In GIMP, how do I apply the Gradient Tool to just one part of a picture?
DON'T use the Blur/Sharpen tool in this post. When I click the Gradient Tool in GIMP, a new separate window pops up! But this isn't what I want! As an exercise, I merely need to apply the Gradient Tool to blend one part of the picture — see the red line beneath. I picked this picture because there are two glaring brazen clear cut boundaries to blend — the boundary between
my black hat vs. sky.
sky vs. water
Here's the unmarked picture.