Thank you, bagginsbill. You've made me use parts of my brain that haven't been exercised since my calculus classes! Still, your explanations are so clear and thorough that I was able to follow your lines of thought, and now I have a better understanding of how the Material Room works.

I wondered about the purpose of the two-color Specular Blender on the Diffuse node. Now that it simulates subsurface scattering, I will have to give it a try.

Also, I was just thinking about doing an ocean scene, so I found your discussion about World space coordinates for water textures particularly interesting.

Finally, what is your Matmatic program, and where can I find it? It sounds most interesting.

RJ