Yeah, chiaroscuro. I didn't know what it meant either. It sounds vaguely ominous, like something an Italian mobster might do to you if you didn't pay off your gambling debts in a timely manner.
But no! What it actually means, is giving a two-dimensional object the appearance of being three-dimensional through the use of shadow.
Or as dictionary.com puts it:
One of our drawing class assignments was surprisingly not to try to draw a perfect circle (we outright traced these, so I guess we're not ready to work for the Pope yet.) but to give these plain circles some life by adding different values to them.
The first one was done with conte, the second one with pencil (I think it turned out the best) and the third one was done with a 0.3 permanent pen, in pointillism... all eeny weeny dots, put down one at a time. To be honest, this one was the most fun and relaxing to do, although it took forEVer. In fact, I decided not to do the shadow because it was really putting a cramp in my time management. That's why I wrote in "awesome speckly shadow here (squint)" although now that I look at it again it seems like something drunk me would have done. NOT TRUE, I was stone cold sober. I wasn't thinking of the fact that we have to hand in our sketchbooks for marking at the end of the class. Oops. Maybe if I bring peanut butter cookies to class she'll overlook it. I'm not above bribery.
Okay, I gotta go. I have some baking to do.