It is fascinating to watch documentaries about people who are singularly devoted to their vocation. The recent crowd-pleaser RBG is like that, with Supreme Court Justice Ruth Bader Ginsburg working so late that she sleeps all weekend. There are also films like Jiro Dreams of Sushi and Bill Cunningham New York, where the subject leads a monk-like existence, all in service of their chosen profession. The documentary Filmworker is of that ilk, with the added wrinkle that its subject Leon Vitali is not just devoted to his craft. He is also devoted to another man’s art, who happens to be a genius. This dual purpose leads to an uneven film, one that leaves more questions than answers.

You may recognize Leon Vitali from Barry Lyndon, the Stanley Kubrick film where he had an important role as Lord Bullingdon. Up to that point, Vitali was a journeyman actor, appearing in all manner of film, theater, and television roles. Something about working with Kubrick changed Vitali: He decided to quit acting, and learn about filmmaking techniques like editing so he could help Kubrick on his new project. Sure enough, Kubrick recruits Vitali to find a child actor for The Shining. The two men develop a symbiotic relationship, to the point where Kubrick would be hopeless without Vitali’s unwavering devotion.

Director Tony Zierra weaves clips from Kubrick’s filmography, along with archival footage and interviews with Vitali, as well as other Kubrick collaborators. The cumulative effect is perplexing, with Vitali not quite able to articulate why he changed his career in this way. Aside from working on the films themselves, Vitali works tirelessly to make sure Kubrick’s work was appropriately preserved, advertised, archived, and restored. The impression is that Kubrick’s films would not be so well-regarded without Vitali behind the scenes.

Vitali’s work ethic required him to lead an irregular life. When Zierra introduces Vitali’s children into the film, it is jarring just because we are made to believe he had no time for anything else. The children sound resigned, even disappointed, by their father’s career. Many of the talking heads, including the actors Ryan O’Neal and Matthew Modine, speak about him with a mix of reverence and confusion. None of them could imagine living like Vitali, so they serve as helpful audience surrogates. We are meant to appreciate Vitali’s preservation efforts, even if his obsession with Kubrick would become his defining personality characteristic.

One bizarre detail about the film is how Zierra frames his interviews. Before he became a director, Kubrick was a photographer, where he learned all the minutiae necessary to film anyone in an evocative way. If Kubrick saw how Zierra filmed Vitali and the others, he would probably be horrified. The lighting is harsh, unearthing every wrinkle and pore on their faces. The camera’s distance is distracting, and borderline uncomfortable. No on-camera interview should ever looks like this, and with good reason. Maybe Zierra deliberately avoided the softer hues of Kubrick’s palette, just to make it clear Kubrick’s style cannot be replicated, but that is a generous interpretation. It is also possible Zierra does not know how to set up a shot.

Throughout Filmworker, Kubrick remains an enigmatic figure. Vitali is protective, even shy, about his relationship with him. There have been behind-the-scenes documentaries about Kubrick’s process before, including the famous documentary about The Shining where he verbally abuses Shelley Duvall in service of her performance. From this film, the impression was that Kubrick was a perfectionist who could be charming or fearsome in any given moment. There are some intriguing details—Vitali appears as eight separate masked characters in Eyes Wide Shut—but the director remains obscure, elusive.

There is a curious subtext to Filmworker. As Kubrick’s other collaborators explain how Kubrick needed Vitali, there is the suggestion they had a co-dependent relationship. In other words, Vitali’s willingness to serve Kubrick only made his outbursts and quirks all the more impossible for everyone else (Barry Lyndon’s set designer had to leave mid-production after having a nervous breakdown). Unfortunately, Filmworker lacks the curiosity for such psychological depth. It is a straightforward biography that’s meant to highlight the sort of people who go uncelebrated in the world of filmmaking. We should thank Vitali the next time we see a 70mm print of 2001: A Space Odyssey, even if Filmworker does not bring us any closer to understanding the man most responsible for it.

Filmworker opens Friday at Landmark E Street Cinema.