Colorful village: Sketch with pen, with digital coloring in Gimp

Look how fun this colored village is! I sketched some houses and churches and a few shrubs on white paper with pen, then imported it into Gimp, cropped it, changed the saturation, and inverted the black/white to make white lines. Then I added an alpha channel (black), then started filling in the shapes with color, and filled the background with white. Here's the original sketch.

I'll make a tutorial soon showing all the different steps. This is just too much fun!