PDF/A with fpdf2¶
New in 2.8.5
What is PDF/A¶
PDF/A is the ISO standard for long-term archiving of PDFs. It restricts features that aren’t stable for preservation (e.g., JavaScript, encryption, multimedia) and requires self-containment (fonts embedded, color spaces defined, predictable rendering).
Choosing a PDF/A Profile¶
| Profile | Description | Actions Allowed | Actions Disallowed | Recommended Use Cases |
|---|---|---|---|---|
| PDF/A-1B | “B” = Basic visual appearance. Earliest profile, based on PDF 1.4; stricter feature set (no transparency/layers). | ✅ Embedding fonts ✅ JPEG/PNG/TIFF images (PDF 1.4 codecs) ✅ Digital signatures ✅ ICC OutputIntent for color management | ❌ Encryption ❌ JavaScript ❌ Multimedia (audio/video) ❌ External content dependencies ❌ Transparency (blend modes/soft masks) ❌ Layers (OCGs) ❌ JPEG2000 images ❌ Embedded file attachments | Legacy/long-term archives needing maximum compatibility; scanned documents where appearance is paramount. |
| PDF/A-2B | “B” = Basic visual appearance. Ensures documents can be reliably rendered visually. Based on PDF 1.7. | ✅ Embedding fonts ✅ JPEG/JPEG2000/PNG/TIFF images ✅ Transparency ✅ Layers (OCGs) ✅ Digital signatures | ❌ Encryption ❌ JavaScript ❌ Multimedia (audio/video) ❌ External content dependencies | Scanned documents where only appearance must be preserved (invoices, contracts for viewing). |
| PDF/A-2U | Adds “U” = Unicode text mapping. Same as 2B + text must be Unicode-mapped for reliable search/extract. | ✅ Same as 2B ✅ Text extractable & searchable | ❌ Same restrictions as 2B | Searchable archives (legal texts, regulations, scientific articles). |
| PDF/A-3B | Like 2B, plus allows embedding arbitrary files as attachments (XML, CSV, DOCX, etc.). | ✅ Same as 2B ✅ Embed external files inside the PDF | ❌ Encryption ❌ JavaScript ❌ Multimedia | Compound documents (e-invoices with XML, submissions needing source data). |
| PDF/A-3U | 3B + Unicode requirement for text. | ✅ Same as 3B + searchable text | ❌ Same as 3B | Archival packages that need attachments + searchable text. |
| PDF/A-4 | Based on PDF 2.0 (ISO 32000-2). Simplified model; no A/B/U tiers—modern baseline. | ✅ Unicode text mapping ✅ Attachments allowed ✅ Transparency, layers, signatures | ❌ Encryption ❌ JavaScript ❌ Multimedia | Modern general-purpose archiving for libraries, government, enterprises. |
| PDF/A-4E | “E” = Engineering. Tailored for engineering/CAD workflows; supports 3D model containers. | ✅ Same as 4 ✅ Engineering/CAD payloads (e.g., model data) | ❌ Encryption ❌ JavaScript ❌ Non-archival multimedia | Engineering & CAD archiving (technical drawings, 3D models, BOMs). |
| PDF/A-4F | “F” = File attachments. Focused on embedded companion files. | ✅ Same as 4 ✅ File attachments emphasized | ❌ Encryption ❌ JavaScript ❌ Multimedia | Data-centric bundles (PDF + XML/CSV/JSON source files). |
How to produce PDF/A with fpdf2¶
Pick a profile at construction time¶
from fpdf import FPDF
from fpdf.enums import DocumentCompliance
pdf = FPDF(enforce_compliance=DocumentCompliance.PDFA_4)
- When
enforce_complianceis set, fpdf2 actively prevents non-compliant operations and will raise errors if you try something forbidden for the selected profile.
Quick example¶
pdf = FPDF(enforce_compliance=DocumentCompliance.PDFA_4)
pdf.add_page()
pdf.set_font("Helvetica", size=12)
pdf.cell(0, 10, "Modern archival PDF, PDF 2.0 based.")
pdf.output("example-4.pdf")
Future: Accessible documents (WCAG/PDF/UA)¶
To enable PDF/A 2A and 3A compliance FPDF needs to be able to produce accessible documents. Those features need to be implemented:
- Tagged PDFs (logical structure, reading order)
- Alt text for images, meaningful link text
- Color contrast and keyboard-navigable annotations