Background: You can make prints of things by taking a slab of metal, carving out the lines you want to be black with a sharp little tool, and then taking a roller and rolling thick gooey ink over the whole thing. You then use a paint scraper to remove all the ink that isn't in a carved line. Press the metal into a piece of paper, and bam, you made an ink print of just the lines you carved.

This was at a certain art school in the northeast. There was a sign instructing students in the above process, and the department only had black ink. A student was reading the instructions out loud, and at a certain point, the sign instructed students to make sure they'd gotten enough ink in the grooves with the phrase "continue using the roller until the blacks are rich." Funny enough on its own, but the nameless student then said "Great, I'm gonna be using the roller for 200 years."