Bistre (#3D2B1F) and Opal (#A8C3BC) appear together across 6 master palettes in our corpus, most prominently in the work of August Friedrich Schenck, Karel Breydel, and Károly Lotz and the Romanticism tradition. Painters typically deployed bistre at an average of 22% of the canvas, with opal at 15%. Third colors most often completing the combination include Eerie black (#1B1B1B), Pine green (#2A2F23), and Shadow (#8A795D).