Graham resisted requests for her dances to be recorded because she believed that live performances should only exist on stage as they are experienced. There were a few notable exceptions. For example, in addition to her collaboration with Sunami in the 1920s, she also worked on a limited basis with still photographers Imogen Cunningham in the 1930s, and Barbara Morgan in the 1940s. Graham considered Philippe Halsman's photographs of "Dark Meadow" the most complete photographic record of any of her dances. Halsman also photographed in the 1940s "Letter to the World", "Cave of the Heart", "Night Journey" and "Every Soul is a Circus". In later years her thinking on the matter evolved and others convinced her to let them recreate some of what was lost. In 1952 Graham allowed taping of her meeting and cultural exchange with famed deafblind author, activist and lecturer Helen Keller, who, after a visit to one of Graham's company rehearsals became a close friend and supporter. Graham was inspired by Keller's joy from and interpretation of dance, utilizing her body to feel the vibration of drums and of feet and movement moving the air around her.