Insertion of nomarski optic - A prism that splits light into two separate waves through specimen. Changes wavelength of light and the interference leads to increased contrast, largest difference is the edges of cells and organelles.
Takes advantage of physics of light and the characteristics of it as a waveform. When two waves are in phase, they are at the same frequ and combine to create a better resolution. If out of phase, reduced intensity of light. When in phase, the unstained cell will disrupt one of the light waves creating a slowed speed for the wave form.