A small boy gazes with joy and awe at a translucent strip of film he holds up to the light - it's an iconic frame from Cinema Paradiso, whose story finds a big-time director reflecting on his childhood friendship with the local cinema projectionist: a relationship that sparked the genesis of his fascination with the moving image.

The shot helped capture the imagination of the Academy of Motion Picture: Cinema Paradiso won an Oscar back in 1990. Somewhere between today and tomorrow, though, the movie industry's fondness for film – in its physical form at least – will indeed become little more than the stuff of nostalgia.

"This year more cinemas are going digital and more projectionists will be affected than in any other year," says filmmaker and independent cinema owner, Thomas Lawes. Screen Digest reported that last year saw digital cinema become the 'majority format' on worldwide screens. Digital dispenses with the need for 35mm film reels and their projectors, and 2012 has found more than 60% of cinemas converting across the globe.

The change inspired Lawes, proprietor of Birmingham's Electric Cinema, to direct The Last Projectionist. It's a documentary charting the story of 'real film' projectionists – alongside that of Lawes's 1909 picture house – just as 35mm's role as the pre-eminent form of distribution and display for film winds down.

"I suspect in the UK it's in the region of a few thousand losing their jobs," Lawes explains. "But a lot of them have been employed doing something else. Here, we have people trained in 35mm who can also now use digital. But the skillset is definitely not as involved. It takes two or three weeks to train someone in the basics of 35mm." By contrast, as Lawes's documentary describes, digital training can be achieved in a matter of hours.

A visit to the Grosvenor cinema projector room on Glasgow's Ashton Lane helps make the massive leap in technology even more apparent. "It's like a jet aircraft sitting beside an old biplane," says David Graham Scott. An award-winning filmmaker (and soon-to-be former Grosvenor projectionist), Scott makes the observation while standing behind two disparate projectors. He's musing over the news he's set to clock-off for the last time after seven years as the cinema's 35mm specialist. On and off, he's worked as a projectionist in Glasgow for nearly 25 years. "I've no problem with the company having to make me redundant, because I understand - it's happening everywhere," he says.

Although the Grosvenor is one of the few cinemas to keep hold of its old projector after introducing the digital upgrade, 35mm won't be used often enough to justify keeping Scott on the payroll. "It's not all specific to the image with digital," Scott explains. "You can program them to control the curtains, lights, even open and close doors in some places."

Long gone are the days when the handler of the reels worked in harmony with a pianist positioned at the foot of the screen. Yet until recently, a sense of ownership over the entertainment still existed for the person behind the scenes. "Working with a digital projector, there's a lack of physical involvement," Scott explains. "It's basically like working on a big PC." Films arrive on hard drives from which they're uploaded – or "ingested" – to the machine. The hard drive can then be sent back to the distributor or on to another cinema.

Scott, who originally studied Film Theory and History of Art, always knew he'd be a filmmaker. "I make creative documentaries, not mainstream, so I've needed a sideline like projecting even though my work's been shown on the BBC and elsewhere."

As a director, he finds the dawn of digital arousing mixed feelings. "If a digital image is next to a film image, you can see the difference," he explains. "Both have positives and negatives. With film, you don't get such defined contours and contrasts. The digital image has a certain harshness to it, but the beauty of it is it's very sharp and there's no dirt or scratching.

"With film there's a certain amount of flicker on screen, but for some that's the pleasure of it – knowing there's a physical process going on. But most people don't care. Many I've brought back here were surprised to see film going through a projector – they thought it would be a DVD."

In having a creative outlet, Scott hopes his redundancy will be less arduous for him than he fears it will prove for others.

"I've seen some classic cases of loners, alcoholics and junkies that have been projectionists, because it's an isolated occupation," he reveals. "It's a sleepy job in a darkened space: you can't have bright lights in a projection box because they shine out into the theatre and disturb people. Strangely enough, this has been a wake-up call for me. I've come alive again and I'm putting more energy into doing my documentary work."

Others, however, can't help but rage against the dying of the light that's meant so much to them for so long. Julia Marchese, who works at the New Beverly Cinema 'revival house' in Los Angeles, began her fight for 35mm after a letter from a major studio announced it would no longer be distributing film reels after 2013.

"This really freaked me out," she says. "I fast forwarded in my head to a time where the studios may not be willing to allow the film prints they have to be rented anymore, and what that would mean to revival cinema. I knew I had to stand up and say something."

Revival houses specialise in movies not currently on general release, and the New Beverly (owned by eminent filmmaker and fanboy Quentin Tarantino) is the only one left in LA screening exclusively in 35mm. Marchese drafted an online petition she hopes will convince studios that old 35mm prints should remain available to those cinemas still eager to show them. Currently going strong, it's seeking the final 250 signatories to help Marchese reach her goal of 11,000 names.

"It's already got so much press that I know it's been seen by everyone I was aiming at," she adds. "Many studios see only in numbers, and that's what really worries me."

Her petition insists: "Nothing can surpass watching a film with a receptive audience, in a cinema, projected from a film print." In the meantime, last month saw her begin work on Out Of Print, a documentary focusing on the revival cinema culture in her native US and beyond.

Despite Thomas Lawes's similar affection for the traditional equipment that links 35mm projectionists to the pioneers who founded the likes of The Electric and other independents, he's clearly no Luddite in his outlook. "Personally, I'm a big fan of digital," he admits. "I use 4K Red cameras for documentary work: they're the best you can get, and I love them. I also like the quality of digital projection – it's really good and consistent. However, there's something evocative about watching a film that you saw when you were younger projected on 35mm, with that slight softness to it and maybe a few scratches. I think there are certain things, much like listening to an old reggae classic on vinyl, that film brings to the party."

Perhaps the greatest irony is that The Last Projectionist itself would not exist save for digital technology. "It couldn't have been made if we had to shoot it on 35mm – I just couldn't have afforded the film stock," Lawes confesses.

Then there's the subsequent issue of distribution to contend with. "We're currently at 26 cinemas, but only need to create five hard drives. The distribution costs for those cinemas is around £300. For 26 cinemas on 35mm we'd have print costs of £15,000. Then creating a 35mm master – at £50,000 – would more than double the budget of the entire film. Some cinemas say they're disappointed they can't show it because it's not on 35mm, but we've told them that if it was, we'd have to charge a minimum guarantee of £10,000. Are they willing to pay that to show the film? Of course they're not."

That aside, both the Electric and the Grosvenor are keen to keep hold of the last in a line of clunky machines that have fired audiences' imaginations for the past hundred years and more. "Now we show a cult or classic on 35mm, like Leon, and make a fuss of doing so: people love it," Lawes says. Such special screenings help his independent cinema stand apart from multiplexes who've hastily switched media without missing a beat. "Celluloid's having its reprieve already through people who'd never given the format a second thought before."

Although Scott expects the odd Grosvenor all-night horror marathon to make good use of 35mm, he's more dramatic in his assessment of the future of film. "Film dying off is a global issue," he says. "2012 might not be the apocalypse as the Mayan calendar prophesied, but it's certainly the apocalypse for film. Hopefully the artists and aficionados can keep it alive."

The Last Projectionist, followed by a Q&A session with director Thomas Lawes, shows at Glasgow Film Theatre, Monday, 6.10pm. A new digital print of Cinema Paradiso shows at GFT on Sunday, 7.30pm and Tuesday, 12.45pm