Northern Virginia artist James Dean never thought his watercolor of a poinsettia would be reproduced 750 million times.

But that's what happened when Dean's painting was selected from almost 5,000 others to be the U.S. Postal Service's official 1985 Christmas stamp, now on sale at post offices around the country.

"It's mind-boggling. I wish I had signed it," said Dean, who has lived in Annandale for 29 years.

Painting a stamp was a radical departure for Dean, who specializes in large, airy watercolors of weathered barns, breezy seascapes and the rustic Maine coast.

"The difficult thing about stamp painting is whatever you paint you have to be able to read it in almost microscopic size. It requires a lot of advance careful planning," Dean said. "I never did anything to be reduced down to postage stamp size."

Jack Williams, manager of stamp design for the U.S. Postal Service, said the special stamps have been issued since 1963 "in response to requests from customers for something Christmasy to use on their Christmas mail."

Each year, Williams said, the 19-member citizen stamp advisory committee receives thousands of suggestions and renderings from artists for its annual contemporary holiday stamp and its traditional stamp, which has a religious theme. He said the final stamp of approval rests with U.S. Postmaster General Paul N. Carlin.

Williams said the committee, which is selected by the postmaster general, judges entries for brightness, reproduction quality and seasonal spirit. "The ultimate criterion is whether it will look good on an envelope," he said. "Dean's poinsettias looked most promising in terms of producing a color stamp. It was so traditionally Christmas . . . it was so bright."

The Postal Service paid Dean $1,500 to copy his stamp three-quarters of a billion times. But Dean, 53, considered the money more an honorarium than an artist's commission.

"It's a great privilege to design and paint a stamp," Dean said, looking out over the Potomac River from his studio in Alexandria's Torpedo Factory Art Center."I also did the background painting for the Statue of Liberty stamp issued this summer. I'm just getting into this stamp thing."

Dean said he repainted the poinsettia four times before the stamp advisory committee would agree to the current green and red design. "The difficult thing about stamp painting is whatever you paint you have to be able to read it in almost microscopic size." James Dean "The final painting took a couple of days to get most of it done and another week of looking at it to put in the finishing touches. I've kind of had it with red and green," he said.

As the founding director of the National Aeronautics and Space Administration's fine arts program, Dean has been practicing his craft for almost 30 years. From 1974 to 1980, he was curator of art at the Smithsonian's National Air and Space Museum, and his portfolio is filled with vibrant watercolors of space shuttle launchings in Florida and shuttle landings in the California desert. In addition to his artistic activities, Dean runs six miles a day and has participated in the Marine Corps, Boston and New York marathons.

Williams said the Postal Service, which now owns the copyright to the stamp design, will store Dean's original poinsettia painting in its archives. He said that the post office orders enough Christmas stamps to meet the anticipated demand and that he expects the 750 million issues of Dean's design to sell out by the time next year's stamp is printed.