Does PDF 2.0 have any effect on PDF/A?

18 Jul 2018 By Dietrich von Seggern

PDF 2.0

PDF 2.0 (ISO 32000-2) has been available as a new standard since August 2017. The result of almost ten years of work by about 30 experts from all over the world is the first PDF specification that has been completely developed within the ISO. Important sections, for example digital signatures, metadata and tagged PDF, have been completely revised. The enormous effort involved in creating PDF 2.0 and the numerous practical tips that have been taken into account are also proof of the importance that PDF has for numerous current business processes and how lively the communication between practice and the ISO is at this point.

From an archive perspective, the question now arises as to what extent the changes to PDF 2.0 are significant for PDF/A. The short answer: None of the changes will fundamentally transform PDF/A. Let's take a look at some possibly relevant innovations in detail: The area of signatures and certificates has been fundamentally modernised. It is interesting that a separate section is dedicated to the topic of long-term signature validation. Some new entries have been included in this to facilitate the overview of certificates used for signatures and to enable "oversizing". In addition, PAdES (ETSI as TS 102 778) and ECC (Elliptic Curve Cryptography) based certificates are supported.

PDF 2.0 gives you the opportunity to define color in a more differentiated way. However, this topic plays only a minor role in real PDF/A applications. The new options will therefore be particularly useful when converting PDF 2.0 to PDF/A-1 to PDF/A-3.

The third heavily revised area that is relevant for PDF/A is tagging, i.e. "invisible" structural information, especially for text. This complex area has been simplified in PDF 2.0 on the one hand, on the other hand the extensibility (by namespa- cing) has been put on a more secure footing. In PDF/A tagging forms an important component in conformity level A - not in the much more widespread conformity level B. But: All three of the aforementioned new features of PDF 2.0 can only be used in PDF/A if there is a new standard part for it. The latest standard parts, PDF/A-2 and PD- F/A-3, are still based on ISO 32000-1 and PDF 1.7. Until then, they will mainly increase the requirements for PDF/A conversion, as they must be removed in the most sensible way possible during this process.

From the PDF/A-3 perspective, it is interesting that ISO has adopted the metadata "invented" by PDF/A-3 for embedded files and that these can now also be found in PDF 2.0. This increases the likelihood that they will be considered and displayed in PDF programs - a clear advantage for PDF/A-3 applications. PDF 2.0 also defines how embedded files can be referenced via URLs, which can be interesting in ECM systems that want to enable links to embedded files, for example.

Some entries for embedded fonts and the document information metadata have been removed from PDF 2.0, both of which have caused some effort in PDF/A conversion due to the PDF/A requirements based on them. This will simplify PDF/A conversion - but only if there is a PDF/A standard part based on PDF 2.0 that ISO is already working on.

The overall effects of the extended or added features from PDF 2.0 on PDF/A are limited. They can only become part of PDF/A projects when ISO publishes a new PDF/A standard part based on PDF 2.0. The current PDF/A standard parts are all based on older PDF versions. First of all, manufacturers of PDF/A-compliant products are required to implement the innovations of PDF 2.0.

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