4k vs. 2k vs. HD (part 1 of 3)

April 3, 2012
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“Immersive” vs. “Involving” experiences.

The 2k spec, for all intents and purposes, is 2048 x 1152, for a total of 2.36 million pixels. HD is 1920 x 1080, for a total of 2.07 million pixels. In other words, HD has 88% of the area (total pixels) that the 2k spec has. On a linear measurement, the difference is only 128 pixels…which only as big as that checkerboard over there.

128x128checkerboard

This wee checkerboard is 128x128 pixels. It's width is the difference between HD and 2k.

That edge-to-edge resolution difference between HD and 2k is only 6%, which most mortals can’t really see.

The 2k spec comes from the digital scanners that scan a film negative from edge to edge. The reality is that Super 35 is, for example, “over-scanned” and the 2048-pixel width of the scan includes some material out of frame, like edge numbers and so on. The total image area of a 1.85:1  aspect ratio is closer to 1850 x 1000 pixels…or 1.85 million pixels total. So film scanned at 2k for digital intermediate results in an image somewhat less than HD, but at a superior bit-depth and color space to any HD cameras producing a REC709 image. Why has this been considered “adequate” for the D.I. process when film enthusiasts laud the superiority of film as 4k or even 8k?

The fact is, film prints degrade with every viewing, so the only time you’ve ever seen 4k in your life is on opening night when the movie first hits the theaters. By the time the film has been run through the projector a few times, the lamp has baked the emulsion on the print and detail has been erased. And it was only ever 4k if the film was color-timed using the traditional process (no D.I.). If you’ve seen an Imax movie that was originated on Imax cameras or 65mm, you’ve seen 4k. If you’ve put two Apple Cinema displays side by side you’ve seen the width of 4k.

The fact is, our experience of watching movies is a long history of 2k or less.

More and more cinemas are using digital projection. Currently 96% of all movie theaters use 2k digital projection, so it doesn’t really matter what the film was originated on (film, digital, HD, 2k or 4k) the maximum resolution of any film we’re likely to see this year is 2k.

The 17″ MacBookPro that I’m currently writing on has a 1920×1200 display (HD + some “leg room”). When I’m about 12″ away from the screen (one screen height) I can’t see individual pixels anymore. At closer than 12″, I can start to see individual pixels across about a 1 degree arc of my vision, where the fovea of my eye has the highest density of light-sensitive cells. Anything outside of that sweet spot is too indistinct.

Is 2k enough?

Part 2 of 3

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2 Responses to 4k vs. 2k vs. HD (part 1 of 3)

  1. tambwejoven on February 23, 2015 at 7:30 am

    okay it good to help people about a new form 2k

  2. » Canon – Too Big? Part II Alexei's Alexa on April 16, 2012 at 8:28 pm

    […] any other camera to deliver 4k. The only way to get 4k on a screen was to scan 35mm film at 4k (a debatable advantage over 2k), The HD spec was enough for Panavision when they created the Genesis, enough for Sony when they […]

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