Portable Document Format (PDF) is a file format created by Adobe Systems in 1993 for document exchange. PDF is used for representing two-dimensional documents in a manner independent of the application software, hardware, and operating system.Adobe Systems Incorporated, PDF Reference, Sixth edition, version 1.23 (30 MB), p. 33

Each PDF file encapsulates a complete description of a fixed-layout 2-D document (and, with Acrobat 3-D, embedded 3-D documents) that includes the text, fonts, images, and 2-D vector graphics which comprise the documents.

PDF is an open standard that was officially published on July 1, 2008 by the ISO as ISO 32000-1:2008.

History

PDF's adoption in the early days of the format's history was slow. Adobe Acrobat, Adobe's suite for reading and creating PDFs, was not freely available; early versions of PDF had no support for external hyperlinks, reducing its usefulness on the Worldwide Web; the additional size of the PDF document compared to plain text meant significantly longer download times over the slower modems common at the time, and rendering the files was slow on less powerful machines. Additionally, there were competing formats such as Envoy, Common Ground Digital Paper and even Adobe's own PostScript format (.ps); in those early years, the PDF file was mainly popular in desktop publishing workflow.

Adobe soon started distribution of its Acrobat Reader (now Adobe Reader) program at no cost, and continued supporting the original PDF, which eventually became the de facto standard for printable documents on the web (a standard web document).

The PDF file format has changed several times, as new versions of Adobe Acrobat were released. There have been eight versions of PDF with corresponding Acrobat releases:

• (1993) - PDF 1.0 / Acrobat 1.0
• (1994) - PDF 1.1 / Acrobat 2.0
• (1996) - PDF 1.2 / Acrobat 3.0
• (1999) - PDF 1.3 / Acrobat 4.0
• (2001) - PDF 1.4 / Acrobat 5.0
• (2003) - PDF 1.5 / Acrobat 6.0
• (2005) - PDF 1.6 / Acrobat 7.0
• (2006) - PDF 1.7 / Acrobat 8.0
• (2008) - PDF 1.7, Adobe Extension Level 3 / Acrobat 9.0

The ISO 32000-1:2008 PDF open standard was published by the ISO on July 1, 2008. PDF is now a published ISO standard titled: Document management -- Portable document format -- Part 1: PDF 1.7

According to the ISO PDF standard abstract:

ISO 32000-1:2008 specifies a digital form for representing electronic documents to enable users to exchange and view electronic documents independent of the environment in which they were created or the environment in which they are viewed or printed. It is intended for the developer of software that creates PDF files (conforming writers), software that reads existing PDF files and interprets their contents for display and interaction (conforming readers) and PDF products that read and/or write PDF files for a variety of other purposes (conforming products).