Nice Piece..don't be afraid to add lots of blacks.When drawing Batman an artist has to be careful not to make the shot look as if it's in daylight, Batman is a dark character, the world he's in is dark..so lots of blacks. Brush helps, because a pen is not the correct tool to use for large areas of black.Frank Cho is able to use a pen-[Pigma/Microns], appear to be a brush,but why add all the extra work and not just learn how to use a brush..but each artist has to find their own level & technique..for inking tips try Gary Martin's books on inking from "Darkhorse". Good stuff.