Chemical patination demonstrated by Andrew Lacey (British, b. 1969) on a replica casting of a lion relief after Antoine-Louis Barye (French, 1795–1875) at an October 2018 CAST:ING workshop on patination and gilding at the Laboratoire de Recherche des Monuments Historiques (LRMH), Champs sur Marne, France. To start, Lacey simultaneously heats the bronze relief while gradually applying a solution of potassium polysulfide to create a dark-black background color on the bronze. Next, a layer of ferric nitrate serves to build a brown undertone. This is followed by a green textured layer by stippling copper nitrate solution over the surface at a slightly lower temperature. The final image shows the relief with two different finishes—the left-hand side had hot wax applied to the surface, while the right-hand side was waxed cold—demonstrating how the type of wax application at the final stage can radically alter the appearance of a patina.