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Geometry, aspect ratios, and why you should love those black bars on your TV

Since the dawn of man, few things have united us spindly bipeds like our common, loathsome, blind-rage hatred for black bars in our video. Black…frickin’…bars?! Instead of the movie?!? How dare they?! HOW…DARE…THEY?!?

This is America. We want more of things, not less. We want 244-ounce sodas with unlimited refills, and hamburgers with numerous patties covered in enough sauce and cheese to make the cholesterol fairy blush, and chickens stuffed in ducks and crammed into turkeys! We deep-fry cubes of butter and have “smalls” that would be extra-larges anywhere else in the world. And, dammit, we want movies filling the entire screen with picture, not black bars!

And nothing sets a TV watcher’s blood a-boilin’ like seeing a bastard, red-headed stepchild of a rectangle being placed onto a perfectly sensible square

If I learned anything from my high school geometry teacher, it was that a square is a square is a square. IS A DAMN SQUARE! It is always the same. Always. Big, small, anywhere in between, you can always count on a square to have the same 1 to 1 proportion.

But a rectangle…? Ah, those things are right bastards, coming in all manner of sizes and proportions. 1.78:1, 2.20:1, 2.35:1, 2.39:1, 2.66:1, 2.93: 1… How dare they?! Rectangles exist outside the boundaries of any civilized society, with no respect to a video watcher’s moral high-ground and common decency. And nothing sets a TV watcher’s blood a-boilin’ like seeing a bastard, red-headed stepchild of a rectangle being placed onto a perfectly sensible square and filling it with God-awful, lifeless pixel black bars.

It’s at this point that I’m undoubtedly going to blow a few minds…the rectangle is actually the right way. And black bars actually mean that you are watching more of the movie – all of the movie – not less of it. For movies, black bars are a – wait for it – good thing!

So, what if there was a way to actually come to terms with the hateful rectangle? To embrace it as the way to view films in all their sadistic rectangular glory? To tame the rectangle, to own it and make it the preferred way to watch movies at home? What if…

Understanding the Rectangle

First, we need to understand why a rectangle is and is not always the same. The means a quick lesson in math, video technology and artistic intent.

First, aspect ratios are expressed in a ratio of width to height. A ratio of 1.5:1 (said “one point five to one”) would be one-and-one-half times as wide as it is tall, and a ratio of 2:1 would be exactly twice as wide as tall. Our modern HDTV displays have a ratio of 16×9 which is reduced down to 1.78:1. (That’s it for the math stuff. Really. Though, you know, quick shout out to Pythagorean Theorem, yo! )

Now, what we refer to nostalgically as a “square” in our old TVs was actually not a square at all, but a thinly disguised rectangle, albeit one with very square-ish proportions. The TV that you grew up with had an aspect ratio of 4×3, or 1.33:1, or roughly a third wider than it was tall.

4:3 TV
Image used with permission by copyright holder

Was this arbitrarily selected on the geometric whims of Philo Farnsworth and RCA? No. The 4×3 aspect was selected because it very closely resembled the Hollywood film standard employed from 1932-1953. Thus it made a lot of sense for the NTSC (National Television Standards Committee) to adopt it as the shape for TV when it came out.

Movies were filmed in this shape, TV was in this shape, the stars were aligned and video lovers the world over rejoiced. Of course, there was no such thing as Blu-ray or DVD or VHS tape, but still, you have to imagine Caligula-like celebrations where videophiles of the day gathered and drank wine off each other’s bellies and plucked grapes from unmentionable orifices celebrating the beautiful synergy of film and TV sharing one singular aspect, dreaming of a day when they would watch films at home on a screen completely devoid of devilish black bars.

Problem is, Hollywood worried that if people could have the same experience at home, they’d stop coming to the theater and just wait to watch the movie at home. So, Hollywood did what Hollywood can do: they changed the game.

And black bars actually mean that you are watching more of the movie – all of the movie – not less of it. For movies, black bars are a – wait for it – good thing!

They decided to offer a much more immersive, wider presentation and went to 35 mm film stock with an aspect ratio of 1.85:1 or almost twice as wide as it is tall. Then when new technologies such as 70 mm and anamorphic became available they moved to those and went to even wider 2.20:1, 2.35:1, 2.39:1 and even 2.93:1 – almost three times as wide as it is tall – for Ben Hur. The rectangular Kraken had been released and there was no putting it back.

Today, no one puts baby in a corner, and no one tells a director what aspect ratio to use. Directors select the aspect they prefer to use artistically to tell the story they have in mind, with 1.85:1 often being used for comedies and character driven films and 2.39:1 used for big sweeping vistas, epic films and summer blockbusters. But ultimately, it is the director’s decision. Steven Spielberg typically prefers 1.85:1, George Lucas 2.39:1, James Cameron releases films in different aspects, and Chris Nolan used multiple aspects – 1.78:1 and 2.39:1 – within his Dark Knight movies. At the end of the day, it is probably close to a 50/50 split as to whether films are in the 1.85 or 2.39 format.

Embracing the Rectangle

When you place a rectangle onto a square (or, more accurately, a rectangle that is more square-ish in ratio) you basically have two options: keep the rectangle a rectangle or change the rectangle into a square.

Changing rectangles into squares isn’t as common any longer with 16×9 shaped TVs, but was commonplace with older 4×3 TVs and was done via a process known as pan-and-scan. They basically zoomed in on the image, filling the frame vertically and whacking off the side bits. Of course, these “side bits” contained a significant bit of picture information and can often result in completely destroying the composition and balance of a film. This graphic shows how much of the image is lopped off to get different aspect to fit onto a 4×3 screen.

Film Aspect
Image used with permission by copyright holder

The other option – a word that raises the hackles of many home viewers across the nation – is called “letterboxing.” With letterboxing, you keep the film in its original glorious rectangular shape and place it onto the square, letting the chips fall where they may and then filling the rest of the screen with perceived contrast improving black bars. Sexy? No. But it allows you to see the film in the way that the director intended. And, seriously, who amongst us will admit to not wanting to watch Gigli, Battlefield Earth and Piranha 3D in their full cinematic splendor?

Pwning the Rectangle

The problem with most rectangle-on-square viewing sessions is that you are dealing with a smallish square to begin with, and putting a smaller rectangle into the already small square is just salting the TV watching wound. Also, a typical TV screen is fixed in size; what you bring home from the store or unpack from Amazon is what you get and what you’ve got. Unless, you want to, you know, buy a new set or whatever.

But for home theater owners with a front projector, there is another option to the fixed rectangle-on-rectangle conundrum. With a front projector, you have the ability change the size and shape of your screen either physically – often impractical – or with masking. Masking is black material that comes in from the sides or top or – if you’re especially bold – both the sides and top of the screen to crop in just the part that you want to be visible. ie – no more black bars, and full picture in all its cinematic glory. This, incidentally, is exactly the way they handle multiple aspects in the commercial cinema.

Instead of a 16×9 (typical HDTV-shaped) screen, many home theaters are moving to a 2.35 or 2.40:1 aspect screen. The benefit of this is that big, epic blockbuster films get bigger, more epic and even blockbuster-ey being viewed larger than TV programs. The result is that movies like Star Wars and Lord of the Rings and The Matrix get larger and more strong-like-bull in size than the Teen Mom and Honey Boo-boo re-runs you’ve secretly been watching. Behold the size differences here:

That’s 33% more square inches of video watching pleasure! Are you not entertained?!?

Two Ways to Wide

There’s two ways to make widescreen projection work at home, one is by zooming and enlarging and the other is with scaling and an anamorphic lens system.

Zooming is a relatively simple and very inexpensive option where you just make the image physically bigger until the black bars are blown off the screen and only the active image appears. With the deep black levels that many projectors can achieve today, the light spill from the black-bars that is zoomed off the screen is hardly visible, if at all. Additionally, many new projectors from Sony, JVC, Epson and Panasonic include an awesome feature called Lens Memory. This allows the projector to store memory positions for the lens and screen size to automatically zoom, focus and reposition for either a 16×9 or 2.35 image at the press of a button.

The second option is the same one employed in commercial theaters and involves the use of a separate anamorphic lens that sits in front of the projector’s primary lens. Here’s an image of the Panamorph UH480 lens that I use with my Marantz projector:

Marantz PJ with lens
Image used with permission by copyright holder

The leading manufacturers of anamorphic lenses for the home market are Panamorph and Schneider and they work with almost every model of projector. Using an anamorphic lens is a two-step process. To illustrate, here is an image from The Empire Strikes Back Blu-ray completely unaltered:

AtAt widescreen
Image used with permission by copyright holder

The image is letterboxed and far smaller than a 16×9 image. The AT-AT walker is small and unimpressive. One good flick and it would probably topple right over. The Empire would not be pleased. The first step is to digitally stretch – or scale – the image vertically. This process can happen inside the projector, in the Blu-ray player or in a modern A/V receiver. The image is stretched 33% to fill the vertical portion of the screen and eliminate any black bars. Once stretched, the image looks like this:

AtAt vert stretch
Image used with permission by copyright holder

The geometry is now incorrect, making a circle into an oval, or an AT-AT into a gangly, awkward creature that is picked on at school and laughed at in PE. You are now using the entire vertical resolution of your projector – all 1080p worth – instead of “throwing away” hundreds of thousands of pixels to make those hateful-hateful black bars. This also gives a slight bump in light output. To correct the geometry back to accurate, the anamorphic lens moves in front of the primary lens (either manually or automatically with a transport called a sled) and optically stretches the image horizontally, resulting in a picture that looks like this:

AtAt anamorphic
Image used with permission by copyright holder

Just look at that magnificent AT-AT bastard now! Powerful! Massive! Inspiring fear and crushing Rebel scum-filled hearts the galaxy over!

With front projectors and screens getting cheaper – and better – constantly, the dream of owning a truly awesome, black-bar-less home theater system is well within the grasp of many people now. Even people whose last names don’t end in Gates or Buffett.

But even if a widescreen projection system is beyond your means, remember that the next time you see a bit of black above and below your movie that you are actually seeing more of the film. The actors on the very edges of the screens will thank you for it.

4:3 TV image courtesy of [vita khorzhevska/Shutterstock]

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John Sciacca
Former Digital Trends Contributor
John Sciacca is a full-time custom installer/designer and an a-lot-of-the-time writer whose groundbreaking columns, reviews…
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