Dark Field Microscopy
Dark field microscopy is a method which also creates contrast
between the object and the surrounding field. As the name implies, the
background is dark and the object is bright. A annular stop is also used
for dark field, but the stop is now outside the field of view. Only light
coming from the outside of the beam passes through the object and it cannot
be seen directly. Only when light from the stop is deflected and deviated
by the object can it be seen. This method also produces a great deal of
glare and therefore the specimen often appears as a bright silhouette rather
than as a bright object of which much detail can be determined. The following
diagram shows the setup of the dark field light path.
(Redrawn
from Gray)*
Please remember that when using dark field optics, that
any dirt or dust or other garbage on your slide or specimen will shine
just as brightly as your object of interest. Make sure your slide is immaculately
clean.
*Diagram redrawn from Gray , P. 1964. Handbook of Basic
Microtechnique McGraw-Hill: New York.
 Back
to Homepage
|
Back
to Transmitted Light
|