Strictly speaking, the title of the Ellipse Arts Center’s theater design show, “It’s Only a Paper Moon,” is a misnomer. These days, it’s almost always a styrofoam moon.

Styrofoam columns, too. And picture frames, bricks, tables, arches, porticoes, gazebos, trees, and gravestones. Also cups.

“Same stuff,” says Jon Palmer Claridge, director of arts programming for Arlington County’s Cultural Affairs Division, holding up a standard-issue white foam coffee cup next to the word “Montague” carved in what seems a solid granite mausoleum slab hanging on a gallery wall. In Folger Theater’s Romeo and Juliet last season, this slab was part of a tomb that looked as immovable as the Lincoln Memorial. Even in the gallery’s fluorescent light and from a distance of 10 inches, the illusion of weight and solidity is persuasive.

“Four small pieces of double-stick tape,” smiles Claridge as he sips his drink. “That’s all that’s holding it to the wall.”

Sure enough, look closely and there’s one tiny, 16th-of-an-inch chip in the paint where the powder blue of insulation foam shows through. Available in wall-size sheets at Home Depot for $4.35, it’s the medium in which designer Tony Cisek makes his art.

John D. Antone favors plywood. That’s what he used to create what the gallery’s staff calls the “La-Z-Boy Crucifix” for Scena Theatre’s Too Much of a Prayer. At the gallery, it qualifies as an intriguing sculpture, but as a nearby photo illustrates, with a loincloth-clad actor on board it’s positively iconic.

A celebration of the increasingly sophisticated design work gracing the area’s professional stages, “It’s Only a Paper Moon” weaves a theatrical spell with hundreds of such items culled from 21 area theaters. Everything from preliminary doodles, colorful spec drawings, and exquisite scale models to actual props, costumes, and set pieces traces the evolution of a remarkable array of productions from concept to reality.

Duelling Uncle Vanyas bracket the gallery space, with a 10-foot-high wall from Jos. B. Musumeci Jr.’s Round House setting on the right of the entrance and a pair of Lindsay W. Davis’ sumptuous costumes for Arena’s mounting on the farthest wall to the left. Arrayed in between is a generous sampling of theatrical touchstones from the last few seasons: the metal-trimmed, deco-inspired throne from Washington Shakespeare Company’s Wall Street updating of Richard III, a belligerently phallic calla lily from Olney’s sexualized, white-on-white Importance of Being Earnest, and the no-longer-anatomically-correct wolf suit that got castrated by some timid troupe after the costume startled audiences in Signature Theatre’s Into the Woods.

Shakespeare Theatre’s Peer Gynt is represented not merely by the pendulous-breasted, warty-nosed Troll King costume Paul Tazewell designed for Ted Van Griethuysen but also by a pair of set models crafted with such attention to detail by Ming Cho Lee that it’s possible to see precisely what he thought the lighting scheme would look like. In all, the work contributed by some two dozen designers to more than 35 productions is represented.

Though the models, drawings, and props are all compelling objects in themselves, a good part of the exhibit’s appeal is its emphasis on process. Examining the price inventories accompanying James Kronzer’s swirling, attention-focusing set model for Studio Theatre’s Love! Valour! Compassion!, gallery visitors will discover that the designer went $3,000 over budget. And in a nearby spotlight, it’s possible to trace the evolution of a colorful quilt Anne Gibson crafted for the Theatre of the First Amendment’s kiddie show Tiger, Tiger, Tiger, from postage-stamp size in a set model to postcard-size in a design sketch to the real thing hanging on the wall.

There’s also the fact that, for once, it’s not necessary to sit through hours of drama to appreciate a designer’s brilliance. Grant the collaborative process its due, but frankly, Robin Stapley’s splendidly rusting freighter with a hole in its hull was so much the best thing about Washington Jewish Theatre’s otherwise execrable Berlin to Broadway With Kurt Weill that the chance to examine it in scale-model form, blessedly unaccompanied by singers, seems a real boon.CP

“It’s Only a Paper Moon” runs until May 9. See City List for details.