Christopher Romano

Emission should do it. Put a principled or glow shader on them, turn on emission or "emission illuminates objects" in principled, and they should light up the ground plane. If that works, then there's something in your code.

Maybe you need to crank your emission up by a factor of 100 and see if that makes a difference.

So your material is reading the texture from the Rocks_Wetmap null, I presume?

I have two silly questions...

First, if you bypass the null, but still point your material to it, does it work properly in your material? And second, if you add another operator after the null, like a brightness cop or whatever, does the information pass through as expect?