I've only read the first edition, but I'm a bit surprised to read that as I don't recall them assuming any knowledge, except maybe some basic geometry and vector math.
I think there has always been some assumption that you know a bit about raster images, and colour and compositing. I remember it being the type of thing that anybody who has been involved in graphics code probably already knows so well that it’s second nature, but I also know these are things not every programmer has internalised.
