(b New York, 12 Dec. 1928). American painter, an important figure in the transition from Abstract Expressionism to Colour Field Painting. In her early work she was influenced by Jackson Pollock and she developed his drip technique by pouring and running very thin paint—like washes of watercolour—onto canvases laid on the floor. She first used this method in Mountains and Sea (1952, the Helen Frankenthaler Foundation’s collection, on loan to NG, Washington), which is regarded as one of the seminal works of post-war American painting. It particularly impressed Morris Louis and Kenneth Noland when they saw it in her studio in 1953. In 1962 Frankenthaler switched from oil to acrylic paint, which allowed her to achieve more richly saturated colour.