The CID font F1 family has the following characteristics:
Helvetica, Times-Roman, and Courier do not support CJK characters. If your document contains a single Chinese character, the renderer will switch to a CID fallback (often F1). cid font f1 family
While modern font engines (DirectWrite, Core Text, HarfBuzz) rarely expose the user to "F1," anyone working in PDF repair, e-discovery, or print engineering will continue to encounter this relic. The CID font F1 family has the following