pdffonts -subst yourfile.pdf Output example:
If you have ever opened a PDF only to see missing font warnings like "Cannot find or create 'CIDFont+F1'" or found that text renders as gibberish in a RIP (Raster Image Processor), you have encountered the CIDFont naming convention. This article provides a deep dive into what F1, F2, F3, F4, F5, and F6 represent, why "full" embedding fails, and how to resolve these issues once and for all. 1.1 What is a CID (Character Identifier)? Unlike traditional fonts (Type 1 or TrueType) that use a simple 1-byte encoding (maximum 256 characters), CID-keyed fonts support large character sets—often thousands of glyphs—required for CJK languages (Chinese, Japanese, Korean) as well as complex symbol sets. Adobe developed CIDFonts to bypass the 256-character limit.
| Problem | Solution | |---------|----------| | PDF shows missing CIDFont+F1...F6 | Identify actual font using Acrobat/pdffonts | | Need full glyph set for editing | Use Ghostscript with -dSubsetFonts=false | | Error when moving PDF between systems | Replace synthetic names with real font names | | Prevent future issues | Export PDFs with 100% subset threshold or full embedding |
A CIDFont is essentially a database of glyphs, each identified by a unique . The mapping from a character code (like Unicode) to a CID is handled by a CMAP (Character Map) . 1.2 The Naming Convention: Where Do F1, F2, etc., Come From? When a PDF is created and a CIDFont is embedded without a predefined PostScript name, the PDF writer (e.g., Adobe Acrobat, Ghostscript, or a print driver) generates a synthetic font name . The format is: