Chagall Reference   Decolouriser       12.5.93
==============================================

   The 'Decolouriser' is a tool with no colour 
   of its own but which transforms all colours 
   over which it passes to grey-tones. 

   Its operation is therefore restricted to 
   colour pictures.

   It is opaque in action, with an even structure 
   and a sharp edge. 

