20th
“Here’s the thing about purple and magenta. They are neither/nor colors. They are neither hot nor cold. And in a comic book, what you want with color is to use hot colors that pop out of cool colors, which recede back. Purple is both red and blue, and magenta is a very cold red. Green sometimes falls into this as well, because it’s blue and yellow. That’s why in the Golden Age and Silver Age, heroes wear blue, yellow, and red. The bad guys wear purple and green. Superman: Blue, red, yellow. Lex Luthor: Purple and green. The Hulk is an exception, but he’s an anti-hero. He was never originally supposed to be a real hero; he started out as more of a monster. Hawkeye wears purple, originally a villain. Madame Medusa wears purple, originally a villain.” (via Colleen Coover Talks ‘Girl Comics,’ Superhero Anatomy & Hating Purple [Interview] - ComicsAlliance | Comics culture, news, humor, commentary, and reviews)