| Description |
The Portable Document Format/Archive is a format designed for long term preservation by Adobe Systems. PDF/A is an ISO standardised version of PDF, with all of the features from PDF that would impede long term preservation removed. A major principle of PDF/A is that it is self contained and not reliant on externalities thus all font and colour information is encoded into the file. PDF/A files are larger than other types of PDF files due to the need for embedded information. PDF/A3 supports three levels of compliance: PDF/A-3a (Accessible), PDF/A-3b (Basic). and PDF/A-3u (Unicode). The PDF/A-2 standard is a constrained subset of ISO 32000-1 (PDF 1.7), which includes PDF 1.0-1.7 and is defined by ISO 19005-3:2012, which has the formal name 'Document management - Electronic document file format for long-term preservation - Part 3: Use of ISO 32000-1 with support for embedded files (PDF/A-3)'. The primary new feature in PDF/A-3 is the ability to embed any source format within a PDF/A file. |
Details: File format summary
: detailed report on file format 
Digital Preservation Department / The National Archives
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