In situ hybe emulsion

Peter Ashby p.r.ashby at
Tue Jan 30 10:47:47 EST 2001

In article <3A76DFF7.89870998 at>, Rachel 
<rgeddy at> wrote:

> I can see the sections, but the emulsion is dark grey. When I view the
> sections under darkfield, the ones which don't have emulsion on them 
> shine
> with silver grains, and the emulsion, and the sections under the emulsion 
> do
> not shine at all; the field is completely black. I am working with plant
> tissue sections, if this makes any difference at all.

Hmm, if there is no emulsion over the sections there will be no silver 
grains. It sounds very much like you have a problem with emulsion 
thickness. Is the grey bit of the emulsion at one end of the slide? You 
would get this if after dipping you don't blot the end or the emulsion 
is too cold for dipping. Coating slides with emulsion is a bit of an 
art, it sounds like you have partially succeeded since you have some 
sections with silver grains. You now have to work on dipping to get an 
even, thin emulsion layer on the slide.

My PhD supervisor had an emulsion spreader made out of plastic. It was a 
roller with a lip on either side with the recess the width of a slide. A 
cross section of the roller is below.

         ||          ||
         ||          ||

Once you have a roller, you use a warm pasteur to drop emulsion on the 
warm slide and then gently roll the emulsion over the slide. The 
drawback is the gently bit and if there are any particles on the slide 
they will scratch the sections. I suspect you problem is that either the 
emulsion or the slide are too cold during dipping and/or you don't blot 
the excess from the end of the slide.


Peter Ashby
Wellcome Trust Biocentre
University of Dundee
Dundee, Scotland
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