"Migrations: A National Exhibition of African-American Printmakers," on view in the Gallery of Art at Howard University is a show full of promise, promise since fulfilled.

More than two years have passed since it was organized - at Howard - for a Latin American tour. It was then a good, strong survey exhibit, open-minded and moving. Today, its mood seems retrospective. It suggests, but does not show us, the blossoming that has since taken place in what one might call the new black art.

Washingtonians are lucky. We have in Howard University's College of Fine Arts an institution that has served as a major clearing house, and engine, for that intensifying movement. "Migrations" takes us back to early 1976, and includes work from the '60s. It shows us what African-American art was then, not what it has become.

Twenty-six black artists are represented here by 79 prints, woodcuts, silkscreens, lithographs, etchings and engravings. Among these works are many that we have seen before. Charles E. White, an "old master" of black art, is, for instance, represented by three prints from 1970.

The three strong and vibrantly colored silkscreens by Lloyd McNeil were printed here at Lou Stovall's Dupont Center Workshop in 1970 and 1971. Just as strong and poster-like, but more militant and blunter, are the prints of Barbara Jones-Hogu. She worked, in Chicago, with the group called Africobra. The spark struck in that city in the early '60s by "The Wall of Respect" has not been extinguished, but the torch has to a large degree passed to Washington since then.

The new black art is recent years has grown subtler and finer. Africobra often yelled. Today it seems to sing. The artists of the Howard school now take more from Africa, from its patterns, motifs, rhythms, than they do from Europe, but the energy derived from the rediscovery of Africa is not fully felt in the current show.

It is a print show, after all. When one sees an etching, an engraving or a lithograph one feels between the artist and the viewer that the very act of printmaking - the press, the plate the stone, and the traditions of the media - have been somehow interposed.

There is much within this show that conjures not just the black life of our nation, but the older art of Europe. "Sunlight and Shadow," Robert H. Blackburn's colored woodcut, with its hints of guitars and French cafes, might have been produced by an early cubist. In Nefertiti's three handsome linocuts one feels the reinforcement of Bauhaus Good Design.

But there is also much that is heartfelt and original. Look, for instance, at Valerie Maynard's image of an "Artist Trying to Put It All Down," at Percy Martin's "Bushman" etchings (they peer past the academy deep into the caves), at "Lobotomy I" by Carole M. Byard, at "Carryin' On" by Juanita Cribb, or at the strong and yet dissolving "Couples" by Bill Harris, who now teaches here at the Ellington School for the Arts.

There are artists here from St. Louis, New Orleans. Philadelphia, New York and California, but of the 26, 10 have worked at Howard. There is a current running through that school, a sense of common mission. It produced this exhibition.

No grants from the Endowments, or from the foundations, paid for "Migrations." Instead, five Howard men - Bill Harris, Winston Kennedy, Ed Love, Acklyn Lynch, and George Smith (most of them are teachers now, though some of them were students then) - put up the cash themselves and organized the show.

They had been invited to do so by the museum in Cali, Colombia. They gegan by calling friends, and acquaintances and selecting artists. Their choices were not ruled by one attitude or style. "We met once a week," says Kennedy. "We figured that if each week we solved one specific problem, we'd get the whole thing done."

The sort of thing has happened frequently at Howard. Art Department head Starmanda Bullock and the members of her faculty have somehow managed to arrange a whole series of exhibits, with catalogues and posters, thoughtful installations and freshly painted walls, and they have done so with a budget that would make most curators laugh.

The budget for the gallery at Howard is $5,000 a year.

Much larger sums than that are regularly spent here on one-room museum shows. "Migrations" comes to Washington from the National Gallery in Caracas. "Peasant Paintings from Hunsien County of the People's Republic of China," the exhibition that will follow, recently was seen at the Art Institute of Chicago. Howard manages to survive in these big leagues only because the faculty and students there design the posters (Winstons Kennedy did the one for "Migrations"), paint the walls, and hang the shows themselves.

They do all of us a service. "Migrations" was not meant to be a definitive exhibit. It is one part of a whole, one tile of a large mosiac. Howard's exhibitions, more than those of any other gallery I know, show us how these artists see their feelings, their community, America, the past, Africa, themselves. This exhibition closes on Sept. 23.