getting tint on DCP output from DCP-O-MATIC

[UCCP]

Dear Team ,

We are using DCP-O-MATIC ver 2.10.5 & using DPX sequence as source for DCP making .
It has been observed tint on exported output . We have tried different sources but having same
result .
Please find below link with sample images , screenshot of settings
https://drive.google.com/drive/folders/ ... sp=sharing
Please let us know your inputs on this
Thanks
Best Regards
Amol

[Carsten]

How (and why) do you create the dpx files?

I see that you set P3 for color conversion. Are you sure your source dpx files are P3? Photoshop tells me it is actually sRGB, so I suggest you choose sRGB and create a short test. All other settings appear okay to me, except that you should probably set the J2K encoding rate somewhat lower, e.g. 220MBit/s to be on the safe side.

I see that your source examples is black and white. It is not easy to create actual black and white in electronic projection, but usually, the audience adopts to a slightly tinted black and white presentation quickly. It may be more complicated when your work switches between color and black and white.

If you chose P3 instead of a correct sRGB, the tint will not be 'slight', but quite obvious.

- Carsten

[UCCP]

Dear Carsten ,

Thanks for your reply .
We are exporting DPX sequence from Resolve , color grading software with color space P3 .
In photoshop , it is obvious that it will show RGB . Please correct , We understood that DCPs are in color
space P3.
Regarding source element , same B&W sequence exported from easyDCP software , does not shows any tint .
Our audience are not household persons but a technical team who are checking quality of DCP.

Please give concrete solution for this issue

Best Regards
UCCP

[Carsten]

If Photoshop signals it as sRGB, it means it is interpreting it as sRGB as well. And if it shows neutral in Photoshop interpreted as sRGB, this is a clear indication that it IS actually sRGB.

This is what I get when I create a DCP from DPX00086673.dpx with P3 interpretation in DCP-o-matic (I assume DPX00086673.dpx is your actual source file) :

vlcsnap-2021-08-30-15h13m01s069.png

This is it's histogram - it shows a clear green shift:

Bildschirmfoto 2021-08-30 um 15.21.40.png

This is what I get when I set DCP-o-matic to interpret as sRGB:

vlcsnap-2021-08-30-15h18m25s731.png

This is it's histogram - it is (nearly) neutral:

[Carsten]

Bildschirmfoto 2021-08-30 um 15.22.51.png

I don't know your background in Resolve - but it is possible to grade in P3, but still export in sRGB or rec.709


DCPs are not in color space P3 - they are in color space X'Y'Z' - they are converted to P3 within the projection system. So, all DCP mastering software will usually convert from source/master color space into X'Y'Z', and server/projector will convert from X'Y'Z' to P3 for display.

That said, not sure if DCP-o-matic is interpreting dpx as P3 correctly.


BTW - DCP-o-matic 2.10.5 is severely outdated.