One positive aspect of PDF is that it leads to amusements like the following message (from GPL Ghostscript 8.01):
   **** Warning: Fonts with Subtype = /TrueType should be embedded.
                 But TimesNewRomanPS-ItalicMT is not embedded.
   **** Warning: Fonts with Subtype = /TrueType should be embedded.
                 But TimesNewRomanPSMT is not embedded.
... 17 similar warnings skipped ...
   **** This file had errors that were repaired or ignored.
   **** The file was produced by: 
   **** >>>> Acrobat Distiller 6.0.1 (Windows) <<<<
   **** Please notify the author of the software that produced this
   **** file that it does not conform to Adobe's published PDF
   **** specification.
The viewing software then substitutes other fonts, so the desired fixed format is not achievable with such a file.
Anton Ertl