PDF/A is an ISO standard which specifies the use of PDF for the long-term preservation of compound documents as electronic data; based on Adobe PDF 1.4
The primary purpose of this International Standard is to define a file format based on PDF, known as PDF/A, that provides a mechanism for representing electronic documents in a manner that preserves their visual appearance over time, independent of the tools and systems used for creating, storing, or rendering the files.
A secondary purpose of this International Standard is to provide a framework for recording the context and history of electronic documents in metadata within conforming files.
Another purpose of this International Standard is to define a framework for representing the logical structure and other semantic information of electronic documents within conforming files.
PDF/A addresses primary areas of concern:
Offers consistent, long-term retrieval and rendering
Includes document metadata for search and retrieval
Engineered for reliable migration and future compatibility
Developed and maintained by PDF/A working group
Based on needs of and includes government and industry participants (Adobe, Appligent, US Courts, US National Archives, IBM, IRS, HP, Honeywell and Xerox)
PDF/A Requirements
File should be
Unambiguous, predictable
Self-contained – no references
Stable presentation - No dynamic actions or forms
Uniform file format - Header, trailer, no encryption
Device-independent rendering of graphics
Embedded fonts, character encoding
Transparency prohibited
Only elements of PDF1.4 allowed… no extensions
PDF/A Overview
Two levels of conformance
Minimal (not tagged PDF)
Full (tagged PDF)
External actions restricted - No dependence on external content
Readers not required to act on hyperlinks
XMP metadata - Adobe XML Metadata Framework
Forms based on appearance, not data