Examining the history and process of both digital and photochemical film, Side By Side weighs up the merits of both at a time when digital cameras look set to make the more traditional methods of shooting on actual film stock obsolete.
My past encounters with Reeves have found him an awkward interviewee, vaguely suspicious, unwilling to articulate anything but the barest of information.
But today, he's pumped with enthusiasm for what is clearly a passion project.
Side by Side began when Reeves was working on the 2010 low-key thriller Henry's Crime, in which he starred.
"This experience was really based upon interest," he explains. "The cinematographer Paul Cameron was showing me these images on this 5D digital camera, and we were looking at the digital image and the photo-chemical image side by side and I was like, 'Film is going away? Woah! What's happening? Is this the end of film? What is going on here?"'
It was at that point that Reeves partnered up with Kenneally, who was working as post-production supervisor on Henry's Crime, and decided to document this transitional moment in film.
"From the very beginning, Keanu had a strong curiosity to know how everything worked, while we were in post," Kenneally later tells me.
"How does the lab work? Where does the film go next? And then how does it go to digital? He really dissected it all and wanted to know the process. I've seen him do that with the camera too - he breaks things down. He's just interested in things and how they work."
If the film carefully sidesteps the highly subjective question of which format is better, the roll call of interviewees is illustrious. Directors such as Martin Scorsese, David Lynch, Steven Soderbergh, Christopher Nolan, Lars von Trier, Robert Rodriguez, David Fincher and James Cameron all make appearances, alongside cinematographers such as Michael Ballhaus (Goodfellas), Vittorio Storaro (Apocalypse Now) and Anthony Dod Mantle (Slumdog Millionaire).
It doesn't stop there, with lesser-known below-the-line talents given equal billing. "As I started learning more about the subject," notes Reeves, "it would be like, 'Well, why aren't we talking to them?' So we'd go, 'Let's go and see if we can meet them!"'
Most are not former collaborators, though Reeves does call upon the creators of The Matrix - the Wachowski siblings - to discuss what became a groundbreaking moment in film-making.
So does he view The Matrix, with its revolutionary digital effects, with different eyes now? "I think you have to because time has gone by," he replies. He cites the influential "bullet time" sequences, where the camera appears to rotate around a slowed-down image.
"The deeper thing that happened was it was computer-generated. It was a digital moment. And that can only be put in the context by the passage of time, generally speaking. John Gaeta, who did the visual effects, knew what was going on, and so did the Wachowskis - but I didn't."
Though it's not addressed directly in the film, we move on to the subject of actors being replaced by digital avatars in the future. "I think technologically that would be possible, but I think it would depend on the film-maker, in terms of whether they want reality or not," says Reeves.
He admits he's concerned about the possibility of manipulating an actor's performance digitally - "like putting tears in your eyes when you don't want tears".
Though if you were being cruel, some of Reeves' more wooden performances probably would benefit from some digital tinkering.
With Reeves proving an adept on-camera interviewer, he admits most of those asked to participate were enthusiastic because it was a subject close to their hearts. "When we walked into a room, it was never like, 'Who are you? Why am I here?"'
It's easy to imagine that for someone who has been in the business as long as he has, meeting film folk would be par for the course. But you sense something of the fanboy in Reeves.
"Sometimes, I'd be like, 'You know we've just interviewed George Lucas. He's just hung out with us and told us the deal. The real deal."'
Who: Keanu Reeves
What: Side by Side
When: Screening at the New Zealand International Film Festival from July 19
Also: Side by Side is one of the works in the New Zealand International Film Festival's "Framing Reality" section which also includes the Peter Jackson/Fran Walsh produced West of Memphis and the acclaimed Bully, among a wide array of documentaries which also includes this year's best doco Oscar winner Undefeated and the Bob Marley biography Marley. The programme for the Auckland festival, which starts on July 19, is out next week. For a sneak preview of what's in it, see Saturday's Weekend TimeOut.
- TimeOut / The Independent