Problem with colormodel in pdf driver

You may want to consider a dotchart instead of a barplot.  Then you can distinguish between groups by using symbols, grouping, and labels rather than depending on colors/shades of grey.

  

Thanks Greg. The only problem is that I was trying to illustrate the use 
of barplot() ...

I guess for now I can always use the pdf() driver with the default RGB 
colormodel and then use command line tools (e.g. ImageMagick) to convert 
the resulting graphs to grayscale...

Thanks all for the help.

Luis

Luis Torgo
   FEP/LIAAD - INESC Porto, LA   Phone : (+351) 22 339 20 93
   University of Porto           Fax   : (+351) 22 339 20 99
   R. de Ceuta, 118, 6o          email : ltorgo at liaad.up.pt
   4050-190 PORTO - PORTUGAL     WWW   : http://www.liaad.up.pt/~ltorgo