Monitor Brightness for Grading P3 vs Rec 709?

[Peter Moretti]

FWIU, to grade in the P3 colorspace, the monitor should have a brightness of 16Fl. And for Rec 709, 35Fl.

Is this correct and normally followed?

Thanks MUCH!

 

[shannyla]

16 Fl is the luminance that you should get on a screen from a DCI projector running in P3 mode, and if that is what you are using to grade then that is what the luminance should be.

If you try and run a monitor at 16Fl you run into the issue that the perceptual brightness is far lower than 16Fl from a projector and this affects the grading process adversely.

I may be wrong but I believe that the far greater area of a screen compensates for the lower brightness. By the same token a digital projector run at 30Fl, in addition to using an almighty amount of electricity, looks a bit like staring at the sun and in colorimetric terms appears to be very wrong.

In our grading suites we run the monitors at 30Fl, which gives us a perceptual match when we take the same material to our digital cinema, which uses a Christie CP2000 projector running at 16Fl (pretty much the standard digital cinema projector).

I suspect any number of other contributors will be able to prove that I'm wrong, but that has been my experience over the last ten years of working with digital cinema.

 

[Graeme Nattress]

Yes, area and brightness go hand-in-hand with one another.

Graeme