In order to get a particular graphic file to work, a certain font or
header file might need to be sent first. The Dvips program provides
support for this with the `header' \special. For instance,
to ensure that `foo.ps' gets downloaded:
\special{header=foo.ps}
As another example, if you have some PostScript code that uses a PostScript font not built into your printer, you must download it to the printer. If the font isn't used elsewhere in the document, Dvips can't know you've used it, so you must include it in the same way, as in:
\special{header=putr.pfa}
to include the font definition file for Adobe Utopia Roman.