Why Are Black Bars Still Visible on HD or 4K Ultra HD TV?

There is a good reason you may see black bars on your TV screen

Example of Black Bars on Letterbox Image
Example of Black Bars on Letterbox Image. Getty Images - Richard Wong - Moment Collection - 114254526
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When viewing theatrical films on your HDTV or 4K Ultra HD TV - you may still see black bars to the top and bottom of some images, even though your TV has a 16x9 aspect ratio.

16x9 Aspect Ratio Defined

What the term 16x9 means is that the TV screen is 16 units wide horizontally, and 9 units high vertically - This ratio is also expressed as 1.78:1.

No matter what the diagonal screen size is, the ratio of horizontal width and vertical height (Aspect Ratio) is constant for HDTVs and 4K Ultra HD TVs.

For useful online tools that can help you determine the horizontal screen width in relation to screen height on any 16x9 TV, based on its diagonal screen size, is provided by GlobalRPH and Display Wars.

Aspect Ratio and What You See On Your TV Screen

The reason that you end up seeing black bars on some TVs and movie content is that many films were, and are, made in wider aspect ratios than 16x9.

For example original HDTV programming is made in the 16x9 (1.78) aspect ratio, which fits the dimensions of today's LCD (LED/LCD), Plasma, and OLED HDTVs and 4K Ultra HD TVs. However, many theatrically-produced films are made in either the 1.85 or 2.35 aspect ratio, which is even wider than the 16x9 (1.78) aspect ratios of HD/4K Ultra HDTVs. Thus, when viewing these films on an HDTV or 4K Ultra HD TV (if presented in their original theatrical aspect ratio) - you will see black bars on your 16x9 TV screen.

Aspect Ratios can vary from movie to movie or program to program. If you are watching a DVD or Blu-ray Disc - the aspect ratio listed on the package labeling will determine how it looks on your TV.

For example, if the film is listed as 1.78:1 - then it will fill the entire screen correctly.

If the aspect ratio is listed as 1.85:1, then you will notice small black bars on the top and bottom of the screen.

If the aspect ratio is listed as 2.35:1 or 2.40:1, which is common for big blockbuster and epic movies - you will see large black bars on the top and bottom of the image.

On the other hand, if you have a Blu-ray Disc or DVD of an older classic movie and the aspect ratio is listed as 1.33:1 or "Academy Ratio" then you will see black bars on the left and right side of the image, instead of the top and bottom. This is because the movies were made before the common use of widescreen aspect ratios, or was originally filmed for TV before HDTV was in use (those old analog TVs had an aspect ratio of 4x3, which is more "squarish" looking.

The main thing to be concerned about is not whether the displayed image fills the screen, but that you are seeing everything in the image that was originally filmed. Being able to view the entire image as originally filmed is certainly the more important issue, rather than be concerned about how thick the black bars are, especially if you are viewing the image on a projection screen, which is a large image, to begin with.

On the other hand, when viewing a standard 4x3 image on a 16x9 set, you will see black or gray bars on the left and right side of the screen, since there is no information to fill the space.

However, you can stretch the image to fill the space, but you will distort the proportions of the 4x3 image in doing so, resulting in objects appearing wider horizontally. Once again, the important issue is that you able to view entire image, not whether the image fills the entire screen.

The Bottom Line

The way to look at the "black bar issue" is that the TV screen is providing a surface upon which you view images. Depending on how the images are formatted, the entire image may or may not fill the entire screen surface. However, the screen surface on a 16x9 Television is able to accommodate more variations in image aspect ratio realistically than older 4x3 analog televisions.