The optical microscope is a very useful tool for the observation of materials and can be used to gain valuable information about a large variety of specimens. Some knowledge of the material and the information that is required is essential to determine the best techniques to employ when preparing and examining specimens.

Sample preparation is a critical part of microscopy, as this determines the quality of the images produced. Many techniques, when correctly applied to a specimen, can enhance the information present.

One of the limitations of the optical microscope is that of resolution. However, this is not always a problem in many areas of metallurgy, as high resolution imaging is more commonly carried out in a scanning electron microscope (SEM).

In addition, for 'transparent' specimens, in particular those of anisotropic materials, polarised light microscopy can offer large benefits, with high contrast possible.