"I couldn't imagine a more ideal showcase for works of art in glass than this crystal tower with its constantly changing light," writes Elena Canavier, director of the Public Art Trust, referring to the glass-sheathed atrium of the Washington Square building and the exhibition, "Translucid Sculpture," currently installed therein.

The exhibition's title is perhaps too limiting -- the selection mixes crafts pieces, sculptures, pictorial works, architectonic conceptions and objects that fall somewhere in between these often amorphous boundaries -- but in any case the setting and the works do complement one another.

In morning sunlight, shards of rainbow colors cast by the prisms in Rockne Krebs' "Deco Palm" enliven the surfaces inside architect Chloethiel Woodard Smith's atrium at Connecticut Avenue and L streets NW, where the show will remain on view through May 17. Throughout the day visitors can enjoy interesting views of the outside world by peeking through pieces assembled on pedestals alongside the atrium's glass panes at balcony level.

Among the more decorative utilitarian objects is a bowl, by Michael D. Jones, whose flowing form is imbedded with a luscious green color. Among the more outlandishly nonuseful pieces is an accretion of richly colored blown-glass parts by Lawrence D. Huff, a work that looks like a lamp, could perhaps be misused as a vase, and most definitely is a surreal free-standing still life composition that spoofs good taste.

Predictably there are a number of jewel-like blocks of glass in the exhibition, by far the more successful of which is "Rose," an elegant and perfectly contained investigation of inner space conducted by Czech artist Jaroslav Svoboda. Other artists using the solidity and transparency of glass or plastic to expose interesting contrasts between interior and exterior space are David Schwarz, who employs the curvature of an ovoid block to transform the linear markings on its surface, and Emile Benes Brzezinski, who shows us the markings of birch trees from the inside out.

Of artists who use glass to, more or less, paint or draw a picture, the most ingenious is perhaps Juan A. Mayer, who incorporates sheet glass into a tautly balanced abstract drawing on the wall rather than, as he says, "relegating glass to the role of protection for the drawing underneath it." In the works by Doug Anderson and Dan Dailey, perfection of craft and narrative wit are married with seeming effortlessness.

Pieces that demonstrate to what superb ornamental and/or symbolic uses glass can be put in buildings -- and also remind us how infrequently this occurs (an ironic reminder in a building that uses so much unadorned glass) -- include a leaded glass construction by Sal Fiorito, two wonderfully expressive relief molds of figures by Kent Ipsen, and a set of carved plexiglass panels by Robert Bassler.

Artists working in more purely sculptural ways to explore the spatial ambiguities of glass or plastic include Krebs, with his prism tree and an earlier piece, "Shop Flower" (1969-77), made of jutting planes of transparent plastic; V.V. Rankine, with her totemlike "buildings"; Douglas Navarra, with his weighty pyramid construction; and Tom Butter, with his spiky abstract constructions made of colored fiberglass and resin. Lou Stovall's Silk-Screens-----

"Master Prints from Lou Stovall's Workshop," a compact exhibition on view through May 25 at the Kathleen Ewing Gallery, 1609 Connecticut Ave. NW, is two things. Above all it is a tribute to Stovall's great skill and his widely respected, fanatic dedication to the art and craft of silk-screen printmaking. And it also is a little trip down memory lane. Stovall's Workshop was created in 1968, and early on he attracted many of the best and brightest artists in Washington, of older and younger generations, to experiment and learn with him.

The silk-screen process, with its superb registration and the stunning transparency of its thin layers of color, was perfectly adapted to the hard-edge concepts of the city's color painters. Thus, among the finest works on view are early ones by Paul Reed and Gene Davis. But Stovall quickly moved to push the known boundaries of the medium, so that another early print, "Victory," by Jeff Donaldson, in addition to being an affecting portrait of an aging couple, is a tour de force of stencil cutting: Literally hundreds of separate, interconnected and overlaid marks of color are visible in the print.

In his own familiar, circular landscape images, Stovall successfully explored effects not customarily associated with silk-screening -- hundreds of meticulous engraving-like lines in the grasses or rocks or trees, for instance, or richly textured cloudy skies. But challenges set by painters have stimulated his greatest feats: the subtle whites on whites in the Sidney Guberman print, the thick opacity of forms in the Sam Gilliam, the luminous glow of colors and tactile surfaces in the Jacob Kainen. To this day Stovall seems unwilling to concede there is an effect he cannot reproduce through the diaphanous screens.