The Portable Document Format (commonly known as “PDF”) is a file format developed in the early 1990s as a way to share computer documents, including text formatting and inline images.
From 1993 until 2007 the PDF specification (known at that time as the “PDF Reference”) was published in eight editions (1.0 to 1.7) by Adobe Systems. To promote widespread adoption from the outset, Adobe made these documents freely available and their use royalty-free.
To download any of the pre-ISO editions of the PDF Reference, visit Adobe’s PDF Reference Archive.
In 2008 ISO published Adobe's PDF Reference 1.7 (with minor, non-technical changes) as ISO 32000-1. Under a special one-time agreement between Adobe and ISO, an “Adobe version” of ISO 32000-1 was made available as a free download from Adobe’s website. Purchased directly from ISO, ISO 32000-1 costs 198 CHF (Swiss francs).
In July, 2017, ISO published ISO 32000-2, the long-awaited PDF 2.0. In addition to numerous clarifications and corrections, this document enhances and extends the PDF format in a wide variety of new areas. PDF 2.0 is available from ISO for 198 CHF (Swiss francs)