Theories and Principles of Staining

Special staining is considered to be a chemical reaction which demonstrates the presence of a particular type of tissue, cell, organelle or substance. The main objective of staining tissue sections is to impart colour to specific tissue constituents. It is used to highlight important features of the tissue as well as to enhance the tissue contrast. Therefore it is necessary to understand how a dye molecule exhibit a certain color and how it becomes attached to a specific site. Stained materials absorb certain components of white light illuminating the specimen and therefore appear colored.