AutomatonBrass

Polished warm brass — the surface of everything on an automaton that is alive and working: plinths, chests, heads, wings, shoulders. Fully metallic and low roughness, so it takes a hard specular highlight and reads as a worked, oiled part rather than a painted one.

Also carried by the brass slivers half-eaten inside a blight's crust, which is what makes the rust read as corrosion growing over the machine.