During the 1960s, Frankenthaler moved away from her use of drips and splatters of paint toward larger single stains and blots. In 1963 she began using acrylic paint as opposed to turpentine-thinned oil, resulting in the expansion of form and the production of bolder, more saturated colors. Canyon of 1965, painted in acrylic, exemplifies Frankenthaler's paintings of the 1960s as it flows out from a boldly colored center, in this case red. The painting takes advantage of the fluid nature of acrylic paint, which floods laterally across the surface of a canvas to create a hard, defined edge rather than a soft, blotted edge as in the thinned oil paint she used in her earlier work. Frankenthaler was attracted to the more saturated and intense effects of acrylic paint and the color relationships she could produce using this medium.
Although Canyon, with its large red field surrounded by a sea of blue-green, might seem nonrepresentational, Frankenthaler's work conveys her immediate response to nature; her ideas are expressed in large color shapes and in the ways the hues act on each other. Frankenthaler has left visible only a small area of the bare canvas, in the upper edge of the painting, as she wishes to emphasize the play of color on color rather than color on canvas. By 1965, the year Canyon was produced, cropping played a significant role in Frankenthaler's process; she allowed cropping to shape the canvas, emphasizing the abstract quality of the composition.