What is PDF/A?
PDF/A is an international standard (ISO19005), a subset of the PDF standard, specially designed for long-term archiving of electronic documents. This standard guarantees that the document can always be viewed in the same way, even after some time and with different software programs. The PDF/A standard is divided into two parts. Only the PDF/A-1 is approved, and is divided into two levels:
PDF / A-1a maximum required by the standard
PDF / A-1b minimum required by the standard