Here is another reason bump maps are superior. You cannot do this with a normal map. The information is encoded differently.

A bump map does not specify changes in brightness. It specifies changes in height from the original un-bumpy polygon.

Here I used the bump map not only to alter the normals, but also to alter the colors and the specularity.

Again, you cannot do this with a normal map.

---

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)