for the input -

However I think you're reading way too much into what I intended.

All I really wanted to do was to show the main differences between modern LEDs and xenon incands by _*visual comparison*_.

None of the photos were meant to be for any measurements.

DeSaturation is the simplest removal of color (without panchromatic bias like converting to greyscale or taking the photo in black & white) as it literally desaturates/removes the color - L.A.B. may be a bit more "accurate" - but I don't think the relative difference is that great - at least I don't think to the point where any of the results would be adversely affected.

The simple white balance as found on most digital cameras was all I wanted to use - 
Fixed Daylight White balance - to show how lights actually are, when compared to "daylight".
Tungsten white balance - because I was asked to show the incands using this balance, 
since our brains compensate/adjust for artifical lighting - 
AWB (Auto White Balance) - I added this - just because the digicam I used had pretty good AWB.

Again I intended the photos only as a visual comparison - 
so *no* calculations were ever involved.

sRGB or AdobeRGB - I used simple *sRBG* (_editted to correct my mistake_) - because it is the standard for most JPG/photos on the web - 
attempting to show AdobeRGB on the web is going to cause exactly the the sort of color shift you mentioned.

I'm more than happy to be corrected, and/or improve the simple visual comparisons - 
but I did not intend the use of a camera as a measuring instrument.

Perhaps you'd care to click on the links in my sig to see that I may have just a little experience in photography?


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## kosPap (Jan 10, 2008)

UnknownVT said:


> Many thank for the input -
> 
> However I think you're reading way too much into what I intended.
> 
> All I really wanted to do was to show the main differences between modern LEDs and xenon incands by _*visual comparison*_.


 
Indeed and this is the way I did not say that results were invalid...My comments was on the method details....BTW isn't sRGB the web standard?



> Perhaps you'd care to click on the links in my sig to see that I may have just a little experience in photography?


 
hmm I see we share the same passion for concert photography...You can follow the link in my sig to see mine...


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## Daekar (Jan 10, 2008)

UnknownVT said:


> Anyway I have a saved copy - and from that - on *Visual Acuity* -
> 
> "_Also, the refractive characteristics of the eye causes blue light to focus in front of the retina and red light to focus behind the retina, when compared to yellow light that is focused on the retina. _



Well! That _is_ helpful information, and begs other rhetorical questions:
1) Will warm-white emitters display any detectable improvement in vision sharpness when compared to say, cool or cold whites?
2) Are yellow-tinted sunglasses better for discerning details afar?
3) Is this the reason that roadsigns with a blue background are harder to read far away than an equivalent green sign?
4) Does this mean that reading by red light will give you eye strain?
5) Why do we seem to always pick the two worst colors, blue and red, for alarm-clock faces? (I can BARELY read the blue clock on the front of my computer from across the room... and no, it's not just me...)
6) Is that why the new blue LED-bars for police cars always look more like bright blurry points of light rather than bright sharp points? (It makes them look bigger and are more "visually magnetic" IMHO)
7) Does that mean it's better to have a yellow motorcycle than a red or blue one, if you're interested in being visible?

All out of questions for the moment...

EDIT: I'm back with more:
8) Does this mean we have a definite and irrefutable reason to claim that HID bulbs with color temperatures of 4200K/4300K produce more useful output for the same number of lumens than those with 6000K+?
9) Is this why the lines in the road are yellow? (At least the centerlines are in the US - I can't speak for the rest of the world as I haven't gotten a chance to visit anywhere else but Canada and Bermuda)
10) Does this imply that there might be visual advantages to developing a yellow stain for use in microscope slides?

I'm sure more will occur to me...


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## soffiler (Jan 10, 2008)

Daekar said:


> Well! That _is_ helpful information, and begs other rhetorical questions:
> 1) Will warm-white emitters display any detectable improvement in vision sharpness when compared to say, cool or cold whites?
> 2) Are yellow-tinted sunglasses better for discerning details afar?
> 3) Is this the reason that roadsigns with a blue background are harder to read far away than an equivalent green sign?
> ...


 

Fascinating stuff, isn't it? I think this thread is really going somewhere.

My answers to your questions (even though they're supposed to be rhetorical)

1) Quite possibly yes. I've got a modded Pelican M1 using a warm-white Cree, and it's beam pattern is quite similar to my SF G2L using the stock SSC P4 but the P4 is more neutral/cool than the Cree. I am going to run them both on my bars for tonight's night-ride and test one vs. the other.

2) I think so, yes. That was the whole push behind the original "blu-blocker" sunglasses, and they really do seem to work. I've got amber, clear, and grey lenses for my Rudy Project sunglasses and often use the amber on cloudy days (when others might not think to wear sunglasses at all). Cloudy days equate to higher color-temperature i.e. more blue - they seem "gray" because the intensity is much lower than a sunny day. The amber lenses markedly sharpen up a cloudy day.

3) seems reasonable, yes.

4) "..._when the eye is emmetropic for yellow light, it is myopic for blue light and hyperopic for red light..." _Myopia is difficulty focusing on distant objects. Hyperopia is difficulty focusing on near objects. I think the answer to this question is yes.

5) dunno the answer to that

6) Yes again. I've noticed the same thing. First time I ever noticed the blurry-blue effect was years ago, attending rock concerts when I was younger. When the light man would illuminate the whole stage blue, suddenly, the whole scene was blurry, and it would pop right back instantly if switched to yellows or whites.

7) I ride a yellow motorcycle. My other two choices in that model and year were red or blue. ('05 BMW R1200GS) Funny you should mention that!


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## soffiler (Jan 10, 2008)

GuyZero said:


> ...Then we tried the amber filter and found that our favorite setting was full power on the amber light and medium power on the white light. This did produce a more 3D image to our eyes, but I would not call it dramatic. The biggest difference was how it seemed to make everything sharper, easier to focus on, and a little higher contrast. Leaves and evergreen bows stood out from the brown tree trunks. Dry grass suddenly showed a lot more detail, and the scene was also brighter, as you'd expect....
> 
> I find it interesting having just read VT's post quoting that yellow light provides the best focus for the human eye. That's exactly what We experienced when we added the yellow light to the mix: colors could still be distinguished but everything just seemed to snap into better focus.


 

Perhaps it's time to drag out this dissertation on "selective-yellow" lighting for automobiles:

http://www.danielsternlighting.com/images/S-Yellow.pdf


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## robm (Jan 10, 2008)

Firstly - cracking thread UnknownVT :thumbsup:

But just something that struck me when looking at the map and Macbeth comparisons:

What light source does the scanner use, as this is the reference (and gives good real world colours to your eyes)?

Thanks


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## Daekar (Jan 10, 2008)

soffiler said:


> Perhaps it's time to drag out this dissertation on "selective-yellow" lighting for automobiles:
> 
> http://www.danielsternlighting.com/images/S-Yellow.pdf


 
I actually thought of that this morning on the way to work! I'd be willing to bet we've hit on the real reason why they're good. Nice motorcycle by the way, I love the GS series... when I test-rode an '06, I was grinning like an idiot the whole time.


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## UnknownVT (Jan 10, 2008)

kosPap said:


> ....BTW isn't sRGB the web standard?


 
You're right, I was wrong here -
I work in whatever the default color space that both my digicam and my photo editor works in JPG - which _*is*_ *sRGB* - 
and there is no color shift that I can see when displaying the picture using the Windows Viewer, IE, FireFox or any of my photo editors - 
I am pretty fussy about my photos so I think I would see a color shift - especially for the reproduction of the Macbeth chart - that's why I had a control white image.

My apologies for this mistake - that's from typing in the late late night/early hours.

I'll edit to correct my post to reflect that I do work in sRGB color space.


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## UnknownVT (Jan 10, 2008)

robm said:


> What light source does the scanner use, as this is the reference (and gives good real world colours to your eyes)?


 
The scanner is an old cheapo HP ScanJet 2100C (bought 2001) - the light source is a light strip - can't be certain - but it kind of looks like a daylight fluorescent. 

However the scanner is pretty accurate - I've used it for years now for most of my web stuff and yes, the scan of the printed color chart does look like the physical print in real-life.

I suppose I should have also taken the chart in real daylight as one of the controls - but it was night and the direct (built-in) flash shot I took had way too much reflection to reproduce correctly.

However I just realized that I did take the chart in good sunlight - but as part of my socks adventure (post #*82* ) - it was very tilted in perspective - so I correctd the perspective tilt, cropped the photos, and reproduce them here with the original scanned control white reference -

















From these samples I would say the Canon A610 I used has slightly more compressed dynamic range in these shots than the scan. Despite that it is also punchier - as with most consumer digicams - the red in C3, greens in C2 and B5 all appear brighter. There is also a noticable jump in blue C1 and C6.


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## robm (Jan 10, 2008)

Thanks for checking that UnknownVT - I just wanted to clarify that the 'control' was a realistic one.

The interesting point is that the light source closest to 'realistic':


> However the scanner is pretty accurate - I've used it for years now for most of my web stuff and yes, the scan of the printed color chart does look like the physical print in real-life.


is a 'daylight' fluorescent, which the comparison shots indicate is also closer to the LEDs than incandescents so we sort of have, in your tests, in descending order:

daylight (which I assume is what we are aiming for with regards colour rendition)
fluorescent daylight/scanner
LED
incan

I also agree with a statement you made earlier regarding the claims that incandescent look more 'natural':
When it is dark (i.e. when we normally use flashlights) our eyes are used to either faded sunlight, or domestic incandescent lighting, the sudden introduction of a small area of 'close to daylight' looks very wrong, now if we could gradually fade this in (in about the time taken from first light/dawn to midday) - it may look more natural


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## UnknownVT (Jan 10, 2008)

robm said:


> The interesting point is that the light source closest to 'realistic':
> is a 'daylight' fluorescent, which the comparison shots indicate is also closer to the LEDs than incandescents


 
Well the scanner uses software to reproduce the best color accuracy.
The scanner has the advantage of a "known" light source to correct - whereas say the AWB on a camera is working from the given scene which might have a real color bias anyway.

(_the following is not aimed at you - or anyone in particular - _
_it's just a general overview_)

Anyway like I said I am only doing and intend a visual comparison - my methods may not be the absolute scientific - but then none of the equipment, software used were measuring instruments - even though they may well be more accurate than average.

The point is just about anyone should be able to reproduce my results with commonly available and inexpensive equipment that most people probably already have - at least close enough so that the discussion/results are not going to deviate that much from what has already been presented.

We are not really looking at subtle differences here - 
I mean who in their right minds/eyes can deny the huge yellow/orange bias of incandescents - that is what I was showing initially.

So in context any use of manual white balance, color spaces, or LAB mode is just not going to make that much difference, if any, to this ad-hoc experiment - 
which was always meant to be a visual comparison......and not a scientific measurement.


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## D MacAlpine (Jan 11, 2008)

Daekar said:


> Well! That _is_ helpful information, and begs other rhetorical questions:
> 1) Will warm-white emitters display any detectable improvement in vision sharpness when compared to say, cool or cold whites?
> 2) Are yellow-tinted sunglasses better for discerning details afar?
> 3) Is this the reason that roadsigns with a blue background are harder to read far away than an equivalent green sign?
> ...


 
I'll have a go at a couple of these, Steve has already provided my answers or better to the rest.

7) Yellow is always going to be the best colour for overall high visibility, but I think that is to do with the way it contrasts and clashes with the background rather than visual acuity (obviously other colours would be better against a yellow background such as a field of oilseed rape in flower!). From what I have seen high visibility clothing, generally "dayglow" yellow with retroreflective stripes, isn't so popular in the US as it is over here. Take a look at this video for an idea of the effect. For it to work well it does need to be a really bright yellow though.
Two more points; my bike is also (mostly) yellow and I believe that the problem with motorcycles is not that other road users don't see them - but that they either don't look in the first place or fail to react to what they have seen. The proof of this is how much more reaction you get from drivers if you look like a cop (the right bike in white, white helmet, black leathers etc.) in comparison to being equally or more visible, but not triggering the "it's the law!" reflex in them.

9) Centre lines are white over here and in much of the rest of the world, where they're present at all, sometimes including crushed glass to improve grip and add a bit of retroreflectivity. We have yellow lines by the kerb for parking restrictions. Again yellow will tend to contrast best against a dark road surface, but I don't think it improves much on white in the situations where you can't see the road markings (light reflecting off wet roads etc.)

Edit: I've just been out in the car, in the dark, and I can say now that the yellow lines we have on the roads definitely do not show up as well under car headlights as the white lines. These are old lines on side roads with the centre (white) markings being well worn. Just another useless snippet... (need to shut up now, must NOT get drawn in on road markings or yellow jackets.......)

10) From what I understand the stains used in histology are selected for their ability to colour certain types of tissue or structures selectively. I believe that they already use filters to increase contrast, so I think that the answer to this one is no.

Apologies to Vincent if we're adding another line to his map of places this thread has drifted off to!


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## UnknownVT (Jan 11, 2008)

D MacAlpine said:


> 7) Yellow is always going to be the best colour for overall high visibility, but I think that is to do with the way it contrasts and clashes with the background rather than visual acuity
> Apologies to Vincent if we're adding another line to his map of places this thread has drifted off to!


 
Not at all - these are valuable points for discussion.

Many years ago when I commuted on a bike - that is a pedal bicycle - and for secondary (high) school - I read a pamphlet from the AA (not Alcoholics Anonymous oo: ! - but Automobile Association - in Britain - equivalent to AAA in USA) that black - yellow gave the highest color contrast combination - I was surprised because I was taught in art classes white was the "opposite" to black - but nevertheless this was the information I retained - and eventually come to confirm for myself.

Notice most internationally recognized caution/hazard signs are black symbols on yellow - and for Brits even the AA's own logo is black on yellow.......

So that's color contast - 

But using a light of a particular wavelength/"color" - we may have to allow might different -
Just as we know (or have discovered) that the "camera never lies" is not really true - as most of us can see well enough and recognize colors pretty well under incandescents - even though compared to real sunlight - tungsten/xenon lighting is distinctly yellow/orange - and with a few exceptions mostly cause people problems when trying to distinguish shades of blues or seeing yellow on white.

Further - some might be equating say yellow LEDs with incand's yellow -
nothing can be further from the truth - color LED's are mostly a single wavelength of light - whereas incands are a pretty full spectrum of visible light - but with a lower color temperature or yellow/orange bias - so the experiments of adding red, orange or yellow LEDs to the mix of white LEDs - only adds to the peak wavelengths of those respective LEDs - and does not really help even out or the "accuracy" of the overall combined spectrum.

I'll just repeat the shots from an incand and orange LEDs of the Macbeth color chart here - and see the difference 
Scorpion Daylight Balance ....................................................... 2x Orange Fauxton LEDs rendering -







- the orange LEDs show only a monochromatic result - whereas the incand albeit very yellow/orange biassed - still shows color in the patches - it would do not good whatsoever even if we adjusted the white balance for the orange LEDs - whereas, as already seen, the incands when white balance adjusted can reveal almost daylight like results.........

There seems even some confusion that direct sunlight is "yellow" and equating that to incands - _NO, NO, NO! -_ sunlight's color temperature is about 5,500K wheras even the best xenon incand cannot exceed about 3,200K which is significantly lower - go back to Post #*52* where there is literally daylight balanced shot of the Macbeth color charts showing the Scorpion next to the sunlit shot.... 
(oh, I'll just show them here....)









So there is a difference between light wavelengths/colors and colors of objects as seen by our eyes -

I do think (and these are only my thoughts) it is a combination of color contrast, and the fact we have better acuity with yellow wavelengths of light - 

I'll go back to my anecdotal (or maybe even "empirical") evidence that the light shone through Serengeti Drivers sunglasses - which I (and many) know enhances visual acuity and contrast - looks remarkably like the shots from the incand xenon Scorpion - so no wonder many of us see better with incands outdoors.......


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## norman$ (Jan 11, 2008)

Hey folks-

I occasionally lurk around here, and may never have posted before. However, there are a few things I thought I might be able to add for consideration. I've paid a good deal of attention to color perception partly because of some work I did in computer graphics and displays vs printed colors (like some others I saw) but also my interest in genetics, physics and colored gems- as will become clear. 

First is that the human eye not only has the issues with focusing blue (and to a lesser degree, red) as described, but also has significantly different sensitivities to different wavelengths of light. The eye is much less sensitive to blue and red than mid-spectrum light (yellow). That is, if I have a nice, monochromatic 650 nm red light source putting out X watts of light energy, another at 450 nm, and a third at 530nm, the 530 nm yellow will look will look much brighter than the blue and red even if one can prove that the amount of light put out by each is the same. 

BTW, the focus issue is that most materials will bend light different amounts depending solely on the wavelength- that's why prisms give rainbows. (in optics e.g. telescopes, camera lenses, and microscopes, this results in rainbows around things if uncorrected- when corrected the lenses are "achromatic") But different materials do it more than others- diamonds and certain other materials do it quite strongly, while crystalline pure quartz does is very very little (if you had 2 prisms, the quartz would give a very narrow rainbow, while the diamond a very broad one). In gems it's called "dispersion", and is the primary reason diamonds are so sparkly- you get lots of different colors out compared to e.g. quartz or sapphire. Good simulants like cubic zirconia or "moissanite" reproduce this quite accurately, some older ones (rutile, strontium titanate) are TOO sparkly.

The second is that the light interacts with various objects and their chromophores differently- a fine example of how funny absorption spectra of objects interacts with differing spectra of light sources and the uneven sensitivity of human vision to various wavelengths all come together to give color-changing gemstones: alexandrite (a rare chrysoberyl), and rare garnets, sapphires, and other minerals will drastically change their apparent color depending on the light source- usually shown as daylight vs. incandescent (or fluorescent vs incandescent). (in these cases the chromophore in question is chromium and/or vanadium stuck in the otherwise colorless crystal lattice... except garnets, which often have intrinsic color... and the compounds generally absorb mid-red and green but not long red or yellow) .

The same thing happens with lots of other subjects but is less apparent most times- but more than one author above noted that they saw lots of different colored leaves when the light changed from the yellowish incand to the blue-heavy LED. THis is really very, very common but hard to notice because people perceive only what they pay attention to- e.g., very little of the overall stimulus, and then its usually just a comparison between A and B, not any absolute measurement.

And different people have different light receptors and do in fact have different color perception- the most obvious is colorblindness- usually the lack of one of three color-sensitive compounds in the eye. Even though I con't perceive what you or someone else does, I can perceive and report that I can tell the difference between yellow, green, blue, and red in all the usual shades and intensities. Colorblind people simply cannot distinguish between certain shades of red and green or blue and yellow. BUT there are subtler differences, too- the eye has red, green and blue- absorbing compounds, and some people have different versions that absorb slightly differently- the light-absorbing compounds of the retina in some people absorb at different wavelengths even if overall they still allow for "normal" color vision by most tests. To such people, the colors of objects around the variant vision compound will appear distinctly different from "normal" people in that object X will look more or less different than object Y of similar hue and saturation. So a "normal" person would say that object 1 is closer than X to Y, whereas variant vision would cause the viewer to say that X is closer in color to Y than object 1. 

Weirder still is people who have more than the usual three vision compounds- they can distinguish between more colors than we can because of subtle differences in the spectra coming from objects, usually in the green range (one lady could readily distinguish between paint and grass of the "same color" and even used different words when describing them, saying the grass was more like a nearby fence painted yet a third color of green that to the author did not seem very close to either the sample green paint or the grass). Birds generally have 4 such color receptors and in humans the condition is called tetrachromatism- google it for more discussion.


For gems, this all means that even non-color changing stones will have a different perceived color depending on the light source as well as on the viewer. Usually it doesn't really matter- but the next time you see a nice blue (real) sapphire, funny colored garnet (anything but pure "red" or "green"), try to view it under different light sources because it might look great (or crappy) under the halogens in the store, but look great in the fluorescent lights of the mall (and your work place), and in natural sunlight, still different depending on the time of day. I've got a few neat color changing garnets, and they vary from golden/plum to blue(ish)/red. Alexandrites (none of which I can afford) go from green to red, but other crysoberyls go from yellow to green. (all ordered sun or fluorescent vs incandescent) Neat, neat stuff. 

So... It really is in the eye of the beholder. All you can do is get a light and see if it is useful under your preferred conditions.



Sorry for the long winded exposition, but I have an academic background (but by now, you're asleep I bet- I would be)

Ciao-

Nominally, Norman$.


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## hank (Jan 11, 2008)

Norman$, best post yet on a subject I find fascinating, I hope you'll write more, or point to elsewhere if you're, for example, one of the scienceblogs writers. As the big push comes to phase out incandescents in ordinary home use, the differences in color (emission spectra as well as color temperature) of the new lights have started to to attract a _lot_ of attention. Your post helps a lot.
http://www.nytimes.com/2008/01/10/garden/10lighting.html?ref=garden


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## UnknownVT (Jan 11, 2008)

FWIW - It was a nice sunny day today - so I went outside to take some Control Sunlit shots of both the Map and Macbeth chart ~3:30pm EDT - Atlanta, GA, USA -

Macbeth - Control Sunlight shots - compared to Scanned Control White Ref -















Map - Control Sunlight shots - compared to Scanned Control White Ref -


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## soffiler (Jan 12, 2008)

norman$ said:


> ...Sorry for the long winded exposition, but I have an academic background (but by now, you're asleep I bet- I would be)


 
Superb first post, norman$ ! I sincerely hope you stick around and continue to share your knowledge with us. Your academic background shows more than a little, and your grammatical skills are excellent. No snoozing here.


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## UnknownVT (Jan 13, 2008)

UnknownVT said:


> So in context any use of manual white balance, color spaces, or LAB mode is just not going to make that much difference, if any, to this ad-hoc experiment


 
Earlier discussion pointed out that using simple deSaturation of an image maybe different from splitting out and using only the Lightness Channel for lumiance information. 

This however required using LAB mode color space in PhotoShop - I don't have PhotoShop - 
so since then I've been scrambling to find a means of splitting out the Lightness Channel to compare to the desaturated imges posted here.

Then I realized that Paint Shop Pro (often called the poorman's PhotoShop) does not have LAB mode - but actually can split out the Lightness channel.

This I did, and present the Lightness channel here next to the original numbered deSaturated Macbeth Scan








I think it's hard to see any difference - if any - between these two images 
- however I actually used the eyeDropper tool in my photo editor on the images to read/measure the gray value 
(in the case of the deSaturated image - it still thinks it's RGB - so it has RGB values - but R=B=G - values are the same) -

I checked the center of the 4 central patches -

...... DeSat ... Lightness
B3 ... 141 ....... 142
B4 .... 87 ......... 88
C3 ... 112 ....... 112
C4 ... 166 ....... 166

So yes, there is a _*very slight*_ difference - 
but surely not enough to make any difference to the visual comparison.......?


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## UnknownVT (Jan 15, 2008)

Good color rendering artificial lights?

A friend sent me some links to -

Solux Daylight bulbs

Ott-Lite 

There's a comparison of Solux to Ott (but done by Solux)

Although these are room lighting - perhaps one could adapt one of the Solux bulbs (12V bi-pin) for use in say a typical 12V handheld spotlight?

Has anyone got experience of these lights?


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## MrMom (Jan 26, 2008)




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## hank (Jan 26, 2008)

I can't imagine wanting either a Solux or Ott as a flashlight.

Solux is incandescent, meant for color balance in museums as I recall.
Ott is a strange fluorescent with enhanced ultraviolet emission.


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## UnknownVT (Jan 27, 2008)

hank said:


> I can't imagine wanting either a Solux or Ott as a flashlight.
> Solux is incandescent, meant for color balance in museums as I recall.
> Ott is a strange fluorescent with enhanced ultraviolet emission.


 
Thank you - you have just illustrated a point.

Both these bulbs claim much truer color balance (daylight like) than any flashlight - either LED or incand.

But probably no one would be interested in adapting them in a flashlight - nor would anyone design a bulb to have the same spectrum as these for flashlights......

Why? because color accuracy/CRI etc are still pretty low on the scale of things compared to brightness for flashlights.

Now that we see LEDs surpassing most incands for sheer brightness - we may see a slow down in the pursuit of brightness (which I doubt  - as a lot of the LED development is _NOT_ for flashlights - but for commerical and domestic lighting) 
which means there will be more research in color accuracy 
and hopefully deliberate color spetrum balance to enhance vision for specific tasks.......
that means we will probably eventually see these in flashlights and benefit.


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## jzmtl (Jan 27, 2008)

On the original topic of puny led lights, if you want to laugh, go to bottom of LED forum, change display setting to from beginning, then go to last page, which should go back to 2000 or so. Look how little interest there is in this forum, and how puny the little led lights are.


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## srvctec (Jan 27, 2008)

*Re: Puny LED flashlights (Not!)*



Culhain said:


> I own only two colors of socks: dark navy blue and black. Under sunlight they are easy to match. Mostly, I neglect to sort them until I'm getting dressed in the dark. I find that LED lights (from 5mm to M60 Malkoff) are of no help in sorting the blues from the blacks. My SF E2O is my preferred sock matching light as it clearly shows the difference between blue and black.




Interesting. (I just came across this thread- so a little late to the show) I find my LED EDC (currently a Nitecore DI) to be far better for me to tell navy from black either on my dress pants or socks. I can't hardly tell at all in the incan light of the room which is which, but shine my LED light on the clothing in question, and I can instantly tell what color it is.

This is a very interesting and informative thread!! This is why I love CPF! :twothumbs


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## traumerei (Oct 10, 2008)

Hi UnknownVT - great thread.

Have you looked at the latest neutral white LEDs? Dereelight has got their Q2 5A tint pill which makes the Rebel look blue:

https://www.candlepowerforums.com/posts/2629938

And here are some shots from the new Cree MC-E in 6C tint.
https://www.candlepowerforums.com/threads/204649&page=9

I'd be really interested to see how the 6C in particular stacks up against incans since they would theoretically be near the same temperature wise and so the spectral differences between the two technologies would be highlighted.


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## milkyspit (Oct 10, 2008)

traumerei said:


> Hi UnknownVT - great thread.
> 
> Have you looked at the latest neutral white LEDs? Dereelight has got their Q2 5A tint pill which makes the Rebel look blue:
> 
> ...




Just a comment in general based on my own musings with various warm white, natural white, high CRI emitters and the like... the tint of the beam itself doesn't necessarily have any correlation with its effectiveness in rendering the color spectrum accurately. A warm white beam can have poor color rendition (CRI) and a cooler beam could theoretically have excellent color rendition. There's what the beam itself looks like (represented by the bin code of the emitter's tint), and what the items illuminated by the beam look like (reflected at least somewhat in the emitter's CRI rating).

There's also the concept that perhaps CRI is itself a flawed measure... this has been hinted at in the past by McGizmo, among others. I'm not saying it is or isn't, and in fact haven't formed a strong opinion on that aspect at all as of this writing. The basic argument, I think, has to do with how and when the black-body radiator line and associated color theory was developed, and the nature of artificial lighting at that time... with completely new sources of light such as LED, some of the original assumptions may not hold true. Again, I have no idea if that's the case! Just mention in the interest of completeness.

Finally, if all the above has already been well-covered ground, please accept my apologies! I'll be the first to admit I haven't absorbed every last post in this thread, even though I did make an honest attempt.


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## UnknownVT (Oct 10, 2008)

traumerei said:


> Have you looked at the latest neutral white LEDs? Dereelight has got their Q2 5A tint pill which makes the Rebel look blue:
> And here are some shots from the new Cree MC-E in 6C tint.
> I'd be really interested to see how the 6C in particular stacks up against incans since they would theoretically be near the same temperature wise and so the spectral differences between the two technologies would be highlighted.


 
Thanks for the input.

I have not had hands on any of the warmer to neutral tinted LEDs, so cannot speak from direct experience. The links to the beamshots look interesting.

However I have something of an issue with the use of "neutral" for the LEDs - 
for example the cited 5A tinted Cree - according to the Cree binning-labeling pdf - the color temperature is in the range 4000-4300 degK - this is much warmer than daylight (5500-6000 degK) and cooler than incandescent (2800-3300 degK) - a good compromise perhaps to avoid the too cool tints - but hardly "neutral".

Please see the reference Color Temperature at Wikipedia -
I regard daylight as "neutral" this is mostly defined as 5500-6000 degK...
Most LEDs are cool white like the Cree WC bin - about 6500-7000 degK just enough to make things look blue-green. I think only a slight downward shift (for me) is enough to the magic 5500 degK like a W3 bin - probably even WD or WP (toward red and away from green) would be improvements.

This is a long thread - I attempted a sort of summary of my position/opinion so far in Post #*73* - the main thing I got out of this is 

higher CRI does _*not*_ necessarily = color accuracy 
which in turn does _*not*_ necessarily = better vision.

I attempted to illustrate this by my comparison of LED light shone through Serengeti Drivers vision enhancing sunglasses(!) compared to an incandescent Streamlight Scorpion in Post #*69* 

When I have some warm tinted LEDs on hand I will come back to this thread to do more comparisons.

I only just come across this quote (ref: Wikipedia on fluorescent lamp):

" _High CCT lighting generally requires higher light levels. At dimmer illumination levels, the human eye perceives lower color temperatures as more natural, as related through the __Kruithof curve__. So, a dim 2700K incandescent lamp appears natural, and a bright 5000K lamp also appears natural, but a dim 5000K fluorescent lamp appears too pale. Daylight-type fluorescents look natural only if they are very bright._ "

(CCT = Correlated color temperature - section on the Color Temperature page at Wikipedia )

This may help explain why we seem to see better with incandescant flashlights and why LEDs can look pale or washed out.

_*EDIT to ADD*_ -
I almost missed this gem - which may go a _LONG_ way to explain some of the impressions we have when using flashlights -

Kruithof curve at Wikipedia 

This is only a very short reference article but is _VERY_ enlightening - and to think I almost missed it - please click on the link and check it out!


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## milkyspit (Oct 10, 2008)

UnknownVT said:


> I only just come across this quote (ref: Wikipedia on fluorescent lamp):
> 
> " _High CCT lighting generally requires higher light levels. At dimmer illumination levels, the human eye perceives lower color temperatures as more natural, as related through the __Kruithof curve__. So, a dim 2700K incandescent lamp appears natural, and a bright 5000K lamp also appears natural, but a dim 5000K fluorescent lamp appears too pale. Daylight-type fluorescents look natural only if they are very bright._ "
> 
> (CCT = Correlated color temperature - section on the Color Temperature page at Wikipedia )




UnknownVT, I've observed in field testing the same phenomenon the Wikipedia article describes. Great find! :thumbsup:


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## UnknownVT (Oct 10, 2008)

milkyspit said:


> UnknownVT, I've observed in field testing the same phenomenon the Wikipedia article describes. Great find! :thumbsup:


 
Thanks milky - 
click on that Kruithof curve at Wikipedia link for an even better (scientific) explanation - it's a gem......


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## HKJ (Oct 10, 2008)

Another thing to look at, for color rendition, is the spectrum of the leds, as long as a light source has holes in it spectrum, it can not give a perfect color rendition, some colors will be missing.

White leds today are based on blue leds, with phosphor to convert some of the blue light to other colors. This will usual leave some big holes in the spectrum, both for cool white, neutral white and warm white.
Using multiple types of phosphor and very precise dosage of it will probably improve the color rendition in the future.


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## milkyspit (Oct 10, 2008)

HKJ said:


> Another thing to look at, for color rendition, is the spectrum of the leds, as long as a light source has holes in it spectrum, it can not give a perfect color rendition, some colors will be missing.
> 
> White leds today are based on blue leds, with phosphor to convert some of the blue light to other colors. This will usual leave some big holes in the spectrum, both for cool white, neutral white and warm white.
> Using multiple types of phosphor and very precise dosage of it will probably improve the color rendition in the future.




That's the concept behind my own 'pinky' family of builds: SilverFox's "Pink Panther"; Mr. Mom's "Mother Nature"; Proline's "Lamberghini"; others. There are photos and beamshots scattered throughout my own *Project-M Thread* and *Milky Eye Candy Thread*.

Vincent, thank you for the link! :bow:


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## UnknownVT (Mar 18, 2009)

I know this is an old thread - 
but when looking up more references to the Kruithof curve - 
I came across this -

The Color of White

" _The traditional response to the question of the optimum light source for viewing art has been to use the same type of light in which the object was either created or intended to be seen by the artist. Prior to the use of modern high color temperature sources like fluorescent lamps, this would have been either natural light (preferably northern light which has a very high color temperature), or sources such as a candle, gas light or an incandescent lamp which have very low color temperatures. Based on the fact that many artists preferred to work in daylight, it has been assumed that daylight is the best illumination source for viewing art. Many museums have spent enormous sums of money on systems that incorporate high color temperature natural light, especially for galleries where oil paintings are exhibited. Is this assumption about using high color temperature natural light valid? According to research published over half a century ago, the answer is an unequivocal "no"._ "

well worth reading - 
this may go some way to explain some of the input in this old thread....


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