When working on large-scale pen and ink drawings, I mount my paper on the wall and work standing up. This requires ink pens that still flow with ease despite the odd angles that the drawings require. I have experimented with a wide variety of pens and really like Pilot Precise Grip Extra Fine Point and Bold Point ink pens. I'm able to achieve continuous lines and scratch marks over large surfaces without wearing out the tips of the pens. I've recommended these pens to many students over the years and they have all developed outstanding drawing processes on a variety of interesting surfaces.