Skip to main content
Service phase: Beta

This service is still in development. Give us your feedback or view this page on the current PRONOM service.

Format

Acrobat PDF/A - Portable Document Format

Download XML

Summary

Name
Acrobat PDF/A - Portable Document Format
Version
1a
Identifiers
  • MIME: application/pdf
  • Apple Uniform Type Identifier: com.adobe.pdf
  • PUID: fmt/95
Format type
Page Description
Disclosure
Full
Description
The Portable Document Format/ Archive is a format designed for long term preservation by Adobe Systems. PDF/A is a simplified version of PDF 1.4, with all of the features from PDF 1.4 that would impede long term preservation removed. Removed features include Javascript, Audio/Visual content, LZW compression and encryption. 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/A supports two levels of compliance PDF/A1-a (Accessible) and PDF/A1-b (Basic). PDF/A1-a is fully ISO 19005-1:2005 (PDF/A-1) compliant whereas PDF/A1-b is less stringent and not compliant. PDF/A1-a requires tagged PDF and Unicode whereas PDF/A1-b does not.
File extensions
pdf
Source
Digital Preservation Department / The National Archives

Relationships

Has priority over

Internal signatures

Acrobat PDF/A-1a

Note
Describes a signature for the PDF/A-1a form. Identifies the byte sequence which equals - xmlns:pdfaid="http://www.aiim.org/pdfa/ns/id/ which is the PDF/A identification namespace within the PDF/A meta-data, followed by <pdfaid:part>1<pdfaid:part> and <pdfaid:conformance>A<pdfaid:conformance>, which are the two mandatory elements and values for PDFA/1a. See ISO 19005-1:2005 and Technical Corrigendum 1 for further information.

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
144
Byte Sequence
255044462D312E[30:37]
Endianness
Little-endian
Min Frag Length
Variable
Offset
None
Max offset
None
Byte Sequence
786D6C6E733A7064666169643D(22|27)687474703A2F2F7777772E6169696D2E6F72672F706466612F6E732F6964*7064666169643A70617274(3D22|3D27|3E)31(22|27|3C2F7064666169643A706172743E){0-120}7064666169643A636F6E666F726D616E6365(3E|3D22|3D27)41(22|27|3C2F7064666169643A636F6E666F726D616E63653E)
Endianness
Little-endian

PDF/A-1A 2

Note
Describes a signature for the PDF/A-1a form. Identifies the byte sequence which equals - xmlns:pdfaid="http://www.aiim.org/pdfa/ns/id/ which is the PDF/A identification namespace within the PDF/A meta-data, followed by <pdfaid:conformance>A<pdfaid:conformance>and <pdfaid:part>1<pdfaid:part>, and which are the two mandatory elements and values for PDFA/1a. See ISO 19005-1:2005 and Technical Corrigendum 1 for further information.

Byte sequences

Min Frag Length
Absolute from BOF
Offset
0
Max offset
144
Byte Sequence
255044462D312E[30:37]
Endianness
None
Min Frag Length
Variable
Offset
None
Max offset
None
Byte Sequence
786D6C6E733A7064666169643D(22|27)687474703A2F2F7777772E6169696D2E6F72672F706466612F6E732F6964*7064666169643A636F6E666F726D616E6365(3E|3D22|3D27)41(22|27|3C2F7064666169643A636F6E666F726D616E63653E){0-120}7064666169643A70617274(3D22|3D27|3E)31(22|27|3C2F7064666169643A706172743E)
Endianness
None

Changelog

  • Updated in V103

    Release date
    11 March 2022

    Acrobat PDF/A - Portable Document Format (1a): Update to signature following error. Removal of whitespace causing issues in FIDO. Submitted by Vanderbilt University, Preservica and Misty De Méo.

  • Added in V101

    Release date
    15 February 2022

    Acrobat PDF/A - Portable Document Format (1a): Additional signature added to allow for PDF conformance and PDF part tags to be alternated. Extension to BOF offset and 0-120 byte gap between part and conformance tags added to original signature. Submitted by The National Archives of the Czech Republic.

    Acrobat PDF/A - Portable Document Format (1a): Signature researched and samples provided by The National Archives of the Czech Republic.

  • Updated in V89

    Release date
    8 March 2017

    Acrobat PDF/A - Portable Document Format 1a: Adjusted signature due to findings by Koninklijke Bibliotheek

  • Updated in V88

    Release date
    27 September 2016

    Acrobat PDF/A - Portable Document Format 1a: Gave priority over x-fmt/453 - TrueType Font as suggested by Archives New Zealand. Additionally gave priority over Acrobat PDF - Portable Document Format versions 1.0-1.7 due to clash identified by Docuteam.

  • Updated in V81

    Release date
    18 February 2015

    Acrobat PDF/A 1a: MIME Type added. Submitted by Docuteam.

  • Updated in V74

    Release date
    31 March 2014

    Acrobat (PDF/A) Portable Document Format 1a: Increased flexibility of VAR signature sequence.

  • Updated in V51

    Release date
    15 July 2011

    Acrobat PDF/A - Portable Document Format 1a: Existing signature refined following request from Archaeology Data Service and record title updated to distinguish different versions.