Portable Document Format (PDF)
Portable Document Format (PDF) is a file format used to present documents in a manner independent of application software, hardware, and operating systems. Each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, graphics, and other information needed to display it. In 1991, Adobe Systems co-founder John Warnock outlined a system called "Camelot" that evolved into PDF.
While Adobe Systems made the PDF specification available free of charge in 1993, PDF was a proprietary format, controlled by Adobe, until it was officially released as an open standard on July 1, 2008, and published by the International Organization for Standardization as ISO 32000-1:2008, at which time control of the specification passed to an ISO Committee of volunteer industry experts. In 2008, Adobe published a Public Patent License to ISO 32000-1 granting royalty-free rights for all patents owned by Adobe that are necessary to make, use, sell and distribute PDF compliant implementations. However, there are still some proprietary technologies with published specification defined only by Adobe, such as Adobe XML Forms Architecture, and JavaScript for Acrobat, which are referenced by ISO 32000-1 as normative and indispensable for the application of ISO 32000-1 specification. The ISO committee is actively standardizing many of these as part of ISO 32000-2.
History:
PDF was developed in the early 1990s as a way to share documents, including text formatting and inline images, among computer users of disparate platforms who may not have access to mutually-compatible application software. It was among a number of competing formats such as DjVu (still developing), Envoy, Common Ground Digital Paper, Farallon Replica and even Adobe's own PostScript format (.ps). In those early years before the rise of the World Wide Web and HTML documents, PDF was popular mainly in desktop publishing workflows.PDF's adoption in the early days of the format's history was slow. Adobe Acrobat, Adobe's suite for reading and creating PDF files, was not freely available; early versions of PDF had no support for external hyperlinks, reducing its usefulness on the Internet; the larger size of a PDF document compared to plain text required longer download times over the slower modems common at the time; and rendering PDF files was slow on the less powerful machines of the day.
From version 2.0 onwards Adobe distributed its Acrobat Reader (now Adobe Reader) program free of charge, and continued supporting the original PDF, which eventually became the de facto standard for fixed-format electronic documents.
In 2008 Adobe Systems' PDF Reference 1.7 became ISO 32000:1:2008. Thereafter, further development of PDF (including PDF 2.0) is conducted by ISO's TC 171 SC 2 WG 8 with the participation of Adobe Systems' and other subject matter experts.
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