The other day I asked for technical questions regarding Photoshop or Manga Studio that I could answer. Here are a few! REMINDER: I’m no expert, there’s almost always more than one way to do things in these programs, I’m not claiming my way is the best, don’t complain, etc.
“what are masks for/are they useful in drawing and painting in photoshop?”
Masks are very useful! A mask is basically a grayscale alpha channel which determines the transparency of the layer it is attached to. For example, take this handsome drawing of popular cartoon character Beartato: