I recently discovered the burn brush, though I don't know when a proper time to use it is. I keep buring my photos and I can't tell if I like the original(s) or the burned ones instead. It's only a 10% burn so it's minor differences. So far I've kept the burnt look for one photo, made it look smoother, more natural. But for the others I just can't tell one way or the other. So, when do you burn?