In Poser 4 there are four color squares across the top of the materials editor: object, highlight, ambient, and reflective. These corespond to the P5 channels of Diffuse, Specular, Ambient, and Reflection. In the image above, there is the default (ambient at black and 0), ambient color channel set (as in P4), and ambient in P5 with a setting of two. The effect in the background can have it's core color changed simply by changing the ambient color channel. make any more sense?