a couple of years ago I was working as a lab assistant in a university computer lab. Part of my job was to check the printers hourly (in labs on 5 different floors) and see if they needed more paper. Being extremly lazy I wrote a program that would log into the printers web based panel. This panel displayed a paper level indicator as an image. I discovered tgat the image filenames contained the percent full as a number (0, 25, 50, 75, 100). I had my program regularly check all the printers, parse the paper level and alert me if any printer was at 25 or empty.