Word of warning to anyone thinking about watching: it's just plain WEIRD and the animation's quite bad in S1. Then in S2 and S3 the animation's better. Still weird writing for the whole thing.
I think that's being unnecessarily fancy and I'm just here to cut monsters up. All attempts at random artsiness are going to go over my head because there's no chance I'll read that deeply into it. :T
As side characters that tend to drop entirely out of focus. Especially when the magical cast gets large enough to justify it.
... though the first one that comes to mind where that doesn't has everyone in the know, and of the 'normal people', one is a ninja who can run on water and another can punch an explosion. Because he watches a lot of action movies.
And I don't think brightness would matter so much. Maybe resolution and zoom. But brightness wouldn't compensate for a lack of contrast against a dark background.