For the same reason the inside of all cameras (that I have ever seen) are flat black, this would be my first choice. It would be easier, in my opinion, to add safelight light where needed, and not have to deal with stray light, than trying to reduce bounced or reflected light where not wanted. Viewing light also is easy to add.

If it is a dual purpose room, then the other use would rule this out. JMHO