One of the highlights of the 35th Telluride Film Festival, which took place over the Labor Day weekend, was the documentary “Prodigal Sons,” by Kimberly Reed, who endeavored to film the reaction of her family and friends as she returned to Helena, Mont., for her 20th high school reunion. Her hometown had known her as Paul, the school’s star quarterback. Other than her rivalrous and mentally impaired adopted brother Marc, no one seemed fazed by her “transition.” Ms. Reed, however, had a shock in store when Marc set out to learn the identity of his birth parents: Turns out his mother was Rebecca Welles, the daughter of Orson Welles and Rita Hayworth.

Marc and his uncanny resemblance to Orson Welles haunt the film like a deranged, troubled doppelgänger of genius — genius shorn of everything other than a small talent (he can play the piano by ear) and a terrible anger. Watching the fury bust out of him, one thinks of the power and limitations of DNA, and of the bizarre fact that, of all people, Welles should have left, unknowingly, an antithetical image — even a refutation — of the fabled brilliance and prodigality that haunted his life and his reputation ever after.

The Welles controversy is fairly one-dimensional; it wouldn’t exist if he had died at 26, having conquered and innovated theater, radio, and cinema. But his stature and his girth continued to swell in inverse proportion to the broad acceptance of his work, so that long before he died in 1985, at 70, he had generated a near-religious schism. On one side are those who bemoan a squandered talent; on the other, those who relish the quality and fierce independence of his later work. Welles became a cause as his art took a backseat to a martyrdom he alternately embraced and rejected — especially after his contribution to the one film regarded as a consensus masterpiece, “Citizen Kane,” was challenged by Pauline Kael, who ludicrously concluded that it was really the work of his co-scenarist, Herman Mankiewicz.

There is a moment in Welles’s “Don Quixote,” which was recently released on DVD by Image, when Welles, appearing as himself, receives an award from a convention of sherry manufacturers and is introduced as being “famous for his interpretation in ‘The Third Man.'” Welles laughs his ho-ho laugh, and we can hardly fail to recall that he spent most of his life tilting at windmills and that his fame was only as valuable as the work it procured.

“Don Quixote” is a central part of the legend — the unfinished work (one of several) to which Welles devoted the most time and from which he may have received the most pleasure. It began in 1955, when he shot tests, purportedly for a television adaptation, with actor Mischa Auer, who appeared in Welles’s “Mr. Arkadin” that same year. A couple of years later, he began filming in Mexico with Francisco Reiguera as “the knight of the mournful countenance,” and Akim Tamiroff as Sancho Panza. By 1958, the project had evolved sufficiently for Welles to tell the critic André Bazin that it was being improvised in the style of silent comedy (with dialogue to be dubbed later), was set in the modern world, and would not run more than 90 minutes.

During the next decade, Welles returned to his “Don Quixote” periodically when time and finances permitted, until Reiguera died in 1969, followed by Tamiroff in 1972. A wraparound narrative involving child actor Patty McCormack was filmed but rejected, perhaps because she outgrew childhood. Welles began to speak of it as a private work, like a novel — it was his to finish as and when he pleased. He edited and dubbed or, more likely, test-dubbed several scenes, voicing Quixote and Sancho himself. But at his death, he left cans of film in several countries, and no script or memo to guide the material’s organization.

In 1992, Oya Kodar, Welles’s companion for many years and the executor of his estate, authorized the Spanish director Jesus Franco, who had assisted Welles on the sublime “Chimes at Midnight” (1965), to assemble all the material he could gather and edit it into a film for a cultural expo in Spain and the festival at Cannes, where it generated almost universal outrage. A DVD was issued in Spain and Brazil, with English and Spanish audio tracks, Portuguese subtitles, and short essays on the making of the film.

Welles’s “Don Quixote” has never been released in America until now — nor has there been much demand since the contributions of Mr. Franco (who made good Eurotrash horror films in his prime) were regarded as indiscriminate butchery.

The problems with the Franco version are undeniable: The film stock looks worn and gray. Little attempt was made to carve a film from the accumulated footage (112 minutes are included), much of it repetitive and some of it tweaked with dreadful optical effects. The English dubbing makes Japanese lizard movies sound fastidious by comparison. For a narrator, they chose an actor who tried to mimic Welles. For Quixote and Sancho, they hired actors who are polar opposites from Welles, destroying all continuity between his dubbing and that of the others. Welles’s voice-over is uneven — he occasionally sounds like Hank Quinlan from “Touch of Evil” — and, in one bizarre passage, as Sancho discusses sainthood, Welles revives the faux-Irish accent he used in “The Lady From Shanghai.”

Image reproduces the lame Franco print, right down to a reverse-frame glitch at the 39:50 mark, but with no explanatory essay at all and without the Spanish and Portuguese. The company might have produced a worthy DVD with a commentary explaining the film’s history, and distinguishing between scenes that Welles cut and raw footage. Instead, it promotes the DVD as “Orson Welles’s Don Quixote,” subtitled “The Lost Dream Project,” and advertises it as starring Welles, who appears with his camera for mere seconds, and Ms. McCormack, who does not appear at all. (A fascinating scene that Welles shot with McCormack, set in a movie theater as Quixote slashes the screen to rescue someone in distress, has been viewed more than 14,000 times on YouTube and might have been included as a bonus.)

That said, I can’t go along with the consensus that this material is to be shunned as a worthless travesty. Given how long it’s taken for even this to be made available on these shores, it is entirely possible that none of us will be alive when a more professional and creative version is offered — and even then, a best-case scenario will produce a speculative version of what Welles intended. This print is tough going, but there is much at which to marvel. The first half, once the deadly narration is finished, suggests Samuel Beckett, as the two principals jabber alone in the wilderness. The attempted comedy never quite jells, but many images are memorable; someone could publish an impressively illustrated “Don Quixote” with captured frames from the film.

The second half is far more engaging. As in the novel, some of the finest scenes occur when Sancho goes off on his own, and the highlight of the film is a 12-minute sequence beginning with him wandering into a desolate town that promptly comes alive with the running of the bulls. Henry Fonda is there, a tourist with his camera, and as the bulls enter the ring, two of them run smack into each other. This is the kind of stuff all too familiar from newsreels, but never like this. It’s a mini Welles essay on barbarism, much as “Don Quixote” is intended as his valediction of courage. A subsequent scene in which Sancho finds his master imprisoned in an oxcart and meditates on the times they’ve had, superbly played by Tamiroff, is kin to a parallel scene in “Chimes at Midnight.” Beyond these and other particulars, though, is the overall enchantment of watching what Welles could do in his spare time with a camera and a couple of actors. As a home movie, even the butchered “Don Quixote” has transcendent moments.