I was watching this tutorial and he suggested G’MIC. There is a filter called debanding noise, I need it badly. I was trying to do it manually but I can see the previews are working. Just the plugin has errors and crashed once. I really need this or a filter from another plugin that works in 2.10.20. I installed it to the default location. Here is a screenshot of the error ( I had a different error with a different filter but this filter is what I needed).
I have a 3900x, 850w PSU, 32GB DDR4 @ 3600 cl16, vega 56, x570 Aorus Elite, 2 AIO coolers for CPU & GPU, Gimp 2.10.20, G’mic 2.9.1.
And the before and after screenshot (preview can show “difference”).
Just tested here, and the filter seems to work for me.
I’m not the author of this filter, so maybe not the best person who can help, but would it be possible to get one image you have, so that we can try to reproduce the bug ?
I have reinstalled gimp from a spinning rust to my 850 EVO, just to rule out not being on the C: drive was causing the error. I did reproduce the error afterwards but now I am not crashing the plugin and I hear the fans ramp up (but very low CPU/GPU usage while processing). I think now I default to select all before running the plugin.
However it is very hard to distiguish between before and after with the default settings. It does not look like the preview IMO. I see you have some NSFW content in a article but I still wouldn’t feel comfortable posting an untouched version, and I can’t find the rules here. So without too much delay I’ll post the edited but not edited with Q-mic first. Then I’ll try to get the best result. I’m zooming into the sheepskin rug as that is where the banding is most pronounced.
We don’t really have rules about content, except that content should be your own and you take responsibility for what you post. Nothing hateful. But photography has NSFW elements, and we are OK with that. I guess we don’t want hardcore pornography, but the line, at least with my moderator hat on, is blurry.
But it probably won’t work as well as you hope because it is design to remove exactly horizontal or vertical lines from digital cameras. You image appears to be a scan and the lines are not exactly horizontal.
What I suggest you do instead is use Iain Noise Reduction 2019 with a guide image.
The guide image is a slightly blurry version of your image. It is on the layer below the active layer in GIMP. In GMIC set the Input layers to Active and below. Then adjust the amount of Fine noise reduction.
Because the banding is horizontal I used a vertical blur just large enough to blur out the fine bands on the guide image.
This deals with the fine banding, but you also have wider bands which are much harder to deal with.
