Three Reasons PDF/A is Future-proof
I have had several archivists ask me if I think PDF/A is a safe bet. How can one be certain all these electronic documents are going to be accessible in fifty or a hundred years?
This is a great question and one archivist around the planet fret over at night. As we imagine the ghosts of prosperity laying blame at our feet for allowing a digital dark age. So, in this epic battle of mankind vs. file obsolescence, is the PDF/A file format the best weapon in our arsenal?
In short, the answer is a resounding yes. And here’s why:
1. PDF/A is Independent & Self-Contained
The PDF/A document can render its information regardless of the operating system or the technological environment it is accessed in. Everything needed to reproduce the PDF/A as it was originally created is embedded into the package itself. For example, in a normal PDF, the fonts used in the file are pulled from the local user’s operating system. So, if a PDF calls for some rare font not already installed on the user’s system, then the system likely to render it using a default font instead, or worst, not load at all. PDF/A, however, includes the fonts as part of the file. This applies to all aspects of the PDF/A. Including embedded files, metadata, and text.
“If somebody gave you a set of bits, there are well-understood strategies for ensuring that you can return a faithful copy of those original bits in the future.”
Most importantly, the PDF/A file can be reconstructed in whole from its binary encoding (1’s and 0’s). What do I mean? Let’s imagine future archeologists excavating an old, well preserved hard drive from our era. Without the operating systems and hardware to run the drive, they can only scan the physical hard disk’s surface and reproduce the laser-etched bits imprinted upon it as binary string of data. They can convert this binary data into hexadecimal. Then they can look for the magic-number (hex 25 50 44 46) of the PDF/A format and reconstruct that raw data back into the original PDF/A format (Programs such as PDF24 convert Hex to PDF). Because the PDF/A has everything it needs in one file, all in one place, every component is preserved in the process.
PDF/A hexadecimal data extracted from Binary
The PDF/A format ensures the authenticity of digital documents. Whenever you open a PDF/A, a window in Adobe Acrobat pops up letting you know the file is “…read-only to prevent modification.”
This prevents anyone from accidentally altering the file in any way. However, if someone was determined they could remove the PDF/A settings and change whatever they like. However, this would alter the file’s checksum and that would be readily detectable. So, the PDF/A file coupled with a checksum can ensure a file is authentic to its original intent. This is an important capability now for legal credibility. However, I predict future historians debating the authenticity of born-digital objects, where the oldest verifiable document holds more historical authority than it’s derivatives. As digital archivists, we need to establish authenticity at ingest by recording checksums of our accessions and creating checksums for their PDF/A counterparts.
3. PDF/A is Officially Official
First, PDF/A is backed by the International Organization for Standardization and is an open, non-proprietary format. We have three increasingly complex standards:
[PDF/A-1](https://en.wikipedia.org/wiki/PDF/A) : ISO 19005-1 PDF 1.4
PDF/A-1a requires pure Unicode, embedded hierarchy, language specification, and full tagging for handicap accessibility. PDF/A-1b doesn’t hold these requirements.
PDF/A-2 : ISO 32000-1 – PDF 1.7
PDF/A-2 allows for digital signatures and the capability to embed other pdf/a documents inside of them. Digital signatures can be used to verify the origins and authenticity of the digital object. This format is rarely used.
PDF/A-3 : ISO 32000-1 – PDF 1.7
PDF/A-3, the latest specification from 2012, allows the embedding of common file formats such as CSV and TXT. Presumably, PDF/A-4 will allow for embedded audio and video.
You can read all about this at the PDF Association’s website. Or you can read this excellent overview:
The governments of the world needed a sustainable file format and the PDF/A specification delivers. State agencies around the world are now using the format for all official documentation. The result of which can only lead to wider and wider support for the indefinite future.
Organization PDF/A Status U.S. National Archives and Records Administration Recommended European Commission Recommended German government Recommended French government Recommended Dutch government Mandated National Archives of Sweden Accepted National Archives of Norway Recommended Brazilian federal legislature Mandated U.S. Courts Mandated Victoria, Australia, Public Record Office Mandated
Not only are governments around the world now mandating the PDF/A format for official government electronic documents but it has become an industry standard as well. The medical industry, for example, has started to adapt to paperless workflows and use the pdf/a document format for patient records they are mandated to keep. See this article for more information.
According to an AIIM (Association for Information and Image Management) study in 2010, 90% of the companies surveyed were creating PDFs to archive their scans and office documents. It has replaced microfilm and microfiche as the archival format of choice.
With governments, businesses, archivists, and the health industry relying on PDF/A’s for long term electronic document preservation, I believe we have reached the critical point of international adoption and saturation. With such widespread usage, PDF/A is future-proof. Too much has already been invested. Ultimately, future generations will have no choice but to keep the PDF/A format accessible.
