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PDF/A-1a, PDF for Long-term Preservation, Based on PDF 1.4, Level A Conformance
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Format Description Properties
• ID: fdd000251
• Short name: PDF/A-1a
• Content categories: text
• Format category: file format, bitstream encoding
• Last significant update: 2007-02-06
• Draft status: Partial
Identification and description 
| Full name | ISO 19005-1. Document management - Electronic document file format for long-term preservation - Part 1: Use of PDF 1.4, Level A Conformance (PDF/A-1a) |
| Description |
Part 1 of the PDF/A ISO standard [ISO 19005-1:2005] is a constrained form of Adobe PDF version 1.4 intended to be suitable for long-term preservation of page-oriented documents for which PDF is already being used in practice. Level A conformance (PDF-1a) indicates complete compliance with the ISO 19005-1 requirements, including those related to structural and semantic properties of documents. Level B conformance (PDF-1b) indicates minimal compliance to ensure that the rendered visual appearance of a conforming file is preservable over the long term.
See PDF/A-1.
|
| Production phase |
A final-state format for delivery to end users and long-term preservation of the document as disseminated to users. |
| Relationship to other formats | |
| Subtype of | PDF (Portable Document Format) |
| Subtype of | PDF_1_4 |
| Subtype of | PDF/A-1 |
Local use
| LC experience or existing holdings | See PDF/A-1. |
| LC preference | See PDF/A-1. |
Sustainability factors
Quality and functionality factors
| Normal rendering for text | See PDF/A-1. |
| Integrity of structure |
PDF/A-1a requires representation of the logical structure of the document as specified in section 6.8 of ISO 19005-1. The standard recommends that creators "should attempt to capture a document's logical structure hierarchy to the finest
granularity possible." Nevertheless, the standard also indicates that "PDF/A-1 writers should not add structural or semantic information that is not explicitly or implicitly present in the source material solely for the purpose of achieving conformance." Hence, the logical structure of a document will only be represented to the degree the creator or process during creation takes steps to incorporate relevant structural tagging. |
| Integrity of layout | See PDF/A-1. |
| Integrity of rendering of equations, etc. | See PDF/A-1. |
| Beyond normal rendering | Level A conformance with PDF/A-1 requires that images have alternate text descriptions. The natural language in which the document is written must be declared, and sections of text in other languages explicitly marked using an internal mechanism defined for PDF 1.4. Also see PDF/A-1. |
File type signifiers
| Tag type | Value | Note |
| Filename Extension | pdf |
The standard does not indicate that a different extension should be used to distinguish PDF from PDF/A. |
| Internal Identification | pdf |
The standard specifies that the PDF/A version and conformance level of a file shall be specified using the PDF/A Identification extension schema defined in the standard. This schema has two mandatory elements: pdfaid:part and pdfaid:conformance. A PDF-1a file should have the integer value 1 for pdfaid:part and the value "A" for pdfaid:conformance. |
Notes
Format specifications
URLs
• See PDF/A-1.
Print
• See PDF/A-1.
Useful references
URLs
• See PDF/A-1.
Last updated Thursday, 08-Feb-2007 18:46:32 EST
