There’s a semi-public printer on my psychology research lab floor – “semi” in the sense that anyone can use it, but they need to be connected to the same network as the printer, and have it properly set up. As most of us probably know, printers are notorious for causing problems at the worst moments (such as your color inkjet printer using all the cyan and yellow the day before a paper is due, so you have to turn in your paper printed with pink text). Public printers are just as bad, but about five times worse.

Yesterday, someone on my floor came running to me for help with the printer.

The problem? She intended to print page 72 of a 300-page PDF document. Instead, she accidentally printed 72 copies of the entire 300-page PDF document, and didn’t know how to cancel the print job.

By the time I made it over to the printer, there was about a ream’s worth (500 pages) of paper already on the output tray, and the printer was still going strong.

I wasn’t really familiar with the printer user interface because whenever I use it, it’s usually to print one or two pages, and I usually just walk up to the printer and grab the sheet(s) without having to check or touch anything else. But clearly, the life of an entire tree was in my hands, so I took a careful look at the controls.

There was a red button labeled “Stop.” I pushed it.

On the touch screen, it asked me to verify my choice. I hit “Yes.”

The printing stopped.

Apparently, if you accidentally print over 21,000 pages, you enter a state of such intense panic that you become color blind (or just blind in general) and can’t see a red Stop button.

I wonder what she ended up doing with that random ream of unnecessarily printed paper…