At least I think it's the same effect in both of these examples ... it's used in BSG when they're on nuked-and-occupied Caprica, and in Buffy when she has those desert visions of the First Slayer.
I've never watched an episode of Buffy, but the BSG scenes just looked deliberately overexposed to me. Either in the raw footage or by boosting the exposure/brightness levels during the edit. Probably to imply that Caprica had been nuked and was therefore "hot."
Yeah it’s just overexposed and yellowed in post. As for the name, I’ve heard it called the Breaking Bad Effect or Mexicoizing. That’s for the BSG scenes. (See also: Star Trek Nemesis) They might have done a little of that for Buffy, but I think that’s something different. It looks to me like SMG was shot under different lighting and composited in, but those screenshots don’t have the matte lines I’d expect for that era. Maybe they actually shot on site but gave her really careful shade and diffusion.
It gained popularity after Soderbergh's wretched movie Traffic where all the scenes shot in Mexico (or what was supposed to be Mexico) have a sepia/yellowish tint to them. Damned near everybody has used in the years since. I think that the first time it was really used to show a post-apocalyptic landscape was really fucked was in The Day After TV movie from the 80s but I could be wrong.
