How to imitate the blur on subject outlines after removal of background using GIMP?

Question

Using GIMP I masked out an unwanted person who was situated in the background of my image. This person was partially concealed by my subject. I used the path tool to trace the outlines of my subject and then masked out the backgound using clone and heal.

My problem is that this left very sharp borders on some out-of-focus parts of my subject, wich I would like to blur.

My best guess was using the 'paint along path' option while using the blur tool, but this got me insufficient results as the background got blurred without much colour of my subject bleeding into it. I still have all paths used to mask out the background so using these might be a good way to minimise effort.

Maybe someobody can suggest different settings on the blur tool or a method using a gradient along a path?

Ive also tried doing it manually but this takes a lot of time and it would be very practical to know a better way of doing this in the future. This is how the border of the subjects arm looks after the masking of the background

And this is how I would like it to look, I did this manually with the stamp tool.

Answer 1

You need to feather the selection/path a few pixels... select menu>feather

Answer 2

Without a tablet:

• Fuzzy-Select the background, so that you have a selection that ends near the sharp edge.
• Select>Grow by one pixel so that the selection is on the edge.
• Select>Border by about the width of the blur you seek to make a thin selection that straddles the edge.
• Intersect this with a more general selection (or use the quickmask and paint black on the areas that should remain untouched)
• Select>Feather the selection by about the width of the border.
• Apply a Gaussian blur

With a tablet

Just paint over the hard edge with the Blur tool and a soft brush. This is difficult to do with a mouse, but there are two ways make it a bit easier:

• Use the same steps as above to make a ribbon selection along the edge (not need to feather or restrict futher)

• Use a path to guide your hand:

  • Fuzzy-select the background+Select>Grow as above
  • Select>To path
  • View>Snap to active path

  the snapping will keep you on track (especially if you zoom a bit).