Like so many dichotomies, the black/white magick one collapses if you scratch too deeply. But, from my vantage black magicks/sorcery involves predation, fear, and ego. It's often materialistic and narcissistic. On the other hand, white magic usually manifests as nurturing, expansive, and dissipative. Perhaps it's all in my head, but I generally find it very easy to distinguish which form of practice magicians prefer. I find that it affects their ... for lack of a better term, presence.