For starters, you should understand that magick isn't like what it is portrayed as by the media and pop culture. It isn't like Harry Potter, where you can snap your fingers, and Boom! Whatever you want appears before your eyes. It is subtle in its workings and merely influences the world around it, not controls.
As for black and white magick, this is only my opinion, they do not exist in essence. They are simply labels given to more complex things, as the world is not just black and white. It is a variety of colors that the average human eye can observe.