It was an assistant to Zapruder, even more excited than the dressmaker was about seeing the President, who persuaded him to go back to his house and pick up his home-movie camera. The boss agreed. Although his camera was only a basic, 8mm affair, a wind-up manufactured by Bell & Howell, it would be nice to capture the President, in town, for his children and grandchildren to see in the years ahead.
And so it was that later that morning, as the motorcade was approaching down Elm Street, that Zapruder, with his assistant's help, balanced himself on a concrete block on a grassy bank, his movie camera at the ready. As the motorcade swung into the Plaza, Zapruder began to shoot his film. Aside from a brief moment when his view is obscured by a road sign, he succeeds in keeping the President perfectly in the camera's frame. The 60-year-old dressmaker was an amateur film-maker, but he had a steady hand.
Of course, Zapruder had set out to capture a bit of history. An immigrant from Russia, he was fiercely proud of his adopted town and this, he was sure, would be a great day indeed. How could he possibly have known that it was not just everyday history that he and his camera were about to witness?
The Zapruder film, just 26 seconds in length, was destined to become arguably the most precious stretch of celluloid exposed this century. Its value, first and foremost, was as the only live record of an event that tore the soul from the United States - the assassination of a popular President in the prime of his power and life. Its crudely juddering frames, in colour, but with no sound, were to soak deep into the consciousness and the popular culture of America for decades to come. It was also to become the object of fierce battles and controversy, not least as the principle source of encouragement for the conspiracy theorists. For years - and still today - those buffs would contest the finding of the Warren Commission in 1964 that the President was shot by a lone gunman, Lee Harvey Oswald, from the Book Depository.
And three-and-a-half decades later, the film would eventually come to pit the heirs of Zapruder (the dressmaker died of cancer in 1970) against the US government itself. That contest is being played out in Washington DC right now. At its heart is a question that would seem to be virtually unanswerable: how much is the film worth? What price can be put on such naked, essential history?
The fight began with a decision taken last year by an austere body of historians and archivists created by Congress in 1992, called the Assassination Records Review Board. Wound up at the end of this September, its task was to dig out and deliver to the public every nugget of material with some relevance to the Kennedy shooting, and which different government agencies had kept secret for so long.
The point of the exercise was to quell the suspicion that still lingered among the public, and which was rekindled by Oliver Stone's 1991 epic, JFK, that Washington was guilty of covering up the truth about the assassination. It was never expected to render its own judgement on what happened, but simply get as much of the evidence out into the open as was humanly possible.
One of the board's achievements was to declare the Zapruder film the property of the American people. Although the original footage had rested in cold storage in the National Archives since 1978, it still belonged to the Zapruder heirs, who were free to sell it to the highest bidder at any time. Kermit Hall, one of the board's members, is clear that appropriating the film for American posterity was the right thing to do. "If there was any single major contribution of the board, it was the public taking of the film, putting it for ever in the public domain, and not letting it end up as the trophy of some Saudi prince to be cut up and sold as pieces of a relic," he said. "It was among the hardest of the decisions, and the very best we made."
On that fateful morning in Dealey Plaza, Zapruder apparently understood at once what controversies lay ahead. As soon as the presidential limousine had passed out of sight beneath an overpass, with the President's head blown open and Jackie Kennedy lunging for help from the secret service agent riding on its rear fender, he told a reporter from the Dallas Morning News what he had filmed. The reporter then informed a secret service agent, and all three headed first to the newspaper and then to the local Kodak plant to have the film developed at once. Before the day's end, Zapruder had a lawyer draft a legal document forbidding government investigators from making additional copies and allowing them to leak out.
The next morning, on 23 November, he sold the still photograph rights, and then the rights to the moving pictures themselves, to Life magazine for $150,000. In making his decision, he told the editor from Life who had contacted him, Richard Stolley, that he had already had a dream. In it, he was walking through Times Square when he was accosted by a barker extolling passers-by to step inside a sleazy cinema to watch on the big screen as the President's brains spurted out on his car's upholstery.
When Zapruder later watched his own work at the Warren Commission, he wept. "The thing would come every night," he said of his by-then recurring nightmare. "I wake and see this." After splashing frames of the sequence across its pages, first in black and white and then in colour (though not the frame when the President's head actually explodes), Life kept hold of the film, as it had pledged to Zapruder. It released it only to the Warren Commission and, years later, once more when Clay Shaw was tried in New Orleans - and eventually acquitted - for acting as a co-conspirator.
In 1975, however, after a grainy bootleg version was aired on an ABC television talk show hosted by Geraldo Rivera, Life began to feel the burden of its responsibility. Three years later, it sold the film back to the family for $1m. For so many years, the Zapruder footage had remained essentially hidden from the public. The Rivera showing was the first time the full sequence had been given general exposure.
It was probably only with the release of Oliver Stone's JFK, however, that large sections of the American public saw what Zapruder had captured. Mr Stone, whose mission was to debunk the Warren Commission and re-ignite the theories of government conspiracy, paid the family $40,000 for the few snippets in the film.
In the meantime, however, Zapruder's work had become a frame of reference for contemporary American culture. It had spelled out for the first time the extraordinary and entirely compelling power of photographic footage as the only medium capable of showing what is real and true. It informed countless other feature movies, such as Antonioni's Blow-Up (1966), in which a London photographer develops and manipulates photographic footage to discover evidence that he had missed in reality.
And it prefigured the culture of "live TV" that has become so central to our television society today. The most iconic news stories of our time are nowadays almost always defined by those live moments caught on film; the more grainy, the more compelling. We have the single protester before the tanks in Peking in 1989; the helicopter-eye's view of OJ Simpson fleeing police in his white Ford Bronco; the security-camera images of James Bulger being led away by the hand in a shopping centre. We have no footage of Clinton and Lewinsky, but the commercial videotape of the interrogation of the President by Ken Starr and his assistants was one of this summer's home rental bestsellers.
There was, however, another runaway seller in the video stores this summer. It was called Images of an Assassination, and tells how the Zapruder family essentially managed to get the jump on the government before it was finally forced to surrender its precious film. Late last year, Zapruder's heirs hired a firm of photographic specialists to make a new, digitally enhanced copy of those 26 seconds. A firm called MPI then transferred the results to video for general sale to the public. The result is devastating to watch and managed to spark a whole new controversy about the film. Arguments are still
raging as to whether it is proper for the film, which from 1 August became the official property of the nation, to be distributed so freely to the public. Editorial writers and historians squealed that the family - with a 20 per cent royalty on sales of the video - had committed a gross crime of commercial indecency. At the very least, they said, it was an affront to the Kennedy family, for whom the assassination is still a matter of deeply private pain.
The video, in all its new, digital glory, is indeed unspeakably shocking. While the first 40 minutes are dedicated to some already well-known history and tedious descriptions of the technical wizardry that was employed to clean up the original footage, the showing at the end of those 26 seconds will leave any viewer feeling completely numb. You are treated to six different versions, some in slow-motion and the last two with the frame zoomed close into the head of the President. So close that when the second bullet strikes the skull, his brains explode forward like a mass of pink hamburger meat. You may also be tempted to join up with the conspiracists: that second bullet very obviously seemed to come from the front, and not from the rear, of the Depository Building.
As to how much the Zapruder heirs should be compensated by the government for surrendering ownership of the film, a settlement is still not reached. The family started the negotiation with this figure: $18.5m. Not a modest sum for a flickering 26 seconds taken by a man briefly out of his office for what was essentially a coffee break. The US Justice Department was unimpressed. Its counter-offer was for $750,000, which it then reluctantly increased to $3 million. A stalemate has since ensued.
It will be next June before we know the final sale price. Last month, both sides agreed to the establishment of a panel of arbitrators. This will consist of three wise men, one chosen by the Zapruder heirs, another by the government, and the third by the first two. Two other conditions were agreed. Although the film will belong to the nation, copyright will still remain with the family. Thus it will stand, in order to control any commercial use of the film or any attempt to take money for it. And a ceiling was set on whatever sum is finally agreed - of $30m.
"Who cares how much it costs?" asked John Newman, who is a history professor at the University of Maryland and one of the leading experts on the assassination. "As history, it is like the Enola Gay, the B29 bomber that dropped the first atomic bomb on Hiroshima. A whole generation of people, and their psyches, have been affected by that film, which they've seen over and over again."
About that, the professor is not wrong.