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PDF Differences

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This is a public (repository for responsible reporting of commonly-seen PDF issues. The PDF files in this repository are targeted test files highlighting specific issues seen across multiple widely-used implementations. Implementations at fault will not be named or identified.

The issues identified in this repository are not security related - they impact portability and interoperability; PDF's "prime directive"!

Detailed documentation for each test case is provided as MarkDown files and in an associated article on https://www.pdfa.org.

The PDF test files

  • PDF files are as minimal (short) as possible and well-commented internally.

  • PDF files are pure text except for the 2nd line comment with 4 binary bytes. This is so they may be easily viewed in text editors and development environments used by software developers.

  • PDF files have valid conventional cross-reference tables with ample whitespace and line-breaks to further enable easy reading.

  • PDF header versions are 1.7. These files do not cover new features or change to features introduced in PDF 2.0 unless explicitly noted otherwise.

  • PDF files avoid excessive on-page descriptive text as this makes files larger and more internally complex, obscuring the purpose of allowing developers to quickly and easily understand each test case.

  • To further ensure rapidity and ease of comprehension, these PDF files purposely do not use many "best practices" such as metadata, embedded fonts, device independent color, etc., and they avoid other large data or complex features that inhibit direct inspection in a text editor (such as Linearization, XMP, cross-reference streams, object streams, compacted syntax, etc) unless necessary to the test case.

  • Screenshots used in the ReadMe files have been purposely resized to 600 pix wide after capture. Screenshots should not be compared at a pixel level to determine correctness (the image processing was a small attempt at trying to stop this)!!

  • Correct renderings are always the last image in the MarkDown, encouraging readers to read everything for a full understanding of the correct appearance.


PDF files are copyright by the PDF Association and distributed under a Creative Common Attribution 4.0 International (CC BY 4.0) license. Any source code in this repository is licensed under Apache License, Version 2.0.

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Targeted PDFs demonstrating commonly seen PDF differentials and interoperability issues

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