03-11-2018, 08:01 AM
When it comes to lots of images (frames) I tend to think IM first, but I did look at Gimp possibilities.
The Gimp levels tool using the alpha channel can 'cancel' faint marks. Reducing the gamma setting to a small value, < 0.4 seems to get rid of them. That can be scripted. A simple one-liner as a python plugin attached.
That will act on all layers in a stack, could be much more sophisticated, needs one of the clever guys if it 'sort-of-works' with your animations. Have to be careful with the entered value, higher values remove edge anti-aliasing.
The Gimp levels tool using the alpha channel can 'cancel' faint marks. Reducing the gamma setting to a small value, < 0.4 seems to get rid of them. That can be scripted. A simple one-liner as a python plugin attached.
That will act on all layers in a stack, could be much more sophisticated, needs one of the clever guys if it 'sort-of-works' with your animations. Have to be careful with the entered value, higher values remove edge anti-aliasing.