…that after a few fumbled attempts I was going to just give up? 
but you caught me, so I couldn’t.
I used “greater than”, because it didn’t come to me that if white is 1, it needs to be “less than”, and greater than works for black, I presume? I also felt like I didn’t really understand what I was doing with the nodes but then it suddenly came to me that I was only creating the mask while the math node was connected to the surface. New stuff, new stuff…
