HDR Reference White

In our blog post detailing the color correction workflow for HDR10, a reader asked where reference white and 18% gray should fall on the waveform monitor, and we incorrectly answered 100 nits for reference white and in the 40s for 18% gray. While typical white levels presently used in PQ production range anywhere from 145 – 250 nits, it is recommended that HDR Reference White (diffuse white) be 203 nits or 58% of the full PQ signal (input) level, as shown in the illustration below. It should be noted that 203 nits is only a recommendation for 1,000 nit peak brightness displays: that figure gets progressively higher for displays brighter than 1,000 nits.

If however, you’ve got graphics at 203 nits over a dark image, they may overpower the scene, whereas if the scene is very bright, the graphics may be difficult to see; larger areas of diffuse white may also appear brighter than a small area – which is why 203 nits is only a recommendation and not carved in stone!

“When creating text and graphics, it is important to prepare them for an HDR/PQ finish further downstream in the workflow as they can produce unexpected results. For example, white text/graphics created at code value 1023 (10bit) will appear as 100% white which is around 100 nits on a calibrated SDR display. This same text/graphic will again present itself at 100% white in PQ which would translate to 10,000 nits on a PQ display”. – Dolby

4 thoughts on “HDR Reference White

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  1. Thank you so much for your courteous response.
    ( I had asked you that question in your previous blogpost 🙂 )

    Looks like time for me to re-grade my BMPCC footage now.

    Also here is a small video I did in HDR – https://youtu.be/JnmbNSEOWgk

    It’s not super accurate… I just took all the old footage I had shot in BMPCC and Sony A6300 in RAW… and did simple Tone Mapping from BMD Film Gamma & Slog2 ( for Sony ) to HDR ST2084 spec ( I guess that’s why HDR PQ is… With Max Brightness set to 1000nit )

    Before shooting most of the Clips in the video above.. I used to take a small 2-3sec clip of Color Check Passport Video…

    So I guess I’ll try to re-adjust the clips based on the new Reference you provided for Diffused White and 18% Gray.

    Again Thanks.
    ( In one of clips in the video above…it’s my Nephew and my sister in a high dynamic range … I do see I am reaching the limits of the original BMPCC .. )

    1. Looks like you had fun playing around with all that footage! I like the backlighting in the shot of your sister holding your nephew. 203 nits is the official number for HDR Reference White, which is why I shared a link to a paper in the blog post arguing why 200 nits should be the standard. But that’s nitpicking! 😂

  2. Also, I am using LG CX OLED as a reference monitor.

    I override the HDMI Signal using their secret ( not a secret anymore ) menu – 1113111

    I set the Gamma to HDR ST2084 , Color to Rec 2020 and Mastering to 1000nits..

    Hope what I am doing this correct..in terms of setting up the TV for mastering…

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