Staining is a technique used to enhance contrast in samples, generally at the microscopic level. Stains and dyes are frequently used in histology, in cytology, and in the medical fields of histopathology, hematology, and cytopathology that focus on the study and diagnoses of diseases at the microscopic level. Stains may be used to define biological tissues, cell populations, or organelles within individual cells.
A stained histological specimen, sandwiched between a glass microscope slide.
Example of negative staining
Microscopic view of a histologic specimen of human lung tissue stained with hematoxylin and eosin.
PAS diastase showing the fungus Histoplasma.
A microscope is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisible to the eye unless aided by a microscope.
Microscope
18th-century microscopes from the Musée des Arts et Métiers, Paris
Carl Zeiss binocular compound microscope, 1914
Electron microscope constructed by Ernst Ruska in 1933