Strange Drain color

I did this while at my lady friend's house using 'shades of grey' india ink felt tip pens, a triangle, a compass and some pencils to draft. I then scanned it and used some custom brushes via photoshop to 'watercolor' in the background roughly. I may recolor it to look pertier' in time.

So, should I pursue this technique further? Eh, eh? Comments appreciated!