Copper (#B87333) and Straw (#E4D96F) appear together across 6 master palettes in our corpus, most prominently in the work of Otto Gustav Carlsund, Aleksander Gierymski, and Mary Cassatt and the Concrete Art (Concretism) tradition. Painters typically deployed copper at an average of 34% of the canvas, with straw at 5%. Third colors most often completing the combination include Laurel green (#A9BA9D), Gold Fusion (#85754E), and Light French beige (#C8AD7F).