Editing Microscopy (section)

== Ultraviolet microscopy ==
Ultraviolet microscopes have two main purposes. The first is to use the shorter wavelength of ultraviolet electromagnetic energy to improve the image resolution beyond that of the diffraction limit of standard optical microscopes. This technique is used for non-destructive inspection of devices with very small features such as those found in modern semiconductors. The second application for UV microscopes is contrast enhancement where the response of individual samples is enhanced, relative to their surrounding, due to the interaction of light with the molecules within the sample itself. One example is in the growth of [[protein crystallization|protein crystals]]. Protein crystals are formed in salt solutions. As salt and protein crystals are both formed in the growth process, and both are commonly transparent to the human eye, they cannot be differentiated with a standard optical microscope. As the [[tryptophan]] of [[protein]] absorbs light at 280&nbsp;nm, imaging with a UV microscope with 280&nbsp;nm bandpass filters makes it simple to differentiate between the two types of crystals. The protein crystals appear dark while the salt crystals are transparent.