Using ACES to archive to 2020 ST2084 4000nits

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Hi to all!

I’m working on a archiving workflow that involves ACES but does not archive into ACES Ap0. The reason I’m looking into this is to offer our clients a way to archive at a budget price point.

As you all know archiving to uncompressed EXR can be “heavy duty”. So I thought that there might be a cheaper way to do this. Again I know it’s not the “ACES way” but I’m just trying to think outside the box for our less fortunate cinema scene. And would be great to have some feedback.

I’l start off by saying that this could be done before and after the grade.

It’s pretty simple:

  • Export to ST2084 4000 nits in REC2020 ProRes 4444 from the grading session.
  • Conform to files and apply a 2020 ST2084 IDT and view thru the correct ODT (DCI-P3 or REC709).
  • Online and package
  • Export all versions of master (709, P3 etc… we don’t much HDR yet).
  • Make a final version of the movie (textless) in ST2084 4000 nits REC2020 for archiving.
  • If “non graded master” needed just go back to grade and export without any grades and reconform.

Would be curious to know if this is viable.


would love to hear from some of the @ACES crew, @nick or @jim_houston. :wink:

Tried the same workflow today in ACEScct. Worked super well also. But not sure if all of this is “legal”! Or, even worth the bother.


from a math standpoint, ST2084 only needs 12 bits. since EXR is 16, you have saved space.
As to lossy Prores or lossless EXR compression, that’s up to you.

Thanks Robert! Testing DWAA this week.