TeX fonts in Adobe Type 1 (“PostScript”) format

Are you using “TeX fonts” in Adobe Type 1 format — such as:

• Computer Modern,
• AMS fonts, and
• extra “LaTeX” fonts (s.a. line, circle, symbol)?

You can find the above at the American Mathematical Society web site.

Ever wondered about their provenance?

It turns out that these fonts all 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,
• MathTıme and
• MathTıme Professional,

You can extract the water mark using a simple tool:

• Show_Water_Mark.exe (Windows application);
• Show_Water_Mark_CMD.exe (command line application); or
• Show_Water_Mark_CMD.c (C source).

Notes:

• 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 (later) watermarks.