Sam Gilliam's first taste of success came in the late 1960s with his drape paintings, which brought the Washington Color School's raw, stained abstract canvases literally out of their frames and off the wall. Back then, they were colorful, innovative, spectacular and very now.

In our now, they're beautiful, still-spectacular specters that seem to haunt every Gilliam exhibition. Attend the opening of one of his shows and you'll often encounter someone, usually a person who was young, hip and high in 1969, saying his latest work is nice, but the drape paintings, they were really great, you know?

I don't. The implication is that Gilliam, Washington's best-known artist, a man whose works are in major museums across the United States and Europe, peaked with the drapes and his subsequent work hasn't quite measured up.

People can provide several arguments supporting that conclusion. His collages and constructions, like those currently on display at Marsha Mateyka Gallery, strike some as unfocused, diffuse and packed with too many diverse elements: references to European, American, African and Asian art, rubbery materials, piano hinges, push pins, plywood. The inspiration seems borrowed, synthesized. Not like the drape paintings. They were original.

It is a puzzling attitude and it's wrong. Which isn't to belittle the drape paintings. When I was a student at Oberlin College in 1973, the Allen Memorial Art Museum acquired a Gilliam painting that was draped over a sawhorse. It's a beautiful artwork, colorful, soft and lyrical but with tensile strength, a simple idea with complex visual and intellectual overtones, the kind of work that resonates for a long time.

The same thing can be said of Gilliam's new work at Mateyka. But the resonance is different. To use a musical metaphor, the chord structures, key changes and rhythms are more complex, in some cases bordering on chaos. There's an awful lot going on in some of these pieces, particularly the collages. But the music is coming from the same place that produced the drapes. A clear, logical line connects the old work to the new.

Gilliam has pursued the notion of making three-dimensional paintings since early in his career. That's why he created the drape paintings and brought the picture into the viewer's space. Before he abandoned the frame and the wall, he was a gifted and thoughtful colorist, like Morris Louis, Kenneth Noland, Gene Davis and the other Washington Color School artists.

It was inevitable that his quest for 3-D would lead him toward sculpture and that the presence of the object would occasionally obscure some of its painterly qualities. But the changes are not that great. The birch plywood and piano hinges of a piece like "Summer," in which Gilliam succeeds in painting every hue of a Washington summer day on a few panels, create a flexible surface that extends into the room. Think of the wood as canvas and the hinge as both a grommet and a fold in that fabric. Sound familiar?

Despite their physical limitations, some of the plywood pieces are metaphorically richer than some drape paintings. "Along the Canal," for example, is a modest-size piece, about 3 feet high and 2 feet wide, made from four birch plywood panels painted with acrylic. The top panel is shaped like a half-moon. Beneath it is a rectangular panel, with two smaller panels attached to its sides, forming wings. When closed, they obscure the underlying panel.

The lovely mix of colors--scarlet, lemon, magenta, brown and blue, to name a few--suggests an autumn day on the banks of the C&O Canal. When the side panels are open, the work seems like a medieval altarpiece devoted to Washington's natural glories. Close them and it's a pure abstraction, geometric shapes and fields of barely modulated color. That's a quick trip through art history in a small package.

Some of Gilliam's plywood paintings in the past few years haven't had as much condensed power as his new works. But not all of the drapes were kickers, either. Few artists produce an unbroken string of masterpieces.

His collages, made from pieces of paintings stuck together with push pins, have also been uneven at times. Some seemed overly whimsical, others forced. At times, it seemed he was going in an unpromising direction.

That isn't the case with the new collages. They are like cubist African kimono sculptures. They have the flow and formal presence of the Japanese garment, the fractured planes of a Braque painting, the vivid colors of West African art and structural and compositional elements drawn from European, American and West African sculpture. All that in three dimensions, encased in a glass box.

Is it a synthesis? Absolutely. That's what makes Gilliam a great artist. He's a master synthesizer, following his own path but constantly absorbing influences and turning them into something fresh, unique and compelling. Unlike some artists who've had relatively early success, he's had the courage to keep exploring. And he didn't let the drape paintings become a product or a trap.

"I realized how much they meant and I realized I had to lose them," Gilliam says. "The drape painting was only thinking. The roots of that thinking are in what I do now. You have to ask yourself what kind of artist you want to be. I had to get out on a limb and then decide how I wanted to get back. You have to constantly challenge yourself to find inspiration and to learn how to work. That's the most important thing."

Sam Gilliam, at Marsha Mateyka Gallery, 2012 R St. NW, Wednesday-Saturday, 11 a.m.-5 p.m., 202-328-0088, through Nov. 15.

CAPTION: Sam Gilliam's three-dimensional painting "Room of Lovely Symbols" at Marsha Mateyka Gallery.

CAPTION: Gilliam's "Along the Canal," whose plywood panels open and close, suggests an autumn day on the C&O Canal.