I need help guys. I've searched a ton on Youtube and I don't even know what to call the feature I'm trying to discover. What you see below is from a board game I'm making to use on Vassal. As Germany conquers territory, I can change the color to match. What I can't figure out to do is to find a way for GIMP to autogenerate that fuzzy darker border color you see on the original map. I can use airbrush and follow the edge of the border myself to make them, however I don't want to do this 300 times. It's tedious and it would look sloppy. Surely, there is a way to do some kind of drop shadow kind of thing, but on the inside. Every Youtube was all about the exterior.
I tried a few zones using an airbrush, but it just could not replicate it nicely. The original has a nice fade going on while my airbrush doesn't fade anything like that. It's to abrupt when it reaches the width I set. I suppose that's another question on how to configure an airbrush to do that. The technique I'm looking for would not need the airbrush anyway since it should simply fill the border for me with the color I choose and width and fade.
