There’s a whole subgenre of these high-contrast works in Porter’s late style, but my favorites are pieces like “Untitled (View Outside Southampton Studio)” (1968) and “Amherst Campus No. The effect is to re-create not the trees but the flow of the painter’s own aesthetic experience. A painting obtained reality just by transmitting the artist’s own “kinetic and visual sense of the world,” Porter wrote. The painter Larry Rivers described Porter’s portrait of him as “flat and rather empty,” and that applies to pretty much all of them. The only portrait in the exhibition with a spark is “Jimmy and John” (1957-58), of the poets James Schuyler and John Ashbery.