On April 22, 1935, a tourist from New York named Fred Hill waded through the crowd at the White House Easter Egg Roll, pointed his movie camera at the South Portico and captured seven seconds of history.

As Hill filmed, President Franklin D. Roosevelt, who had been disabled by polio 14 years before, emerged and — with the help of a cane and his bodyguard — walked unsteadily to wave to the crowd.

Walking was something Roosevelt did with great difficulty. He looked awkward and vulnerable, and he was rarely filmed doing so.

On Wednesday, the Franklin D. Roosevelt Presidential Library and Museum unveiled the newly acquired Hill footage, which it says offers a fresh, remarkably clear glimpse into one of the great secrets of FDR’s public life.