The following questions will help you to determine which White Light imaging technique is best for your needs.
If you need to view everything in a liquid sample, or if you need to produce an image of your specimen against a black background you should use the Darkfield technique.
If you need to obtain enhanced contrast information on an unstained sample using transmitted light then you should use DIC.
If you need to perform quantitative or qualitative studies on an anisotropic (directionally dependent) specimen (e.g. fiber, mineral, etc.) then you should use Polarized techniques.
If you need information on a thin specimen that has been stained with histological stains (such as H&E staining) then you should use a Brightfield method.