I drew this with my brown Hi-Tec C Pilot pen. Since the ink in the brown pen isn't waterproof (the black ink is, mostly), I decided to see what would happen if I created a wash effect with a waterbrush. Now I'm thinking about getting some real sepia ink for further experiments...
This is very successful, showing light shining through the liquid. I love using watersoluble line as a source of wash. It livens up the sketch so much.
Thanks. I had second thoughts afterwards, so it's good to have another opinion.