Staining
![A stained histologic specimen, sandwiched between a glass microscope slide and coverslip, mounted on the stage of a light microscope.](/Images/godic/202412/20/Microscope_with_stained_slide3524.jpg")
![Microscopic view of a histologic specimen of human lung tissue stained with hematoxylin and eosin.](/Images/godic/202412/20/Emphysema_H_and_E3524.jpg")
![PAS diastase showing the fungus Histoplasma.](/Images/godic/202412/20/Histoplasma_pas-d_small3524.jpg")
![Gömöri methenamine silver stain demonstrating histoplasma (black round balls).](/Images/godic/202412/20/Histoplasma_in_granuloma_gms3524.jpg")
Staining is an auxiliary technique used in microscopy to enhance contrast in the microscopic image. Stains and dyes are frequently used in biology and medicine to highlight structures in biological tissues for viewing, often with the aid of different microscopes. Stains may be used to define and examine bulk tissues (highlighting, for example, muscle fibers or connective tissue), cell populations (classifying different blood cells, for instance), or organelles within individual cells.