Originally Posted by AdamAttewell
Struggling a little with calibrating HDR can you point me in the right direction?
I don't use CalMAN, so take the following replies with a grain of salt.
I found ViperLogic's workflow over on the HDR thread & have been following it but I struggling to get my EOTF curve to match the target even with maxing out the gamma controls except points one & nine.
I have then maxed out the contrast control but I still cant match the EOTF curve.
The HDR ST.2084 PQ curve is supposed
to be "absolute" (unlike SDR gamma which is relative). However, most people find it is far too bright for projectors in a dark room, and scale the curve down in luminance.
I am using the Digital Cinema mode with power consumption on medium for this run.
I have followed his guide as closely as possible the only things I am unsure are about are as follows:
1. When using the two point grayscale controls I need to have the gamma formula “ST 2084 HDR” selected & then change to “ITU BT2390 EETF” when using the gamma controls like this?
BT.2390 is for tone mapping of the highlights (and also the shadow details, but that's the topic for a separate discussion). If you don't use it, all the highlights beyond the projector's peak luminance will be clipped.
2. In CalMAN there is no option to set “Diffuse White” but it is probably called a different name?
It's simply called "White Level".
Would this be the “use measured white level” option?
"Use measured white level" would apply a multiplier to scale the target curve such that the measured white level becomes the target white level.You would normally only do that if the display already has an HDR curve that you're trying to fine-tune to match ST.2084.
“Set "Diffuse White[nits]" to what you personally would like, one school of thought is set it to what you use for 100% for SDR movies eg somewhere between 20 or 40 nits.”
If you're using a custom gamma curve the "measured white level" has no significance and you should set the White Level to a suitable level based on your preference and the peak luminance you're getting. 20-25 is a good starting point; a higher value will make the overall picture brighter, but less “HDR-like”.
3. Again there is no “Target MaxL” option in CalMAN, I am unsure if this is called “use measured white level” also or is something else?
You can't really set Target MaxL; it's whatever peak luminance you're getting.
4. Last but not least which Colorspace should I be using? BT.2020 HDR or D65 P3?
HDR10 uses BT.2020 colorspace. However, most consumer displays can only reach P3 gamut, so you would aim for P3 during calibration. I'm not sure if that's built into the CalMAN workflow.