Reduced Image White Point When Using RCM with P4K.

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Daniel Prohaska

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Reduced Image White Point When Using RCM with P4K.

PostWed Apr 21, 2021 4:42 am

I need some urgent help with resolve colour management.

When I try to use RCM in Resolve 17 with my pocket 4K, the image gets clipped to around 768 on the waveform. None of the presets make a difference. I remember not having this issue in the R17 beta. I have searched everywhere but it seems like no one else has had this issue. I have even seen videos of people selecting the exact same CM setting and having their P4K footage look properly converted.
Changing the input colour space of clips also makes no difference to what is shown on my monitor/the scopes.

My workaround so far has been to reduce the ISO/Exposure of each of the affected clips in the Camera Raw tab and then bringing the highlights back up, but this is very tedious and I would strongly prefer if I didn't have to do it.
Attachments
Wonky Scopes.PNG
The point where the highlights get clipped.
Wonky Scopes.PNG (203.51 KiB) Viewed 560 times
RCM settings.PNG
Davinci WG RCM preset
RCM settings.PNG (13.21 KiB) Viewed 560 times
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Jim Simon

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Re: Reduced Image White Point When Using RCM with P4K.

PostWed Apr 21, 2021 2:04 pm

I saw this as well. One of the reasons I prefer to work in ACES.
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dnozadze

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Re: Reduced Image White Point When Using RCM with P4K.

PostThu Apr 22, 2021 6:55 pm

Hi Daniel,

I had this issue as well a while back. it was due to a color transform node. I set the tone mapping method to simple. Changing it to Davinci or Luminance should do the trick. If it still doesn't do it, simply increase the input/output nits value in the colorspace transform node.

Hope this helps,

Dawid
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John Paines

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Re: Reduced Image White Point When Using RCM with P4K.

PostThu Apr 22, 2021 7:21 pm

Assuming this is braw, go into the raw tab and reduce the Exposure value. That *may* recover the clipped highlights. You don't specify you GPU -- it may be hardware related.
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Jim Simon

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Re: Reduced Image White Point When Using RCM with P4K.

PostFri Apr 23, 2021 4:08 pm

Oh, John has it. I'd forgotten that I saw the issue with my older GTX 970, but not with a somewhat newer 1070.
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Daniel Prohaska

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Re: Reduced Image White Point When Using RCM with P4K.

PostSun Apr 25, 2021 4:57 am

John Paines wrote:Assuming this is braw, go into the raw tab and reduce the Exposure value. That *may* recover the clipped highlights. You don't specify you GPU -- it may be hardware related.


Reducing the exposure does bring back the data, but as I said in the post, I don't want to have to do this for every shot.

I have a GTX 1080ti and Ryzen 5 3600

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