Copper (#B87333) and Russian violet (#32174D) appear together across 6 master palettes in our corpus, most prominently in the work of Egon Schiele and the Expressionism tradition. Painters typically deployed copper at an average of 12% of the canvas, with russian violet at 1%. Third colors most often completing the combination include Zinnwaldite brown (#2C1608), Rust (#B7410E), and Rich black (#010203).