[jumaro]

Not sure if it helps you, since you seem like you already tried a lot. I was confused about the different ways to do this, so I wrote down the ways I found: https://makandracards.com/darktable/477993-remove-chromatic-...

[Saris]

Thanks, yeah I think I've tried the first 2 methods. I'm expecting something like an eyedropper to come up where I click the fringing, but I think it's something else I need to do.