Rich black (#010203) and Seal brown (#59260B) appear together across 6 master palettes in our corpus, most prominently in the work of José María Casado del Alisal, Tamara de Lempicka, and Charles Laval and the Academic Art tradition. Painters typically deployed rich black at an average of 42% of the canvas, with seal brown at 10%. Third colors most often completing the combination include Zinnwaldite brown (#2C1608), Dark sienna (#3C1414), and Saddle brown (#8B4513).