Clement A. Wells Jr.'s public debut as a musician was a leap onto the stage at a mid-1940s SRO matinee at the Howard Theater. The seemingly audacious act was actually at the invitation of his friend Lionel Hampton, who handed his mallets to Wells and stood aside while the 16-year-old took a turn at the vibraphone.

Ever since, vibraphonist and vocalist Wells has been a presence on the D.C. jazz scene.

That he is also a familiar presence in international circles of philately is known to only a few of the many who have enjoyed his unique musical skills. And fewer still are aware of this Armstrong High School graduate's talents as a needlepoint portraitist, an art he combines with his interest in stamps. In celebration of Black History Month, the Black Studies Division of the Martin Luther King Memorial Library is sponsoring an exhibit of Wells' needlepoint portraits of American blacks who have appeared on postage stamps here and abroad. The display will be in the G Street window of the library through February. In the library's main lobby at noon tomorrow, Wells will give a slide lecture, "A Tribute to American Jazz Musicians on Postage Stamps," followed by a concert featuring his vibes and compositions by some of the jazz artists depicted on the stamps, including Miles Davis, John Coltrane and Duke Ellington.

Pointing to a large sheet of graph paper on his living room coffee table and then to a needlepoint mesh canvas on his lap, Wells explains how he makes his portraits: "I take a photo, a color slide, of the image on the stamp and then I project it on this graph paper, make a rough outline, and then I block it in.

"Then I paint the canvas -- I'm using acrylic -- and then I do the needlepoint," says Wells, pointing alternately to graph and mesh. "Like here I do seven squares and then I mark it off and block it in, then I paint these lines. See, like here, I paint these too and then I block those in." Wells says that to complete a portrait takes about two months of working three or four hours a day. "It's a tedious process," he admits. "But it's the method I use."

Wells' interest in stamps had its genesis in the collection his father gave to him when he was a youngster. The stamps were put aside for years and then, "after my father passed away, I thought it would be nice to start a collection in remembrance of him." That was about 20 years ago, and today, with more than 100,000 stamps, Wells is in touch with collectors all over the world and is regarded by the U.S. Postal Service as the leading authority on blacks on postage stamps. Wells' needlepoint, which he took up in the mid-1970s, has been on display at the Bureau of Engraving, Howard University's Moorland-Spingarn Research Center and area churches. His month-long show at the King Library includes portraits of King, poet Paul Dunbar, abolitionist Harriet Tubman, vocalists Ella Fitzgerald and band leader Count Basie.

More American blacks are honored on stamps than blacks from any other country, Wells says. But only 15 or so U.S. stamps honor American blacks The unkindest cut of all for students of jazz is that only Scott Joplin, W.C. Handy and the forthcoming Duke Ellington stamp represent the idiom on U.S. stamps, while the Republic of Congo has an entire series in homage of American jazz artists. But when this indigenous Afro-American art form gets its due one day on U.S. postage, be sure that Clement Wells will be at the head of the line for first-day issues.