Lots of gamma ;o Well, that's part of it, the other is using variations in a way to make it possible to 'paint in.' It only took me the better part of a year to fully understand, and I'm still finding out new ways to use it!
I think this style is my favorite one to use; texture is one of my favorite things to explore in abstract fractals, and I really love how it turned out here. Calling it "Van Gogh-ish" is a nice compliment as well; I find a fascination with the way he uses brushstrokes in his paintings. Thanks for the nice comment!