Phase contrast is a microscopy technique that improves a contrast of unstained biological specimens. It allows for visualizing differences in light phase caused by passing different parts of the specimens, otherwise invisible to human's eye. This technique was developed in 1930's by Frits Zernike, who was awarded a Nobel Prize in 1953.

Phase contrast microscopy links:

• Molecular Expressions Micrscopy Primer: Phase Contrast Microscopy

Trypanosoma gambiense, blood smear 40x N.A. 0.75	Penicillium sp. 45x N.A. 0.66	Cheek epithelium cells 45x N.A. 0.66
Potato starch 45x N.A. 0.66	Oxytricha sp. 45x N.A. 0.66	Human blood 45x N.A. 0.66