Resolution - Print Size Chart The numbers on the chart stand for dots per inch (dpi) they say the human eye does not see much beyond 96 dpi, that should give you a good example of what will work to make a good quality print.
Understanding Logo File Formats -- Great info explained in an easy to understand logical way! Know which file is used for what and what you should use & get from your Designer! :) Great for referencing and learning. I need PSF/AI, & high res.