In the decades before the Roaring Twenties, nice girls didn’t wear makeup. But that changed when flappers began applying cosmetics that were meant to be noticed, a reaction to the subdued and feminine pre-war Victorian attitudes and styles typified by the classic Gibson girl.
Before the 1920s, makeup was a real pain to put on. It’s no wonder women kept it to a minimum. The tubes, brushes and compacts we take for granted today hadn’t yet been invented. Innovations in cosmetics in the ’20s made it much easier for women to experiment with new looks. And with the increasing popularity of movies, women could mimic the stars—like Joan Crawford, Mae Murray and Clara Bow, an American actress who epitomized the flapper’s spitfire attitude and heavily made-up appearance. Fun Smithsonian article linked from Miss Crawford above.