Would you like a Python script example that iterates through all CIDFont subsets in a PDF and reports their original font names and glyph counts?
qpdf --qdf --object-streams=disable document.pdf unpacked.pdf grep -A5 "/CIDFont" unpacked.pdf You will see something like: cidfont+f1 f2 f3 f4 f5 f6
Editing a PDF with multiple CIDFont subsets causes missing characters. Cause: Adding text not present in any existing subset ( +f1 .. +f6 ). Fix: Subset the missing glyphs into a new subset ( +f7 ), or embed full font. Would you like a Python script example that
Example simplified PDF object:
If you are working on a specific PDF with f1…f6 and need to reduce or analyze them, tools like cpdf (Coherent PDF), hexaPDF (Ruby), or pymupdf (Python) give programmatic control. This is an excellent and highly technical topic
This is an excellent and highly technical topic. The notation cidfont+f1 , cidfont+f2 , etc., is specific to and PDF internals, usually observed in PDF stream dumps , PostScript printer logs , or extracted font debugging output .
12 0 obj << /Type /Font /Subtype /CIDFontType0 /BaseFont /AAAAAA+NotoSansCJK /CIDSystemInfo << /Registry (Adobe) /Ordering (Identity) /Supplement 0 >> /FontDescriptor 13 0 R /DW 1000 /W [ 1 [500] 2 [600] ] >> endobj Pitfall: Text extraction returns garbled CJK text. Cause: Using +f1 ’s CMap incorrectly. Fix: Ensure your extractor uses the CMap referenced in the PDF (usually /CMap /Identity-H ).