One of the benefits of the widespread adoption of high-definition television sets and HD capable media players like Blu Ray players and HD-capable streaming boxes has been a push for film and television studios to re-release old content in beautiful HD. But how exactly are they producing HD content 20+ years after the fact?

Dear How-To Geek, First, let me open by saying I’m not a very clever man, and I’m sure the answer to my question is readily apparent to everyone but me. With that in mind though, I’m really curious about all the newly released content over the last few years that features HD quality footage of very old material. For example I was looking for a Cheers box-set on Amazon and saw that they have plenty of standard definition DVDs, but they also have all the original seasons in HD. The show first aired back in 1982 which was practically thirty years before HDTV sets got a majority share in the U.S. market. The HD version of the show was fantastic looking and, to boot, was in 16:9 widescreen format! You could actually see more on the screen than when you watched the show back in the day. Same thing with really old movies like Ben-Hur; it came out in 1959 but you can get a beautiful HD Blu-ray copy today. The movie looks stunning on a nice big HDTV set, the colors are crisp, it’s like it was filmed yesterday. So what’s the deal? How is it that technology from decades ago (and even a half century ago) can yield such a high quality video for today’s modern televisions? Sincerely, HD Curious

While we enjoy answering questions of all stripes, be they about simple hardware problems or abstract concepts, we really enjoy fun little questions like the one you’ve posed today because it’s a geeky inquiry for the sake of geeky inquiry. Let’s take a little trip down memory lane and the history of movie and television production to illuminate how our beloved movies and shows from decades past can look so amazing today.

Throughout the 20th century movies and television shows were recorded on a variety of film mediums. Major motion pictures were shot on 35mm film (and some big budget films were shot on 65-70mm film). Television shows were typically shot on 16mm film. Very low budget television shows and movies were shot on 8mm film. The reference image below, courtesy of the Australian National Film & Sound Archive, shows the relative scale of common film standards:

The thing about film is that it’s incredibly high “resolution”. We enclose resolution in quotations in the previous sentence because film doesn’t technically have a resolution in the sense that a digital display or capture device does. Film has no pixel count; there is no orderly arrangement of little red, blue, and green markers into any sort of grid.

Film instead has grains. The very nature of film is that it is a transport medium for a chemical emulsion that, when properly exposed to light under controlled conditions, captures the scene before the camera lense in incredible detail. Long before we were talking about how many millions of pixels a cutting edge digital camera could capture, even the simplest of film cameras was capturing millions upon millions of “pixels” in the form of film grain which yielded high levels of detail.

How high a level of detail are we talking? Because film and digital video/photography are not analogous it’s essentially impossible to say “a film frame of X size has Y resolution” and the very topic has been the subject of some controversy over the years.

That said, without getting into a huge film versus digital debate, we can highlight the differences that are relevant to your question. Specifically, we can talk about how high the “resolution” of various film is when starting with a high quality film sample. Remember, however, that the film doesn’t get an actual resolution, in the digital sense, until it is captured by a scanning device and actually digitized for use in broadcast media, Blu-ray discs, or streaming services.

35mm film, the kind of film used for most old movies, can easily be considered around 20 megapixels or greater in resolution. The lesser used but absolutely enormous 65-70mm film has, as you’d guess, roughly double the potential resolution of 35mm film and could be converted into a 30-40 megapixel image. Coincidentally Ben-Hur, the movie you referenced, was shot on 65mm film.

Standard 16mm film has roughly half the surface area of 35mm film and can be considered around 10 megapixels or greater in resolution. 8mm film, the film many old home movies and budget films were shot in, varies the most widely in quality but typically depending on the equipment used and the film quality can have anywhere from 1-5 megapixels or so. As an aside, many people think of the blurry and low-quality home movies their parents or grandparents shot on 8mm film back in the 1960s and 1970s as representative of 8mm film but those low-quality films are really more representative of the low-quality of consumer cameras and consumer film they were with and on.

Even though film and digital video aren’t equivalent mediums the numbers we threw around in the previous paragraph are useful as a frame of reference; not because anyone is realistically going to attempt to convert a still from Ben-Hur into a 40 megapixel mural but because it provides a way for us to compare how much information is packed into a frame of film compared to a modern HDTV frame.

The resolution of a 1080p movie, when translated into a “megapixel’ count, for example, is a mere 2 megapixels (as there are roughly two million pixels in each frame). Even the new 4K video that blows everyone away with its realism only provides a little under the equivalent of nine megapixels of resolution per frame.

Given that high quality 35mm film shot with quality gear can yield 20 megapixels or more of resolution when scanned with high-end equipment it becomes readily apparent how it’s very easy for movie studios to go back and, assuming they’ve preserved their original negatives properly, completely remaster a film to look absolutely amazing compared to what they released on VHS in the 1980s and DVD in the 1990s.

Even television shows like the Cheers episodes you reference were shot in such a fashion that they have more than enough available information in the film frames to make the jump from standard definition broadcasts to HD video and, assuming there was financial motivation to do so, could even be remastered for a future 4K release with ease.

For the sake of comparison and to highlight the power of the remastering process, let’s take a close look at two screen captures from the movie, Ben-Hur, you used as an example in your question (and that we used to create a composite image for the header of this article).

The first screen capture is from the DVD release of the film. Keep in mind that the film was cleaned up for that release too, but the limitations of the standard definition DVD are obvious:

The second screen capture is from the Blu-ray remastering. The film’s sharpness and restored color are apparent.

The above screen capture doesn’t even show off the true potential for detail the 65mm film master can provide. A future remastering of the film coupled with a large 4K HDTV set could yield a viewing experience that lets you count the creases in bridles and the hairs on the horses’ heads.

Speaking of remastering, now that we’ve solved the mystery of where all that old HD video goodness comes from, let’s have a little fun looking at how it’s created. Earlier this year Gizmodo visited the team behind the Criterion Collection film remasters, a team of skilled individuals that take great care in restoring old films and digitizing them.

Thanks to advances in technology, the careful touch of trained restorers, and the proper storage of old Hollywood and television film reels, we’re able to enjoy beautifully restored content from decades past on our shiny new HDTV sets.

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