Glyphs are graphical representations of characters (letters, digits, and symbols). While displaying font characters, some characters that are completely missing result from an incorrect sub-setting for TrueType fonts, only an empty glyph is displayed.
In the case of Type 1 fonts, however, the system uses .notdef glyph (replacement character) instead. This is often simply a box containing an X.
- Open the design source file
- Find missing glyphs/characters using Type > Find Font in InDesign
- Replace with a character which was used in the layout
- Again create a PDF, using Gelato print presets