Helen Frankenthaler, the pioneering American abstractionist, whose preferred technique of staining thinned paints into unprimed canvas became the hallmark of Color Field painting, died today at her home in Darien, Conn. She was 83.

Born to wealthy New Yorkers, Frankenthaler attended high school at New York's Dalton School (1945) and college at Bennington in Vermont, studying with Paul Feeley and graduating in 1949. In 1950 she met Clement Greenberg, and a five-year-long relationship with the influential New York critic ensued. Equally significant for the young artist was her friendship with the New York School poet and curator Frank O'Hara, whom she met in 1951 and remained close to until his death in 1966. Frankenthaler and O'Hara were among the brilliant artists and poets associated with Tibor de Nagy Gallery, directed in the 1950s by John Bernard Myers; she had her first solo show there in 1951. She was friends with all the major Abstract Expressionist painters, and in 1958 married Robert Motherwell. They divorced in 1971.

In 1952, following a trip to Nova Scotia, Frankenthaler produced her transformative painting Mountains and Sea (currently on extended loan to the National Gallery, Washington, D.C.) by applying thinned, delicately pigmented oils to unprimed canvas attached to the floor. She was not the first to use what she called a "soak-stain" technique, but artists prior to her had stained their canvases only selectively. Here, in combination with charcoal drawing, Frankenthaler deployed staining as her primary technique on a scale (the painting was 7-1/2 by 9 feet) that rivaled "first-generation" Abstract Expressionist colossi.

She notably departed from her predecessors, favoring an unfinished look, refined palette and overtly lyrical quality, as well as a fairly explicit conjuring of landscape elements. Morris Louis and Kenneth Noland saw Mountains and Sea in Frankenthaler's studio in 1953, and her stained canvases influenced them and other Color Field painters.

Frankenthaler disliked being identified as a "lady painter" (unlike Joan Mitchell, who used the sobriquet defiantly), though she was one of just a few female Abstract Expressionists to be critically noted from the start. She was given a retrospective at the Jewish Museum early on, in 1960, when O'Hara was still a curator there, and in 1969 at the Whitney Museum of American Art. A large exhibition of works on paper was mounted at the Solomon R. Guggenheim Museum in 1985, and in 1989 she had a retrospective at the Museum of Modern Art and the Modern Art Museum of Fort Worth.

She was also an important printmaker, experimenting first in lithography at Universal Limited Art Editions (ULAE) in 1961, but exploring all print mediums at one time or another. Her most significant contribution was in woodcut, in which she grew quite adventurous, particularly in her collaborations with master printer Ken Tyler, with whom she began working in 1976. Using porous handmade paper and numerous blocks, Frankenthaler conceived over a dozen large-scale woodcut projects in which a subtle, dreamy painterliness defies the inherently graphic nature of the medium. There was a traveling retrospective of her prints at the National Gallery of Art in 1993, and, in 2002, a survey of her 23 woodcut projects at the Yale University Art Gallery and Naples Museum of Art, in Florida.