Why Are There Black Bars on My TV When I Watch Movies?

"Why are there black bars on my TV screen when I watch movies?" I've heard this question a million times. It was even more common a few years ago when we all still had the old style tube TVs, but even now, you'll occasionally see black across the top and bottom of your HD set. And now, there's black on the left and right sometimes! What's up with that?

After earning a Bachelor of Arts in film and video in college, working in the home entertainment department of a major retailer for a year, then at a video store for a year, and then at a major camera rental house in Hollywood for over 6 years, I've learned a little bit about those black bars on your TV set, and I'll attempt to explain them in layman's terms:

First of all, every TV show and movie you watch is shot for a particular aspect ratio. The aspect ratio is the length of the top or bottom of the frame divided by the length of the side of the frame. For example, old school tube TVs are a 4:3 aspect ratio ("Four by Three"). The frame is 4 units wide and 3 units high. Another way to express this is "1.33," since 4 divided by 3 equals approximately 1.33 (Folks in the industry say "One-Three-Three"). It doesn't matter if you had a big screen or just a little 13" set in your dorm room, it's all the same aspect ratio, and it has nothing to do with the size of the screen. It's really all about the shape of the screen.

All TV shows prior to the advent of HDTV were presented in a 1.33 aspect ratio. So, everything from I Love Lucy to Full House was 1.33, or 4:3.

Now, if you've upgraded to an HDTV set, you'll notice that the screen is significantly wider than your old TV. This new aspect ratio is 16:9 ("Sixteen by Nine"). Or, if you divide 16 by 9, you get "1.78" ("One-Seven-Eight").

Take a popular modern show, say, Lost, for example: If you're watching it on an HDTV set, not only do you get a better quality picture, but you get the wider 1.78 aspect ratio. People watching on the old style televisions can watch the same show, but they are viewing it in the old 1.33 aspect ratio.

So, when the camera guys shooting Lost start filming, they have to keep in mind two separate formats; all of the vital information must be contained within the 1.33 frame (for the people watching on old tube TVs), but the 1.78 frame can't pick up anything that shouldn't be in the shot, such as lighting equipment or the boom operator. The end result is that people watching on HDTV will get a more cinematic experience, and will actually see more information on the extreme left and right of the shot, usually just more beach or ocean or jungle; nothing crucial to the telling of the story.

Now, there are two common aspect ratios for cinema: 1.85 and 2.40. As you might have guessed, 1.85 ("One-Eight-Five") means that the top or bottom of the frame is 1.85 times longer than the side of the frame, and with 2.40 ("Two-Four-Oh"), the top or bottom is 2.4 times longer than the side. You may also hear people talk about 2.35 or 2.39 aspect ratios, which are, for all intents and purposes, the same thing as 2.40, or "anamorphic widescreen." Some of these movies were shot with true anamorphic lenses, and others were shot 2.40 with regular spherical lenses...but we'll talk about that in another blog. Movies like The Big Lebowski and The Truman Show were shot in 1.85. Movies like Star Wars and Lord of the Rings were shot in 2.40.

When either of the cinematic aspect ratios is viewed on an old tube TV, the frame must be "letterboxed."

That means that black bars are added to the top and bottom of the frame in order to preserve the original aspect ratio.





They used to offer "Full Screen" versions of movies for people who preferred to have the image fill their entire screen. However, viewing a film in this manner meant losing up to a third of the original cinematic image.




Now, with 1.78 televisions, the 1.85 films have an aspect ratio so close to that of the TV screen, that they can be stretched to fill the entire screen with no noticeable distortion, although to perfectly preserve the original image, there would need to be very thin bars at the top and bottom of the screen.




2.40 films are still too wide to match up perfectly to an HDTV screen, so when viewing a film of that aspect ratio, there will still be black bars at the top and bottom of the screen.









And, unfortunately, viewing any old TV shows on an HDTV means having black on the left and right of the screen.





Of course, most new TVs have a "fit to screen" option that will stretch an old 1.33 image to fill a 1.78 screen, but not without noticeable distortion to the image.

I've encountered a number of other scenarios since I've owned my HDTV. For example, I've noticed that very old DVD discs that have letterboxed 1.85 versions of films, when viewed on an HDTV, will have the correct aspect ratio, but will refuse to fill the entire screen. The image will be surrounded by black on all sides. Any attempt to force the image to fit to the screen will cause it to stretch to a 2.40 AR, filling the screen from left to right, but leaving black on the top and bottom, and causing significant distortion to the image.

If anyone else has encountered any other weird aspect ratio scenarios, please leave me a comment below, and I'll try to check it out! Thanks for reading.