Kbase Article of the Week: Use the Dock on your Mac to Check on a Printer or Print Job →

Apple Support:

When you print, your printer icon appears in the Dock. The icon may have a colored badge that indicates its status.

  • Red badge: The printer is printing. The badge shows the number of print jobs in the printer queue.
  • Green badge with a pause symbol: The printer is paused. If you print to it, you’re asked whether to resume printing or queue the print job to print later. If you queue the print job, your document waits in the queue until you resume printing. You might want to do this if you aren’t currently connected to the printer.

  • Yellow badge: The printer has a problem you need to fix. For example, it could have a paper jam or need ink, toner, or paper. You may need to resume printing after you fix the problem.

If you print a lot, this is a genuinely useful feature.