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prathvish hegde
problems rec709 to dci_xyz in resolve
on Jun 5, 2013 at 2:12:52 pm

hi guys ,

we have graded a short film shot on 5d and we graded the film in rec709,D65(x=312,y=329,dolby prm) and now the client wants a dcp output.
i tried to export the short film by applying the rec709_2_dci_xyz LUT provided in resolve and with the render setting as tiff xyz 16bit.
the problem is the dcp guy (DCP done on clipster)says the tiff is in RGB colourspace(he tried changing the colourspace even then),the output comes same as the source file he got from me that is greenish.

what could be the reason? am i doing any thing wrong?

please throw some light.

prathvish hegde
colorist
(DaVinci Resolve and 2Kplus)

http://www.youtube.com/playlist?list=PLRPJQ3fIEoojI3JMa4rHKb9gqq8VeIZ81


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Pepijn Klijs
Re: problems rec709 to dci_xyz in resolve
on Jun 5, 2013 at 2:26:47 pm

I think you are apllying the conversion twice. Once with the LUT and the second time by rendering to TIFF XYZ.

So try with just the TIFF render options and see what they say.

But isn't Clipster itself a better option to do the colortransform? I mean, isn't it easier to deliver in TIFF RGB and let Clipster do the magic?

In my little experience doing DCP's I never got a decent result out of Resolve. Luminance shifts and white point shift. (too yellow).

Editor/Colorist, Amsterdam, The Netherlands
http://www.pepijnklijs.nl


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prathvish hegde
Re: problems rec709 to dci_xyz in resolve
on Jun 5, 2013 at 3:04:28 pm

i had given them rec709 and i was not happy with the output so wanted to see if converting to xyz and exporting is a better option.

i will try by exporting xyz tiff without applying rec709 to dcixyz lut.

prathvish hegde
colorist
(DaVinci Resolve and 2Kplus)

http://www.youtube.com/playlist?list=PLRPJQ3fIEoojI3JMa4rHKb9gqq8VeIZ81


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Juan Salvo
Re: problems rec709 to dci_xyz in resolve
on Jun 5, 2013 at 4:16:00 pm

Pepijn is right with the diagnosis of the problem.

However, the correct way to do this conversion, would be to apply 709-xyz lut and render tiff as RGB.

The conversion itself is fairly standardized, but it's critical to have a properly calibrated 709 monitor. If you don't have that, there is no telling what will come out.

What's more, you've still got the issue of the exhibiters calibration to contend with. Though I think theater owners tend to be pretty good about that.

Colorist | Online Editor | Post Super | VFX Artist | BD Author

http://JuanSalvo.com


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Pepijn Klijs
Re: problems rec709 to dci_xyz in resolve
on Jun 5, 2013 at 6:47:53 pm

[Juan Salvo] "Pepin is right with the diagnosis of the problem.

However, the correct way to do this conversion, would be to apply 709-xyz lut and render tiff as RGB."


Totally right there Juan, sorry for the confusion, I forgot about that. I actually wonder why that output to XYZ TIFF option is in Resolve, as it seems to be unsuitable for any kind of use. You have a clue Juan?

Editor/Colorist, Amsterdam, The Netherlands
http://www.pepijnklijs.nl


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Juan Salvo
Re: problems rec709 to dci_xyz in resolve
on Jun 5, 2013 at 6:55:29 pm

Yes. It's perfect when you're working in P3.

Colorist | Online Editor | Post Super | VFX Artist | BD Author

http://JuanSalvo.com


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Pepijn Klijs
Re: problems rec709 to dci_xyz in resolve
on Jun 5, 2013 at 7:14:00 pm

Really? Never knew... Thanks for clarifying that!

Editor/Colorist, Amsterdam, The Netherlands
http://www.pepijnklijs.nl


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prathvish hegde
Re: problems rec709 to dci_xyz in resolve
on Jun 6, 2013 at 6:20:59 am

thanks jaun and pepijn.

will try that thankyou guys

prathvish hegde
colorist
(DaVinci Resolve and 2Kplus)

http://www.youtube.com/playlist?list=PLRPJQ3fIEoojI3JMa4rHKb9gqq8VeIZ81


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Chris Martin
Re: problems rec709 to dci_xyz in resolve
on Jun 6, 2013 at 2:44:39 pm

We don't get a proper transform using the Resolve preinstalled 709toXYZ LUT on projects that have been graded to 709 SMPTE Head Range (64-940) viewing environment. My guess is that the Resolve 709toXYZ LUT is not accounting for making color decisions at Head Range.

Chris


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Juan Salvo
Re: problems rec709 to dci_xyz in resolve
on Jun 6, 2013 at 3:08:32 pm

Internally resolve is always operating in Full 0-1023 range. So if you're grading internally with headroom (60-940) then yeah, nothing will behave appropriately.

Colorist | Online Editor | Post Super | VFX Artist | BD Author

http://JuanSalvo.com


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Chris Martin
Re: problems rec709 to dci_xyz in resolve
on Jun 8, 2013 at 4:27:18 am

Working full range internally but grading sdi out to head range. Since Resolve's lut is based on full range it can't do a proper transform of decisions made in in 64-940.


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Juan Salvo
Re: problems rec709 to dci_xyz in resolve
on Jun 8, 2013 at 5:00:25 am

Sure it can. You just need to add a shaper lut. I'm a bit confused by what you mean working full range internally but grading out to head range? If inside resolve your intended black point (let's say it's true black) is falling on 0 and your intended white point is on 1024. Then you're working full. If it's at 64-960 (internally in resolves scopes, regardless of outside scopes) then you're not working full, and would need a shaper lut feeding into the 3d transform.

Colorist | Online Editor | Post Super | VFX Artist | BD Author

http://JuanSalvo.com


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