TeX fonts in Adobe Type 1 (“PostScript”) format
Are you using “TeX fonts” in Adobe Type 1 format
— such as:
You can find the above at the
American Mathematical Society web site.
Ever wondered about their provenance?
It turns out that the Type 1 font files contain hidden “water marks”
in the encrypted section.
Other fonts designed for TeX do as well, including:
- European Modern,
- Lucida Bright and Lucida New Math,
- Lucida Bright Expert,
You can extract the water mark using a simple tool:
In Windows, the font folder (default c:\windows\fonts)
does not show the files in that folder, but something
constructed from registry entries (it is a so-called
“active” folder). To see the water marks of
PFB files of fonts installed there, first copy them
to another folder.
The amount of information that can be hidden depends on the size
of the font. As a result, some small fonts have incomplete
water marks, while longer ones have repetitions.
Commerical versions of the CM and AMS fonts will have different
Recent revisions of some of the fonts may not have these watermarks
because font modification software does not preserve such metadata.
Berthold K.P. Horn,