Is it open?

According to Wikipedia, PDF is an open format.

But the ISO charges 198 Swiss francs for you to download the PDF 2.0 specification.

Now according to free_file_format (first ref in the wikipedia/open_format article):

..open format should refer to any format that is published for anyone to read and study..

I think the above automatically makes PDF 2.0 a non-open format.

Is it Free?

From what I know what made the previous spec PDF-1.7 free was this patent that clearly granted usage rights to any implementor: https://www.adobe.com/pdf/pdfs/ISO32000-1PublicPatentLicense.pdf

...Adobe grants every individual and organization in the world the royalty-free right, under all Essential Claims that Adobe owns, to make, have made, use, sell, import and distribute Compliant Implementations....

But the absence of such a document for PDF-2.0 in combination with the following ISO article for PDF-2.0: https://www.iso.org/news/ref2199.html

ISO 32000-2, Document management – Portable document format – Part 2: PDF 2.0, is the first PDF specification developed entirely within the ISO guidelines and process. It’s clearer, cleaner, supports non-proprietary technologies and ensures a level playing field for software vendors that create, display, edit or otherwise process PDF electronic documents. In addition to staying true to PDF’s core value, PDF 2.0 provides a solid foundation for new use-cases, capabilities and workflows.

automatically makes PDF also a non-Free format.


Is PDF really a non-open / non-Free format, or am I missing something?


2 Answers 2



An "open file format" only means that the complete specification - simply speaking - on how to encode or decode data from/into the PDF 2.0 format are published (which is the case for PDF). It doesn't say where it has to be published and/or if you have to pay for the publication.

..open format should refer to any format that is published for anyone to read and study.

I think you misunderstand "anyone". It doesn't mean that everyone has to be able to "afford" a copy (or get it for free). It only means nobody can be restricted from reading and/or using the information. This is regardless of how they obtained the information by buying the publication, buy getting it through a library borrowing from a friend or even obtaining it illegally e.g. by downloading a pdf-version from an unauthorized source. In case of the latter they can only charged creating or obtaining an illegal copy but not for reading/studying it.


Even though a file format is open it does not mean you can "use it" by for example implementing it in you're software product, if there are patents registered which concern (aspects of) the file format. At least not without Adobe's permission.

As you say correctly yourself. If there is a patent the owner of the patent has to explicitly grant the right for usage. But this is not the case for PDF 2.0 so no explicit right of usage has to be granted. And for the parts that are based on the PDF 1.7 patents, it's not relevant since the right for usage has been granted (strictly speaking no new patents have been acquired beyond PDF 1.3).


Concluding that the format described under ISO 32000-2:2017 (PDF2.0) is indeed a free (no royalties have to be paid due to patents using the format) and open (it's a fully disclosed format) format.

  • PDF 2.0 is not a totally new format, and the patents by Adobe are phrased in such a general manner (of course), that they apply to both 1.3 and 2.0. The most that can be said is that 2.0 is a derived work of 1.7, so the Adobe patents still legally apply.
    – harrymc
    Oct 11, 2018 at 19:24
  • @harrymc thanks for the comment... in what way is that different from what I said?
    – Albin
    Oct 11, 2018 at 22:02
  • "strictly speaking there are only patents for PDF 1.3" is impossible, since 2.0 is a superset, and original rights are kept for a derived work.
    – harrymc
    Oct 12, 2018 at 7:37
  • @harrymc ah, I see, thanks. Yeah, I wrote that since that last patent that has been applied for was in regards to Version 1.3. Thanks, I will rephrase that.
    – Albin
    Oct 12, 2018 at 8:17

I quote Wikipedia :

PDF was standardized as an open format, ISO 32000, in 2008, and does not require any royalties for its implementation.

Intellectual property

Anyone may create applications that can read and write PDF files without having to pay royalties to Adobe Systems; Adobe holds patents to PDF, but licenses them for royalty-free use in developing software complying with its PDF specification.

The PDF associations defined two ISO standards for PDF :

ISO 32000-1 (PDF 1.7)

ISO 32000-1 is the first ISO specification for PDF. The document is an ISO formalization of Adobe’s own PDF Reference 1.7, and is technically identical to the Adobe document.

As with previous versions, Adobe’s PDF Reference, PDF 1.7 was (and remains) freely downloadable from Adobe.com (as is the document’s errata). By special arrangement with ISO, ISO 32000-1 is also available at no charge from adobe.com.

ISO 32000-2 (PDF 2.0)

Unlike previous PDF specifications, however, PDF 2.0 is an open standard. Any subject-matter expert whose country is a member of ISO’s TC 171 SC 2 can join the other experts at the table, and help determine the nature and direction of the world’s de facto electronic document format.

The first specification (PDF 1.7) was made open to the public by Adobe and is free to download, free even for downloading from the ISO. The second specification (PDF 2.0) was written by ISO members, so needs to be purchased to download.

As a clincher, the Adobe® Acrobat® SDK End User License Agreement says :

Adobe has a number of patents covering technology that is disclosed in the Portable Document Format (PDF) Specification, version 1.3 and later, as documented in PDF Reference and associated Technical Notes (the "Specification"). Adobe desires to promote the use of PDF for information interchange among diverse products and applications. Accordingly, the following patents are licensed on a royalty-free, nonexclusive basis for the term of each patent and for the sole purpose of developing software that produces, consumes, and interprets PDF files that are compliant with the Specification:

U.S. Patent Numbers:


In addition, the following patent is licensed on a royalty-free, nonexclusive basis for its term and for the sole purpose of developing software that produces PDF files that are compliant with the Specification (specifically excluding, however, software that consumes and/or interprets PDF files):

U.S. Patent Number:


These are the only patents on PDF, still held by Adobe, which had released them for royalty-free public use, which includes the ISO as member of the public. However, Adobe remains as the only patent holder.

I have also managed to find the first pages of the PDF 2.0 Format Specifications, which contains a copyright notice :

© ISO 2017, Published in Switzerland

However, that document also has this paragraph :

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and / or on the ISO list of patent declarations received (see www.iso.org/patents).

I have downloaded this list of patents which might affect this document, and I note that not even one of them belongs to the ISO. In fact, the ISO does not request patents, only publishes standards.

So the situation is currently : Adobe holds patents that are free for public use. ISO had published a standard for PDF 2.0 that is a superset of the PDF 1.7 standard, so is still subject to these patents.

Conclusion : The ISO holds copyright to the document, but not any patents.

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