I'm pretty sure they can see black or red incandescent bulbs, but I've used them for years as "night lights" (extra over-head warmth) & if my snakes are at all
stressed about it, I truly can't tell. I'll add that I use lamp dimmers (rheostats) on them, so it's not bright light & they're never full-on. I don't currently keep BPs,
in case that makes any difference to you; I keep mostly rat snakes these days, also a rosy boa & an Australian spotted python (< she basks the most of all...she
spends most of the over-nights on her driftwood & under her black light), but my Florida & Trans Pecos rat snakes enjoy these lights too. (just not corn snakes,
they like to be cooler, in my experience)

Incidentally, for nocturnal snakes there's also moon light in the natural world...so? I know this question has been kicked around for years, not sure it was ever
settled though, & none of my snakes are talking, one way or the other...

And no, I don't stay up all night to watch my snakes: though I do enjoy watching them, after you've kept as many as I have for as many years, some of this wears
off, lol.