I am using a Panasonic GH5 with V-Log L profile and in my videos in the shadows and some other areas, there is reddish/magenta color blocks and I am unsure if there is a way to remove this as it occurs on a lot of my videos. I am using 4K ALl-I 400Mbps 10-bit 4:2:2. I found this video before which has helped remove other chromatic aberrations and color fringing:
However, when I try to remove the reddish/magenta color blocking this way, it just ends up effecting all reds in the video, even ones I don't want changed. Here is an example that shows the issue. I too this video of a gull and as you can see on its chest beside its legs, it has this noticeable issue:
This is an unedited screenshot of the video and edited version with a saturation boost and adding the Panasonic V35_to_Rec709 LUT::
Here is close up of it and you can see the problem is there on the video, its nothing to do with what settings I apply on the video, first is unedited and second is edited:
Here is a short sample clip of the edited video itself so you can see the issue on the video. As I mentioned the settings I added didn't cause the issue, only made it more noticeable. The video is in DNxHR 4K 10-bit 4:2:2 HQX. If you zoom in on the birds chest, you can see the extent of the issue. Link: Dropbox - GH5_Gull1_Sample.mov Download it rather than play it.
Can anyone help?
7
Replies
I downloaded your clip and took a look at it on a 10-bit 4K monitor at 800%. If you pause and look at a single frame there is a bit of a color shift in the gray part of the image.
If the video is playing back at speed, even with a magnification factor of 800% it is nearly impossible to notice. My approach would be to simply open up Lumetrey color and use the curves section to desaturate the purple a little bit, then complete the rest of the color grading. Something like this will greatly improve the image and the color grading with about 30 seconds work.
Which will take you from this:
To this:
By making some minor adjustments in the center Red Green and Blue channels to neutralize dial in the white balance, adding a slight S curve to the overall gamma to bring up the contrast, and putting a dip in the Magenta saturation. This makes the color fringe, which I'm not sure is caused entirely by chromatic aberration, almost completely disappear when looking at a single frame and invisible when playing back at full speed.
If you really want to isolate those specific colors and neutralize them then it is going to require you to create a procedural matte based on the exact hues you want to change. Colorama is probably the tool I would use for that. Then you'll need to duplicate the layer, set up a track matte, apply the correction and desaturation to just those fringes, probably add in some hand roto so the other colors are not affected, and then composite the whole thing back together. In my never humble opinion, that would be a waste of time. Just a little color grading and a dip in the Magenta saturation on the whole image will remove nearly all traces of the problem from the video when viewed at full resolution playing back at full speed. You will go crazy trying to fix every frame. The only way to truly judge the quality of your image is to watch it at full speed. This looks pretty good to me:
Before:
After:
AdChoices