>>7618909 (OP)Yes it's accurate, not photorealistic but as accurate as it needs to be. Don't worry about the names of things either, halftone/midtone/middle gray/midvalue/middletone/medium/whatever it's the same thing. For cel shading it's still "accurate" cel shading just strips off most of the parts and doesn't soften transitions between the values. If you want accurate lighting that looks flat check out this page from 3DTotal's Color & Light, it explains how to construct each band of tones around the sphere accurately, just don't blend them and you have a nice setup for cel shading.