Even at 98, the Brooklyn-born artist Alex Katz shows no signs of slowing down. When he was young and studying at the Cooper Union, he focused on modern art and was taught to paint from drawings. “Most painters, when they get older, they get worse. And the real good ones get better,” Katz said in 2015. “And this is like, my stab at saying, ‘I got better.’” The artist’s solo exhibition at the Gladstone contains some of his most aggressively ambitious works yet: 11 very large paintings dominated by a bright orange hue and inspired by the road that leads to his summer house in Maine. Katz refrains from preemptively labeling the works as paintings, drawings, or studies. They are instead products of his own authentic style. —Maggie Turner