Tutorials Video

Kerns Powers: Where 16:9 Actually Comes From

By Infinite Creation · Profile

unknown-2010

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At a Glance

Kerns H. Powers, an engineer at the David Sarnoff Research Center, derived 16:9 in the early 1980s as the aspect ratio that minimises wasted area when reconciling the range of film and television shapes then in use. It was adopted for high-definition television and is now the default shape of nearly every screen.

Anchor year: 1984, the 16:9 derivation
Worked at: David Sarnoff Research Center, United States
Strand: overlooked, a shape everyone lives inside

Career

The problem as it stood

By the 1980s content existed in a spread of shapes: 1.33:1 television and academy film, 1.85:1 widescreen, 2.35:1 anamorphic scope, and others. A single new television shape had to be chosen for high definition. Any choice would mean letterboxing or cropping most existing material, and the argument was mostly aesthetic and commercial rather than analytical.

What he actually did

Powers reframed it as a geometry problem. He represented each candidate format as a rectangle of equal area, overlaid them on a common centre, and looked for the shape that best compromised across the set: the rectangle whose worst-case wasted area, when fitting any of the others into it, is smallest.

How it worked

Normalising by area rather than by width or height is the key move: it makes the comparison fair between tall and wide formats. With equal-area rectangles centred together, the outer bounding rectangle and the inner common rectangle both tend toward roughly 1.78:1, which is 16:9. The result is a genuine mathematical compromise, not a preference.

What it made possible

A single agreed shape for high-definition television that no format loved and none was ruined by. It became the SMPTE and ITU standard for HDTV and then the default for computer displays, phones, tablets and online video: one of the most universally adopted decisions in the history of the medium.

What happened to him

Powers continued at the Sarnoff Center and in SMPTE standards work. He died in 2010. His name is essentially unknown outside broadcast engineering circles, despite the ubiquity of the result.

Where the credit landed

Every screen in the reader's house is the shape it is because of this analysis, and the derivation is usually reported as though 16:9 were an arbitrary committee choice. This is the standards-body pattern again: the shape belongs to SMPTE and the ITU, so no individual gets attached to it. It is also a rare case where the standards process produced a genuinely principled answer rather than a negotiated one.

Known For

16:9 is a compromise optimum, not a taste: it minimises worst-case wasted area.
Normalising formats by equal area is the move that makes the comparison fair.
The same reasoning still applies when deciding how to frame for multiple deliverables.

Knowledge Base

What You'll Learn

Aspect ratio is the most visible constraint in the medium and the least understood.

Why not just pick the most common shape

Choosing 1.33:1 would have made every widescreen film letterbox badly, choosing 2.35:1 would have pillarboxed all television. Powers' method asks a different question. Which single rectangle is least bad for everything at once, and answers it geometrically. That is why 16:9 satisfies nobody completely and works for everything adequately.

Where This Fits

16:9 is a display decision, the last link of the chain set out in A History of Broadcast Technology.

FAQ

Q: Why is 16:9 the standard aspect ratio?
A: Because it is the shape that minimises worst-case wasted area when reconciling the film and television formats in use when high-definition television was being specified. Kerns Powers derived it by overlaying equal-area rectangles for each format on a common centre.

Q: Is 16:9 the same as 1.78:1?
A: Yes. 16 divided by 9 is approximately 1.78, and both notations appear in broadcast and film documentation.

Sources

Two of his own SMPTE papers were checked against their publication records. Neither of them is the derivation itself, and saying so is more useful than citing something weaker. Checked 20 August 2026.

Kerns H. Powers, HDTV Standards Considerations for Electronic Cinematography and Post-Production. SMPTE Journal, volume 91, issue 12, pages 1153 to 1157, December 1982. Sole author, and contemporary with the early 1980s work described above.
Stanley N. Baron and Kerns H. Powers, Common Image Format for International Television Program Exchange. SMPTE Journal, volume 99, issue 6, pages 438 to 441, June 1990. The common image format is the problem 16:9 was derived to solve. No published derivation of the ratio itself could be located, so the 1984 anchor year above rests on secondary accounts rather than on a document.