Is there any infer red that is worth having without night vision? How bright of a red light can I have that wont ruin night vision? How many lumens can it be so someone cant see you far away?
Also thinking about replacing an interrior car light with a red bulb to perserve my night vision.
Your eyes can't see infrared light, although many cheap IR LEDs emit some visible light also. Asking "How many lumens until someone can see me" is like asking "How loud until someone will hear me?" It depends - environment, individual, distance, and so on. You can see a dimly glowing bulb for miles if it's in plain sight.
As far as I can tell, red is considered a "night vision color" because your eyes do not respond to it very effectively. This seems to mean that for the same number of photons bouncing around, you won't see as well (and neither will people looking for you). But I WANT to see! Here's where we get into me making conclusions based on my limited information.
I can't see very well by red light - nobody's eyes can, but I think I'm worse off. Even if I have an incandescent light with a red filter on (to avoid monochromatic color, the worst type ever), I can just barely tell bright surfaces from dark. I can't tell if wood is wet (rotted), or if puddles are holes. For me, that's never a useful light for seeing. If I'm going to have enough light to see, I'll need more red light than most any color, and more light of any one color than if I have white. So give me a superdim white LED any day, and I'll be happy.
