Valid characters in "post" glyph names?

Adam Twardoch (List) list.adam at
Thu Sep 22 17:18:05 CEST 2011

Dear list members and Adobe folk,

the "post" table OT spec, nor the "post" section in the OT spec
recommendations does not specify the the list of valid characters to be
used in PostScript glyph names:

but the "post" table spec does refer to the Adobe document "Unicode and
Glyph Names".

The URL in the spec is
which redirects to:
(might be a good idea to update the spec).

The Adobe document, now titled just "Glyph" (kind of ambiguous), used to
mention in an older version the "minimal spec" for a well-formed glyph
name, i.e.:

(1) The PostScript glyph name must only include uppercase or lowercase
English letters, European digits, the period or the underscore, i.e.
from the set [A-Za-z0-9_.]
(2) The PostScript glyph name should start with a letter, except the
special glyph name ".notdef" which starts with a period.

This recommendation (especially the first point) was very useful because
it made a point that glyph names should not, for example, include spaces
or some other special characters, which can cause serious problems with
an OT font.

The Adobe document then continues to explain how the glyph names can be
"valid" in the sense of being compatible with PDF text extraction. That
is fine to be in a general document, but I'm kind of bothered that the
minimal "well-formed" recommendation is:
(a) not present in that Adobe document anymore
(b) not present in the recommendations section of the OT spec

I'd like to propose to add the points (1) and (2), or at least the point
(1) to both the Adobe document and to the recommendations section for
the "post" table in the spec.



May success attend your efforts,
-- Adam Twardoch
(Remove "list." from e-mail address to contact me directly.)

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