Lovettsville artist Pierre Mion has been summoned once again to depict two of Washington's historic buildings for the Postal Service.

Mion, who last year painted the first picture cards the Postal Service has issued, has produced two more paintings for what is to be the third card in the series. The card, which honors two buildings owned by the Daughters of the American Revolution, will go on sale next Thursday.

The card is the product of a determined lobbying campaign by one of Washington's most venerable organizations. For almost eight years, the DAR lobbied the Postal Service for a commemorative stamp to mark its 100th anniversary.

In the process, the Postal Service went through five postmasters general, but members of the DAR persisted. The group's successive presidents-general went toe-to-toe to speak with each postmaster general, never relenting on the DAR's case for a stamp.

Thursday morning, the DAR will get its payoff. It won't be the commemorative stamp its leaders wanted, but it will be one of Mion's picture postcards and it will be issued during the organization's centennial celebration.

Because "fraternal organizations" are not supposed to qualify for stamps under the Postal Service's criteria, postal officials point out that the card will not be issued to honor the DAR, but rather two of its buildings in the District, which occupy a block near the White House.

Both the DAR's 88-year-old Memorial Continental Hall, which faces 17th Street NW and, in the same block, the 4,000-seat Constitution Hall, which faces 18th Street NW, are saluted on the cards.

Both buildings have been designated National Historic Landmarks by the Interior Department and are honored in a postcard series that pays tribute to historic buildings.

Blair House, the presidential guest house on Pennsylvania Avenue, and Georgetown University's Healy Hall previously were part of the series.

Mion painted the Blair House card, as well as the stamp that celebrated Virginia's 200th anniversary as a commonwealth.

He also did picture postal cards saluting the White House and the Jefferson Memorial, the first two of what the Postal Service calls its "Extraordinary View Cards."

As part of a new marketing ploy designed to bid for a share of Washington's tourist trade, the picture postcards come complete with an imprinted stamp.

The Government Printing Office has printed 3 million of the DAR cards, which will sell for 50 cents each, about the price of most picture postcards with stamps.

One side of the new card features Mion's painting of Memorial Continental Hall, built in 1902 for $50,277. The other side shows a smaller painting of Constitution Hall in the card's stamp area.

The cards will go on sale Thursday in ceremonies in the DAR Museum Gallery, 1776 D St. NW.

The 10:30 a.m. dedication, open to the public, will be part of a weeklong DAR celebration.

The organization, which now has 200,000 members in more than 3,000 chapters, has weathered considerable controversy in its first century.

Perhaps no event provoked as much controversy as its 1939 decision to deny famed contralto Marian Anderson, who is black, use of Constitution Hall on the grounds that "all dates were taken."

The furor that erupted led Eleanor Roosevelt to quit the organization, and the incident raised questions about the organization's commitment to minorities, which troubled the DAR for years.

Anderson later sang in the hall but not until years after she came to Washington and held a protest concert on the steps of the Lincoln Memorial.

The DAR, chartered by Congress as the counterpart to the Sons of the Revolution, subsequently admitted blacks, provided they could prove they were descended from a colonial patriot or someone who fought in the Revolutionary War. The same requirements apply to white applicants.

The DAR since has published four books on black patriots and one of its genealogists spends most of her time tracing the families of black patriots, said public relations director Jane Miles Hemphill.