Copper (#B87333) and Smoky black (#100C08) appear together across 6 master palettes in our corpus, most prominently in the work of M.C. Escher, Lyubov Popova, and Eduard Ender and the Romanticism tradition. Painters typically deployed copper at an average of 29% of the canvas, with smoky black at 18%. Third colors most often completing the combination include Bistre (#3D2B1F), Zinnwaldite brown (#2C1608), and Café noir (#4B3621).