The word “counterstain” refers to a staining technique used in microscopy and histology. It involves applying a second stain to a specimen that has already been stained with a primary stain. The purpose of the counterstain is to enhance the contrast of certain structures or to highlight different components of the specimen, allowing for better visualization under a microscope. For example, in a typical procedure, a primary stain might bind to specific cells or tissues, while a counterstain provides color to the background or other structures, making them distinguishable from the primary-stained areas.
