Just a super quick sketch from imagination. Mostly an experiment with sketching using an Noodler's Ahab Flex Nib Fountain Pen with a Fine Nib and Noodler's Air Corp Blue-Black bulletproof ink, water-brush for the ink wash on Pocket Moleskine. About 7 minutes.
I am starting to think that Noodler's bulletproof inks might be bulletproof only after several days of drying. They seem to not be waterproof even after 24 hours. I had the same experience with Bulletproof Black, Heart of Darkness, Golden Brown and now this AirCorp Blue Black. I tried on several different types of paper including Moleskine journals, W&N Watercolor Cold Press Paper and simple Copy machine paper. Same results.