Strangely, enough, it’s often easier to convert older movies to 4K than newer ones! Here’s why.

Many newer movies were shot on digital from the get-go. No cans of film to worry about – but you’re stuck with whatever technology was available at the time. Some of the first digital-only films, like the second set of Star Wars films, were shot at 1080p or 2K. New 4K versions of those films have to use clever technologies like upscaling to make the picture more appealing.

35mm film, by contrast, on which older movies were shot, is an analog technology. The inherent resolution of a frame of 35mm is somewhere above 20 megapixels, better than most digital cameras today! That’s why you can blow up an old photo to wall-sized, whereas if you did the same thing to a low-rez digital image it’ll look pixelated.

So if you’ve got a high-quality can of film with your movie on it, you could scan it at well over 4K resolution (in fact, not far off 8K) and legitimately call that a 4K movie. Because you’re scanning from the chemically-assisted representation of real life burned onto celluloid, not an electrical grid from an electronic charge-coupled device.

(Incidentally, the same principle applies to audio. Microphones and quality tape from the 1960s captured a great deal of depth and detail that isn’t audible on a bog-standard MPEG file, which is why “remastering” from original analog recording is often worthwhile. Beware, though, of the current craze for retro vinyl versions – many of them are digital files burned back onto analog discs, so the original range of sound is lost!)

Knowing this, you may ask: so why did the world go digital? And the answer is simply that it offers more flexibility. No cans of film to ship to distant cinemas, a digital file does not degrade unless the hard disk fails, and algorithms can downscale, upscale, stream, store, and copy that file at low cost.

Many directors and film buffs still love 35mm film; like old photos or books, it has a patina, story, and history that’s fascinating to explore. True experts can tell what film stock, manufacturer, even factory a can of film was produced with just by looking at the movie (different production processes produced different shades of colour, warmth etc.) But for business reasons, digital is the mainstream now.