Bright-field microscopy

An example bright field micrograph. This image shows a crossection of the vascular tissue in a plant stem.

Bright-field microscopy is the simplest of all the optical microscopy illumination techniques. Sample illumination is transmitted (i.e., illuminated from below and observed from above) white light and contrast in the sample is caused by absorbance of some of the transmitted light in dense areas of the sample. Bright-field microscopy is the simplest of a range of techniques used for illumination of samples in light microscopes and its simplicity makes it a popular technique. The typical appearance of a bright-field microscopy image is a dark sample on a bright background, hence the name.

Light path

Main article: light microscope

The light path of a bright-field microscope is extremely simple, no additional components are required beyond the normal light microscope setup. The light path therefore consists of:

Bright field microscopy may use critical or Köhler illumination to illuminate the sample.


Bright-field microscopy typically has low contrast with most biological samples as few absorb light to a great extent. Staining is often required to increase contrast, which prevents use on live cells in many situations. Bright field illumination is useful for samples which have an intrinsic colour, for example chloroplasts in plant cells.

Bright-field microscopy is a standard light microscopy technique, and therefore magnification is limited by the resolving power possible with the wavelength of visible light.





  1. Advanced Light Microscopy vol. 1 Principles and Basic Properties by Maksymilian Pluta, Elsevier (1988)
  2. Advanced Light Microscopy vol. 2 Specialised Methods by Maksymilian Pluta, Elsevier (1989)
  3. Introduction to Light Microscopy by S. Bradbury, B. Bracegirdle, BIOS Scientific Publishers (1998)
  4. Microbiology: Principles and Explorations by Jacquelyn G. Black, John Wiley & Sons, Inc. (2005)
  5. Microscopy and Imaging Literature

External links

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