Night vision and headlamps

[IceIceBaby]

It might sound weird but, would one consider whiteout conditions as fog conditions in term of visibility?

Can one bridge the problem by using yellow or amber filters on the headlamp?

For regular night travel what can be lost in the way of vision using red filter?

[Gary_Yngve]

When it's dark, your vision is primarily through your rods.

The peak luminous efficiency for low-light (scotopic) illumination is at 507 nm, whereas in normal lighting (phototopic), the peak is at 555 nm (known as the Purkinje shift). The luminous efficiency curves are roughly bell curves, and the scotopic curve performs considerably better than the phototopic curve in the 400nm to 555nm (violet to yellow-green) range.

 

In other words, your rods are not as good at perceiving reds than your cones, so a red filter in low light would probably be a bad idea.

[IceIceBaby]

When it's dark, your vision is primarily through your rods.

The peak luminous efficiency for low-light (scotopic) illumination is at 507 nm, whereas in normal lighting (phototopic), the peak is at 555 nm (known as the Purkinje shift). The luminous efficiency curves are roughly bell curves, and the scotopic curve performs considerably better than the phototopic curve in the 400nm to 555nm (violet to yellow-green) range.

 

that was intense thank you for your last line I did understand that one

[ketch]

The Yellow/ amber lighting is not much help for obscured conditions. Your eyes are quite sensitive to the blue/white and it also alters your night vision the most. With Red light has very little effect on the night vision but also you cannot see very well. The presence of white or blue virtually eliminates what use it is(ever try a red flashlight on a moonlit night?). Yellow light is in the middle slightly on the red end of the stick. It gives you fair vision without much damage to night vision.

 

The real help in whiteout/fog is to not have a focused beam. The more difuse the beam is the less it will reflect back to blind you. Even a clear diffuser works for this. Thats why you can buy white fog lights for your car.

 

Anecdoteally fog lights are now built this way (short diffuse beam) but the discovery was made in a foggy rally. When the driveing lights were blinding one of the drivers He taped a newspaper over the lens as a diffuser. It worked great, his competiters colored their lights yellow with celophane thinking that it was the color that did it. They left again just as blind as before. It was the diffusion of the newspaper reducing the bounce back.

[wormfighter6]

Having some experience with red lenses they suck. It will not effect your night vision as much as a white light but there is no reason for you to be "tactical" a red lens would be illadvised.

[K_Y_L_E]

I have noticed that there are way too many rods and not enough cones out there climbing. ......little hidden meaning......sorry

The only use I have found for red light is in the tent. It helps avoid getting slapped by your climbing buddy. I absolutely hate it when they feel the need to shine the light in your face while talking. I would not pack any extra though, as it is not that big of a deal. I have a cheap-0 "Rayovac" headlamp. It is actually pretty sweet. It has 3 modes #1 is a halogen light that can be focused (and it pretty damn bright) #2 is a blue LED that is nice for around camp or slogging up a boot trail, #3 is a red LED that is nice for tent use or also around camp. It is a lightweight lamp and it uses AAA's which is nice. It can be found at most general purpose stores I got mine at a SUPER WAL-MART in Missoula. It was awesome!!!! I could buy a gun/ammo/gunrack, oil for my truck, A "U.S.A." T-shirt, can of chew, pork rinds and a six pack of Billy Beer!!