In order to study biological material with the transmission electron microscope (T.E.M) complex series of techniques and processes is required. These processes are similar to those used in light microscopy, but some modifications are necessary because of differences in image formation. The processes involved are fixation in order to preserve structure, dehydration to remove all traces of water from the specimen and embedding to give mechanical support to the tissue during microtomy.

Almost all the reagents used in processing specimens for electron microscopy are potentially hazardous substances to various degrees. Many chemicals employed for fixation, rinsing, dehydration, embedding and staining are potentially capable of causing harm to workers. They can be absorbed either by skin contact or by inhalation. Therefore, some precautions should be taken before handling.