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10bit/ch display panels are becoming common. The latest generation UHD TVs can display 10bit/ch, some consumer TVs have as high as 1000nit output. Very recently HDR computer monitors have (finally) come on the market. And both LG and Sony now make smart phones that claim to have HDR-capable display screens.

How should we process our still photo RAW files to display (with maximum dynamic range fidelity) on the HDR capable displays? (Actual 10bit/ch, or greater DR)

What software should we be using to process the RAW files?

What output format should we be using?

One would think that JPEG2000 is a logical choice, given it is used in Digital Cinema to support 12bit/ch. But there is little support for it in the still-camera community. (E.g. do any still cameras generate JPEG2000 internally?)

The disparity is likely to get worse, as we're probably going to see home theater projectors with 12bit/ch and high-NIT capability in the future. We already have them in commercial theaters. The Dolby Vision encoding standard for home video supports 12 bit/ch. (maybe HDR10+ does too) Consumer use of 12bit seems only a matter of time.

How do we leverage the fancy sensors in our DSLR cameras (that often cost more than our expensive HDR-capable UHD TV set) to actually display 10bit/ch wide dynamic range still photos to those TVs, computer monitors and smart phones? What is the RAW file processing software chain? What is the output file standard we should use?

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Your first step is to find out what formats the TV can decode. JPEG2000 is one candidate TIFF is another, but the TIFF spec is a can of worms allowing creation of new tags with alternative decoding mechanisms. There are many TIFF decoders that don't understand all the variants.

Second test: Can you actually see 10-12 bits of dynamic range. Paper doesn't even support 8 bits -- the contrast range is about 100:1 for a well made print, less than that for halftoned images.

The advantage of deeper bit ranges is the ability to remap to a lower contrast range without artifacts.

Due to the way the human eye reacts to light, the only way I suspect that you can see 10 bit dynamic range is if:

  • Lighting external to the screen is minimal (trip over the dog level)
  • The image itself has very little zone IX and X regions, and not much VII. Too much white, and your eye constricts, which means you can't see squat in the shadows.

Zone system: https://en.wikipedia.org/wiki/Zone_System

  • 8 bits per channel really isn't enough. See marksblog.com/gradient-noise – Mark Ransom Feb 2 '18 at 6:14
  • There are 1000 nit displays. Hwood may standardize on 4000 nits peak luminance for post. SONY demoed a 10,000 nit display at CES2018. NVIDIA said at ces2017 that their prototype computer lcd panel could be driven at 12 bit/ch. Their current computer display (working with ASUS and others) is 10bit/ch HDR LCD at 120 fps. The curve ball may be Samsung, with their non-organic (ie conventional) LED displays. No longevity or burn-in issues, no lag, potential for high luminance, color depth limited only by quality of the DACs driving the LEDs. It appears that HDR TV is here now. – RMEnger Feb 2 '18 at 10:40
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    I'm not doubting that the display can do this. I'm saying that except under special circumstances I (maybe you, but certainly me) can't see them. A nit is a unit of light intensity. 10,000 candelas per square meter just means it's bright. It does not say that portions that are shining at that level on half the display will still allow you to distinguish between levels of 10 and 20 elsewhere on the screen. – Sherwood Botsford Feb 3 '18 at 16:21
  • @RMEnger The needs of a screen intended to display video (in which the contents of the scene change dynamically from one frame to the next) are not the same as the need to edit a static photo so that the full range of brightness levels it contains can be perceived by the viewer simultaneously. – Michael C Mar 4 '18 at 0:12
  • I want to confirm that @Sherwood Botsford is incorrect. He is assuming he cannot see the difference. The trick to understanding HDR benefits is to actually see a proper HDR display in person. What's magical about them is you visit a HDR display -- the pinpoints of light from things like neon signs and pinpoints of light are insanely bright without interfering with my ability to see super-dark shadows. So I'm able to see the 1nit greys. – Mark Rejhon Apr 3 '18 at 23:28

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