Interview: Delving into PDF 2.0 with Justin Durkan

With the imminent release of PDF 2.0, we interviewed fellow Nitronaut and PDF Association Board Member, Justin Durkan, to find out more about the announcement and what it means for our customers.

Tell us a bit about yourself, Justin?

I am the Director of Desktop Engineering at Nitro. My team is responsible for the evolution of Nitro Pro, our desktop PDF productivity solution. I am also Nitro’s representative on the Board of the PDF Association.

How did you become involved with the PDF Association, and when did you become a member on the Board?

Nitro has been involved in the PDF Association for many years. As a partner member, Nitro is entitled to a seat on the Board. As head of product development, I have been involved with the PDF Association since joining Nitro. I became a Board member in May 2016.

Can you shed some light on the development of PDF 2.0? Was there a specific instigator for the new specification?

PDF (Portable Document Format) is the world’s most popular document format and has been around since the early 1990s. It was created by Adobe® to overcome several issues with the then popular PostScript format, and it has been updated and modified many times since. In 2007, Adobe® asked the ISO to give PDF official status as a worldwide standard. They offered their specification for PDF to the ISO as a starting point, and in 2008 the ISO published ISO 32000-1 as the standard for PDF version 1.7.

As an open standard from the ISO, PDF was open to everyone and was no longer something controlled solely by Adobe.  The standardization process nailed down the technical details of what PDF was and would continue to be into the future. Users were free to use software from other than Adobe® to process their documents, and companies such as Nitro now had the freedom to innovate.

However, there were some problems with the original standard in that a number of technologies available within PDF remained owned and controlled by Adobe–for example, the XFA and JavaScript extensions in Adobe® Acrobat®. Put simply, the PDF standard may have been open but some of the items referenced within that standard were not.

To help fix this, the ISO immediately began the process of preparing a revised standard for PDF – now commonly known as PDF 2.0. Since 2008, the ISO has been working on this new specification to correct a number of ambiguities in the original standard document and to ensure that everything referenced in the new specification would itself be an open standard.

Furthermore, the PDF Association liaised with ISO on developing PDF 2.0. In this capacity, the Association has been shepherding the evolution of various drafts of the new specification. This collaboration is now coming to a conclusion with the imminent publication later this month of a revised standard for PDF,  ISO-32000-2.

There’s been some information released on the technical specifics (Nitro & PDF 2.0), but can you tell us what that really means for end users and customers from a day-to-day workflow perspective?

Sure! The new PDF 2.0 standard document is very comprehensive and runs to over 950 pages, and for those brave enough to read it all, it would be evident that it’s targeted more at developers than end-users.

Included in the new PDF 2.0 standard are the following:

  • Corrections to the previous standard (PDF 1.7)
  • Implementation details captured and documented to permit all vendors to implement PDF processing the same way
  • In the previous standard, the idea was that applications, like Nitro Pro or Adobe® Acrobat®, were deemed to conform if they did what the standard specified. The new standard, instead, defines what PDF documents should contain and what these contents actually mean. The emphasis has moved from what was termed a conforming application to a new idea that applications process conforming documents. With the advent of PDF 2.0, applications like Nitro Pro or Adobe® Acrobat® cannot themselves be labeled as conforming to the new standard. Instead, applications can only claim to produce or accept PDF files that conform to the new standard.
  • The new standard permits an application to produce or process documents that conform to the standard in some ways but not in others. This means that a vendor can choose to not support all features of PDF 2.0. Those parts that they do support, they must do so in accordance with the standard. In other words, no proprietary extensions or partial implementations are permitted under the standard. If a vendor supports PDF documents that include CAdES signatures, for instance, they must do so fully as the standard defines.
  • Rich Media, 3D, geospatial and other dynamic content have been standardized. Previously these would have been implemented in a proprietary fashion by individual vendors.
  • Semantic tagging has been overhauled. This will bring significant usefulness as vendors leverage this for improvements to accessibility and archiving. Vendors will also be able to leverage this for conversion, machine learning, and reflowing content.
  • The previous PDF standards permitted PDF files to include references to external documents and data. If these external references were not publicly accessible, the transfer of the PDF to other users meant that all the files had to be packaged together into something like a zip file and this zip file was transferred. With PDF 2.0, it is now possible to embed these external files into the PDF itself. The PDF file itself now becomes the package rather than the zip file. The end user now receives one file with everything in it.
  • XFA has been deprecated. Over time we anticipate the industry will replace XFA with a standards-based alternative.

PDF 2.0 also adds the following new features with the new standard:

  • Unencrypted wrappers. This will permit, for instance, a plain-text cover letter instructing users that the remainder of the document is encrypted PDF and potentially how credentials may be acquired to access it.
  • Black point compensation. This will improve rendering of dark features of a document.
  • Projection annotations
  • 3D and Rich Media annotations
  • CAdES signatures. These are compliant with European Union standards for digital signatures.
  • Long-term validation of digital signatures. Useful for archiving.
  • Document security store. This facilitates long-term validation.
  • Document timestamp dictionary. This facilitates long-term validation.
  • Geospatial features. This will be of value to customers that utilize maps in their workflows.
  • Pronunciation hints for improved accessibility.
  • Namespaces for Tags permits identifying and specification of custom structure elements.
  • Document parts for high-speed variable transaction printing purposes.
  • Associated files to allow internal or external files streams be associated with objects with the PDF file and to identify the semantic relationship between them.
  • Support for PRC for 3D content.

 

For end users, PDF 2.0 means that when vendors bring implementations forward with these features, they can rely on the implementations being done to a standard that ensure interoperability. A PDF 2.0 file containing tagged information from one vendor will be understood by another vendor’s product if they both have implemented PDF 2.0 tagging.

Vendors are not obliged to do everything in the standard; however, if a vendor implements a particular subset of features from the standard, it is required to fully implement each such feature in accordance with the standard. So, for example, a vendor that support PAdES signatures must do so exactly as the standard defines and must implement all aspects of PAdES as defined in the standard. It’s not an “all-or-nothing” standard but it is an “all-or-nothing” specification for each individual feature.

As Director of Engineering at Nitro, what does PDF 2.0 mean for your team and future Nitro Pro releases?

Over time, Nitro Pro will incrementally add support for the subset of PDF 2.0 features that best matches the needs of our customers. First and foremost we will ensure that PDF 2.0 documents will be openable and modifiable by Nitro Pro.

This new standard contains many features, some of which would be more meaningful than others for our customers. Therefore, Nitro intends to work with our customers to identify the most relevant features for inclusion in future versions of Nitro Pro. All new documents produced by these future versions of Nitro Pro will conform with the new standard.

Okay, one final question—as you mentioned, this is the first PDF update in 10 years, so what does the future hold for PDF innovation?

PDF 2.0 itself is a massive body of work, and it is unlikely that a PDF 3.0 will be published this decade. So, in the short- and medium-term, there may only be updates to the standard that will emerge quickly to address specific areas of clarification or corrections.

PDF 2.0 has sufficient flexibility to permit usage or implementations that provide a special capability outside of the PDF-ness of the document. For instance, there is currently a technical working group within the PDF Association which is evolving an idea to make PDF more responsive to the device form factor. This initiative defines a set of rules and tags for documents that conform to PDF 2.0. Using these rules and tags, a specially designed viewer would automatically be able to reflow the document to respond to form factor or form factor changes. This is a use case of PDF 2.0 documents rather than being a whole new PDF standard. Documents with the specified tags will be reflowable in viewers that follow the specified rules.

An idea like this is just one currently being explored within the PDF Association. As a Board member, Nitro will definitely be involved in leading the ongoing evolution of the PDF standard.

For additional information, please check out our blog post or get in touch with your Nitro Account Manager today.