Understanding TV Aspect Ratios

3d1Many of you probably purchased or received as a gift a display panel TV this holiday season. Welcome to the 21st century. Of all my tech gadgets, my Panasonic plasma displays are among my favorite. Regardless of whether you have an LED, plasma, or OLED display (lucky dork), you need to understand aspect ratios and letterboxing.

The following is an excerpt from Chapter 6: Display Panels / TV, from my Kindle book Home Theater for the Internet Age.

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Curt Robbins


A TV’s aspect ratio is a comparison of the width and height of the picture displayed. Why is this a concern when this book doesn’t unnecessarily delve into technical matters? Because there’s consequences to a mismatch between the aspect ratio of your display device and that of the content you’re viewing.

Old TVs used to sport an aspect ratio of 4:3, the origins of which date back to 1909 with the standardization of 35mm film in cinema and the emergence of Hollywood. A 4:3 aspect ratio meant that TVs were four units wide and three units tall (regardless of the overall size of the display). This worked well back in the days when TVs displayed only over-the-air content, nearly all of which was broadcast in 4:3—meaning the aspect ratio of the content precisely matched that of everyone’s display unit. Ah, the good ol’ days. Things have gotten a bit more complicated in terms of the aspect ratios supported by both Hollywood and display manufacturers.

Aspect ratios can be expressed as either ratios or decimals. The “standard,” or non-widescreen aspect ratio of 4:3 from the old glass tube TV days, can be expressed as 1.33 (or 1.33:1, a “decimal ratio”). This means that the display is 1.33 units wide and one unit tall (decimal aspect ratios always assume a height of one unit). The common 16:9 aspect ratio, for example, is a decimal of 1.78 (again, shorthand for 1.78:1). Most modern movies are produced from 1.85 (just a smidge wider than 16:9) to 2.33, 2.39 (often indicated as 2.40), and sometimes even ultra-wide 2.59.

Letterboxing

Preserving the aspect ratio of any content wider than 1.78:1 (16:9), when displayed on a 16:9 display panel, results in letterboxing—the black bars above and below the video. The letterboxing necessary for 1.85 format films is so slight that many consumers simply don’t notice it. It is easily perceived in films that are 2.33 or wider. Conversely, vertical letterboxing, or pillarboxing, is employed when 4:3 content, which is more narrow, is displayed on a 16:9 TV.

Pan & Scan

Pre-digital TV stations that broadcasted widescreen films (originally intended for commercial cinemas) back when everyone had 4:3 aspect ratio TVs sometimes employed letterboxing to preserve the original aspect ratio of the film. More commonly, however, movie studios engaged in pan-and-scan, a process of applying a 4:3 aspect crop to a widescreen or even ultra-widescreen film (thousands of which feature aspects ratios in excess of 21:9, or 2.33).

plasma display panelAs you can imagine, this pan-and-scan process discarded sometimes significant amounts of the movie display, severely bastardizing the intentions of thousands of movie directors and producers. Why? Simply because people wanted to watch widescreen content intended for movie theaters on their non-widescreen home TVs. Back in the day, when most people viewed tons of Hollywood films on their small and fuzzy TVs, they rarely saw what directors intended. On the rare occasions when letterboxing was employed, the image was too small on a common 19-inch TV for comfortable viewing from regular seating positions. No wonder grandma was into knitting, grandpa worked on motorcycles, and the words “home” and “theater” never found themselves in the same sentence.

Aspect Ratio Evolution

Aspect ratios have evolved within the worlds of display devices (TVs and movie theaters) and content producers (Hollywood) at a variety of competing and typically confusing ratios. At the most narrow, this includes the original silent films at 1.33, or 4:3 (1909-1937). This was, as you might have guessed, the aspect ratio that was adopted by consumer televisions that persisted until after the turn of the century; such old school TVs can still be found in some homes.

Other popular aspect ratios included 1.37 (Academy Ratio, beginning in 1937), 2.59 (Cinerama, from 1952 to 1974), 2.35 (CinemaScope, launched in 1953), 1.85 (VistaVision in 1954, nearly identical to today’s 1.78, or 16:9), 2.20 (Todd AO and Super Panavision 70, beginning in 1955), and the ultra-wide 2.76 (a format called MGM 65 that was around from 1957 to 1966). Why all the widescreen format introductions in the 1950s? It was Hollywood’s way of competing with 4:3 television programming, which was keeping people at home and out of movie theaters.

Since 2009, the majority of TVs sold have been 16:9, with all current television programming produced in this aspect ratio (some older content featured on Netflix and other services is in 4:3, revealed by the vertical letterboxing on widescreen TVs). Modern cinema differentiates itself with wider-than-16:9 aspect ratios produced at a few different levels.

The most popular cinematic aspect ratios today are 1.85 (almost perfectly suited to 1.78 widescreen TVs) and 2.39. 2.39 is the widest film format in common use today; it looks best in movie theaters, where it can fill the screen. Thus, by owning a widescreen TV, you can view both movies and TV shows as they were intended—it just might involve a bit of letterboxing.

[See also Goodbye Yellow Brick Plasma.]


Curt Robbins is author of the following books from Amazon Kindle:

You can follow him on Twitter at @CurtRobbins, read his AV-related blog posts at rAVe Publications, and view his photos on Flickr.

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