I think I may have an answer -- PL's beta already has the tool to resolve the colour fringing when a selection is extracted from a synthetic image: the Color to Transparency tool.Martin Huber hat geschrieben: Creating the correct mask values is the hard part. While it is straightforward in synthetic images (like your example), the straightforward solution doesn't work well with photos. And the opposite is true, too: Solutions, that work good with photos are not that good with synthetic images, because with photos we need to use some kind of fuzziness, that is harmful with synthetic images.
At the moment I don't know how to resolve that conflict.
In both Case #1 and Case #2, if I use the Color to Transparency tool on the extracted layer by using the eyedropper to select a remaining fringe pixel and then adjusting the sliders, the colour fringe is successfully removed. No further masking is necessary.
So, it would seem that only a solution that works good with photos is necessary. Whether it's an enhancement to the masking tools of the Border Matting Tool or an "aggressiveness" slider for the "Remove Color Border" option of the Extract Selection option/tool is an open question.