Re: What brightness level to calibrate to on HDR
Peak white depends on the individual HDR-capable display’s light output limitations. Not even professional mastering monitors are currently standardized for HDR. In theory, HDR programs can go all the way to 10,000 nits (2,990 fL). Currently, only laser projection can possibly reach that kind of light output.
The ITU has a recent recommended practice document for HDR: ITU-R BT.2100-0 (07/2016) “Image parameter values for high dynamic range television for use in production and international programme exchange.” http://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.2100-0-201607-I!!PDF-E.pdf . It specifies minimum black level in reference viewing environment conditions, but not maximum peak white. A calibrator will have to watch how an individual display’s peak white setting affects black level and EOTF.
It should also be noted that most consumer display environments will likely not adhere to reference conditions. Therefore, black level and shadow detail will not be perceived correctly by the viewer. Reference HDR image quality will not be fully realized in a non-reference viewing environment, with more than 5 nits of ambient light under the ITU recommendation. The new SMPTE revised viewing environment document has yet to be completed.
Best regards and beautiful pictures,
Alan Brown, President
SMPTE, THX, ISF, Lion AV Consultants
“Advancing the art and science of electronic imaging”