You need a ring annulus - it blocs light from the center and only allows it
around the edges - it has semi-circular slits around the edge. It is not a
lens, just a light blocker.

Tim Morken
CDC, Atlanta 

-----Original Message-----
From: Charles Read [mailto:csu15397@mail.claytonstate.net]
Sent: Monday, January 27, 2003 3:27 PM
To: histonet@pathology.swmed.edu
Subject: Help with DARKFIELD MICROSCOPY


Hey everybody,

I own a LW Scientiic Observer IV (microscope that is) with brightfield
lighting.  There is a 'tray' for lack of a better word, where you can put
colored lenses to color the light.  On a microscope at school there is a
similar 'tray' that has a few different color lenses and a setting that puts
the scope into darkfield, my question is:  Is darkfield lighting
accomplished with a lens?  If so, where can I get a lens that would fit my
scope?  Thanks in advance!!!!!!

-CR