I like using chalks, it is not very precise, but they sure are fun to play with. Also, like I was mentionned, it has a kind of ghostly effect, and when I think and lookat them, it's true! White and a little foggy, seems to fit the description well.
So maybe portraits are not the most imaginative drawings that you can do, but they sure help you get better at drawing forcing you to pay attention to detail. So it is important to do some. This one was done using quite a few layers of chalks, with a few touches of black charcoal.
Here are some progress pics
I hope you guys like it, thanks for the view.