I can show you a simple setup for this:
So you’ve got your fill and matte to head into you action or comp node for comping over your BG. For the fill, I apply a slight pixel spread stretch (doesn’t even need to be slight, can be big for this process), and THEN a pixel spread interpolate iteratively like show in the set up. You can shrink the matte down going into these if you want. If you just comped this it looks bad. So the last step is taking that pixelspread fill you have, and comping it over the original fill. This comp node is set to Photoshop blend modes and Color. So Photoshop: Color. In this simple example here’s BnA for this comp:
Without Photoshop color fix:
With:
Important to note, Photoshop color blend mode goes nuts in Linear, so need to be in Log or Rec709 for this to work. Fixes color fringe issues on blue screen and green screen really nice and procedurally. Won’t fix luminance issues but there’s other methods for that.