Can paper be massive? Can steel be delicate?

Yes, if they're in the hands of Janos Enyedi, a local artist who deftly manages such apparent contradictions in "Images of Industry," a masterful exhibit now on view at the Athenaeum, 201 Prince St., Alexandria.

Enyedi builds -- of paper -- meticulous architectural models of factories, warehouses and loading docks. He also is displaying welded-steel sculpture. His nostalgic evocation of a childhood surrounded by Chicago's industrial architecture might seem anachronistic -- more reminiscent of the industry-admiring period of Carl Sandburg than of the era of Three Mile Island -- the appearance and presence of his Anthony Caro-like Constructivist sculptures displayed beside his architectural models gives his exhibition a spirit distinctly modernist.

Beautiful craft is critical to the success of this work. His impeccable constructions of hand-folded and hand-cast paper, basswood and welded steel make their points through the skillful manipulation of visual paradoxes. Industrial grime and smoke are represented by antiseptically clean, intricately folded paper models elegantly boxed in Plexiglas.

Scale subtly serves these apparent contradictions: Though his Cubist welded-steel sculptures suggest the massiveness of industrial forms, they turn out to be less than three feet high.

The net results are cool, jewel-like objects, that exquisitely conjure up their opposite: the gritty, the heavy, the chaotically energetic. His show closes Feb. 23. Robert Cwiok's Envelopes

Craft is also an important element of Robert Cwiok's art. Cwiok is a local artist. His show at the Arlington Arts Center, 3550 Wilson Blvd., offers numerous conceptual permutations on the motif of the envelope. His constructions, drawings and paintings flit between form and symbol, existing sometimes as abstract investigations of geometry and color, sometimes as aide-me'moires or anthropomorphic evocations (envelope flap equals extended tongue), and sometimes as metaphors (envelopes as transmitters and/or receptors of information).

Taken individually, many of these works are handsome and thoughtful pieces. But when seen collectively, the artist's ideas are overwhelmed, and these eventually repetitive objects become exercises in cleverness rather than examples of his stated interest in exploring "the dualism between art and illusion." 40 Artists' Photography

Also at the Arlington Arts Center is a group show of mixed-media photography called "The Altered Image."

The 52 works are indeed "altered," for, as curator Allen Appel says, the 40 local artists represented "scratch their negatives, airbrush them, and set them on fire. They cut up their prints, color them, scribble on them, paint them, Xerox them, and drive over them with their cars."

The motivation behind this sadism, automative and otherwise, is probably as varied as the number of artists in the show. Many undoubtedly subscribe to that school of photographic thought which holds that the illusion of reality inherent in photography is a barrier to a deeper, perhaps more metaphysical, reality.

Such a belief -- generally held by people unhappy with art made by a machine -- might be thought avant-garde, but it is an impulse as old as photography itself. In fact, the genesis of modernist photography came in reaction against Pictorialism, that 19th-century movement in photography in which the machine art of the camera was made more tractable by manipulating photographic materials until they resembled watercolors and paintings.

One thing we learn from this uneven, but almost always interesting show is that "altered" images are not necessarily enhanced images. Generally speaking, if it was a good photograph before being hand-colored or made into a Xerox transfer it remained a good photograph despite the alteration. G. Michelle Van Parys' "Darn It, Another Dollar Gone," a fine photograph that shows a '40s woman ruefully examining a run in her stocking, remains a fine photograph, no matter how enhanced. In a few rarer cases, however, images are improved by their transformations: One by Stephen Bohrer has definitely become more pensive and intense by his combination of several portraits into a collage. And Margaret Paris and Ruth Schilling gave otherwise banal black-and-white landscapes subtle notes of nausea and even horror by the addition of not-so-subtle day-glo colors.

And then there are a number of works that simply didn't exist before their alterations. For example, I liked Terry Gips' crazy-quilt collage of a beach house combined with words. The image, besides being an effectively vertiginous design, gave the effect of a nonstop, slightly schizoid conversation lasting an entire weekend.

Both shows at the Arlington Arts Center close Feb. 14.