#1 DON'T USE BACKPALS ANYMORE!!!!
You have access to something that is far greater and that is seteffect. Backpals are nasty...and the reason you see distorted color is because the tileset has a differing color palette than what the backpals have....if you want to use the horrid things, then make palettes based on your tilesets instead of using the defaul graal ones...or just simply not use custom tilesets
