I've used LOTS of various brands of pens and I have a pretty good idea of which are best for a smooth paper surface, a rough textured surface or even a high gloss surface. Some ink simply wont attach itself to the high gloss. I have one set of pens I just got that actually sits on that glossy surface well, but it takes a while to dry.
In this case I got to draw the Joker on an iPhone case that was incredibly smooth and glossy. I forgot to take a picture of it, but thanks to Facebook, it popped up and I can show it off here.
I was afraid the lines might smudge a little, hopefully it's dried enough now that there wont be any more smudging.
JOKER - iPhone case - 394
Just a heads up if you ever get a sketch like this, I'd get a spray fixitive or a spray varnish to clear coat it and set the inks. Otherwise eventually this will all rub off handling it so much. OR get the drawing done on a matte surface kind of case and give the artist fine sharpies to use to make sure it's permanent ink.