Darkfield Illumination

Darkfield microscopy is a specialized illumination technique that capitalizes on oblique illumination to enhance contrast in specimens that are not imaged well under normal brightfield illumination conditions. After the zeroth order (direct) light has been blocked by an opaque stop in the substage condenser, light passing through the specimen from oblique angles at all azimuths is diffracted, refracted, and reflected into the microscope objective to form a bright image of the specimen superimposed onto a dark background.
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Darkfield Illumination

Transmitted Darkfield Illumination

Transmitted darkfield illumination can be used to increase the visibility of specimens lacking contrast for satisfactory observation and imaging by ordinary brightfield microscopy techniques.

Reflected Darkfield Illumination

Darkfield illumination with reflected light enables visualization of grain boundaries, surface defects, and other features that are difficult to detect with brightfield illumination.

Darkfield Microscope Configuration

An easy instructional step-by-step guide to configuration of transmitted light microscopes for use with both low and high magnification darkfield condensers is provided in this review.

Troubleshooting Darkfield Microscopy

There are numerous problems associated with darkfield microscopy and photomicrography or digital imaging ranging from insufficient illumination and condenser mis-alignment to using a field stop of incorrect size.

The Evident Scientific Microscopy Resource Center gallery of darkfield illumination photomicrography and digital imaging contains a wide spectrum of images captured under a variety of conditions and utilizing many different specimens.

Darkfield Interactive Java Tutorials

Explore various aspects of darkfield microscopy theory and practice using these tutorials, which are designed enable visitors to simulate configuration and operation of a microscope under darkfield illumination.

Contributing Authors

Mortimer Abramowitz - Olympus America, Inc., Two Corporate Center Drive., Melville, New York, 11747.
Kirill I. Tchourioukanov and Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.