Quote - It would do that if you went into any math channel, including Bump itself.

The point of the subtract is to offset it so the most common mid-gray value becomes neutral. But here the subtract is of 0, doing nothing at all - nada, zip - useless node.

From a guy who says every polygon must have a purpose - this node must go.

Yeah, okay, I see. I did know that those channels didn't see the color... or should have remembered that more clearly, I guess

So the subtract would be relevant though, if an offset value was required, to make a neutrallly calibrated bump or displacement map, I take it?

If an offset was required though... how to tell, or measure what value it should be??