PDF/A-3 and long-term preservation: what to know
Not all PDFs are equal when it comes to preserving documents over time. PDF/A-3 is an ISO standard designed specifically for long-term archiving. In plain words: what changes and why it matters for technical documentation.
Try opening a file from twelve years ago. Often the document is still there, but does not open as it should: missing fonts, distorted layout, different colors, or simply impossible to read. For manuals, catalogs, technical datasheets and certificates that have to last, the format is not a detail: it decides whether, in ten or twenty years, that document will still be readable and findable. This is where PDF/A-3 comes in.
Why an ordinary PDF is not enough for archiving
Any ordinary PDF can do things that, over the years, make it fragile: referencing fonts installed on the computer (which one day might not be there), using device-dependent colors, being protected by encryption, containing elements that depend on external software. PDF/A is a controlled subset of PDF: it keeps only what guarantees reopening the document identically, anywhere and years later.
What makes a file truly archivable
- All fonts embedded in the file
- No encryption: the content is always accessible
- Device-independent colors (ICC profiles)
- Metadata embedded in XMP format
- Self-contained: no references to external content
- No JavaScript, executable files, audio or video
PDF/A-3's extra gear: the file inside the file
The standard has grown over time: PDF/A-1 in 2005, PDF/A-2 in 2011, PDF/A-3 in 2012 and PDF/A-4 in 2020. PDF/A-3's innovation is powerful: while the earlier versions allowed only attachments that were themselves compliant, PDF/A-3 lets you embed an attachment of any type. In practice you can keep, inside the same archivable file, the PDF a person reads and the source file for the machine (an XML, a CAD drawing). It is the same principle as the European hybrid electronic invoices ZUGFeRD/Factur-X, whose PDF part must be exactly in PDF/A-3.
An honest clarification: PDF/A-3 makes the container, that is the PDF, compliant. The file you embed inside (an XML, a CAD) does not automatically inherit the same preservation guarantees: it too has to be looked after. The attachment is added value, not a shortcut.
It is not just technical: it is also the law
In Italy the AgID Guidelines on the preservation of digital documents, in force since 1 January 2022, identify PDF/A as a format suitable for preservation: among paginated formats, PDF is fine for preservation only if it is PDF/A. The criterion is clear: choose formats that guarantee the document's readability and findability throughout its entire life cycle, defending against technological obsolescence.
How long do you have to keep documents?
Longer than you might think, and in many sectors the law says so. Technical documentation is not material to throw away after the sale: it must be kept, and it must be possible to produce it years later.
| Area | Minimum duration | Reference |
|---|---|---|
| Technical documentation of machinery | at least 10 years | Machinery Regulation (EU) 2023/1230 |
| Medical devices | 10 years (15 for implantable ones) | Regulation (EU) 2017/745 (MDR) |
| Accounting records and invoices | 10 years | art. 2220 Italian Civil Code |
What changes with MobileReplica
MobileReplica distributes and archives manuals, catalogs and certificates in standard, durable formats like PDF/A-3, searchable word by word and available offline too, inside the company's branded app. No proprietary lock-in: the documents stay readable and findable over time, when they are really needed, even years later.
Documentation distributed and archived in formats like PDF/A-3, designed for long-term archiving.
Full-text search retrieves the document in a few seconds, even years later: the findability AgID requires is no longer a problem.
Updated from a single point: no outdated copies, so you always know which document is valid.
Open, recognized standards: your documents stay readable over time, independent of any single piece of software.
What is the difference between a PDF and a PDF/A?
PDF/A is a controlled version of PDF designed for archiving: embedded fonts, no encryption, device-independent colors, self-contained. It serves to guarantee that the document stays identically readable even years later.
Why PDF/A-3 specifically and not the earlier versions?
Because PDF/A-3 can embed, inside the same archivable file, the source file (XML, CAD, spreadsheet) alongside the readable PDF. It is the standard used, for example, by European hybrid electronic invoices.
Is it a proprietary standard?
No. PDF/A-3 is defined by the international standard ISO 19005-3:2012 and does not depend on a single software vendor.
How long must technical documentation be kept?
It depends on the sector: for machinery at least 10 years (Regulation (EU) 2023/1230), for medical devices 10 years (15 for implantable ones), for accounting records 10 years (art. 2220 Italian Civil Code).