>    
   > Being a physicist, I tend to make integrating spheres myself, using    
   >    
   > cheap'n'cheerful Chinese ping-pong balls with several layers of spray    
   >    
   > paint on the outside.  My favourite recipe is 5 or so coats of Krylon    
   >    
   > 1502 white, followed by 3 coats of Krylon 1602 ultraflat black.  That    
   >    
   > works pretty well for lots of jobs, e.g. measuring LED output.   
   >    
   >    
   OK - I've been thinking about. In your integrating sphere, either theoretical   
   or actual - do you have an estimate of an average number of bounces the light   
   suffers before you capture it in the PD? I assume you have an led source and a   
   PD poking into the    
   sphere side by side.    
      
   While I'm at it - any simple way to get a spectrum?   
      
   tia   
   JB   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)