> Quote - just a note: the step node can give you a really simple threshold function. if you want pure, hard edges, step is definitely what you should try.

grabs the manual
Why yes! With a Step node, Value2 is the diffuse light threshold value.
Much simpler - thanks!

(Note: Step gives an inverted output compared to Round, so swap over the two Blender inputs).

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)