"Sam Francis: The Fifties," at the Phillips Collections here, is a little exhibition that may help right a wrong. It is about time that the early and audacious abstract paintings of Sam Francis get the credit they deserve.

Of the first-rate first generation abstract expressionists, Francis is the pioneer most regularly neglected. His paintings aren't at fault. The chalky-gray abstractions he made in 1950 are beautiful, original and early. The trouble with Sam Francis is that he was raised on the wrong coast and worked in the wrong town.

He did not know Arshile Gorky, did not write manifestoes, join the mural project of the WPA or spend the bitter war years discussing modern painting over mugs of coffee in Manhatan cafeterias.

Sam Francis was, instead, born in San Mateo, and spent his happy childhood in sunny California. When he moved toward abstract art, he did so on his own, on a special, painful path. And when at last he left his home to paint in the big city, he chose to go to Paris rather than New York. h

These factors work against him. They are not the right credentials for a charter membership in the so-called New York School.

Francis, too, was a few years younger than his famous New York peers, and in his wholly abstract pictures of the early '50s, there is a sweetness that their harsher pictures fight. The early paintings at the Phillips are not as harsh as those of Franz Kline or as blank as Barnett Newman's. They lack the shadowed anguish of so much New York art. In their loyalty to the traditions of fine brushwork and the scale of the easel, and in the airy warmth of their dappled light, they still seem partly French and partly Californian, and not at all New Yorky -- though perfectly in tune with the most advanced spirit of their time.

In the early 1950s, when de Kooning was still painting his scarifying women, when Kline was still a big character calligrapher, Sam Francis was already a pure color field painter. On the grounds of primacy alone, he deserves a high position in the story of post war abstract art.

In a sense it was the war itself that brought Francis to painting. In 1943, after two years at the University of California, Berkeley, Frances gave up college to join the U.S. Army Air Corps. The decision almost killed him. In 1943, the plane that he was flying on a training mission crashed. Francis was to spend the next four years on his back. It was while in the hospital, when given a set of watercolors as a form of occupational therapy, that he began to paint.

'Painting," he said later, "became a way back to life for me. Now it is no longer this, but a way of life. But those four years on my back it was life itself. I painted to stay alive."

And, perhaps to free himself from his own bedbound weight. There is in his art a sense of air, of rising, of swimming the very corpuscles of light. "I feel trapped by gravity," he's said. "I would like to fly to soar, to float like a cloud, but I am tied down to a place. No matter where I am, it's always the same. Painting is a way out."

Francis left the hospital in 1947. That year, in Carmel, he made his first abstract picture. It is true that by the date something of the New York avant garde had been brought to San Francisco.Hans Hofmann had taught at Berkeley in the 1930s; the two MacAgys, Jermaine and Douglas, both curators, had brought to California works by Gottlieb and by Pollack. Clyfford Still taught at Douglas Mae Agy's California School of Fine Arts between 1946 and 1950, and Mark Rothko spent two summers there. But still there is in the first abstractions of Sam Francis somthing that one finds in no one else's art.

In 1950, having finished college, Frances went to Paris. He would live and paint there for most of the decade.

The first works that he made there were gray as winter skies. By 1953 his painting had begun to grow both darker and more luminious, had begun to fill with palm-sized shreds of color, quanta of dark light much like those that seem to swim on the inside of your eyelids when, on summer afternoons, you lie dozing in the sun.

By the end of the 1950s, his colors had grown hotter, his fields had grown more open, he had begun predicting the pictures he would make in the next two decades.

Most of the 19 oils and watercolors at the Phillips were borrowed from the private collection of Robert Elkon, the New York dealer. The essay in the catalog was written by Diane W. Upright. It should be noted that the Phillips has now mounted two fine exhibits in a row. This one will close April 13.