Thanks! I'm glad you like it and that the b/w works for you. I'm usually so afraid to just ink black areas in my drawings, even though I know that they can make things look better, that the silhouette thing seemed like a good step to get used to it, because at least with that there's no angst over what to make black. :)
I guess it could be New York, after all he worked there also, and the fire escape image might have been a New York one. I didn't go for a specific Gotham feel or anything, mostly once I had done the pencil sketch of him and looked at that silhouette, I just thought a fire escape might look interesting in b/w also to give it an anchor, and not be too difficult to manage. Then I searched for images and did a somewhat sloppy ink job over one that seemed to fit best. It was really much faster work than I usually do. Mostly because for me one of the reasons to set myself exercises is to actually draw something and finish it in a reasonable amount of time, problems or not, rather than to end up fidgeting about detail endlessly.