When FXX broadcast a marathon of the entire run of The Simpsons to date, they cropped the remastered images, slicing off the top and bottom of the original image to fit into wider HDTV sets. The Simpsons, like many shows of its era, was originally broadcast in a 1.33:1 aspect ratio. This is what TV images looked like for decades. HDTV sets display a ratio of 1.78:1 (often referred to as 16:9, or 16x9), which is obviously wider. To show an older TV image on an HDTV set, you have two options: 1.) Center the image and put black bars on the sides (a practice known as pillarboxing), or 2.) Crop or stretch the image to fit the wider display.
The first option is always preferable. The goal isn't to fill up your display with an image, but to view the image as it was originally intended using the best of our abilities. Before HDTVs, this meant opting for widescreen editions of VHS tapes or DVDs, which used letterboxing to insert black bars above and below the image to preserve a wide picture on a more narrow display. Many movies today will still be letterboxed on an HDTV, but because the display is already a good deal wider than old 1.33 TV sets, the bars are smaller and less noticeable.
That's just for modern features, though. For older features and TV series, which were often created and distributed in a 1.33 ratio (or 1.37, aka Academy ratio), watching them on an HDTV and seeing a true representation of the work means having black boxes on the sides of the image. It's the same principle as letterboxing; the bars are just in a different place.
Filmmakers and TV creators weren't oblivious to the shape of the screens that would show their work. They composed and photographed images specifically in a 1.33 ratio. And this is where it gets important: a filmed image isn't just a delivery device for plot, but a visual representation of the emotions of the characters and viewers interacting in the film space. Close-ups, tight shots, the interplay of camera positions. These aren't haphazard, randomly chosen things. They're all done with a purpose. And when you chop or distort the image, you twist and damage the intended emotions of the scene.
When Buffy the Vampire Slayer was released on DVD, some fans wondered why it wasn't being presented in widescreen, especially as HDTVs began to gain footing in the market. Series creator Joss Whedon had this to say about it:
The fabulous episodes of BUFFY (and that one crappy one, sorry about that, seemed really cool when we wrote it...) were not shot in a widescreen format. They were shot in the TV 4 by 3 ratio. Now I'm a letterbox fanatic.... I want to see the whole screen, as framed by the director. The BUFFY's I (and others) shot were framed for traditional TVs. Adding space to the sides simply for the sake of trying to look more cinematic would betray the very exact mise-en-scene I was trying to create. I am a purist, and this is the purest way to watch BUFFY. I have resisted the effort to letterbox BUFFY from the start and always will, because that is not the show we shot. This is.
The latest show to receive the HD remastering treatment is HBO's The Wire, and it looks like it will unfortunately be cropped to fit HDTV sets, too. This is, of course, an affront to the creators of the original image, who knew what they were doing when they photographed one of the greatest TV series ever made. From a 2007 piece about the show:
The Wire for each of its five seasons has been produced in good old fashioned 4 x 3 standard definition. DP Dave Insley recalled, "The reason the show has stayed 4x3 is because David Simon thinks that 4x3 feels more like real life and real television and not like a movie. The show's never been HD, even 4x3 HD and that (SD) is how it is on the DVDs. There is no 16x9 version anywhere." As a viewer with an HD set I will point out that like much of SD television that makes its way to HD channels, it appears that HBO utilizes state-of-the-art line doubling technology. It may still be standard definition, but line doubled it looks considerably better on a high definition set than it would on a standard definition set.
Insley explained, "When the show started 2001 / 2002 they framed it for 16 x 9 as a way of future-proofing. Then a couple of seasons ago, right before Season 4 began shooting, there was a big discussion about it and after much discussion -- David, Nina, Joe Chappelle, the Producers, the DPs -- and we discussed what should be the style of the show. David made the decision that we would stay with 4x3. The DPs pretty much defined the look to be what it is now. And it's been consistent for the past two seasons."
Watching a TV show or a movie isn't just downloading the plot into your brain. If it were, you could get the same emotional and aesthetic experience by reading episode summaries on Wikipedia. The visuals, including the framing, are crucial to an understanding of the work. All the pieces matter.