Guide

PDF/A: The ISO Standard for Long-Term Document Archival

PC By Pablo Cirre • Updated May 7, 2026

PDF/A: The ISO Standard for Long-Term Document Archival

PDF/A is a family of ISO standards that define a subset of PDF specifically designed for long-term archival. Where regular PDF allows external dependencies (linked fonts, external media, JavaScript, encryption), PDF/A mandates self-containment: everything needed to render the document identically must be embedded within the file itself. Understanding PDF/A's requirements, conformance levels, and use cases is essential for anyone working with legal documents, government records, medical records, or any content requiring decades of reliable access.

Why PDF/A? The Problem with Regular PDF

A standard PDF file can reference:

External fonts: A file saying "use Times New Roman 12pt" relies on that font being installed on the viewing system
External color profiles: Color rendering may differ between systems
Encryption: An encrypted PDF cannot be read by a future viewer without the key
JavaScript: Interactive elements may not function in future viewers
Linked media: External images, audio, or video files that may not exist in the future
Proprietary extensions: Vendor-specific PDF features that may not be implemented by future software

PDF/A prohibits all of these, ensuring the document will render identically on any compliant viewer in the year 2100.

PDF/A Conformance Levels and Parts

PDF/A has evolved through multiple ISO standards:

PDF/A-1 (ISO 19005-1:2005)

Level	Description
PDF/A-1a	Conformance Level A — full accessibility: tagged structure, Unicode character mapping, logical reading order
PDF/A-1b	Conformance Level B — visual appearance preservation only; no structure requirements

PDF/A-2 (ISO 19005-2:2011)

Based on PDF 1.7. Adds:

JPEG 2000 image compression support
Transparent graphics (PDF 1.4+)
Optional content (layers)
Embedding of PDF/A-1 and PDF/A-2 files
Improved color management

Level	Description
PDF/A-2a	Full accessibility (tagged, Unicode)
PDF/A-2b	Visual preservation only
PDF/A-2u	Visual preservation + Unicode character mapping

PDF/A-3 (ISO 19005-3:2012)

Identical to PDF/A-2 except it allows embedding of any file type (not just other PDF/A files). This enables embedding source data (XML, CSV, original Word document) alongside the rendered PDF — critical for e-invoicing (ZUGFeRD, Factur-X standards).

PDF/A-4 (ISO 19005-4:2020)

Based on PDF 2.0. Replaces A/B/U levels with:

PDF/A-4: basic requirements
PDF/A-4e: engineering (allows embedded 3D models in U3D/PRC format)
PDF/A-4f: allows arbitrary file attachments (like PDF/A-3)

What PDF/A Prohibits

Prohibited Feature	Reason
Unembedded fonts	Font unavailability makes text unrenderable
Encryption	Prevents future access
JavaScript	Behavior may change with viewer versions
Audio/video content	External media may be unavailable
External content references	Links to external files may break
LZW compression	Patent concerns (historical, but retained for compatibility)
Colorspaces without ICC profiles	Color rendering would be device-dependent
Transparency groups (PDF/A-1 only)	Complex rendering requirements
Embedded TrueType with PostScript outlines	Compatibility issues

What PDF/A Requires

Required Feature	Purpose
All fonts embedded	Identical text rendering
Color spaces with ICC profiles (or DeviceGray/DeviceRGB/DeviceCMYK with OutputIntent)	Consistent color reproduction
XMP metadata	Structured, machine-readable document properties
Valid PDF structure	Correct cross-reference tables, object streams
Document information dictionary	Title, author, subject, keywords

The XMP metadata requirement is particularly important: PDF/A mandates a pdfaid:conformance and pdfaid:part property in the XMP:

<rdf:Description rdf:about="" xmlns:pdfaid="http://www.aiim.org/pdfa/ns/id/">
  <pdfaid:part>2</pdfaid:part>
  <pdfaid:conformance>B</pdfaid:conformance>
</rdf:Description>

Without this, a file is not self-identifying as PDF/A even if it meets all other requirements.

Creating PDF/A Files

From Microsoft Office

Word/Excel/PowerPoint:
File → Save As → PDF
Options → ISO 19005-1 compliant (PDF/A) ✓

LibreOffice

# Export as PDF/A-1b
libreoffice --headless --convert-to \
  "pdf:writer_pdf_Export:{SelectPdfVersion:{type:long,value:1}}" \
  document.docx

Or via GUI: File → Export as PDF → General tab → PDF/A-1b ✓

Ghostscript (convert any PDF to PDF/A)

# Convert to PDF/A-2b
gs -dPDFA=2 -dBATCH -dNOPAUSE \
   -sProcessColorModel=DeviceRGB \
   -sDEVICE=pdfwrite \
   -dPDFACompatibilityPolicy=1 \
   -sOutputFile=output_pdfa2b.pdf \
   /usr/share/ghostscript/PDFA_def.ps \
   input.pdf

# Convert to PDF/A-1b
gs -dPDFA=1 -dBATCH -dNOPAUSE \
   -sProcessColorModel=DeviceRGB \
   -sDEVICE=pdfwrite \
   -dPDFACompatibilityPolicy=1 \
   -sOutputFile=output_pdfa1b.pdf \
   /usr/share/ghostscript/PDFA_def.ps \
   input.pdf

Python — pikepdf

import pikepdf

# Open existing PDF and save as PDF/A (requires all fonts already embedded)
with pikepdf.open("input.pdf") as pdf:
    # Add XMP metadata for PDF/A identification
    with pdf.open_metadata() as meta:
        meta["pdfaid:part"] = "2"
        meta["pdfaid:conformance"] = "B"
    pdf.save("output_pdfa.pdf")

Validating PDF/A Compliance

Creating a file as PDF/A is not the same as having a valid PDF/A file — tools can produce non-compliant output while claiming compliance. Always validate:

VeraPDF (open-source reference validator)

# Validate PDF/A conformance
verapdf --flavour 2b document.pdf

# Validate and output detailed report
verapdf --format text --verbosity 6 document.pdf > report.txt

# Batch validate directory
verapdf --flavour 1b *.pdf

Apache PDFBox

# Validate with PDFBox preflight
java -jar pdfbox-app-3.x.jar PDFAValidator document.pdf

Common validation failures:

Missing font embedding (most common)
Missing ICC color profile or OutputIntent
Missing XMP metadata
Invalid XMP structure
Use of prohibited features (JavaScript, encryption)
Incorrect PDF structure (corrupt cross-reference table)

PDF/A Use Cases and Industry Requirements

Industry	Standard	Conformance Level	Notes
Government / legal	PDF/A-1 or 2	A or B	Many jurisdictions require PDF/A for official submissions
Healthcare (HIPAA)	PDF/A-2	B	Medical records archival
E-invoicing (EU)	PDF/A-3	B	ZUGFeRD, Factur-X embed XML invoice data
Patent offices	PDF/A-1	B	USPTO, EPO accept PDF/A-1b
Banking/finance	PDF/A-1 or 2	B	Regulatory document retention
Museums/libraries	PDF/A-2	A	Highest accessibility for cultural heritage
Engineering	PDF/A-4e	—	Allows 3D model attachments

PDF/A vs. Regular PDF vs. PDF/X vs. PDF/UA

Standard	Purpose	Key Requirement
PDF/A	Long-term archival	Self-contained, no external dependencies
PDF/X	Print production	CMYK color, no RGB, no transparency in v1
PDF/UA	Universal accessibility	Full tagging, Alt text, logical reading order
PDF/E	Engineering	3D content support
Regular PDF	General use	No restrictions

Summary

PDF/A answers a specific question: "Will this document render identically in 50 years?" By mandating font embedding, ICC color profiles, XMP metadata, and prohibiting encryption and external dependencies, PDF/A creates self-contained archival artifacts. For organizations with long-term document retention requirements — government, legal, healthcare, financial, cultural heritage — PDF/A is not optional but a compliance requirement. Always validate PDF/A files with VeraPDF after creation, as many tools produce non-compliant output despite claiming PDF/A export support.

Related conversions

Document conversions that follow this topic naturally:

Related conversions

Put what you just learned into practice — convert your files now in seconds, free and without registration.

Convert →

Convert →

Convert →

Convert →

Convert →

Convert →

Frequently Asked Questions

PDF/A-1 (ISO 19005-1, 2005) is the oldest standard based on PDF 1.4 — strictest restrictions, no transparency, no JPEG 2000. PDF/A-2 (2011) adds JPEG 2000, transparency support, optional content layers, and allows embedding PDF/A files within PDF/A files. PDF/A-3 (2012) is identical to PDF/A-2 but allows embedding any file type (XML, CSV, original source documents) — used for e-invoicing where XML invoice data is embedded in the PDF. For maximum compatibility with legacy systems, use PDF/A-1b. For modern archives with better compression, use PDF/A-2b.

PDF/A-1 (ISO 19005-1, 2005) is the oldest padrão based on PDF 1.4 — strictest restrictions, no transparência, no JPEG 2000. PDF/A-2 (2011) adds JPEG 2000, transparência support, optional content layers, e permite embedding PDF/A arquivos within PDF/A files. PDF/A-3 (2012) is identical to PDF/A-2 mas permite embedding any tipo de arquivo (XML, CSV, original source documents) — used para e-invoicing where XML invoice data is embedded no PDF. para máximo compatibilidade com legacy systems, usar PDF/A-1b. para moderno archives com better compressão, usar PDF/A-2b.

PDF/A-1 (ISO 19005-1, 2005) is the oldest Standard based on PDF 1.4 — strictest restrictions, no Transparenz, no JPEG 2000. PDF/A-2 (2011) adds JPEG 2000, Transparenz support, optional content layers, und erlaubt embedding PDF/A Dateien within PDF/A files. PDF/A-3 (2012) is identical to PDF/A-2 aber erlaubt embedding any Dateityp (XML, CSV, original source documents) — used für e-invoicing where XML invoice data is embedded im PDF. für maximal Kompatibilität mit legacy systems, verwenden PDF/A-1b. für modern archives mit better Komprimierung, verwenden PDF/A-2b.

PDF/A-1 (ISO 19005-1, 2005) is the oldest estándar based on PDF 1.4 — strictest restrictions, no transparencia, no JPEG 2000. PDF/A-2 (2011) adds JPEG 2000, transparencia support, optional content layers, y permite embedding PDF/A archivos within PDF/A files. PDF/A-3 (2012) is identical to PDF/A-2 pero permite embedding any tipo de archivo (XML, CSV, original source documents) — used para e-invoicing where XML invoice data is embedded en el PDF. para máximo compatibilidad con legacy systems, usar PDF/A-1b. para moderno archives con better compresión, usar PDF/A-2b.

Send <strong>PDF</strong> when the document is final and the layout must be preserved exactly (contracts, invoices, certificates). Send <strong>DOCX</strong> when reviewers need to edit, comment, or track changes. Many teams send both: PDF as the canonical version + DOCX for editable feedback. PDF/A is the right pick for legal archival (ISO 19005).

No. Encryption is explicitly prohibited by all PDF/A standards because a password-protected file cannot be opened by future systems without the correct key, violating the self-containment requirement. If you need to protect sensitive PDF/A documents, use file-system level access controls (permissions, ACLs) or digital rights management systems that operate outside the PDF file itself. Legal archival systems typically address access control through their own authentication mechanisms rather than PDF encryption.

No. Encryption is explicitly prohibited by all PDF/A padrãos because a password-protected arquivo cannot be opened by future systems sem the correct key, violating the self-containment requirement. If Você precisa protect sensitive PDF/A documents, usar file-system level access controls (permissions, ACLs) ou digital rights management systems that operate outside the PDF arquivo itself. Legal archival systems tipicamente address access control através de their own authentication mechanisms em vez de PDF encryption.

No. Encryption is explicitly prohibited by all PDF/A Standards because a password-protected Datei cannot be opened by future systems ohne the correct key, violating the self-containment requirement. If Sie müssen protect sensitive PDF/A documents, verwenden file-system level access controls (permissions, ACLs) oder digital rights management systems that operate outside the PDF Datei itself. Legal archival systems typically address access control durch their own authentication mechanisms rather than PDF encryption.

No. Encryption is explicitly prohibited by all PDF/A estándars because a password-protected archivo cannot be opened by future systems sin the correct key, violating the self-containment requirement. If Necesitas protect sensitive PDF/A documents, usar file-system level access controls (permissions, ACLs) o digital rights management systems that operate outside the PDF archivo itself. Legal archival systems typically address access control a través de their own authentication mechanisms rather than PDF encryption.

Round-tripping between similar formats (DOCX ↔ ODT, DOCX → PDF) is generally safe. Round-tripping with format-specific features (Word macros, complex tables, footnotes) often loses fidelity. Embedded fonts survive only if both source and target support font embedding (PDF yes, DOCX yes, plain HTML no). Always preview the result before deleting the original.

Use VeraPDF — the open-source reference PDF/A validator endorsed by the PDF Association: verapdf --flavour 2b document.pdf. Many tools claim to export PDF/A but produce non-compliant files. Common failures include missing font embedding, missing ICC color profiles, and incorrect XMP metadata structure. Always validate after creation. For batch validation in production workflows, integrate VeraPDF into your CI/CD pipeline or document management system.

If the PDF contains real text (not scanned images), <code>pdftotext</code> from poppler-utils or <a href="/convert/pdf-to-txt">PDF to TXT</a> works in seconds. If the PDF is a scanned image, you need OCR — Tesseract is the open-source standard. KaijuConverter's PDF tools auto-detect text-vs-image PDFs and route accordingly.

PDF/A-3 allows embedding arbitrary file attachments within a PDF/A file. The ZUGFeRD (Germany) and Factur-X (France/EU) e-invoicing standards use this to embed a machine-readable XML invoice (conforming to EN 16931) alongside a human-readable PDF. The PDF provides the visual invoice for human review; the XML provides structured data for automated accounting systems. A single PDF/A-3 Factur-X file satisfies both human and machine processing requirements, making it ideal for B2B and B2G invoicing in the EU.

PDF/A-3 permite embedding arbitrary arquivo attachments within a PDF/A file. The ZUGFeRD (Germany) e Factur-X (France/EU) e-invoicing padrãos usar this to embed a machine-readable XML invoice (conforming to EN 16931) alongside a human-readable PDF. The PDF fornece the visual invoice para human review; the XML fornece structured data para automated accounting systems. A single PDF/A-3 Factur-X arquivo satisfies both human e machine processing requirements, making it ideal para B2B e B2G invoicing no EU.

PDF/A-3 erlaubt embedding arbitrary Datei attachments within a PDF/A file. The ZUGFeRD (Germany) und Factur-X (France/EU) e-invoicing Standards verwenden this to embed a machine-readable XML invoice (conforming to EN 16931) alongside a human-readable PDF. The PDF bietet the visual invoice für human review; the XML bietet structured data für automated accounting systems. A single PDF/A-3 Factur-X Datei satisfies both human und machine processing requirements, making it ideal für B2B und B2G invoicing im EU.

PDF/A-3 permite embedding arbitrary archivo attachments within a PDF/A file. The ZUGFeRD (Germany) y Factur-X (France/EU) e-invoicing estándars usar this to embed a machine-readable XML invoice (conforming to EN 16931) alongside a human-readable PDF. The PDF proporciona the visual invoice para human review; the XML proporciona structured data para automated accounting systems. A single PDF/A-3 Factur-X archivo satisfies both human y machine processing requirements, making it ideal para B2B y B2G invoicing en el EU.

Light edits (annotations, signatures, form fields) are fine in any PDF reader. Structural edits (changing paragraphs, replacing images) are awkward — PDF is a presentation format, not an editing format. The robust workflow is: keep the source DOCX/MD/HTML as the master, regenerate the PDF when changes are needed. Tools that "edit PDFs" reverse-engineer the layout and frequently break it.