You wouldn’t think it possible, but a new show of paintings by William A. Newman manages to convey, in just about a dozen works, how he became such a universally admired instructor—maybe the most popular professor of art in the city’s history. “Syzygy,” as the title suggests, is an academically inclined exhibit, a feat of intellectual gymnastics and thorny propositions. Yet it is also accessible, gentle, and even spiritual—qualities, perhaps, that have contributed to his enormous following over more than four decades of teaching.

Newman, who retired this year from the Corcoran College of Art + Design, where he had been a professor of painting since 1973, is a realist painter. But he is bound by few of the conventions that tend to limit Washington painters working in that medium. In “Syzygy,” painting is a means to an end, an investigation that includes photography and sculpture. Newman has never let his technical skill as a painter stand alone as the reason for his work, an easy trap for prodigious painters.

For each of the works in “Syzygy,” Newman combines a painting of an orb-shaped object with a photograph roughly double its size. Newman is squaring the circle in a literal sense here: His compositions depict a sphere bound within a broader plane. He is also swapping respective properties that we traditionally associate with paintings and photographs. At this large scale, Newman’s photographic prints look fuzzy in comparison with his paintings.

“Syzygy” refers to the alignment of celestial spheres—typically, the sun, moon, and Earth. Several of Newman’s orbs are highly realistic depictions of images given to him by NASA for a 2001 mural, a Corcoran project that made its way to Merritt Elementary School in Northeast. Newman’s paintings include several more terrestrial orbs: There is “Saturn on Yellowstone” and “Lunar Eclipse on Trees,” but also “Orange on Grand Canyon” and “Tennis Ball on Great Falls/Potomac River” (all made between 2006 and 2013).

It’s somewhat surprising to find such harmony in Newman’s work. “Cherry on Honeybee Hive” is an explicit reference to past work: Newman, who was diagnosed with chronic progressive multiple sclerosis in 1979, once entertained regular beestings at a time when bee venom was thought to be therapeutic for MS patients. But the natural resonances in “Syzygy” are unexpected for reasons having nothing to do with the disease: The muralist has always been known for his sarcastic bent. In 1975, he erected a mural of a nearly nude Corcoran student at a construction site, a painterly thirst trap for the workers there, earning him the rebuke of the National Organization for Women; in 1984, when he painted an oversized mural of Ronald Reagan with the legend “five minutes” (as in, five minutes till we bombs the Soviets), the Army ultimately showed up and tore down that wall.

The paintings on display at the American University Museum all find their source in Newman’s relationship with nature, but they are as challenging as they are contemplative. At the center of the exhibit are two sculptural works: “Tzimtzum (Void into which the light of existence was poured)” (2010–11) and “Ourobouros” (2010–11). The former appears to take the shape of a tomato or pear; the other might be a distorted green bean or serrano pepper. Both of them were composed digitally and executed in stainless steel (with the help of an assistant based in China). With these sculptures, Newman is tapping into elemental divides: He depicts nature, though it is distorted; he creates something by hand, intimately in a sense, then outsources the manufacturing.

The sculptures especially remind me of the central metaphor in The Golden Bough, the great comparative study on mythology by James George Frazer. He took the title for his study from a passage in The Aeneid, in which Aeneas must procure a golden bough—a dead but living thing—for his passage into Hades. That work has always been a touchstone for me. To see Newman grappling with these themes so manifestly helps me to understand what his students see in him.

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