There are several controls for each Surface: Transparency, (transmittance, attenuation) emission, reflection (ambient, diffuse, shininess), specular and corresponding alpha channels under textures. I find nothing in GS material that explains how these work. I mostly know how to get by in adjusting these settings, but is there other documentation that explains? I may have missed GS documents, but it seems odd if there is no mention of these anywhere.
Todd Oeftger AC25 Mac MacBook Pro 15", 2019, 2.3 GHz i9, 32GB, Radeon Pro 560X 4GB, 500GB SSD, 32" Samsung Display (2560x1440)