Scratchboard.

I love scratchboard drawings. It's one of the few media where both white and black are so vivid. Subtlety is nice and all, but BAM! Bright white! BAM! Solid black! It's great.

This particular scratchboard started white, and we had to add the ink layer ourselves. I deliberately left the ink off of the moon, and made the edges irregular. That way, the borders of the clouds over the moon aren't actually scratched, so they have a different look than the rest of the image.