Ms. Frankenthaler was best known for developing an innovative technique in which she poured diluted paint directly on the canvas, creating washes of color that flowed with the illusion of movement and depth.
Called “stain painting” or “soak stain,” her method helped push the bold, aggressive abstract expressionist art of the 1940s toward a new level of subtlety and beauty.
Ms. Frankenthaler was only 23 when she painted “Mountains and Sea,” a landmark work in the history of modern art. In the early 1950s, she had visited the studio of Jackson Pollock, the leading abstract expressionist, and had come away mesmerized by the way he dripped paint onto canvases lying on the floor.
“It was original, and it was beautiful,” she told the New York Times magazine in 1989, “and it was new, and it was saying the most that could be said in painting up to that point — and it really drew me in.”
Emulating Pollock’s style, Ms. Frankenthaler set a large canvas, 7 by 10 feet, on the floor of her New York studio one day in 1952. She deliberately left it untreated, without a preliminary coat of priming.
Thinning her oil paint to a watery consistency with turpentine, she poured shades of blue, pink, green and gold onto the canvas from coffee cans. The paint soaked into the woven fabric like a wine stain spreading into a tablecloth.
She had not sketched any patterns or images, but as Ms. Frankenthaler stood back from the painting, it reminded her of the rocky coast of Nova Scotia, which she had recently visited. She called the painting “Mountains and Sea.”
“Because her method is intuitive, her pictures flirt with failure,” Washington Post art critic Paul Richard wrote in 1975. “She pours, she looks, she pours again. . . . The color seems to move, to billow. Her outlines grow from inside out.”
In 1953, two D.C. painters, Morris Louis and Kenneth Noland, were invited to Ms. Frankenthaler’s studio by her lover at the time, the powerful critic Clement Greenberg. The artists were so struck by the painting, in which the color and surface blended into one, that they returned to Washington with a new vision.
They made the manipulation of color the focus of their art and soon launched what became known as the Washington Color School or, more broadly, “color-field” painting.
“She showed us the way to think about and use color,” Noland later said.
Although she was considered a charter member of the color-field school, Ms. Frankenthaler resisted artistic labels. She was one of the foremost female artists of her time, yet had little interest in being part of the feminist movement.
In the 1960s, she switched from oils to acrylics and began to use sponges, brushes and squeegees to spread paint across the surface. She made important advances in printmaking, tapestries and woodcuts. In almost all of her work, she followed a private aesthetic vision that valued a soft beauty that was often at odds with the bravura, more aggressive styles followed by many male artists.
“What concerns me when I work,’’ she told the Times in 1989, “is not whether the picture is a landscape, or whether it’s pastoral, or whether somebody will see a sunset in it. What concerns me is — did I make a beautiful picture?’’
Helen Frankenthaler was born Dec. 12, 1928, in New York City and was the daughter of a judge. She attended private schools and graduated in 1949 from Bennington College in Vermont.
She came back to New York to paint and immediately drew the attention of Greenberg, who introduced her to major artists, including Pollock, Lee Krasner, Willem de Kooning and Franz Kline.
In 1958, Ms. Frankenthaler married Robert Motherwell, another key figure in abstract expressionism. They were divorced in 1971.
Survivors include her husband of 17 years, Stephen M. DuBrul Jr., and two stepdaughters.
Ms. Frankenthaler had retrospectives at many major museums throughout her career, including at the Museum of Modern Art in New York and Washington’s Corcoran Gallery of Art and National Gallery of Art. In 1975, she made a long-term loan of “Mountains and Sea” to the National Gallery, which has 28 of her works in its collection.
Ms. Frankenthaler had a patrician, often aloof manner and seldom liked to cast light on the creative energies behind her work.
Many of her paintings suggested imaginary landscapes, with a latent undercurrent of emotion, but Ms. Frankenthaler insisted that her central interest was simply putting paint on canvas in an interesting way.
“Painting is very private and personal,” she told The Post in 1972. “There’s an emotional content, but I’m more involved in the light and color and drawing of a painting. I don’t set out to portray an emotion.”