Base 14 fonts

There are fourteen typefaces that have a special significance to PDF
documents[14]:

    * Times (v3) or Times Roman PS MT (v4.x) (in regular, italic or oblique,
      bold, and bold italic)
    * Courier (in regular, italic or oblique, bold and bold italic)
    * Helvetica (v3) or Arial MT (v4.x) (in regular, italic or oblique, bold
    and bold italic)
    * Symbol
    * Zapf Dingbats

These should always be present (actually present or a close substitute) and
so need not be embedded in a PDF.[15] PDF viewers must know about the
metrics of these fonts. Other fonts may be substituted if they are not
embedded in a PDF.