A light microscope can use multiple types of light to produce multiple types of images, but all of them function on the basis of light focused from below the sample and into either a condenser, which focuses the light, or the lens to be viewed. The objective lens are what causes the actual magnification of the specimen on the slide that is made visible by the light. That is then passed through to the eyepiece at the top of the microscope.
Most light microscopes used in schools or at students homes are bright field illumination. This means that the image of the object being viewed is seen in a very basic manner. The objects on the slides are usually dyed a with a tint so that the color can absorb the light that is passing through it and be viewed. The amount of magnification on light microscopes is not as high as other microscopes, like the electron microscopes. Light microscopes are, on average, limited to a 2,000 times magnification where a transmission electron microscope can magnify an object approximately a million times. Scanning electron microscopes can magnify an object around 300,000 times, making the magnification of the light microscope seem minimal. Compared to the human eye, the abilities of the light microscope are far beyond anything humans could do without the device.