Why Super Heroes Wear Underwear on the Outside

According to previous DC Editor Comics Julius Schwartz, the custom matched the clothing used by circus performers and wrestlers of the time. Although not actually underwear, they wore shorts over tights or leggings. Since super heroes were gifted athletes, it seemed natural to dress them in the same way as the gifted performers. In addition, with early printing techniques being rather primitive by current standards, color changes or divisions at the waist, groin, feet, hands, and chest allow the characters to have certain attributes stand out.