4 November 2022
At this time, grading any HDR content in Lumetri is difficult and frustrating. And I would really appreciate comments from @Francis-Crossman or any other staffers as to how this is realistically expected to work
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As we all know, there are three "general areas" in SDR work: shadows, mids, highlights.
But there are FOUR in HDR workflows: shadows, mids, highlights, and speculars.
When the first attempt at allowing HDR work appeared in Premiere, Lumetri was given a fourth color wheel for speculars. That, in my testing, worked as expected. In fact, all of grading HDR worked as expected.
But then that 4th wheel was removed, and since then, there is no way in Lumetri to check and set detailed highlights versus speculars. The only useful tool for this ... is the RGB Curves tool. Period. So, ok, with some fidgety work, you can work with the speculars brightness versus lower values mostly.
If we try Basic White vs Highlights, that at first seems to do something sort of useful. But the Highlights tool affects all the way down well into the Shadows, so ... by the time you've tried to get separation in speculars with the White versus 'detailed white' with the Highlights, you've blown your midtones way the heck down into the shadows.
Requiring a regrade of ALL other tones in the image.
Color Wheels Highlights versus Mids control certainly doesn't work the upper highlights into specular region.
And yet, this task of controlling the difference between speculars and "normal" or "graphics white" values versus specular values is rather a crucial part of the task.
And I have NO FREAKING IDEA what setting the "HDR Graphics White" option does other than set a metadata item for the export. It certainly has no apparent bearing on working with HDR media. And there's no freaking way you know where that data point sits in any grade you attempt to do.
And as it is nearly impossible to set the upper graphics to where you need them, versus where you need speculars, by any tool in Lumetri, it's actually a useless bit of metadata for the user. You haven't a clue where your graphics & speculars diverge. Not even using the scopes.
Francis told me at NAB to use the 10-bit scales, and just grade as if it was 'normal' 10 bit media. That a typical HLG screen would simply know how to display the image correctly with the meta in the file.
When I pushed about knowing where the whites/speculars and total brights boundary were, he suggested just going to the HDR scales for the scopes and scrubbing through to check the values.
Ok ... that can give you a feel for where your total peak brightness sits. But tells you nothing about speculars vs whites.
I have spent many hours messing about with this, and still have no clue what I am expected to be able to accomplish here. Can I get something out that may work decently for web HDR viewing? Yea.
But I have no way in Hades to know exactly what I'm doing, nor to produce media to any pro specs.
Are we going to get improved tools at some point? We really desperately need them.
Neil
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