Which type of microscopy is useful for viewing colorless specimens?

The phase contrast microscopy is commonly used for examining transparent and colorless objects. It is a type of light microscope that enhances contrasts, and is able to show things that would be difficult to see under an ordinary light microscope.

Phase contrast microscopy was first described by Dutch physicist Frits Zernike in 1934. The phase contrast technique has an optical mechanism that allows living cells to be examined in a natural state, no dye necessary. The change in phase is increased by a half a wavelength by the microscope's transparent phase-plate creating a difference in brightness. The dynamics of the biological processes can be seen with a sharp clarity in high contrast.