Purpose: Long-term archiving of electronic documents with full semantic structure.
Level "1a" ensures:
Tagged PDF (with proper logical structure and reading order)
Unicode text for proper text extraction and searchability
Embedded fonts (for consistent rendering)
Restrictions:
No audio/video
No encryption
No JavaScript
No external content (everything must be self-contained)
Based on: PDF 1.4 (Acrobat 5)