psblack - PostScript filter.

       Copyright (C) 1987-2002
       University Corporation for Atmospheric Research
       The use of this Software is governed by a License Agreement.

NCAR                                                May 1993                                     PSBLACK(1NCARG)

psblack  is  a  filter which reads a PostScript file as input and writes a PostScript file as output.  In
       the output file the filter forces a black background and scales the intensity values (values with  R=G=B)
       so  that  any  intensity  greater  than  or  equal  to  .8 is mapped to white.  This filter works only on
       PostScript files produced by ctrans - the CGM translator in the NCAR Graphics software.

       psblack - PostScript filter.

ctrans(1NCARG), pswhite(1NCARG)

psblack<input_PostScript_file>output_PostScript_file