Helen Frankenthaler's large, atmospheric paintings have a poetic sense of color and shape. During the early 1950's, inspired by Jackson Pollock's technique of "action painting," Frankenthaler began to paint on unprimed canvas spread on the floor. Although Frankenthaler has continued to refine this technique, she abandoned oil paint in the early 1960's and turned to acrylic paint, which gave her a bolder palette. Her new medium also allowed her to further explore the tension between chance and control in her art. In Sagittarius, rich shades of magenta, ultramarine and deep green complement one another and bleed together where they overlap.