Pen and Ink portraits are considered the most difficult of all thing to do as an artist. People are thought of as being difficult to capture and ink is unforgiving so the combination of both make works like this most honored by many. I started using pen and ink via a ballpoint as an artist back in 1968...
http://jerrystith.multiply.com/ The largest ballpoint pen art site on the WWW. there's 800 artists, 5,450 ink drawings, 153 videos and lots of information for your enjoyment. Cheers, Jerry Stith