See Also: dark-field condenser(medicine)
condenser, dark field(medicine)
cardioid dark field condenser(medicine)
paraboloid dark field condenser(medicine)
dark-field microscope(medicine)
dark field imaging(medicine)
dark field illumination(medicine)
dark field stop(medicine)
dark field microscopy(medicine)
dark field objective(medicine)

revocatory (iou) and condenser, dark field (medicine)


revocatory (iou)



revocatory adjective & noun. LME.
[Late Latin revocatorius, formed as REVOCATION: see -ORY1, -ORY2.]
A. adjective. Pertaining to or expressive of revocation. LME.
F. A. Kemble She would (instead of rewriting it) tack on..a sort of revocatory codicil.
B. noun. (A) revocation. rare. Only in M17.

condenser, dark field (medicine)


condenser, dark field
<microscopy> A condenser forming a hollow cone of light with its apex (or focal point) in the plane of the specimen. When used with an objective having a numerical aperture lower than the minimum numerical aperture of the hollow cone, only light deviated by the specimen enters the objective. Objects are seen as bright images against a dark background.

The ordinary bright field condenser of low power, used with a central stop, makes a good dark field condenser. They all form a dark field while illuminating the specimen with a hollow cone of light. The lower limiting aperture of the condenser must be greater than the numerical aperture of the objective with which it is to be used. Thus, no direct light enters the objective, the specimen is seen by reflected or scattered light on a dark background.

See: condensers

See: special dark field condensers: paraboloid, cardioid and Cassegrainian.