PDF/A is one set of standards among a suite of PDF-based standards managed by the International Organization for Standardization (ISO). It was developed to enable the long-term preservation of electronic documents and provides specifications for the creation, viewing, and printing of PDF documents, with the intent of preserving final documents of record as self-contained documents.
The standard does not define an archiving strategy or the goals of an archiving system. Rather, it identifies a "profile" for a PDF file that makes it possible to reproduce the visual appearance of the document the exact same way in the future. This profile specifies what must be included in the file, while prohibiting features that are not suitable for long-term archiving.
- Making the case for PDF/A and Adobe® Acrobat® White paper (PDF: 1.9M)
- Making the case for PDF/A and Adobe LiveCycle® White paper (PDF: 1.0M)
Adoption
Adoption by government and standards organizations
Since it became an ISO standard in 2005, PDF/A has gained significant acceptance. The earliest adopters have been government and standards organizations that define the regulatory standards businesses must live by. Here is a just a sampling of organizations that mandate, recommend, or accept PDF or PDF/A for the long-term archival of documents.
| U.S. National Archives and Records Administration (NARA) | PDF/A | Accepted |
| European Commission (MoReq) | PDF/A | Recommended |
| German government (SAGA v4 ) | PDF/A | Recommended |
| French government | PDF/A | Recommended |
| Dutch government | PDF/A | Mandated |
| National Archives of Sweden | PDF/A | Accepted |
| Austrian National Library | PDF/A | Recommended |
| National Archives of Norway | PDF/A | Recommended |
| Organization for the Promotion of Automated Accounting | PDF/A | Recommended |
| Brazilian federal legislature | PDF/A | Mandated |
| U.S. Courts | Mandated | |
| Victoria, Australia, Public Record Office | Mandated | |
| Italian government archiving standard | Accepted | |
| Taiwan National Central Library | Recommended |
Research studies and customer stories
Research studies
The PDF file format is rapidly overtaking paper for long-term storage, as shown in these two market studies.
AIIM Market IQ study: Content creation and delivery: The on-ramps and off-ramps of ECM
- 90% of the organizations studied were using PDF for long-term storage of scanned documents.
- 89% were converting office files to PDF for distribution and archive.
- In 5 years, use of paper for long-term storage drops to 77%, while PDF rises to 93%.
PDF/A Competence Center survey: Nearly all archiving projects use PDF/A
- 16% of 400 European respondents use PDF/A already.
- 50% intend to introduce it in the next 12 months.
- Older archiving formats, such as TIFF, JPEG, and conventional PDF, decreased about 5% from the previous year's survey.
Key specifications
The current version of the standard is PDF/A-1 and is based on PDF v1.4. The next generation, PDF/A-2, is under development and will add selected features from the newer "umbrella" or master PDF standard, ISO-32000-1, which is now maintained by ISO.
Key characteristics of a PDF/A file:
- Self-contained. Everything needed to render or print a PDF/A file must be contained within the file. This includes all visible content like text, raster images, vector graphics, fonts, color information, and much more. It also means that a wide range of external content references are disallowed, including audio and video content, JavaScript, and executable files. All embedded fonts must be legally embeddable for unlimited, universal rendering.
- Self-documenting. PDF/A promotes the use of metadata, enhancing the document by providing information about the document itself. It provides recommendations, for instance, for documenting file attributes such as file identifier, file provenance, and font metadata. When metadata is used, PDF/A requires the use of the Extensible Metadata Platform (XMP) for embedding the data in the files.
- Device independent. PDF/A requires device-independent components, such as specific RGB or CMYK color profiles, so that the static visual appearance can be reliably and consistently rendered and printed without regard to the hardware or software platform used.
- Unfettered. PDF/A prohibits encryption so that a compliant PDF/A file must be open and available to anyone or any software that processes the file. User IDs and/or passwords cannot be embedded. Access control is typically managed outside the file format by a content or records management system. Live digital signatures can be included in a PDF/A file as long as they are applied after the PDF/A file has been created. To make sure the file remains compliant with the standard, be sure to apply the signature using software that is PDF/A aware, such as Adobe Acrobat 9 or LiveCycle ES2.
- Two levels of compliance. There are two levels of compliance. The lowest level, PDF/A-1b, meets all the core requirements, helping to ensure reliable reproduction of the visual appearance of a document. This specification is often applied to scanned images and preexisting PDF files that are converted to PDF/A. The higher level, PDF/A-1a, requires a document structure called "tags" that provides an underlying structure for the content within the document and facilitates searching, repurposing of content, and accessibility for people with disabilities such as blindness. This higher level specification is typically applied to "digitally born" documents captured directly from applications like Microsoft Word that create document structure during the authoring process.
Resources
The ISO standard
- ISO 190005-1 Document management — Electronic document file format for long-term preservation:
Part 1: Use of PDF 1.4 (PDF/A-1); Addendum Cor 1:2007
Adobe resources
- Making the case for PDF/A and Adobe Acrobat: White paper (PDF: 1.9M)
- Making the case for PDF/A and Adobe LiveCycle: White paper (PDF: 1.0M)
- PDF/A metadata — XMP, RDF & Dublin Core: Technical article (PDF: 293K)
- PDF/A-1 in Acrobat 9 and LiveCycle ES: Technical article (PDF: )
- Creating PDF/A documents: LiveCycle developer LiveDocs
AIIM PDF/Archive committee
PDF/A Competence Center
PDF/A guidance examples
- U.S. National Archives: FAQs; transfer instructions
- European Commission MoReq: The specification
- Victoria, Australia: Standards and guides
- Dutch government: The standard (PDF: 68K) (in Dutch)
- French government: Framework for interoperability (PDF: 2.7M) (in French)
- Organization for the Promotion of Automated Accounting — E-billing: Information (in German)
- Additional examples specified on the PDF/A Competence Center legislation page
Information on the use of digital signatures
- PAdES — PDF Advanced Electronic Signatures, an ETSI standard: Press release, Wikipedia page
- U.S. District Court Judge issues first digitally signed judicial order: Blog post
- Foundations of Digital Evidence: Book
- Digital Signature Assurance and the Digital Chain of Evidence: White paper
- Belgian eID website in Dutch or French
