With flat planes of rich, lovely color, Alex Katz’s landscapes and portraits evoke the smooth aesthetics of advertising billboards and film. The prolific artist is especially well known for his paintings of Ada, his wife and muse. Katz developed his signature style as a reaction against the Abstract Expressionism that dominated the mid–20th century, when he began painting. Instead, he embraced narrative, figurative clarity and the accessible pleasures of Pop art, though he remains untethered to any particular school or movement.