When "JFK" was released in 1991, Oliver Stone talked excitedly about the great speed of the film -- the enormous number of cuts, yanking the viewer back and forth between Technicolor and grainy black-and-white, between clips of actual news footage and purely imaginary scenes (with only the most fragile roots in reality).

"It is like splinters to the brain," the director enthused. "We were assaulting the senses in a kind of new-wave technology. We wanted to get to the subconscious." Stone's vision of himself as tribal shaman (blowing the public mind with stroboscopelike editing, rewriting history with lightning flashes of imagery) sounds quite a bit like the poems Jim Morrison wrote while in film school, before joining the Doors:

Cinema is the most totalitarian of the arts. All
energy and sensation are sucked up into the skull,
a cerebral erection, skull bloated with blood ...

-- and so forth. These very '60s-ish notions found their ideal expression in Stone's telling of the assassination of John F. Kennedy. For if you assume that film reaches down into primitive and concealed layers of the psyche, you can't find a better subject than the most archetypal of rituals, the killing of the king.

That event is shown repeatedly (minus the trippy overtones) in a newly released videotape, "Image of an Assassination." Of all the evidence concerning the Kennedy assassination -- running to more than 17,000 printed pages of the Warren Commission hearings -- the Zapruder film exerts the greatest fascination. With a hand-held camera, Abraham Zapruder recorded the presidential motorcade during the crucial moments before, during and after the sniper fire. Those 26 seconds of film have been searched endlessly for clues. They offer the promise of almost direct access to the moment of truth. In an analysis of the film published by the American Journal of Physics in 1976, Nobel Prize-winning scientist Luis Alvarez gave the most concise statement of what researchers have always believed about the testimony of Zapruder's camera: "It doesn't have the normal human failings."

The images themselves -- the waving president and first lady, Kennedy's grab at his throat, the cloud of blood hanging in the air, Jackie's lunge across the back of the limousine just before it speeds away -- have burned the film into the collective memory in a way no auteur could imagine. And Stone, for one, acknowledged that fact, indirectly. The Zapruder footage, as he told an interviewer, formed the "core" of his docudrama. He interrupted the movie's speed-freak pacing long enough to show the Zapruder record "frame by frame, detail by detail, again and again. To see the president's head blown off in this way hits you in the gut, at the subconscious level. It is the moment in every movie theater where there is a collective gasp by the audience."

The new video presents a digitally processed edition of the original, now held at the National Archives. Most of the scratches and dust have been cleaned up using computer techniques. And the transfer incorporates a strip of film (now filling the left quarter of the screen) never visible during previous showings of the footage. A documentary, running a little more than a half hour, traces the history of the Zapruder footage and the details of the digitization process. Then follows six showings of the film itself, at various speeds, with different kinds of focus.

The cover box is tasteless ("Includes a never-before-seen version of President Kennedy's assassination! A collector's item for all Americans!"). But it's no overstatement to say that watching the digitized version is like seeing the Zapruder film anew. The color, resolution and additional detail are unlike anything available before. And thereby hangs a tale. For if the Zapruder film left its mark on the national memory over the past 35 years, it got there most often through bootleg copies, circulated mainly by conspiracy theorists. When Life magazine reproduced a number of stills from the Zapruder footage just after the assassination, the publisher decided that Americans should be spared the trauma of viewing its most grisly images. He purchased all rights to the film and withdrew it from public circulation for the next several years. (In 1975 the rights were returned to the Zapruder estate, which then deposited it at the Archives.) But while sequestered, the film began its underground existence. Volume 18 of the unabridged Warren Commission Report included frames from the crucial sequence, and some enterprising soul managed to put together a crude re-animation of the black-and-white reproductions. Another researcher, allowed to watch the Zapruder film in the Life archives, surreptitiously filmed the images off the screen using a hand-held camera of his own. (These details are omitted from the new video.) In the late 1960s, the Zapruder film was subpoenaed during the trial of Clay Shaw -- a Louisiana businessman accused by Jim Garrison (the hero of Stone's docudrama) of organizing the Kennedy assassination. Garrison never proved much of anything, except, perhaps, that New Orleans is a very strange place; but his legacy to the world of assassinology was enormous. While the Zapruder film was in his possession, Garrison tended to mention its whereabouts to others involved in studying the events in Dallas. If someone decided to run off a copy when he stepped out of his office, what could he do about it? Not much! More than 100 "Garrison bootlegs" thereby got into circulation. And from them, other boots were made. The turning point came in 1975, when the footage was shown to a national television audience for the first time. The occasion was a late-night talk show hosted by Geraldo Rivera. An excerpt from the program is included on the new video, which is in its own way a slice of broadcasting history. The youthful Geraldo, wearing lapels as big as his head, gives off an almost electric charge of countercultural fervor. His guests include a JFK assassination researcher, who narrates as his own Zapruder bootleg runs, filling the television screen. It is not as muddy as some copies in circulation at the time, but should give today's viewer a sense of the improvements in visibility with the digitized version. The crucial moment is what conspiracy theorists know, with a certain morbidly affectionate familiarity, as "Z-313" -- that is, frame 313, in which the president's brains get blown out, and his head snaps backwards. Thus proving (as Geraldo's guest says, and many have repeated) that there must have been a marksman firing from somewhere in front of the motorcade, probably at the "grassy knoll" in Dealey Plaza; otherwise, if the fatal bullet had come from the School Book Depository, behind Kennedy, his head would have fallen forward. That interpretation is in fact very much open to dispute. The nerves and muscles in the human body make it respond to force in ways somewhat more complex than a sack of potatoes. But the television audience is not concerned with nuances. Everyone in the studio gasps. Geraldo says, "That was heavy." And cut to a commercial break. In the intervening decades, the images have grown more familiar, if not less powerful. After watching those 26 seconds more times than I can count, the impact of Z-313 is still visceral. And within the milieu of JFK assassination investigators, a shift in attitude is evident. For years, the Zapruder footage was a fabled object, rare and virtually unobtainable. Studying the film closely might reveal the truth about what happened in Dallas. It was the closest thing to being there. But now the aura has worn away. The theory has lately been argued -- at great length and in microscopic detail -- that the Zapruder film has been tampered with, somehow, during all those years in the custody of Life magazine or the National Archives. Suspicion feeds on suspicion. As noted, the images on the new video have been passed through high-tech enhancement processes. Which is not the sort of detail to be overlooked by someone who wonders if, perhaps, "They" didn't instruct Zapruder to take his camera, that morning. (Such has been speculated by residents at alt.conspiracy.jfk.) In the early 1960s, director Jean-Luc Godard defined film as "Truth, at 24 frames per second." That, for a long time, was the implicit faith of the small audience devoted to the Zapruder film. Technically, however, it runs at about 18.5 frames per second. And even in a restored and stomach-turningly vivid edition, Truth disappears, somewhere between the sprocket holes.