Rivulets of black, green, blue, and mauve paint skirt this vast stretch of white canvas. Morris Louis created the painting by leaning a large, unprimed canvas against a wall and pouring diluted paint onto the surface. Rather than using a brush to manipulate the paint, he tilted and pleated the canvas to direct the flow, allowing the paint to seep into the raw canvas. (With a primed canvas, the paint would have remained on the surface, separate from the weave.) The result is a lyrical composition that focuses on the purity of the artist’s materials and eliminates the expressive gestures seen in abstract expressionism.