Technical resources

The following technical resource pages are actively maintained by the PDF Association to provide the PDF industry with the latest technical information.

Errata to ISO PDF related standards

This resource lists all resolved errata in PDF-related ISO standards. It is presented as localized marked-up changes (additions, deletions, or editor notes) to the published wording in the relevant ISO standard organized by top level clause. Issue numbers (implemented here as popup tooltips) refer back to closed GitHub pdf-issues with a "proposed solution" label. Due to ISO copyright, only minimal surrounding text from the relevant ISO standard is provided that is sufficient to locate where the resolution is being applied. 

Status of PDF standardization at ISO

This resource summarizes the active and ongoing work items of all ISO committees dedicated to standardizing PDF. ISO Technical Committee (TC) 171 SC 2 Working Groups (WGs) are responsible for many PDF-related ISO publications. ISO TC 130 WG 2 and related Task Forces (TFs) are responsible for PDF/X, PDF/VT, and other PDF-related graphic arts and commercial print applications. ISO TC 130 JWG 7 is the joint working group responsible for ICC and color management.

PDF specification index

This resource provides download links to legacy Adobe PDF references and errata, as well as the full ISO 32000 family of standards. It serves as an archive of the evolution of the core PDF file format.

PDF standards

The index of all published ISO standards related to PDF provides a mapping between ISO document numbers and the PDF nomenclature commonly used in industry (such as PDF/A, PDF/X, XMP, etc).

PDF 2.0 normative references

This resource provides download links for all Normative References of PDF 2.0 (ISO 32000-2:2020). Normative references are other additional standards and specifications where some or all of their content also constitutes technical requirements of PDF 2.0. They form essential reading for all developers of PDF 2.0 technology.

Guide to PDF Association Technical Working Groups

The PDF Association maintains various interest-specific communities facilitating members' discussions on technical issues related to PDF. If your interest is specific to Tagged PDF this article covers the focus on this area.

Guide to GitHub repositories

The PDF Association hosts several public and private repositories in GitHub to facilitate a common understanding of PDF and to develop new ideas around PDF technologies. Private repositories are restricted to PDF Association members and support our communities. Public repositories welcome contributions and comments from anyone.

Upcoming and recent events

Every PDF Association event provides a forum for the PDF industry to meet and discuss a broad range of technical topics, challenges and solutions. The videos of previous presentations provide a good body of knowledge.

Technical publications

The PDF Association provides many technical publications to assist developers and end-users to better utilize standardized PDF technologies. PDF Association publications are qualified and approved through the organization's publication process.

Specifications

PDF Association specifications are industry-ratified specifications that extend PDF.

Technical notes

Technical Notes provide additional clarity on the interpretation of ambiguous, unclear or purposely flexible statements in ISO PDF standards.

Cheat sheets

The PDF Association provides free PDF “cheat sheets” to aid in remembering key terms and concepts without constantly referring to ISO 32000..

Other notes

Adobe's patent release regarding ISO 32000-1:2008 (2011 statement by Adobe's Matthew Hardy).

RFC 8118, "The application/pdf Media Type" (March 2017)

RFC 3779, "The application/pdf Media Type" (May 2004) - obsoleted by RFC 8118.

Application notes & best practice guides

Application Notes provide additional technical information around a specific feature of PDF that enables greater interoperability. Best practice guides offer concrete advice targeting specific outcomes.

Flyers and booklets

The PDF Association publishes numerous flyers, leaflets and booklets in several languages that assist end-users of PDF and their decision-makers to better understand how each PDF ISO standard provides specific benefits to industry sectors.

Test suites and protocols

The PDF Association publishes test suites and test protocols to assist both developers and end-users in assessing ISO-compliant PDF technology solutions.

CC-MAIN-2021-31-PDF-UNTRUNCATED

This corpus contains nearly 8 million PDFs gathered from across the web in July/August of 2021. The PDF files were initially identified by Common Crawl as part of their July/August 2021 crawl (identified as "CC-MAIN-2021-31") and, due to truncation at 1MB, were subsequently updated and indexed as part of the PDF Association's DARPA SafeDocs program efforts. It is hosted by the Digital Corpora Project under the Amazon Open Data Sponsorship program.

“Issue Tracker” corpus

The "Issue Tracker" corpus of stressful PDF files was originally developed under the DARPA-funded "SafeDocs" program. If a “stressful PDF” can be considered as any file that causes problems for a parser, then looking into the problems faced by diverse parsers can be a great learning experience. This corpus now includes bug attachment data from 35 issue tracker repositories across 32 PDF technologies, comprising 31 GB and over 32,500 stressful PDF files.

These issue trackers now span a broad variety of PDF technologies written in a wide range of programming languages. Due to the size, we have packaged the corpus into six compressed tar balls (.tgz files) each containing the data from multiple repositories to make downloading more convenient.

Isartor (PDF/A-1)

The Isartor Test Suite comprises a set of files that can be used to check the conformance of software regarding the PDF/A-1 standard. More precisely, the Isartor test suite can be used to “validate the validators” as it deliberately violates the requirements of PDF/A-1 in a systematic way in order to check whether PDF/A-1 validation software actually finds the violations.

veraPDF (PDF/A)

VeraPDF is the industry-supported open-source validator for PDF/A-1, PDF/A-2 and PDF/A-3. The software and related test suite was developed under the supervision of the PDF Association's PDF Validation Technical Working Group.

PDF/UA Reference Suite 1.1

The PDF/UA Reference Suite is a reference for software developers and practitioners interested in best practices for creating tagged and accessible PDF files. Ranging from publications to transactional records the collection represents a cross-section of document types reflecting the wide variety of uses for PDF technology. Documents included in the PDF/UA Reference Suite demonstrate correct tagging in a number of sophisticated cases, including:

• Content spanning multiple pages
• Complex table structures
• Interactive forms
• Links targeting structure elements
• Scanned documents

Matterhorn Protocol 1.1 (PDF/UA-1)

To promote adoption of PDF/UA - the ISO standard for accessible PDF - by software developers, service bureaus and those interested in document accessibility, the PDF Association's PDF/UA Technical Working Group has developed the Matterhorn Protocol, a list of all the possible ways to fail PDF/UA-1. The 1.1 release of the Matterhorn Protocol, released in April 2021, adds a new failure condition and provides several clarifications. The PDF file is tagged to reflect current best-practice in tagging PDF documents for accessibility and reuse.

Cal Poly PDF/VT-1

The Cal Poly Graphic Communications PDF/VT-1 Test File Suite provides a collection of four sets of graphically rich, robust, valid PDF/VT-1 files for testing and demonstrating products claiming support of consumption of files conforming to the ISO 16612-2 PDF/VT standard.