I had some experience with these techniques in elementary school. We would put objects on light-sensitive paper, and expose it to light. Since this was the first critique of the semester, and none of us at the time knew anything about the class, or our dear professor, I wasn't sure what exactly we were supposed to be getting out of it. I think Chad just didn't want to trust us with the enlargers until we knew a bit more about the class.
See 2D Critique.