Pdf91 — Working with PDF files outside paid software | pdf91.com
Version numbers say what a PDF may contain; archival profiles say what it must not — and validators enforce the second list.
The version history is short. PDF 1.7 was published as the open standard ISO 32000-1:2008; PDF 2.0 followed as ISO 32000-2:2017. Both describe the full, general-purpose format, including features that archives specifically exclude.
PDF/A-1 is the strict early archival profile: it forbids encryption, JavaScript and embedded files. A document that needs to carry attachments cannot conform to it, whatever else is right.
On narrow screens, swipe or scroll the plate sideways.
PDF/A-2 keeps the ban on JavaScript but permits attachments, which is why archives ask for A-2b rather than A-1b. The common archival profile, PDF/A-2b, is standardised as ISO 19005-2:2011.
Rejections at ingestion are usually one of three things: JavaScript somewhere in the file, encryption or password protection on the document, or — under A-1 — embedded attachments. Removing the banned feature and re-validating is the whole repair.
Signed documents add one more clock to watch. PAdES (ISO 31900-2) is the European profile for digital signatures embedded in PDFs, and signing certificates are commonly issued for one to three years — so a signature that validates today may need renewal long before the archive's retention period ends.
Further reading