By default, Afm2tfm uses the encoding it finds in the AFM file. You can specify a different PostScript encoding with `-p ps-enc'. This makes the raw TFM file (the one output by Afm2tfm) have the encoding specified in the encoding file ps-enc. Any ligature or kern information specified in ps-enc is ignored by Afm2tfm, since ligkern info is always omitted from the raw TFM.
If you use this option, you must also arrange to download ps-enc as part of any document that uses this font. You do this by adding a line like the following one to `psfonts.map' (see section `psfonts.map': PostScript font catalog):
zpopr Optima "MyEncoding ReEncodeFont" <myenc.enc
Using `-p' is the only way to access characters in a PostScript font that are neither encoded in the AFM file nor constructed from other characters. For instance, Adobe's `Times-Roman' font contains the extra characters `trademark' and `registered' (among others); these can only be accessed through such a PostScript reencoding.
In fact, the `8r' base encoding used for the current PostScript font distribution (available at @url{ftp://ftp.tug.org/tex/psfonts.tar.gz}) does do this reencoding, for precisely this reason.