> Sadly, the Prof insists that starch was 
> the method used.  I'm not going to look much further.  We are 
> presently testing silver nitrate, alcian blue, artists 
> pigments suspended in acetone, indian ink and finally, poster 
> paints mixed with gelatin.

Maybe talcum powder was used to "stain" the margins? Just an idea.

The most reliable and probable cheapest way to stain margins - at least in
my opinion - is using tattooing paste for cattle, available in shops for
farmers. It is non toxic, of course and it is used normally only by
shepherds ;-)

We buy it from Hauptner-Herberholz, catalogue-#: 71492 Tattooing paste black
(~150g). 

Alexander Nader
Path. Institute Hanusch-Hospital
Vienna