Artists may be notoriously difficult to organize, but there are two groups among them -- the women and the blacks -- who seem to have the knack.

More than 500 members of the National Conference of Artists -- a group of black artists, art teachers, scholars and collectors -- will be meeting here this week. "We are now prepared," they claim, "to formally and seriously enter the areas of politics and economics." Mayor Marion Barry, President Jimmy Carter, and two dozen local galleries have responded to their call.

The Mayor has declared this "African-American Visual Artists Week." The President this afternoon will be the host at a White House reception for some 300 members of the NCA. And in honor of these artists, local galleries that range from the Miya to the Corcoran, from Smith-Mason to the Art Barn, will place their works on view.

The National Conference of Artists was founded 22 years ago at Atlanta University. Though artists who are taught to be original do not find it easy to march in step with one another, and though promoting art may not be the highest of priorities in the black community, the NCA today has considerable clout.

Governmental organizations -- the National Endowment for the Arts, the D.C. Commission on the Arts and Humanities -- helped pay for the conference at the International Inn. Officials from the Equal Employment Opportunity Commission, the Metropolitan Museum of Art, local governments and colleges will meet there to discuss such subjects as "Arts Management and Accounting," "Alternative Spaces," "The History of African-American Arts Movements in the 20th Century," "Government Support for the Arts" and "The Black Artists' Political Role in Society."

Of the exhibitions now on view, none is more impressive than the small invitational at the Corcoran Gallery of Art. The show honors 10 elder black artists -- sculptor Richmond Barthe, and painters Romare Bearden, Margaret Burroughs, Ernest Crichlow, Lois Mailou Jones, Jacob Lawrence, Archibald J. Motley, James L. Wells, Hale Woodruff, and the late Charles White.

Many of these artists deal with the scenes and the concerns of the black community; many deal with abstraction; some -- Bearden, Lawrence, and the young Charles White, whose work from 1942 is in part a self-portrait, in part an abstraction in the cubist mode -- do both things at once.

The Corcoran's invitational was organized by Barbara A. Hudson. "These artists since the 1930s have been virtually unknown," she says."Their accomplishments are apparent. They're coming out now, and it's time. They deserve to be seen." Her exhibition at the Corcoran closes April 6.