Various computer display standards or display modes have been used in the history of the personal computer.They are often a combination of aspect ratio (specified as width-to-height ratio), display resolution (specified as the width and height in pixels), color depth (measured in bits per pixel), and refresh rate (expressed in hertz).Associated with the screen resolution and refresh rate is a ...
OK, I left so many comments in here that I thought I better provide my own answer. The "300dpi" rule-of-thumb comes from the world of offset printing.. 4 color offset printing uses something called a line screen to create a halftone pattern of evenly spaced, but different sized dots.. Offset printing can typically print up to 2400 dpi or even much higher.