In the army sniper training manual (Fm 23-10) it says for equipment to have a red lense on your flashlight.  I have that but never knew what it was for.  Anybody know?

Red light doesn't destroy your night vision.

It is also harder to see at a distance due to it being at the end of the light spectrum.

BrenLover

Makes it easier to catch nightcrawlers.  [:D]

Also people who are a short distance away have a harder time seeing your light.

Red light is not as visible to the naked eye or NVD's. If you ever get a chance to test this you'll be amazed at how bright a white light someone thinks is covered can be. That's why they preach light discipline in the field.

holy crap... i just posted this..lol..thanks everyone.  i was kinda wondering if it was for the fact that it's harder to see.  the only thing is during the day, the lense glows bright red in the sunlight.  i'll just have to keep it out of sight..  not hard.

You still have to be extremely careful even with the red light. Yes, it is harder to see, but it is still [b]VERY[/b] visable at night from long distances. I'm sure SorryOciffer knows this, but I'm just trying to make clear what a lot of people overlook.

The red light is meant to preseve night vision. It kinda sucks for reading maps, because some colors are invisible under it.

If your red lensed fashlight has an incandescent bulb, it may not hurt your night vision, but it will light up everything to someone using NVDs. The incandescent bulbs produce a good bit of heat which is IR radiation, which can be seen by the NVD's and IR sensors used on today's battlefields. If you want to have a high-speed red light, or any other color, look into lights that are based on LED(Light Emitting Diode) technology. They produce very little, or no IR signature, and can last a very long time on very little battery power. The rub is that they are pretty pricey, and they are not very bright. they are bright enough to read by if you are close to the object you are trying to read or fiddle with, but if you are looking for something on the ground, the red LEDs are not powerful enough to illuminate the area. There are some LED lights that use various color of LEDs in an array, that when combine produce a white light which can be brite enough to see the ground in front of you if walking, but that kind of defeats the purpose of getting past the NVD's because you then become visible to the naked eye.

Red light definitely doesn't hurt your eye's ability to see at night.  I think that's why they make tail lights, brake lights and instrument panel lights red.  Imagine if the brake lights in front of you weren't red and blinded you all the time!  We'd all be wrecking.

What about those blue dots people put on their brakes... it shoots a blue/purple beam right in your eyes... they blind the crap outta me... i hate 'em.  I can't stand those new blue headlights either.  They're cool as long as they're not shining in YOUR eyes.  

Sorry, I got up on my soapbox there for a minute.... LOL

What is the blue lens for?

It is amazing how far white light will travel. I remember being on guard duty at night with NVG's on. I could see exactly where our GP Medium was from all the lantern light shinning through the holes in the canvas. LOL!

Let us not forget, Red filtered light doesn't attract as many mosquitos! I've no idea what tactical use the blue light has.
When I was in LRSD we used to put 100mph tape over the lense and leave only a tiny slit for the light to come out. This let enough light to read a map out, but kept us from giving away our position.  And, as Defcon pointed out, Red lenses also make it much easier to catch night crawlers!

Blue is used by medical personnel, something about the red and blood.  

Some units, like artillery, will use the different filters in advanced party operations and laying of the howitzers at night.  Normally red, blue and violet to mark guns 1,2 and 3 respectively and than 4, 5, and 6.