Here is another Albrecht Durer study done on the train. This time I followed Linda's advice and drew guidelines in pencil first before going in with ink. Thank you for your comments.
One of the hardest things about drawing this particular drawing was trying to get the smooth flowing lines in the beard. There are several long lines that I just couldn't get, especially in ink - on a train. As soon as a bump comes along, I lift the pen before the pen skips and ruins the drawing. The original appears to be in black and white chalk on a toned paper.
After doing a little Photoshop magic and comparing the two, I see some errors in my proportions. In my drawing, the nose is too short, the ear is too far forward, and there is not enough skull toward the back of the head. My drawing is in red below...
Linear Mode
