Optical microscopes:

Light Microscope: Dark field

Figure 10.07 shows the light path in a dark-field microscope. This mode is best for observing the pale objects. Only light rays scattered by specimen enter objective lens and the specimen appears light against dark background.

Figure 10.07: Schematic of light path for dark field imaging.

It produces a bright image of the object against a dark background. The contrast increases, which enables observation of more details as shown in the Figure 10.08, which are not seen in the bright background. This mode is used to observe living, unstained preparations.

Figure 10.08: Microscope image under dark field imaging condition.

Fine structures can often not be seen in front of a bright background