Best way to color correct my underwater videos? Obsolete 8-bit effect vs 32-bit float Lumetri?

[Viktor2327462154ps]

Hello,

I have a question about the best way to go about adjusting the colors of my diving/snorkeling videos shot with the latest GoPro 10. I shoot in HEVC, high bitrate, 4k 60 fps and the videos are 8-bit color as I understand. The main problem is often having to add red to the picture, even though I usually use a red filter at depths deeper than 5-10 m.

I found the "Video Channel Mixer" effect through a youtube video showing how much better, and easier, results you get from that effect rather than using the Lumetri panel only. I have used the channel mixer and are satisfied with the results. The best part is how fast and easy it is to use to get a neutral color starting point. However, after some googling around I found out that the effect is classified as an obsolete effect running on old code and will limit the entire Timeline/sequence to 8 bit. Therefore I should only use the Lumetri panel according to some people.

1. Is the Video channel still a good effect as long as I only edit my 8-bit GoPro videos? Or should I try to only use the Lumetri Panel? Will a 32-bit color adjustment through the Lumetri panel be better, in terms of end quality, than the 8-bit Channel mixer? I export x264 VBR 2 pass and max render quality and bit depth.

2. Does it matter for quality if I use the Channel mixer before or after the final adjusments in the Lumetri panel in the effect chain?

3. Will the obsolete effect have any other disadvantage, like longer rendering/export times, worse quality in adjustments.

4. As a more open question, what would you say is the best possible way to color correct underwater videos? Lumetri only, maybe some other effect?

Im pretty new to the video editing as a hobby and just started using Premiere Pro as well so every input would be appreciated.

[Baffy19 · Accepted solution]

This is an important question and I voiced it with regard to certain effects and received an answer from the support staff: "since this effect is placed in the obsolete folder, it means that the developers will continue to balance the new work code or replace it with another more perfect one." Therefore, I recommend using the toolkit located on the Lumetri panel. The quality should not somehow deteriorate, it all depends on how much you make adjustments to the channels.

[Viktor2327462154ps]

Thanks for the input. I will try to use the Lumetri panel.

[R Neil Haugen]

Baffy's got the direct answer, so I marked it Correct. But I'll fill in some details.

1) You may or may not be able to see a difference depending on many factors that all overlap and interact, so I can't give a blanket statement. The 32-bit float processing can sometimes get around what might show as banding/artifacting with 8-bit processing, even with 8-bit clips. And the differences may be very small, indistinguishable really ... or at other times, noticeable.

2) Definitely it matters, and you would want any 8-bit effect processed last. Starting with 8-bit media, it doesn't make as much difference as if you start with 10-bit or better. But in testing this personally a few years back, I could see a small difference with two exports with different processing orders, when using the "Difference" mode to evaluate things.

3) Not really for the first couple, possible for the last one.

4) Lumetri would be the definite choice, it will be around for ever, it's malleable, and the color science is the best in Premiere.

I would recommend working with the Curves panel and working between the RGB Curves tool and the HSL curves tools. Getting "gross" work done with the RGB Curve tool, then doing some hue shifting with the Hue vs Hue tool, where you can tweak individual hues to something slightly different, would be I would think some of the best tools there for your needs.

And you may need to move the center of the Red curve, or both ends, play with different touches of the tool to see what works best.

Also you can try what the white balance tool in the Basic tab does ... but that may not get what you need. It is like grabbing the white-point ends of the RGB Curves tool and moving things around, it affects brights most, shadows hardly at all.

The Creative tab's Tint wheels are very useful for general color balancing, you can push brighter areas one direction and shadows another, or ... you can correct an overall tint by pushing both the same direction and correct BOTH shadows and brights. I use that tool a LOT.

Neil

[Viktor2327462154ps]

Thank you for the very detailed answer. I guess I will just have to spend some time learning all the ins and outs of the Lumetri panel.

[chrisw44157881]

I've tried correcting underwater footage and found that you want to lower the Blue chroma in the whole image without actually reducing overall saturation. This method will work in full 32 bpc.

To setup:
1. make 3 layers
2. 2nd layer, add saturation(minus blue) and s-shape curve. set composite mode to 'color'
3. set 3rd layer with 'inverted' s-shape luma curve, set as inverted luma matte to 2nd layer

now the trick is to split the curves into individual channels, RGB. If you play with the Blue channel, you can move the chroma around underneath the luma mattes. As to the question if you can see 8 bit effects, the answer depends on how hard you push the pixels around. There is a limit called the logarithmic luma limit where the human eye sees actual banding, which will be more pronounced the higher the contrast in either chroma or luma.

[R Neil Haugen]

Using the Track Matte effect on V2 linking to Luma on V3?

Neil

[chrisw44157881]

sorry, yes. I always build my color plans in Ae, and sometimes forget to transfer the differences to premiere's native inputs. Strangely, underwater footage is the exact opposite of film emulation so they do overlap in chroma conversion.

[Viktor2327462154ps]

Thanks for the answer. I will have to digest that information a few times before I can hopefully understand it and try it out. I am pretty new to video editing so that sounded pretty complicated to me, but I will try it out and see what happens.

[R Neil Haugen]

Chris, I'd love a bit more detail on how you're setting that up, what precise effects & all. As it sounds like it's very well controlled for this situation.

Neil

[Viktor2327462154ps]

Thanks for all the answers! I did not expect these fast and detailed replies.

I will most definately try to skip the Channel mixer and rely on the Lumetri tool for color correcting. It might be a steeper learning curve but I guess it will be worth it in the end.