That's super cool. So if I wanted to do that would they have supplies for it at my school's art classrooms? 

You begin with a sheet of plexiglass lookin' stuff. I don't really know what it is. Then you take the picture you wish to create and tape it behind the glass. Then with a sharpened nail or etching needle you scratch the glass. I usually just use crosshatching. But basically,just scratch more in darker areas, less to none in lighter areas. (It will look odd because it will be white) and when you're all done, you spread ink over the entire peice of plexiglass,then rub off the excess. You can go back and add more wherever you desire. Then set on a press with a damp peice of paper over it and this special cloth that spreads the pressure evenly, and put it through the press and wah lahh. I get all my supplies from art class because a huge press isn't really something ya just have lying around at home. It's definitely more complicate than say a charcoal drawing. (sorry for typos I'm lazy)

That is super cool. How does one do etchings?