If you choose to shade with pencil, you should use one with soft graphite. The harder the graphite, the uglier the smudging.
http://en.wikipedia.org/wiki/Pencil * Thomas Edison had his pencils specially made by Eagle Pencil. Each pencil was three inches long, was thicker than standard pencils and had softer graphite than was normally available.[36]
* Vladimir Nabokov rewrote everything he had ever published, usually several times, by pencil.[36]
* John Steinbeck was an obsessive pencil user and is said to have used as many as 60 a day. His novel East of Eden took more than 300 pencils to write.[36]
* Vincent van Gogh only used Faber pencils as they were "superior to Carpenters pencils, a capital black and most agreeable".[36][37]
* Johnny Carson regularly played with pencils at his Tonight Show desk. These pencils were specially made with erasers at both ends in order to avoid on set accidents.[38]