PDF standards
What is PDF/A?
PDF/A is the ISO-standardized PDF family for long-term preservation. It keeps the familiar PDF format but restricts features that could make a document harder to reproduce reliably years from now.
Updated August 23, 2026
Quick answer
PDF/A is archival PDF with stricter rules.
A PDF/A file is still a PDF, but it must conform to a specific part of the ISO 19005 family. The rules focus on self-contained, predictable rendering: required resources such as used fonts are embedded, encryption is not permitted, metadata identifies the archival profile, and other features are constrained according to the selected PDF/A version.
PDF/A vs a normal PDF
Ordinary PDF is a general-purpose document format. PDF/A narrows that format for preservation. The exact requirements depend on the PDF/A part and conformance level, but the practical difference is that an archive-ready file has fewer hidden dependencies on software, fonts, encryption or external resources.
| Question | Ordinary PDF | PDF/A |
|---|---|---|
| Primary goal | General viewing, exchange and workflows | Long-term preservation and reproducibility |
| Fonts | May use a wider range of font arrangements | Fonts used for rendering must be embedded under the applicable profile rules |
| Encryption | Can be password protected or encrypted | Encryption is not permitted |
| Metadata | Flexible | Must identify the PDF/A profile and meet archival metadata requirements |
| Attachments | Generally supported | Rules depend on the PDF/A part; PDF/A-3 and PDF/A-4f support broader embedded-file workflows |
What does a PDF/A file actually need?
PDF/A is not created by changing the file extension or adding an archival label. A conforming file has to satisfy the rules of a specific ISO 19005 part. Exact details vary by version, but the preservation model consistently aims to keep the document self-contained and predictable.
- Embedded fonts: fonts used to render text must be available inside the file under the applicable profile requirements.
- No encryption: a PDF/A file cannot depend on a password or encryption key for future access.
- Controlled rendering dependencies: color information, metadata and other resources are constrained so the document is less dependent on a particular device or application.
- Restricted executable behavior: preservation profiles avoid features such as executable actions that could make future rendering or interpretation unreliable.
- Profile identification: the document records which PDF/A part and conformance level it claims to meet.
PDF/A-1, PDF/A-2, PDF/A-3 and PDF/A-4
The PDF/A family evolved alongside PDF itself. The versions are not quality scores. Each part is based on a particular generation of PDF and permits a different set of capabilities.
| Variant | Base PDF | What changes |
|---|---|---|
| PDF/A-1 | PDF 1.4 | Original 2005 archival standard with a comparatively strict older feature set |
| PDF/A-2 | PDF 1.7 | Adds capabilities available in newer PDF while retaining archival constraints |
| PDF/A-3 | PDF 1.7 | Builds on PDF/A-2 and permits arbitrary embedded files, useful for document-plus-data packages |
| PDF/A-4 | PDF 2.0 | Current generation based on ISO 32000-2; PDF/A-4f supports embedded files and PDF/A-4e supports engineering workflows including 3D content |
What do the A, B, U, F and E labels mean?
The suffix is part of the conformance claim, and its meaning depends on the PDF/A generation. For PDF/A-1 through PDF/A-3, Level B focuses on reliable visual reproduction, Level A adds structural requirements that support logical reading order and text extraction, and Level U in PDF/A-2 and PDF/A-3 adds reliable Unicode mapping for text.
PDF/A-4 reorganized the model. Base PDF/A-4 incorporates the visual-reproduction focus instead of using a B suffix. PDF/A-4f adds broader embedded-file support, while PDF/A-4e adds engineering-oriented capabilities. A label such as PDF/A-2u or PDF/A-4f therefore tells you more than simply whether a file is "archival."
How can you tell whether a PDF is really PDF/A?
A viewer may display a PDF/A banner or metadata value, but a claim inside the document is not the same as validated conformance. If compliance matters, validate the final file against the exact PDF/A part and level your workflow requires.
- 1. Identify the required profile, such as PDF/A-2b or PDF/A-4.
- 2. Run the file through a validator that checks that exact profile.
- 3. Review any failures instead of relying only on the filename, extension or viewer banner.
- 4. Revalidate the final output after any conversion or edit.
Which PDF/A version should you choose?
The right answer is usually determined by the archive, customer, regulator or records policy that will receive the document. If a specification names a profile, use that profile rather than choosing a newer one simply because it exists.
| Requirement | Practical direction |
|---|---|
| A receiving system explicitly requires PDF/A-1, -2 or -3 | Use the named version and conformance level |
| Modern archival workflow without arbitrary attachments | Use the profile accepted by the archive; PDF/A-2 or PDF/A-4 may be relevant depending on its policy and tooling |
| The PDF must carry non-PDF files as part of the package | A workflow may specify PDF/A-3 or PDF/A-4f |
| Engineering document with supported 3D content | PDF/A-4e is the engineering-oriented PDF/A-4 profile |
What happens if you edit a PDF/A file?
PDF/A conformance belongs to the final file, not to its history. A document that was valid before an edit is not automatically valid afterwards. Merging, splitting, extracting pages, rotating pages, compressing content, changing metadata or using another PDF editor can alter structures or resources that the archival profile checks.
The safe rule is simple: if PDF/A compliance matters, validate again after the last change. Also remember that password encryption is incompatible with PDF/A, so an encrypted or password-protected output should not be treated as PDF/A-conforming.
Common PDF/A misconceptions
"It has a .pdf extension, so it can be archived."
A normal PDF is not automatically PDF/A. Conformance has to be created and validated against a specific archival profile.
"PDF/A means the document is accessible."
Not by itself. Some older Level A profiles include structural requirements that help with reading order and extraction, but accessibility is a separate concern with its own standards such as PDF/UA.
"PDF/A files can never contain attachments."
Attachment rules depend on the version. PDF/A-3 permits arbitrary embedded files, and PDF/A-4f supports embedded-file workflows in the PDF/A-4 generation.
"Once validated, it stays PDF/A forever."
Any later edit can change the file. Validate the final artifact that will actually be stored or submitted.
Does eggPDF create or certify PDF/A?
No. eggPDF currently provides general PDF operations such as merge, split, extract, rotate and compression, but it is not presented as a PDF/A conversion, validation or certification service. If your archive or compliance workflow requires PDF/A, use eggPDF only for the document operation you need and validate the final output with software designed for the required PDF/A profile.
Related guides
Sources
We prefer standards bodies, platform documentation and first-party technical sources for factual claims.