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HELP ! issue of color/contrast shift while exporting in XYZ

A

antoine polin

Hello,





I have a big problem : I’m asked to deliver a TIFF XYZ master of the movie I graded. I worked in a color managed environnement (RCM) with TCS DWG/INTER 1000 nits and OCS in REC709 2.4


After deliver, I put the TIFF file on the timeline for a check. InputColor Space is well recognized (DCI XYZ) but I get a small shift of color and contrast while comparing with the original file.


I also tried to export a 4444XQ (and changing the output colorspace in XYZ for the deliver) and putting it back in te timeline.. same thing..


I even tred a new project and compared a REC709 24 export with the TIFF file. Same thing…





Any idea please ???





Thank you, have a good day !
 
Sounds like a data levels mismatch. Can you reconfirm what your export data levels are on the deliver page vs. what Resolve is auto-detecting when you bring it back in?
 
levels are checked and everything is fine. It's not only a gamma /luma shift, there is also a slight turn to green and more sat. When I export in Jpeg 2000 Kakadu (so XYZ also) everything matches.
 
No I didn't. I know this is the way, but mathematically, I don't understand why transforming 709 24 into XYZ then bringing back XYZ in REC709 24 in a colormanaged project would bring such a shift... too mich of a difference ? I know XYZ has no boundaries...
But when I export the movie in JPEG2000 Kakadu, it converts it automatically in XYZ and when I bring back the JPEG2000 suite in my project, there is no shift at all... The shift only appears when :
- I export TIFF 16 bits XYZ (Resolve make an automatic conversion to XYX, no need to change the OTT
- If I change the ODT to XYZ and export like a prores 4444
 
antoine polin said:
No I didn't. I know this is the way, but mathematically, I don't understand why transforming 709 24 into XYZ then bringing back XYZ in REC709 24 in a colormanaged project would bring such a shift... too mich of a difference ? I know XYZ has no boundaries...
But when I export the movie in JPEG2000 Kakadu, it converts it automatically in XYZ and when I bring back the JPEG2000 suite in my project, there is no shift at all... The shift only appears when :
- I export TIFF 16 bits XYZ (Resolve make an automatic conversion to XYX, no need to change the OTT
- If I change the ODT to XYZ and export like a prores 4444
Click to expand...
If you’re physically changing the ODT to XYZ before making a DCP you will get some over saturated colors for certain colors (red especially). If you’re just letting the Kakadu do the conversion it should be fine of you’re viewing in colormanaged project.
 
true that there is no problem with the Kakadu. But changing the ODT doesn't make some colors oversaturated, it makes it a little more exposed (no video/full levels related) and a little shift in colors. Nothing out there, but still, not the same thing. I Can't figure it out
 
I think exporting from Resolve to TIFF XYZ matches to linear gamma (1,0) while X'Y'Z' matches 2,6 for DCI.

If you use ACES, you should find both.
 
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