F for Fake ($39.95 DVD)/The Immortal Story (Thu., June 9, 8 p.m., free, The Rotunda, 4014 Walnut St.)

A giddy hybrid of documentary, essay film and not-so-concealed fiction, Orson Welles' 1974 F for Fake is a chimera stitched together from a handful of abandoned projects, not all of them initiated by Welles. But Welles weaves his disparate threads so deftly that their various origins only add to the film's richness.

Right from the beginning, Welles was a manipulator of truth; in Fake, his conjurer's grin echoes the self-satisfied glee of Charles Foster Kane's journalistic fabrications. The difference here is that Welles presents himself as a "charlatan," even as he promises, "During the next hour, everything I will tell you is true" — heady stuff, unless you know that Fake runs an hour and a half. The movie's germ is footage retrieved from an unfinished documentary by François Reichenbach about the unlikely nexus between two confidence men: art forger Elmyr de Hory and writer Clifford Irving, who followed his book on de Hory with a hoaxed autobiography of Howard Hughes. Although Reichenbach's footage comprises most of Fake's first hour, you never forget whose movie you're watching; even when Welles isn't acting as on-screen narrator or glimpsed among guests at de Hory's Ibiza chateau, his stamp is on every frame.

Where Reichenbach's footage is concerned, Welles is more trickster than outright fraud. His narration and editing is playfully self-conscious, as when he arranges a "meeting" between himself and stock shots of Reichenbach's subjects. As movie magic goes, it's basic stuff, certainly by Welles' standards, but by placing this sequence after an opening in which a caped Welles performs sleight-of-hand for a delighted child, he warns you: Some tricks you'll see, others you won't.

Through de Hory, whose imitations of Picasso and Modigliani are indistinguishable from the real things — Welles wryly says he'd name galleries in which de Hory's paintings hang, if only "the lawyers" would let him — F for Fake explores the way expertise can warp the appreciation of art. Knowledge of an artist's previous work inevitably preconditions our response, alerting us to seek out certain qualities and overlook others. "It's pretty, but is it art?" Welles repeats, encapsulating the tendency to put gut reaction second to expert commentary ("I loved it, but the Times said … "). Irving says that the ease with which de Hory's fakes made it past museum professionals destroyed his faith in "expertise," but for Welles, the question is more pointedly this: If de Hory can make Picassos as well as Picasso, isn't he an artist as well?

It seems like a question more appropriate to a collagist like Stephen Chow or Craig Baldwin than a sui generis talent like Welles. But by this point in his career, being "Orson Welles" had become as much a burden as a boon. Saddled with a reputation as an out-of-control maverick, Welles had to scrape together funding for each new film, several of which fell apart before he was able to finish them. (The One-Man Band, a lengthy documentary on Fake's second disc, chronicles Welles' many unfinished projects.) As much as he savored his fame — Welles delivers part of his narration from a Paris cafe, surrounded by admirers and heaping plates of food — he must have known he'd never escape the picture of himself as a prodigious talent who peaked early and never reached the heights again. That's why Welles even fakes himself, reconstructing Citizen Kane's newsreel opening based on the (bogus) tidbit that Howard Hughes, not William Randolph Hearst, was the original inspiration for Charles Foster Kane.

In F for Fake, Welles holds up Chartres Cathedral, whose designer is unknown, as the utmost in art: an unsigned masterpiece. (De Hory says his forgeries only become forgeries when he signs someone else's name.) Despite Welles' desire to avoid shots that were recognizably "Wellesian," Fake is hardly self-effacing; it's more of a reinvention. Great magician though he was, Welles couldn't make himself vanish.

Released in 1968, The Immortal Story is an hour-long Isak Dinesen adaptation in which Welles plays a hollow-faced South Seas merchant who learns that a cherished story a sailor once told him is actually an urban legend. Rather than absorb the falsehood, the merchant decides to make the legend come true, playing the pivotal role himself: that of a wealthy old man who arranges a liaison between a sailor and a beautiful woman in order to produce an heir for his fortune. The acting, by Jeanne Moreau, Norman Eshley and Roger Coggio (as well as an uncredited Fernando Rey), is deliberately stilted, giving the whole affair a dreamlike resonance. (The Andrew's Video Vault screening pairs Story with the uncut Eyes Wide Shut.) Shot for French television, Story nonetheless features some of Welles' most extreme deep-focus compositions, often using rapid 180-degree cuts to increase the sense of disorientation. It's not major Welles, especially since his own performance is inert to the point of being cadaverous, but its poisonous voyeurism is uncomfortably effective.