Updated draft PDF 2.0 standard publicly available

The Draft International Standard (DIS) version of the latest ISO 32000-2 (PDF 2.0) standard is now publicly available from ISO.

A DIS is the first and last chance for those not actively involved in the respective ISO working groups or as members of the PDF Association to acquire the document, review and provide feedback prior to formal ratification and publication as an official International Standard (IS).

This so-called dated revision of ISO 32000-2 will, after a final round of review and minor edits, replace ISO 32000-2:2017 (which will be withdrawn) with an improved PDF 2.0 specification called ISO 32000-2:202x (the final digit to be determined based on actual publication date). The original ISO 32000-1:2008, based on Adobe's PDF 1.7 will remain available.

Work on the dated revision of PDF 2.0 provided an opportunity for early adopters and implementers to identify typos, editorial corrections and provide additional feedback, with many such improvements resulting. No new features were introduced; however, a number of existing features were upgraded. PDF developers who should already have intimate knowledge of ISO 32000 will be happy to note that clause and table numbering remains the same as in ISO 32000-2:2017.

One of the key changes triggering the dated revision of PDF 2.0, was the need to update Unicode support to accommodate the new Japanese era, Reiwa (令和). Japanese implementations depend on this ligature form of Japanese era names when presenting calendar information. As a consequence of this change, PDF's character collections were all formally updated and moved to Github.

Based on feedback from the subject matter experts (SMEs) of ISO Technical Committee (TC) 171 Sub Committee (SC) 2, Working Group (WG) 8 (the committee responsible for the development of ISO 32000 including PDF Association members), standardized informative notes have also been added to the dated revision in all key locations where important wording changes differ from the original PDF 2.0 standard (ISO 32000-2:2017). As described in the document's Introduction, searching for the key phrase “2020 dated revision” will help readers locate all such key changes. Note that the "dated revision" note is used only to mark changes considered most important to implementers of PDF 2.0.

Other important changes include:

• An update to many Normative References to their latest versions, to add DOIs or URLs (where available) and to ensure that all documents are still available. As stated in the dated revision itself, the PDF Association now maintains a helpful list of resources at https://reference.pdfa.org/iso/32000/;
• Various clarifications on basic PDF syntax and tokenization, including clarification that keys in dictionaries must be direct objects;
• Consistency in requirements as to which kinds of errors need to be ignored;
• Clarification of the alternate image selection algorithm;
• Clarifications to Linearized PDF document structure (Annex F);
• For Tagged PDF, the parent-child relationships between the standard structure elements in the standard structure namespace for PDF 2.0 have been significantly updated (Annex L) as well as updates to the standard structure attribute owners;
• Annexes describing how to extend PDF (Annex E) and how to handle PDF versions and compatibility (Annex I) were re-written.

As a result of the public availability of this dated revision of PDF 2.0 all of the PDF industry-vertical ISO subset standards (PDF/A (ISO 19005), PDF/UA (ISO 14289), PDF/X (ISO 15930) and PDF/VT (ISO 16612)) will also have new parts published very soon that support PDF 2.0.

One of the key benefits of PDF Association membership is ongoing access to all ISO documents, including internal drafts of all PDF and related standards. Access to these early documents, while still in work in progress, allows you much more time for detailed review, time for discussions with other PDF Association members and SMEs, and more time to get those changes that you’d like to see into ISO 32000.