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macrumors regular
Original poster
Aug 8, 2015
The new iPad Pro support HDR video, how far iMac screens are from HDR?


macrumors demi-god
Aug 28, 2015
The new iPad Pro support HDR video, how far iMac screens are from HDR?
There are TVs that have 400 nit brightness but support HDR. Do they display HDR as well as TVs with 1,000 nit brightness? No but it does work to a lesser degree.

The 500 nit brightness means the iMac is closer to being able to display HDR content. Part of the issue is making macOS support HDR.


Jun 30, 2007
Here I was thinking the new iMac Pro would roll with a 4K HDR screen..

Isn't it HDR? HDR10 and 10 bit color only covers 90% of the P3 color space. The iMac Pro supports P3 on it's 5K display. Dolby vision with 12 bit color and the 2020 color space exceeds that, but there aren't any monitors that can reproduce it.


Standard HD TV and Blu-ray uses 8-bit color encoding and displays colors in the Rec. 709 color space. Rec. 709 covers approximately 33% of the human visible spectrum. Dolby Vision uses 12-bit color encoding and can display colors in the Re. 2020 color space which encompasses a bit more than 57% of the visible spectrum. The Ultra HD Premium standards for HDR TVs stipulate that a screen must be capable of handling 10-bit color encoding and be able to display 90% of the colors in the DCI P3 color space which falls between the narrower color gamut of Rec. 709 and the wider gamut of Rec. 2020.

For Dolby Vision mastering purposes Dolby recommends using monitors supporting the P3 color space:

The specs for the new iMac Pro specify P3 and 30 bit color (from the keynote) so it should even handle Dolby Vision 14 bit if that ever happens even if the monitor can't reproduce it. [The tech specs on the Apple website says "Support for 10-bit spatial and temporal dithering" so I'm not sure how that fits in].

Luminance is another issue.
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macrumors 68000
Sep 14, 2007
HDR is about the peak brightness that the screen can reach. The truth is there are HDR TVs with 400nits of brightness but they are not UHD Premium certified - which means that the screen to be certified has to reach at least 1000nits (and be 4K/UHD).

The iMac is up to 500nits - so it could support HDR but I am not sure if that would be a software update or something to be implemented to the hardware either physically (in which can it isn’t) or via firmware.

But even if it did support it the HDR wouldn’t be as good.

However ask yourself this..... Do you want to be sat in front of your iMac watching a film at 500nits!? I would say NO.

Your not sitting next to a TV so its different. (I accept that there are scenarios where maybe you would watch something on the iMac from far away but Apple don’t cater to exceptions to the normal use.)
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