Imaging techniques provides a method to view features in blood not normally shown with phase contrast. This method of illuminates the specimen form the side not from the behind so the background is black. Minute features of the blood are shown in a glowing light as its reflects off their surfaces.
Darkfield microscopy relies on a different illumination system. Rather than illuminating the sample with a filled cone of light, the condenser is designed to form a hollow cone of light. The light at the apex of the cone is focused at the plane of the specimen; as this light moves past the specimen plane it spreads again into a hollow cone.