/////////////////////////////////////////////////////////////////////
From: "Paul Webster" Although eip-polarized light is the fastest way to look directly at gold labeled sections it is certainly not the most economical if you are not fully equipped to begin with.

SIlver enhancement is a simple alternative and works the same as when used for EM. The silver solution is reacted with the gold and then fixed using a solution similar to photographic fixers. As there is no worry about grain size any mordanting steps can be omitted. A simple kit which has worked well for LM in my hands (J. Cell Biol. 1988 106:279-288) is a kit from Amersham called "IntenSe". The silver solution is not light sensitive so it is possible to check the cells or sections with the light microscope before fixing, repeating the reaction until a signal is detected. Detection is easy using transmitted light or phase contrast, the signal appears as black precipitates.
Another alternative is to use enzyme histochemistry, where the signal is detected as a colored reaction product (HRP, Alk.Phos. etc).
I have placed a small discussion on this subject on the WWW - URL http://info.med.yale.edu/cellimg/Cryo-LM.html if you are interested.
...................................................................................................
From: Steven E. Slap "ENERGY BEAM SCIENCES, INC" <75767.640@CompuServe.COM>

The standard procedure for enhancing colloidal gold particles with a silver enhancement kit is:
1) Wash section very thoroughly with distilled or deionized water
2) Mix 3 drops each of initiating solution and enhancing solution in a clean test tube
3) Add several drops of the mixture to the slide and monitor development of silver stain periodically under the microscope at room temperature. Do not expose slide to high intensity light for prolonged periods. Staining is typically complete when stained areas have a brown-black stain. Stop the reaction before non-specific background appears by thorough washings in distilled water.
4) To stop the reaction, wash thoroughly with water. If development is not complete, use fresh solutions and continue silver enhancement. Counterstain as desired. Note that this procedure was written for our own BioSite silver enhancement kit, but should be applicable to most high quality commercially available kits
. These instructions can be found at our WWW site as part of a complete instruction brochure on use of BioSite colloidal gold reagents. (http://www.mwrn.com/ebs/ebs.htm)
....................................................................................

From: dianavd@eye.usyd.edu.au (Diana van Driel)

I routinely enhance labelled wholemounts of retina (300 mic thick) with BioCell (UK) silver enhancing kit. Wash labelled, fixed tissue with water before and after enhancing; enhance till visible under LM. View normally, with tissue mounted under glycerol, as dehydrating seems to turn everything black. It is also more sensitive if you use 1nm gold conjugate as the initial label (also available from BioCell). Darkfield is more sensitive, but normal LM is fine and you can see the rest of the tissue.
.......................................................................................

From: nano@ns1.LIHTI.ORG (Nanoprobes Inc.)
The latest volume edited by M. A. Hayat, "Immunogold-Silver Staining: Principles, Methods and Applications" (CRC Press, Boca Raton, FL, 1995) has many articles on methods of silver enhancement. The earlier series, "Colloidal Gold: Principles, Methods and Applications" (M. A. Hayat, Ed.; Academic Press, San Diego, CA: Vols. 1, 2 (1989) and Vol. 3 (1991) have some useful info as well. Richard D. Powell Nanoprobes, Inc (We sell silver enhancers too). URL: http://www.lihti.org/research/ecodev/incubten/nano/home.html
..........................................................................................

We use the Ted Pella silver enhancement kit with success. Last a long time in the frig or the freezer.
"The Wiz"