Blanche avoided films until she saw the brilliance of the movie The Informer (1935). Stage star Alla Nazimova was indirectly responsible for her getting the role of Madame DeFarge in A Tale of Two Cities (1935). They had never met but when the part was offered to the silent screen star, she felt it was not right for her and told them the only person she thought could play the part was Blanche. Blanche was the 67th and last actress to test for the part.
Other than her third feature film,A Tale of Two Cities (1935), she remained noticeably unhappy with her character film career. She suffered major disappointments in the loss of certain Oscar-winning roles, including The Good Earth (1937), which ended up starring Luise Rainer, and the supporting turn by Katina Paxinou in For Whom the Bell Tolls (1943).