What is the most efficent technique for blending regional palettes in GIMP?

[Ascension]

Yes. When I say paint by hand I mean using the brush like an artist would paint on a canvas. Just plop some color down with a very low opacity and if you need more color then keep plopping more color down until it builds up to the point where you want it. I don't use a pencil for this since it has a hard edge while the brush has a soft edge. As for median color, well - yes and no. I change color a lot; I don't just stick with green for forests, white for snow, brown for mountains, and tan for deserts. I'll use a lot of different greens for a forest and mix in other colors for variation like tan, red, orange, black, blue, etc. With a low opacity the colors pretty much blend themself and, at least in photoshop, I can change the blend modes and things will change/blend in different ways. Say like I am using a light green and have the blend mode set to multiply, if I keep painting green over green then the multiply will make each successive brush stroke darker than the last. Now say I switch to a red and change the blend to screen, then each stroke will get lighter and browner since red and green are opposite. If I switch to overlay instead of screen then each stroke will just get browner but not lighter.

[Porklet]

Yes. When I say paint by hand I mean using the brush like an artist would paint on a canvas. Just plop some color down with a very low opacity and if you need more color then keep plopping more color down until it builds up to the point where you want it. I don't use a pencil for this since it has a hard edge while the brush has a soft edge. As for median color, well - yes and no. I change color a lot; I don't just stick with green for forests, white for snow, brown for mountains, and tan for deserts. I'll use a lot of different greens for a forest and mix in other colors for variation like tan, red, orange, black, blue, etc. With a low opacity the colors pretty much blend themself and, at least in photoshop, I can change the blend modes and things will change/blend in different ways. Say like I am using a light green and have the blend mode set to multiply, if I keep painting green over green then the multiply will make each successive brush stroke darker than the last. Now say I switch to a red and change the blend to screen, then each stroke will get lighter and browner since red and green are opposite. If I switch to overlay instead of screen then each stroke will just get browner but not lighter.

I have already tried them out, and I see what you mean. It does help with adding color gradient (change, you know what I mean). Already, even my most rudimentary attempts at blending are markedly improved, once I employ the Smudge (the Smudge sounds like a Smurf hitman's street name). "Smurf the Smudge? I'm not afraid of that loser. Oh, h-hey there Smudge. I got's your loot."

Thanks for the help. One more question if you don't mind. I am not well versed in color theory, and maybe I have this wrong. Would I be better off having adjacent regions with complimentary colors, i.e. light green to blue green to dark green to etc., rather than grey to green to tan? Or does that not matter as long as I take the time to blend them properly (assuming I can pull it off)?