Basic Question about Colour Conversion

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tpaula
Posts: 2
Joined: Fri Aug 05, 2022 8:29 am

Basic Question about Colour Conversion

Post by tpaula »

Hello,

I'm new with DCP-o-matic and I'm learning to do some basic stuff.
I have a folder with a sequence of TIFFs (RGB 8bit) exported from Davinci Resolve - this will be the video part of my DCP. I would like to know what to choose in the field "Colour" in DCP-o-matic. I thought it was Rec 709 but know I'm doubting about it. Could you help me here with this simple question? I tried to read online but I'm not sure about the correct option, it's still a bit confusing to me.

And also, if you can explain the reason behind the answer that could be great.

Thank you!
Carsten
Posts: 2146
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Basic Question about Colour Conversion

Post by Carsten »

rec.709 should be okay. You probably have worked in rec.709 in Davinci as well.

Davinci allows to set a lot of output parameters - did you check them before you created your TIFF sequence?

- Carsten
tpaula
Posts: 2
Joined: Fri Aug 05, 2022 8:29 am

Re: Basic Question about Colour Conversion

Post by tpaula »

Carsten wrote: Fri Aug 05, 2022 1:46 pm rec.709 should be okay. You probably have worked in rec.709 in Davinci as well.

Davinci allows to set a lot of output parameters - did you check them before you created your TIFF sequence?

- Carsten
Thank you for your reply!
Well, the color space in the project settings of the davinci project, from where I exported the tiffs, is the one below:
Image

The main file used in the project is a DNxHR 444. I don't know if that helps to understand the situation here...

Also in Davinci, when exporting the TIFFS I chose the "Color Space Tag" - "same as project" and the codec "RGB 8bits".
Anyway, when opening the finished DCP on davinci to preview it, it seems like the contrast is much more intense. But I also tried another DCP where I put "sRGB" instead of "Rec 709".

But well, can even I rely on the davinci preview of the DCP?

Thank you for your patience on this matter.
- Paula
Carsten
Posts: 2146
Joined: Tue Apr 15, 2014 9:11 pm
Location: Germany

Re: Basic Question about Colour Conversion

Post by Carsten »

For still images in general graphics application there is a default - sRGB, and 8Bit Full/Data range (0-255). However, Davinci is a video editor, and it is possible to create still image series that use non-standard parameters - e.g. rec.709, and limited range (16-235), which are taken from the video domain.

sRGB, though is very close to rec.709. Maybe you can open your project again, choose the TIFF sequence export, and check the advanced parameters. I think DCP-o-matic can reply properly to any of these non-standard TIFF parameters, but it would be better to have fact knowledge. You could e.g. try full range in DCP-o-matic, or sRGB. You will probably notice that sRGB vs. rec.709 does not make a huge visual difference.

Often, I am able to detect a bad limited/full range setting in the video waveform monitor - it is usually easy to detect crushed or lifted blacks.
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