You are trying to edit a PDF where the font was "subsetted" (only the characters used were saved).
A professional-grade CID font available for free via Adobe/Google. ⚠️ A Note on Safety Cidfont-f4 Font Free Download
This often resolves "f1," "f2," or "f4" errors for Chinese, Japanese, and Korean characters. 3. Use a Font Substitute You are trying to edit a PDF where
You likely encountered a "Font Not Found" error for Cidfont-f4 because: " or "f4" errors for Chinese