Formal and imposing, the portrait photographs of American Presidents are arrayed across Harris & Ewing's doorway: Theodore Roosevelt, William Howard Taft, Woodrow Wilson, Warren G. Harding, Calvin Coolige . . .

Harris & Ewing - photographers of the powerful, the rich and then eminent for 72 years - had captured them all in dignified poses worthy of their stature.

Yesterday, the photo studio, once frequented by Presidents, Supreme Court justices and many other notables, closed, the victim of the financial collapse of its New York-based parent company, American Photograph Corp.

But Harris & Ewing's era had already begun of fade. Its prominent place in the world of photography during the first part of the century was gradually whittled away by the growth of wirephoto services run by news agencies, government photo staffs, television and increasing publication of spot - or candid - photos, rather than formal portraits.

Harris & Ewing's reputation was for formal, elegantly finished portraiture - almost a point of honor among some of its employees.

Bryant R. Baker, the studio's general manager, pointed proudly toward the array of photographs of American Presidents over the entranceway one day las month. "They're not holding a dog's ears and running around," he said. "Those up there - they put out a public image of strength and the father of the country."

"Through the years," Baker added, "we've photographed every President from Roosevelt - Theodore Roosevelt - up to now. We don't have Carter, but we have a painting of him." A portrait of President Carter - not an original Harris & Ewing photograph - was displayed in the studio's window.

Harris & Ewing, most recently located at 1304 G St. NW, was opened here Feb. 17, 1905, by George W. Harris, a protrait photographer who died in 1964. His business partner was Martha Ewing, who doubled as photo colorist and receptionist for the studio. Mrs. Ewing sold out her interest in the firm in 1915 and moved to California.

Though Harris & Ewing has remained a profitable business, its parent corporation has not, according to officials in both firms. American Photograph Corp. executives say the corporation is going out of business because of overall financial losses and refusal of a Minneapolis bank to renew a substantial loan.

James A. Leidich, American Photograph's president, said yesterday that negotiations to sell Harris & Ewing to a prospective buyer had fallen through. "There is nothing pending at this point," Leidich said, adding that Harris & Ewing was forced to close. Its lease also expired Monday, officials said.

Over the years, the executives say, many of Harris & Ewing's historic photographs have been given to the Library of Congress and the National Archives. Others were recently turned over to a dealer in historic photographs in Chicago, they said.

Harris himself, according to his own and others' accounts of his career, drew tremendous satisfaction both from photography and from meeting famous men and women.

"Even though I'm retired now," Harris wrote in The Rotarian magazine in 1955, "I sometimes pick up a camera just for the fun of it. And I can still feel a measure of excitment when I think of the imposing parade of people - soldiers, royalty, actors, politicians, all of them - whose famous features I've helped record."

Theodore Roosevelt was his first important photo subject, Harris noted in an anecdote he often recalled. Summoned to the White House to make what he believed was the first photo of an American Cabinet in session, Harris hesitated because the room was small and poorly lit. "I don't know if I can," Harris told Roosevelt.

"That's no kind of an answer," the President replied, according to Harris' account. "When anybody asks you if you can do anything in photography, tell them, 'Certainly, I can,' Then find a way to do it." Harris said he took the photos and adopted Roosevelt's words as his own motto.

Harris first opened his firm here at 1311 F St. NW, then moved in 1924 to a more luxurious headquarters next door at 1313 F St. NW, where President Coolidge became the first man to be photographed, according to Harris' account. The business, those familiar with it say, grew to include 120 employees, five photo studios and a news photo service, which was shut down in 1956.

As Harris recounted his photographs of famous people, he would mention candid shots of Taft learning from Roosevelt by telephone that he had been nominated for president.

He would recall British Prime Minister David Lloyd George and King Edward VIII. He photographed Alexander Graham Bell and Cordell Hull. His favorite portrait photographer, Harris once wrote, "doesn't belong to a king or a president, but to a poet - Edwin Markham."