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PDF Association

Mission Statement: To promote Open Standards-based electronic document implementations using PDF technology through education, expertise and shared experience for stakeholders worldwide.
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PDF Days Europe 2018 – schedule of sessions

Fittingly for the tenth anniversary of PDF’ becoming an ISO standard, standardization will play a significant role this year. The focus will be on recent developments, with an eye on the future. The agenda also includes PDF market analyses, next-generation PDF for mobile devices, universally accessible PDF files and the industry-supported veraPDF validator initiative.

Hotel Recommendations and Sightseeing Tips for PDF Days Europe 2018 in Berlin

You will visit the No. 1 PDF event – the PDF Days Europe 2018 in Berlin? Great! Here are some hotel recommendations and sightseeing tips near the event location (SI Hotel).

A double anniversary for PDF Days Europe 2018

Richard Cohn, Principal Scientist at Adobe, one of the two co-authors of the original PDF specification in the era of Acrobat 1.0 gives the keynote on 25 years of PDF during the PDF Europe 2018.

PDFcontainer – a proposal

Introduction PDF technology profiles can be leveraged to provide trusted, predictable containers for record types that often present workflow and preservation challenges, with email and case files (associated files in arbitrary formats) as primary use- …

PDF Day: a breakthrough in Washington DC

Over 260 attendees from 40+ federal and state agencies The latest PDF Day event was held on January 29th at the National Archives Building in Washington DC. With a record-breaking number of attendees, the event was a resounding success. PDF is a broadl …

The technical side of the PDF/A standard


After the first part of PDF/A was published, two more parts arrived. These are not replacements for part 1, however; rather, they offer additional options for archiving PDF documents. All existing PDF/A files remain fully valid.

PDF/A-1: The first archiving standard

PDF/A-1 is based on PDF version 1.4, which first appeared in 2001. All resources (images, graphics, typographic characters) must be embedded within the PDF/A document itself. A PDF/A file requires precise, platform-independent colour data using ICC profiles, and XMP for the document metadata. Transparent elements, some forms of compression (LZW, JPEG2000), PDF layers, and certain actions or JavaScript are forbidden. A PDF/A file must not be password-protected. PDF/A-1 expressly supports embedded digital signatures and the use of hyperlinks.

PDF/A-2: Based on PDF 1.7

PDF/A-2 was published in 2011 as “ISO 19005-2”. Based on PDF version 1.7, which has since been standardised as “ISO 32000-1”, it makes use of this version’s new features. This means PDF/A-2 allows JPEG2000 compression, transparent elements and PDF layers. PDF/A-2 also allows you to embed OpenType fonts and supports PAdES (PDF Advanced Electronic Signatures)-compliant digital signatures. One particularly important innovation is the “container” function: PDF/A files can be embedded within a PDF/A-2 document.

PDF/A-3: One more feature

PDF/A-3 has been available since October 2012. A PDF/A-3 document allows you to embed any file format desired – not just PDF/A documents. For example, a PDF/A-3 file can contain the original file from which it was generated. The PDF/A standard does not regulate the suitability of these embedded files for archiving.

Conformance levels: A, B, U

The different conformance levels reflect the quality of the archived document and depend on the input material and the document’s purpose.

  • Level A (Accessible) meets all requirements for the standard, including the logical structure of the document and its correct reading order. Text must be extractable and the logical structure must match the natural reading order. Fonts used must meet stringent requirements. This PDF/A level can usually only be met by converting born-digital documents.
  • Level B (Basic) guarantees that the content of the document can be unambiguously reproduced. Level B files are easier to create than Level A, but Level B does not guarantee 100% text extraction or searchability. It does not necessarily mean that the content can be reused without any problems. Scanned paper documents can usually be converted to PDF/A Conformance Level B without any extra work.
  • Level U (Unicode) was introduced along with PDF/A-2. It expands Conformance Level B to specify that all text can be mapped to standard Unicode character codes.

Nomenclature: PDF/A versions and levels are simply given one after another. A PDF/A-1b file, for example, is a PDF file for long-term archiving, of the first generation, with visually reproducible content.

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Tags: Conformance levels, ISO Standard
Categories: PDF, PDF/A