I actually use blacklight heat bulbs for both of my snakes for overhead heat. I like them because they are a nice low visible light that doesn't keep me up at night.
I know both snakes can see it because both sometimes look right at the light at night when they're out roaming, but it seems more just curiosity than any adverse attention I also haven't seen any stress signs indicating that it bothers them.
I also chose blacklights because of the low amount of visible light they produce because I keep my snakes near a window so they are running on a natural day/night schedule with the rising-setting of the sun here. I haven't heard that these sorts of bulbs in any color have any adverse effects tho.