Photon Yellow vs. White

LRI describes the Yellow as being the same color as a traditional flashlight beam. I have several of the White ones which are VERY white (with a tiny bit of blue thrown in).

How would those of you who have (and have used) both compare the two, and how would you rate the Yellow?

I thought that the Yellow would be an advantage in an Emergency because of its much longer runtime, but I'd also prefer that it not distort color perception too much.

Thanks,

-John

I think you have answered your own question.

I have EDC'd a Photon Yellow for over 6 years - and basically would not be without it.

However it is of "specialized use", and possibly just personal preference.

I like yellow not because it is like traditional flashlight color - it is not - it is much more yellow/amber than say a MagLight and DIMMER.

So why would I like a dimmer and yellow light?

(1) long, LONG battery life - claimed 120 hours, so basically I don't ever have to worry about the light/battery - my recently retired Photon I Yellow is not because battery went flat or obviously the LED burnt out - although the body was definitely worn smooth from use on my keyring. It was purely because I did a body transplant into a 20 for $20 LED light from County Comm - and had a Photon 2 Yellow in waiting as a replacement for over 6 years!.......

(2) DIM is an advantage - for my use in dark situations - where I want to preserve whatever dark adaption my eyes have attained (note this is probably not true "scotopic" night vision) but in a typical dark music venue.

(3) COLOR - I seem to see well by a dim yellow (unlike say Red). For me yellow seems to enhance apparent contrast and definition - albeit with the loss of accurate color rendition. For example I am confident enough to walk outdoors in the countryside by a Photon Yellow only. It is not my first choice, but will work in an emergency.....

(4) Dimmness and color combined - seems to attract less attention - often I just want a quick shot of light but not distract disturb other people or attract attention to myself.

(5) I do EDC a Dorcy 1AAA LED WHITE - in my other pocket for occassions when I need a white light - and often helping others with some light.

But note I had EDC'd the Photon Yellow ONLY for over 5 years, and managed quite well without a white light.

If I had to keep one light only on my person -
it would be a Photon 2 Yellow (or my transplanted Yellow in a 20 for $20 LED from County Comm body)

But YMMV.

You can get even longer runtime by using a single 2032 coin cell instead of two 2016's with a white led. Of course it will be dimmer than the yellow. I set up one of my Countycomm lights that way yesterday just to try it out. It's definitely useable for walking around in the dark, but it doesn't fill a room with light the way that a brighter light does. I like it so far. As another nice point, the lower current makes the light whiter (more neutral). The blue that you see from white-led 2 cell coin lights and similar lights like the CMG Ultra is partly caused by the way those lights overdrive the led.

Green also works very well with night vision, better than yellow in fact. A green Photon II on my keychain was my sole EDC light for years. It's been dimmed but perfectly useable. I thought the dimness was because the two 2016's in it were pooped, and it was only a couple days ago that I got around to opening it up and found there was actually just a single 2032 inside. I put the 2032 back in and it still works dimly but happily.

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paulr said:
Green also works very well with night vision, better than yellow in fact.

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Is this based on scientific fact or just a personal preference, please?

I'm not being argumentative - but for me I know I see much better by yellow than green.

Yes the green light does appear brighter - as a light source - but despite its superior apparent brightness, contrast and definition just is not as good as the dimmer yellow/amber.

Now I will grant this might well just be my eyes and possibly a personal bias - that's why I now always qualify the better contrast and definition of Yellow - as a personal preference - even though I have read elsewhere that yellow does seem to enhance apparent contrast - but I do not have any scientific reference to back this up - so I leave it as a personal preference and try not to make it sound authorative.

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A green Photon II on my keychain was my sole EDC light for years. It's been dimmed but perfectly useable. I thought the dimness was because the two 2016's in it were pooped, and it was only a couple days ago that I got around to opening it up and found there was actually just a single 2032 inside. I put the 2032 back in and it still works dimly but happily.

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Green Photon is supposed to use 2 x CR-2016 according to the specs by Photon Lights themselves - please see this ref:

http://www.photonlight.com/more_info/tech_specs.html

Did you always have a single 2032 in your Green Photon 2? -
or could it be possible at all the 2x CR-2016's were replaced by a single CR-2032 some time later?
As I can't quite see how the Green Photon 2 ever managed to be bright using a single CR-2032.....

I have an old Photon. They originally shipped them with a 2032 inside, and switched to two 2016's later on.

Re night vision, about 2 seconds of Google searching finds this:

http://www.panoptic.co.uk/light_colour.htm

"The evolutionary response to this problem was for the eye to switch maximum sensitivity from 555nm (bright green) when vision is Photopic (during day time) to a shorter 510nm (blue/green) wavelength as the sun sets and our vision goes through the Mesopic phase towards Scotopic (night) vision."

That explains why blue-green (cyan, turquoise) LED's seem the brightest at night.

Another good article: http://www.backpackinglight.com/cgi-bin/backpackinglight/00202.html

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Yes the green light does appear brighter - as a light source - but despite its superior apparent brightness, contrast and definition just is not as good as the dimmer yellow/amber.

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Maybe so. Night vision is about seeing coarse shapes in dim light, to avoid bumping into things in the dark. Contrast and definition are more a function of day vision.

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paulr said:
Re night vision, about 2 seconds of Google searching finds this:

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yes, I have done extensive searching on "night vision", and if you recall, took part in many discussions in CPF.

Ref:
Human Night Vision Preservation

Preserving Night Vision - Colors?

Indeed I have also read about the eye being most sensitive to green in daylight and switching to blue/green for twilight/darker conditions.

However having the eye being most sensitive to blue/green in darker conditions does not necessarily make the light better for seeing clearly by -
and I will make it explicit - to see clearly with reasonably good contrast and definition - and not vague outlines of large object, where I would be extremely uncomfortable and feel unsafe.
(that is afterall why I carry a flashlight in the first place).

As I tried to make it clear that my so-called "dark adaption" is most probably not true "scotopic" night vision, and I also very much doubt anyone's "night vision" is scotopic under normal urban conditions - simply due to the amount of light pollution.

I cannot explain why I see better, clearer, more contrast and definition by yellow than almost any other color.

I can only make subjective surmises/guesses at perhaps at a combination of apparent increase in contrast and possibly less bounce-back glare - whereas green, blue/green and especially blue seems to be glaring, and adversely affects my dark adaption recovery (I sometimes get after images when the lights are switched off - whereas with yellow I don't appear to be affected as much. Red might be as good - but I just don't seem to see details well at all under red light) I am sure if I reduce the intensity of the green, blue/green, or blue lights I would probably suffer less glare - but I am not sure if I would then be able to see details as well under the dimmer conditions - just like with Red - I am sure if I increase the intensity of the Red I would see better - but then the higher intensity would then probably glare more.

Sorry to have gone on so long - but I hope you can understand what I am trying to get at -

To me this is a subject of immense interest -
my own experiences points me to yellow LEDs -
but I also understand if it might just be my eyes,
and even personal bias.

Unfortunately, even though I have also found plenty on the net advocating one color over another -
I am just not that convinced of how authorative any of those references are......

(eg:
USAF Flight Surgeon's Guide: Chapter 8
(about 2/3 down the page under the heading "Night Vision")

Clearly states that red is the correct color to preserve human (scotopic) night vision -
Even so there still remains confusion over whether Red or Green is correct for night vision - to the point where green or blue/green are advocated over red, which, if you think about it, is exactly the diametric opposite to what the USAF surgeon's guide is recommending.)

The idea of green isn't as much to preserve scotopic vision as much as to use it as effectively as possible. That is, if you just want to see where you're going, blue-green is the color of which you'd need the least brightness.

Contrast and definition are another matter. You simply don't get those from scotopic vision. Yellow may indeed work best for that, at least for you.

Usually if I need to see something at high resolution, it's something close up, so with a dim light it's enough to just hold the light very close to the object. Long-running ultra-dim flashlights are for not bumping into things in the dark, which doesn't take much definition.

As usual, "buy both" (multiple lights for multiple purposes) applies here.

Doug Owen kindly sent me various LED colors which unfortunately I ended up having to store where I can't get at them anytime soon. Eventually I'll get them back and try setting up different lights with them and do some experiments. Meanwhile, I'm gaining appreciation for coin lights in general, fooling around with them these past few days. I had lost some respect for them after getting an Arc AAA. The fact is though, a 2032-powered coin light can outlast even a CMG Infinity.

I prefer a yellow led for it's long runtime on two cells.

Matter of fact I make up a bunch of LED nightlites using a single 10mm yellow led mounted to the top of a two d-cell batter holder. They run for months, using only a thin piece of plastic cut from a sode bottle and slipped under the battery connection to turn the light off.

GregR

WOW,

Lots of good info here to think about. (and a sprited debate ta' boot!!!)

Basically, what I was asking was that if I want an LED which is as close to white as possible, but was willing to trade some 'whiteness' for significant increase in runtime, would the yellow be a good compromise???

Ideally I'd like a white photon with the runtime of a yellow.

What kind of runtime would I be looking at if I put a 2032 in the white photon? How dim would it then be?

I'm thinking that my new EDC setup (as far as light goes) will be:

-Inova X5T White on my belt for general utility.
-Surefire E2E HA (actually a L4 w/E2E bezel and lamp so it retains the clickie) in my LRP for 'tactical' situations and when greater throw is otherwise needed.
-Photon II Red as a fob on my Victorinox Tinker in my RFP for times when it may be very important to preserve night vision.
-Photon II White on my Keychain for general utility when the X5 would be overkill, or when I leave the house otherwise 'empty-handed' /ubbthreads/images/graemlins/ooo.gif.

In my backpack (which I have on me ALMOST everyday) I would have a Photon II Yellow, Spare 123's for the X5 and the SF, spare lamp for the SF, CMG Infinity and spare AA's, and maybe a PT Rage w/ a few spare AAA's. I feel that I would be more than covered for most any lighting situation, and in fact this may be a bit of overkill and I will probably whittle this down a bit.

There was a time not too long ago that I carried a White Photon II as my ONLY EDC light...YOU *******S /ubbthreads/images/graemlins/mad.gif!!!!!

Still, what do you think?

-John

PS - is it possible that you guys are kinda' comparing apples and oranges? It seems that Vincent is saying Yellow works well for him to provide contrast without being obnoxiously bright, while Paul seems to be saying that since the eye generally sees Green light the best that green allows your eye to work most efficiently at night (though would still destroy your night vision), while most people agree (I think) that Red works best at night to preserve night vision (though is not regarded as the best light to see by). These seem to be three seperate points which are all valid and, it seems to me, correct. No need to argue. Or am I way off???

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blastjv said:
(and a sprited debate ta' boot!!!)

PS - is it possible that you guys are kinda' comparing apples and oranges? It seems that Vincent is saying Yellow works well for him to provide contrast without being obnoxiously bright, while Paul seems to be saying that since the eye generally sees Green light the best that green allows your eye to work most efficiently at night (though would still destroy your night vision), while most people agree (I think) that Red works best at night to preserve night vision (though is not regarded as the best light to see by). These seem to be three seperate points which are all valid and, it seems to me, correct. No need to argue. Or am I way off???

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Thanks for trying to make peace - but I didn't think we were arguing -

But you do make a good point about cross-purposes.

Indeed blue/green would be the most efficient and least amount of light that the eyes could use in dark conditions - but exactly as you point out not necessarily the color that would enable one could see the clearest -

I always question any color being some kind of a panecea - especially where brightest is equated with seeing best with, or the most "efficient" color again is the best to see by, that also includes my own "bias" to yellow - since I have not read anything authorative (enough) to explain why one color might be "best".

Perhaps it is just personal preference, and different horses for different courses.

I need a light for close work that does not adversely affect any dark adaption my eyes have acquired - BUT I also need to see reasonably well by that light - details - so the currently available yellow LEDs eg: on Photons seems to work for me.

I would be very interested in blue/green with adjustable brightness that adjusts the intensity low enough to use true scotopic vision efficiently - but my understanding and doubt was that the use of almost any light of any brightness - means one is NO longer using scotopic vision - but photopic (day) vision - since detection of any color means the cones are being used....
and whether true night (scotopic) vision was being used in the first place - due to the sheer amount of light pollution in most locations.....

Blastjv, yes, I've posted several times, a 2032 works fine in a white light, it's pretty dim but should run for a very long time.

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paulr said:
Blastjv, yes, I've posted several times, a 2032 works fine in a white light, it's pretty dim but should run for a very long time.

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Paul,

Thanks again.

I understand it would be dimmer and longer, I'm just asking how MUCH dimmer? How MUCH longer?

-John

I suspect it varies a lot from LED to LED. I don't have a light meter to test with. All I can say is, I set up a Countycomm white light with a 2032 and find I can easily walk around in the dark with it. However, a CMG Infinity completely stomps it. I used the Countycomm to find the bathroom last night and found that I could easily read the fine print on the toothpaste tube holding the light 1 foot away from the tube, vs 2-3 feet for the Infinity. So I'll estimate the Countycomm is drawing around 3-5 mA, which would give maybe 40 hours of runtime, though even dimmer at the end.

As mentioned elsewhere too, LRI originally sold the green Photon II with one 2032, which meant they thought it was a marketable product at that brightness. They later switched to two 2016's.

Based on my own experience switching between the colors on an Eternalight Rave'n, these are my ideas on the various colors and night vision.

There are two wavelengths -- yellow and cyan -- which happen to sit at the points between peak sensitivities of two color sensors, and therefore stimulate them equally. This is good, because it means that these colors trigger twice as many sensors -- thereby doubling the effective resolution -- as monochrome red, green or blue.

Of the two, yellow gives better results than cyan for sharpness and resolving details, because there seems to be equal numbers of red and green cones, versus a relative paucity of blue. The latter, in fact, contributes the least to detail resolution, which is why blue gets the shortest end of the stick in most video codecs (compressor/decompressor). So that's why yellow is likely the best monochrome option for resolving details.

However, when it comes to scotopic vision and perceiving overall shapes (like trees and rocks), then IMO any color between green and blue will work. This is because the rods all have the same frequency response across the blue-green spectrum.

The advantage of red for preserving night vision is because scotopic vision is relatively insensitive to it. So, when you need to see *details* (as on a star map) but don't want to "scare off" the blue-green sensitive rods, red works best. But when you just need to see overall shapes so as not to bump into things, very dim blues and greens for the scotopic vision gives the best range for minimal battery power. I've been able to navigate in the woods at night using the blue light from a camcorder foldout screen (stupid me got back to camp very late and had to navigate back to the tent this way.)

Thanks Canuke, that's interesting. I have a few different colors of led coming in the mail and will set up some Countycomms with yellow and with blue-green and try them out. I've always heard that blue-green (turquoise) appears brighter than green. However, at least from the vendor I ordered from, the blue-green leds are less efficient than the green (4000 vs 6200 mcd for the same power and beam angle). Maybe there's some better ones available elsewhere.

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Canuke said:
Of the two, yellow gives better results than cyan for sharpness and resolving details, because there seems to be equal numbers of red and green cones, versus a relative paucity of blue. The latter, in fact, contributes the least to detail resolution, which is why blue gets the shortest end of the stick in most video codecs (compressor/decompressor). So that's why yellow is likely the best monochrome option for resolving details.

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Many thanks for that succinct clarifying summary -

Quickbeam also came to a very similar conclusion, arising out of our long discussion in this thread -

Preserving Night Vision - Colors?

resulting in him setting up this web page:

Choosing a color
http://flashlightreviews.home.att.net/qa.htm#colors