Geoffrey Ward had to cut away from watching a presidential news conference to talk to a reporter about “The Roosevelts: An Intimate History,” the new Ken Burns documentary series he wrote.

That brought Ward to a favorite theme: his conviction that neither Theodore nor Franklin D. Roosevelt could be elected president today. Teddy Roosevelt, with his shrill voice and penchant for outbursts, was “too hot” for the cool medium of television, he said, while “clearly, Franklin was a cripple,” paralyzed from the waist down after contracting polio in 1921, at 39, and today’s press “would compete to see who could find him most helpless.” Yet both succeeded, in part by skillful manipulation of their images in the news media of their eras, one of many threads the 14-hour series explores.

PBS stations will broadcast the sweeping documentary, which weaves together the lives of both presidents and first lady Eleanor Roosevelt into a family narrative, starting Sunday, in two-hour increments for seven straight nights. The entire series will stream on PBS member station websites beginning Monday.

The film starts with Theodore Roosevelt’s birth in 1858 and ends with the 1962 death of Eleanor, Theodore’s niece and Franklin’s wife (and fifth cousin). High-profile biographies of all three have been published in recent years, but viewers may not be aware of the “rather dramatic interfamily relationship between the three Roosevelts,” said David Woolner, a senior fellow and resident historian at the Roosevelt Institute and an adviser on the series. “There’s an interconnectedness that we just don’t really pause to think about.”

When it came to the presidents as media masters, the filmmakers found some 25,000 images from which to draw, Burns said, including one that purports to show Theodore Roosevelt (who led the nation from 1901 to 1909) capturing thieves out West. The incident was real, but the photograph was staged: Friends posed as the bad guys. And while Theodore built the White House’s first press room and loved to have cameras around, Ward said, no photos were unearthed of him playing his daily tennis match. He thought the game would make him look effete.

The documentary, Ward said, is also the “first systematic treatment on film” of all the efforts Franklin Roosevelt — president from 1933 to his death in 1945 — made to appear to walk. It took him seven years to perfect the move of swinging his body forward while holding onto someone’s arm. The man who used a wheelchair and couldn’t get to the bathroom on his own “made everyone believe he stood up to greet them,” Ward said. “He was an absolute magician.”

The modern view “is to see a kind of conspiracy on the part of Franklin Roosevelt to hide the fact that he had this disability from the public,” Woolner said.

But he added that the public was well aware of his polio. What the public didn’t know, he said, “was the extent of his disability.”

Political necessity required an image of strength and health while running for election as the country struggled with the Depression.

“If he were photographed looking helpless, people would not vote for him,” Ward said. “Pity was poison.”

The effort was aided by a complicit news media. While some photographs from Franklin’s first presidential campaign show aides snapping on his braces, that ended when he was elected, Ward said. He was an accessible president, holding 998 news conferences, but the press corps agreed not to photograph his struggle to walk.

Still, some images slipped through. Researchers turned up a clip of the president getting off a train in Bismarck, North Dakota, and an unused snippet from a newsreel when Franklin met Winston Churchill. The series was essentially completed when an eight-second clip surfaced showing him in braces, laboring to walk up a ramp at the 1937 Major League Baseball All-Star Game with the help of an aide. The filmmakers re-edited to insert the home-movie footage, which had been donated to the Pennsylvania Historical and Museum Commission.

The gap between image and reality is of particular interest to Ward, who had polio when he was a child and wears braces. Through his long collaboration with Burns — he wrote “Jazz,” “Baseball” “The War” and “Prohibition,” and was a writer of “The Civil War” — Ward has never gone on camera. But in this series, he appears as an expert, and when discussing Franklin in the fourth episode — much of which is devoted to Roosevelt’s polio struggle — he becomes emotional.

“Part of getting to know Franklin Delano Roosevelt is empathy,” Burns said.

Ward, who wrote the biography, “A First-Class Temperament: The Emergence of Franklin Roosevelt,” and, with Burns, the companion book for the series, said he wants viewers to understand that “this man triumphed, even though he couldn’t walk,” leading the country through the Depression and World War II, the two greatest crises of the 20th century.

“Thank God” his image was manipulated, Ward said. “He was perfectly capable of being president.”