Conformance Class

The PDF/A conformance consists of two components:

1. PDF/A Part (Standard)

There are currently three different PDF/A Standards supported.

• PDF/A-1 (ISO 19005-1): PDF/A was published by the ISO in 2005 to support long-term archiving of PDF documents. The first release, PDF/A-1, was based on the original PDF 1.4 version where a set of standards criteria was introduced such as ensuring the visual reproducibility of PDF documents regardless of future changes to viewer and printing technologies, and making PDF documents accessible to persons with eye vision challenges.
• PDF/A-2 (ISO 19005-2): In July 2011 the ISO released the PDF/A-2 standard that takes advantages of features that only became available in later versions of PDF, up to and including PDF version 1.7. This includes the following features: JPEG2000 compression, embedded PDF/A files, transparency, and optional content (layers).
• PDF/A-3 (ISO 19005-3): The ISO Committee released the third edition of the standard in October 2012. PDF/A-3 contains just one change that is necessary but controversial: PDF/A-2 already enabled the embedding of PDF/A-conform document as attachments. PDF/A-3, however, makes it possible to embed any document format such as Excel, Word, HTML, CAD or XML files for the first time ever.

2. PDF/A Conformity Level

There are three levels that define different requirements on the quality of the document's content (see ConformancePdfALevel.)