Quote - I just drive the Displacement directly from a 2D Image Node and it works, it gives me both positive and negative displacement even without a math node

This is classic misdirection of the self. You demonstrated visual relativity.

Clear your mind of assumptions, close your eyes and imagine the following. (After you read it first, of course)

You are in a temple with magical floor tiles that can move up, but not down, from their natural position. You figure out the magical controls and you raise all the tiles in the temple up two feet, except for the center tile. The center tile you only raise up one foot.

Now you photograph this and you show others that you have moved a subset of the tiles and ask them to tell you which tile(s) were moved and in what direction. Who among them would not tell you that you lowered the middle tile? Yet, in fact, you raised that one and all the others as well.

---

Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)