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Old 20th June 2018, 00:41   #7  |  Link
WorBry
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Join Date: Jan 2004
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OK, here's one of the better attempts at correcting the 'Cave' clip in Resolve using just the RGB Channel Mixer for the color balancing.



The 'soft clip' strategy for dealing with the 'skylight' worked out quite well. It did increase the gain some to compensate for the 'soft-clip'. Could be a bit brighter I guess but I tend to prefer a moodier look.

I think it achieved what I set out to do i.e.

Quote:
Originally Posted by WorBry View Post

...2. Use the 'skylight' opening as neutral (daylight balanced) reference for the channel mix in the first instance.

3. Adjust the mix to achieve best compromise with the 'white' stripes on the Sergeant Major fish.
And by that I'm referring to the fish in the foreground that does appear to be receiving some additional light from above-behind the camera. The fall-out from that however is that the fish just back from it have retained more of a blue/magenta tint. Whatever way I adjusted the mix to try and offset that I was always fighting (and losing) a yellowish or yellowish/green cast to the light flooding in, which didn't look right at all. I sneaked a bit of red in there to bring out some color on the rocks - they looked pretty bland otherwise. In hindsight - bit too magenta maybe, but that could be easily rectified, and all that would do is turn the residual tint on the fish more blueish.

Anyhow, this was the best compromise I could find and evidently there are limitations to what can be done with the Channel Mixer alone in a scenario like this. It clearly begs for further fine tweaking with the 3-way Color Wheels.

With that, I'll give it a go in VDub2. Depending on how it comes out of the Channel Mixer, I see what can be done to tweak it with the '6-axis corrector' or maybe RGB curves.

Edit: Just realized when I brought the rendered file (Cineform) from that Resolve grade into VDub2 to take the above frame shot I forgot to specify full range luma in the decode interpretation options. Here it is again:



That looks better. Some very pale yellow discoloration in the 'skylight' opening is showing through there, but it's barely noticeable. That said, having gone on to replicate the color correction process in VDub2 I am having issues with that. Need to look at it more closely.
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Last edited by WorBry; 20th June 2018 at 06:58.
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