YS252 "an evocation based veil, for example, is often done as a block, but what it blocks isn’t damage, it’s perception" Going off what what's read in the rules saying that veils are spirit only seems to be very stupid and unbalanced. If I'm GMing a game, and you use some element to bend light, that makes sense, then yea it's perfectly fine. Your aeromancer says he's going to change the refractive index of the air around him, yea go ahead. You're going to use fire to heat up the air around you, I might make you hurt yourself more if you fail the control. As for earth magic, since it's domain is electromagnetism, hell yea you can say the light just doesn't reflect off of you, making you invisible. And I don't see a way for water magic to do it that isn't very dangerous for yourself.