The compound microscope forms images in two stages. The objective (first stage) projects a real image of the specimen into the intermediate image plane (IIP) of the microscope at a ratio of magnification (M). The resolution in the IIP is typically between 40 and 100 line pairs permillimeter (Ip/mm). Since the resolution of the human eye is of the order of 5 Ip/mm, additional virtual magnification (V) by the eyepiece (second stage) is necessary to match the resolution of the eye to that of the microscope. The total microscope magnification (VTOTAL) is the product of W x V. The designation VTOTAL is used because the eye views a virtual image in the microscope.