PDF Reference and Adobe Extensions to the PDF Specification

The PDF Reference was first published when Adobe Acrobat was introduced in 1993. Since then, updated versions of the PDF Reference have been made available from Adobe via the Web, and from time to time, in traditional paper documents made available from book publishers.

On January 29, 2007, Adobe announced its intent to release the full Portable Document Format (PDF) 1.7 specification to AIIM, the Enterprise Content Management Association, for the purpose of publication by the International Organization for Standardization (ISO). During 2007 and into early 2008 that intent was turned into a reality. ISO published the approved ISO 32000-1 standard based upon PDF 1.7 in July 2008. ISO will also produce future versions of the PDF Specification.

Since ISO 32000 is equivalent to Adobe's PDF 1.7, Adobe is not producing a PDF 1.8 Reference. However, Adobe is publishing a document specifying what extended features for PDF, beyond ISO 32000-1 (PDF 1.7), are supported in its newly released products. This makes use of the extensibility features of PDF as documented in ISO 32000 in Annex E.

Note that PDF documents conforming to ISO 32000 carry the PDF version number 1.7. Documents containing extended features still carry the PDF base version number 1.7 but also contain an indication of which extension the PDF producer application followed during document creation. Adobe's extensions are as follows:

The Adobe Supplement to ISO 32000, BaseVersion 1.7, ExtensionLevel 3 describes Adobe's extensions and implementation notes for Adobe Acrobat 9.0 and LiveCycle ES 8.2. It also includes extensions and implementation notes for BaseVersion 1.7, ExtensionLevel 1 and 2.

The Adobe Supplement to ISO 32000, BaseVersion 1.7, ExtensionLevel 5 describes Adobe's extensions and implementation notes for Adobe Acrobat 9.1 and Adobe Reader 9.1.

These documents describe Adobe’s extensions and implementation notes relative to the ISO 32000-1:2008, Document management, Portable document format, PDF 1.7. Adobe has submitted these extensions to ISO for inclusion into the next version of the ISO 32000 specification and they have all been accepted for part 2 of ISO 32000.

Note: Each successive Adobe-specific extension level for PDF base version 1.7 is cumulative. In other words, PDF-processing applications that support the fifth Adobe extension level for a particular base level shall also support all previous extension levels for that same base version.