“Magic Trip: Ken Kesey’s Search for a Kool Place,” a film by Alex Gibney and Alison Ellwood that opens on Friday, is an exercise in what they call “archival vérité.” It’s a documentary that uses old footage to recreate a documentary that Kesey intended to make about his 1964 cross-country bus trip — the one so memorably chronicled in Tom Wolfe’s account, “The Electric Kool-Aid Acid Test.”

In all Kesey and the Merry Pranksters, as his crew called themselves, shot some 40 hours of 16-millimeter film, but the project was never really finished. As Mr. Wolfe wrote, “Plunging in on those miles of bouncing, ricocheting, blazing film with a splicer was like entering a jungle where the greeny vines grew faster than you could chop them down in front of you.” Kesey showed all 40 hours unedited a couple of times and also hacked the footage up into various shorter versions before stowing the film cans in his barn, near Eugene, Ore., where they rusted away — until Mr. Gibney and Ms. Ellwood showed up.

Kesey was onto something similar to what we would now call reality television: scenes of people with odd names (Mal Function, Gretchen Fetchin, Generally Famished) getting stoned and behaving weirdly. After publishing the novels “One Flew Over the Cuckoo’s Nest” and “Sometimes a Great Notion,” he had by 1964 wearied of writing or so fried his brain with hallucinogens that he embraced what he saw as a brand new art form: a drug-enabled psychic quest that would document itself as it was happening. The famous bus — a psychedelic-painted International Harvester with a sign in front that said “Furthur” and one in back that warned “Weird Load” — was wired for sound, and there was a movie camera on board. With Kesey sometimes directing and sometimes just standing back and watching, the Merry Pranksters filmed one another and also their interactions with an uncomprehending public when, for example, Neal Cassady drove the bus backward down a Phoenix street as the Pranksters, stoned on LSD, pretended to campaign for Barry Goldwater for president.