PaintToolSAI and Photoshop CS6.
It started as a quick portrait facial study a while back of a girl billowing smoke, then I turned it slowly (so slowly) and painstakingly (so much staking of pain) into the landscape scene you see here. I admit, I got fed up with the background after a certain point and just chucked some free paper textures on it.
Probably took about 40hrs, but I didn't keep track, so potentially anything from like 30 to a million hours, tbh.
Heavily inspired by Tyler Edlin's environment tutorial in the tutorials section on here.
You stake the pain well!