>>1238458Apparently blue is good for seeing through fog (reflects back significantly less than wider spectrum white light) but it's also an alternative color for reading (maps and whatnot) without wrecking your scotopic vision with white light. because maps often have black, green, blue, red, lines, etc. you might need a couple choices of narrowband light to make out the correct colorations.
In practice the reason I use the blue option sometimes is just because it can see more clearly with it than the red when I don't want to blast the white light (like when I'm being sneaky)
