# RED OR GREEN LIGHT



## bigsteve (Apr 25, 2010)

any advantages to putting a red ot green lens on a flashlight? 
or is it for show only?


----------



## Gazerbeam (Apr 25, 2010)

Hi bigsteve take a look at this sticky.


----------



## angelofwar (Apr 25, 2010)

Red to keep your night adapted vision and to keep from waking others up. The green is mostly for hunting, and walking through the woods at dusk or dawn so as not to disturb the critters, since miost of them can't see green light.


----------



## JCD (Apr 25, 2010)

Will it be pointed starboard side or port side?


----------



## Moka (Apr 25, 2010)

angelofwar said:


> Red to keep your night adapted vision and to keep from waking others up. The green is mostly for hunting, and walking through the woods at dusk or dawn so as not to disturb the critters, since miost of them can't see green light.



lol, moist... =P:devil:


----------



## angelofwar (Apr 25, 2010)

Moka said:


> lol, moist... =P:devil:


 
LOL! Most!!! Dang-it!


----------



## ti-force (Apr 25, 2010)

angelofwar said:


> Red to keep your night adapted vision and to keep from waking others up. The green is mostly for hunting, and walking through the woods at dusk or dawn so as not to disturb the critters, since miost of them can't see green light.



I think that's backwards:tinfoil:  , although red is easier on the eyes than white, the critters that a hunter doesn't want to disturb can't see red. Although, I've read that neither green or red can be seen by said critters. As for a human keeping night adapted vision, and if I'm not mistaken, the military uses mostly dim green light for map lights and such. I could be wrong, but I know first hand about turning a red light on around feral hogs. They can't see it, but if you try that with a standard incandescent or LED (white, yellow, blue or purple spectrum), they will book it right on out of there. They will do this = :duck: .


----------



## jabe1 (Apr 26, 2010)

Red will preserve night vision, but the military uses dim green because the night vision equipment will not see it, compared to red, which will look like a flare. IIRC, the rods in the eyes retina are responsible for night vision, yet are not as color sensitive,(and do not perceive red spectrum light) the cones are color sensitive, and yet not as numerous. The highest percentage of cones are sensitive to the red spectrum, then green, then blue. At night, the red will activate more of the retina than another color, although the cones for the blue spectrum are most sensitive. So, to see best without affecting the rods (night vision), use red. Does that make sense? it's getting late...


----------



## ti-force (Apr 26, 2010)

jabe1 said:


> Red will preserve night vision, but the military uses dim green because the night vision equipment will not see it, compared to red, which will look like a flare.



That makes sense. I knew there was a reason, I just wasn't sure what that reason was. That's what I get for assuming . Certainly wouldn't want to give away your location.


----------



## Surnia (Apr 26, 2010)

jabe1 said:


> Red will preserve night vision, but the military uses dim green because the night vision equipment will not see it, compared to red, which will look like a flare. IIRC, the rods in the eyes retina are responsible for night vision, yet are not as color sensitive,(and do not perceive red spectrum light) the cones are color sensitive, and yet not as numerous. The highest percentage of cones are sensitive to the red spectrum, then green, then blue. At night, the red will activate more of the retina than another color, although the cones for the blue spectrum are most sensitive. So, to see best without affecting the rods (night vision), use red. Does that make sense? it's getting late...



rods are sensitive around the 500nm range, which is about between green and blue (closer to green), which is why greenish colours appear far brighter (two sources of activation), and why they kill night vision. Rods also do not respond above 600nm or so, so anything in the red spectrum does not disturb them. This is why red does not affect your night vision capabilities.


----------



## mcnair55 (Apr 26, 2010)

ti-force said:


> I think that's backwards:tinfoil:  , although red is easier on the eyes than white, the critters that a hunter doesn't want to disturb can't see red. Although, I've read that neither green or red can be seen by said critters. As for a human keeping night adapted vision, and if I'm not mistaken, the military uses mostly dim green light for map lights and such. I could be wrong, but I know first hand about turning a red light on around feral hogs. They can't see it, but if you try that with a standard incandescent or LED (white, yellow, blue or purple spectrum), they will book it right on out of there. They will do this = :duck: .




Hunters use a red light,a right pain in the *** goes rabbiting in the field by me at about 1 am with a huge red light.


----------



## ti-force (Apr 26, 2010)

mcnair55 said:


> Hunters use a red light,a right pain in the *** goes rabbiting in the field by me at about 1 am with a huge red light.



.... Don't you hate when that happens?


----------



## Mr Bigglow (Apr 26, 2010)

Red best preserves night vision. In addition to what's already stated, green can be used to reveal red things (say lines on a map, or blood) that will be invisible under red light. I prefer red and blue altho I've been told that yellow-green is the best red alternate of all. Which means I can buy a milspec Kroma, doesn't it?


----------



## angelofwar (Apr 26, 2010)

Mr Bigglow said:


> Red best preserves night vision. In addition to what's already stated, green can be used to reveal red things (say lines on a map, or blood) that will be invisible under red light. I prefer red and blue altho I've been told that yellow-green is the best red alternate of all. Which means I can buy a milspec Kroma, doesn't it?


 
Or an A2-YG...but I'd get the Kroma Mil-Spec )


----------



## [email protected] (Apr 27, 2010)

Surnia said:


> rods are sensitive around the 500nm range, which is about between green and blue (closer to green), which is why greenish colours appear far brighter (two sources of activation), and why they kill night vision. Rods also do not respond above 600nm or so, so anything in the red spectrum does not disturb them. This is why red does not affect your night vision capabilities.



That is almost bang on but not entirely accurate, the Rod cells are sensitive to ALL levels of light intensity so a bright red light will still cause Rhodopsin to photobleach impairing your peripheral monochromatic vision...

Obviously green light effects the Rod cells and to a lesser extent the Cone cells due to their 3-way cell distribution (which varies from one individual to the next) of the three types of Photopsin utilized by the Cone cells the largest proportion are sensitive to Long light Wavelengths of 500~700nm (predominantly Red).

Considering our Cone cells are responsible for detail & acuity it seems only logical that this is the reason for the NVG's applied color frequency and use of green ALS's in field for map reading and up close detail work :thumbsup:

***Current school of thought seems to support the application of "significantly" low level white light for non-military and hunting/tracking applications allowing the engagement of both the Cones and to a lesser extent the Rod cells of the eye for night orientation/navigation as a means of avoiding the associated "night blind spot" resulting from peripheral only night adapted vision


----------



## MrBenchmark (Apr 27, 2010)

[email protected] said:


> That is almost bang on but not entirely accurate, the Rod cells are sensitive to ALL levels of light intensity so a bright red light will still cause Rhodopsin to photobleach impairing your peripheral monochromatic vision...


 
True, although I can tell you from first hand experience that it isn't as bad with red light as with say white light. But an intensely bright light red light will surely wreck your night vision. (It seems to recover a bit faster though.)

Most people don't really have much experience with this, but your scotopic vision really is color blind - when I look through my telescope, other than the planets (which are just intensely bright), most objects are monochromatic - like looking at a black and white TV, really. Most people are also unaware of how little light it requires to see. I won't say you can see well in low light - you really can't, but what's surprising is that you can see *at all* under really dim conditions. 

Why do you care about this, since we have flashlights? I mean, just turn it on and look at stuff, right? Well, if you DO need dark adaptation for some reason, it takes about 30-45 minutes to become fully dark adapted, and only a few seconds of light to lose it. Therefore, if you care about this for some reason (I do - I look at dim astronomical objects that are mostly invisible if your eyes aren't dark adapted) you'll be wanting to use a dim red light if you need light at all. 

Anyway, most people don't have any idea about this stuff because urban lighting being what it is, where most people live it is essentially impossible to ever be fully dark adapted.


----------



## kaichu dento (Apr 27, 2010)

bigsteve said:


> any advantages to putting a red ot green lens on a flashlight?
> or is it for show only?


If you'd like to play around with colors a bit you might get yourself one of the coolest colored emitter lights around: the Quark RGB. It's got 4 colors of output and the RGB of course stands for Red, Green, Blue, in addition to the white output. You can vary output for all colors and the light will save a setting for the colored output separate from the white output.


----------



## darknessemitter (Apr 28, 2010)

ti-force said:


> I think that's backwards:tinfoil:  , although red is easier on the eyes than white, the critters that a hunter doesn't want to disturb can't see red. Although, I've read that neither green or red can be seen by said critters. As for a human keeping night adapted vision, and if I'm not mistaken, the military uses mostly dim green light for map lights and such. I could be wrong, but I know first hand about turning a red light on around feral hogs. They can't see it, but if you try that with a standard incandescent or LED (white, yellow, blue or purple spectrum), they will book it right on out of there. They will do this = :duck: .


 
The charts I've seen of deer vision sensitivity shows that they should be least sensitive to red light, and should be able to easily see green light. I'm not a hunter, so I'm not sure if there may be some other reason that deer might be less responsive to green light in some situations, but it seems they should definitely be able to see the light. (they don't perceive the color green the same as we do since they only have 2 types of cone cells, but they can still see the light). 

Other types of animals may be sensitive to different parts of the spectrum. It seems to me that house cats can see the 630nm wavelenght of typical "red" leds, but I'm not sure about other animals.


----------



## ti-force (Apr 28, 2010)

darknessemitter said:


> The charts I've seen of deer vision sensitivity shows that they should be least sensitive to red light, and should be able to easily see green light. I'm not a hunter, so I'm not sure if there may be some other reason that deer might be less responsive to green light in some situations, but it seems they should definitely be able to see the light. (they don't perceive the color green the same as we do since they only have 2 types of cone cells, but they can still see the light).
> 
> Other types of animals may be sensitive to different parts of the spectrum. It seems to me that house cats can see the 630nm wavelenght of typical "red" leds, but I'm not sure about other animals.



Yeah, deer can't see red light, so that's best for sneaking into the woods before day break without scaring them away. Like you, I'm really not certain about the green. I've seen information supporting that they can see green and I've seen information stating that they can't see green so I don't know. Maybe they can only see certain greens, or like you said, in certain conditions:shrug:. I do know this: If you shine an incandescent light (or non-red LED), without a red filter at certain animals, they will run away very quickly most of the time if they're uncomfortable with where they are. I have seen the same animals just stand there, but if you use a red filter, they don't even know they're illuminated.


----------



## Pacecar (Apr 28, 2010)

A series of articles worth reading on this subject.

"The Eyes Have It"

http://www.predatorxtreme-digital.com/predatorxtreme/200810/#pg83


----------



## darknessemitter (May 4, 2010)

Pacecar said:


> A series of articles worth reading on this subject.
> 
> "The Eyes Have It"
> 
> http://www.predatorxtreme-digital.com/predatorxtreme/200810/#pg83


 
Interesting, according to that article canines and felines have cone receptors in the "red" and "blue" ranges and lack one centered in the green range (although their red and blue cones still overlap into the green wavelengths). 

This is different from what I recall about deer vision, where they have cones in the green and blue range, but lack one in the "red" range which is why deer aren't supposed to be able see red light. Keep in mind that for humans, and appearently cats & dogs, the "red" cone actually peaks in yellow-green, and just barely has enough sensitivity out in the real red wavelengths to allow us to see them at all. The closest that deer vision gets is yellow-orange out on the edge of their "green" cone sensitivity. I guess they might still be able to see a red light in the dark if you shine it right at their eyes, but it would probably look pretty dim to them. 

Um, but going back to the article, it sounds like what they were implying about the coyote's perception of green would be of more importance in selecting the color of your camo, and not so much the color of your leds. They say that coyotes would percieve green as being in shades of white or grey, but that means if you shine a green led at a coyote at night, they would still see it as a bright white light in the dark. 

In contrast, if you shine a red led at a deer, it might be able to see *some* light in the dark (this might depend on whether it's 630nm orange-red or the deeper 660nm red), but would appear a lot dimmer than any other color. 

Maybe think of it like when we look directly into a near-infrared light, sometimes a feint red glow is visible, but it's barely visible even in total darkness.


----------

