Originally Posted by geo8rge
Just for the record I do not use a red headlight. I wonder if you could combine red and white leds to get a superior beam (brighter with less loss of night vision), that would comply with laws and common sense.
It's the brightness of the beam in the shorter wavelengths (bluer light) that interfers with your night vision. The rod cells in your eyes are more sensitive to the blue light but they are also insensitive to red light. That's why you can preserve your night vision with a red light. The light doesn't overwelm the rod cell and allows you to pick up the blue light that is coming from stars and reflections from the sun in the atmosphere.
Since you are already using a white light with lots of shorter wavelength light in it, adding red won't do anything. The best thing to do is just add more light (white) and overwelm the darkness
