Between the dark and the daylight, the specters appeared on the sidewalks of Washington.

By dawn yesterday, the ghastly, ghostly white outlines were all over Connecticut Avenue, Georgetown, Capitol Hill, Bethesda, Pennsylvania Avenue, McPherson Square. Yesterday was the 40th anniversary of the devastation of Hiroshima by nuclear bomb, and these were the shadows of that day, the reminder of lives vanished in smoke.

The outline of a man with bare feet and a briefcase. The profile of a dancing couple. A child holding on to a doll for dear life, or death. A fish tank. Babies. Birds. People in motion. Cats and dogs sprawled.

As the first commuters were mired in traffic, drivers and passengers looked out at the strange, blurry, whitewashed drawings. To some, they looked like the sketches police make after road accidents. Not many knew what they were, but they were far too chilling to be mistaken for children's drawings or advertisements for some new thing.

By lunchtime, the white outlines had become a dirty gray and smudged and feathered.

Mamie Small walked gingerly on the figures that filled the sidewalks just north of Dupont Circle. "What are they?" she asked her friend Jean Nicolazzo.

She asked the right person.

"I was up all night painting them," said Nicolazzo. "They're shadows -- shadows of Hiroshima."

"Today is the 40th birthday of the bomb," said Dave MacAuley, near an antinuclear demonstration in Dupont Circle park. "We painted the shadows all the way from Fifth and E streets to 14th and E." Jane Lidsky worked with him. They wore matching T-shirts that said, "Animals are not ours to eat, wear, or experiment on." His jeans were worn through at the knees. "We really didn't have much trouble. The police did make us move away from the FBI sidewalk. This is a crucial time. People need to know what happened."

Georgianna Rathbun, one of the organizers, said the International Shadow Project, as it is called, was sponsored by the Portland, Ore., Performers and Artists for Nuclear Disarmament. "We have confirmed projects in 41 states and more communities than I can count. Here we had 144 painters and assorted volunteers."

Jeff Robinson, a legal assistant in an environmental law firm, was up all night with a group of lawyers poised to defend any painter who was arrested. "Insofar as I know, no one was arrested," he said when he finally woke up yesterday afternoon at 4. "I believe everyone has checked in by now. A few were hassled by the police -- told to move on. But no one was pulled in."

Added Robinson, "It all started with a picture -- a picture of a shadow left by a person consumed by the bomb. Within 300 meters of ground zero, people were vaporized, leaving just a dark spot where they'd been. A soldier coming down a ladder from a lookout. A person taking off his shirt. I found the thought of those shadows very moving."

Darryl Rogers was a zone leader on Dupont Circle with Sheila Rotner. "We divided the area into five zones with 20 painters. They were supposed to paint the figures and put up leaflets saying what it was all about. And stencil 'Hiroshima 1945 -- Washington ?' on the sidewalk."

By lunchtime, the leaflets were hard to come by.

"I think it was a worthwhile experience," Rogers said. "Some people don't even know that the bomb dropped on innocent people. We need to educate the people so it won't happen again."

"I didn't know what the white figures were," said Reginald Jackson, walking down Connecticut near Dupont Circle with David Knarr. "Until we saw the peace demonstration in the park, and then I thought, 'It must be a reminder of the Hiroshima bomb, 40 years ago.' "

"I don't understand it, I'm afraid," said one woman, who went quickly on.

"Don't step on the people," said a passer-by.