“The Brushstroke plays a big part in the history of art,” the American artist Roy Lichtenstein said in 1991. “In my hands, the brushstroke becomes a depiction of grand gesture.” In other words, the brushstroke is the story. “The Loaded Brush” focuses on a period in Lichtenstein’s career—the 1980s—when he experimented with the painted stroke. Included is Artemis and Acteon (1987), exhibited in Europe for the first time. —J.V.