Adobe PDF icon
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Filename extension | .pdf |
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Internet media type |
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Type code | 'PDF ' (including a single space) |
Uniform Type Identifier (UTI) | com.adobe.pdf |
Magic number | %PDF |
Developed by | Adobe Systems |
Initial release | 15 June 1993 |
Latest release |
1.7
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Extended to | PDF/A, PDF/E, PDF/UA, PDF/VT, PDF/X |
Standard | ISO 32000-1 |
Open format? | Yes |
Website | www |
Filename extension | .fdf |
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Internet media type | application/vnd.fdf |
Type code | 'FDF' |
Developed by | Adobe Systems |
Initial release | 1996 | (PDF 1.2)
Extended from | |
Extended to | XFDF |
Standard | ISO 32000-1:2008 |
Open format? | Yes |
Filename extension | .xfdf |
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Internet media type | application/vnd.adobe.xfdf |
Type code | 'XFDF' |
Developed by | Adobe Systems |
Initial release | July 2003 | (referenced in PDF 1.5)
Latest release |
3.0
(August 2009 ) |
Extended from | PDF, FDF, XML |
Standard | ISO 19444-1) |
Website | XFDF 3.0 specification |
The 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.
PDF was developed in the early 1990s as a way to share computer documents, including text formatting and inline images. It was among a number of competing formats such as DjVu, Envoy, Common Ground Digital Paper, Farallon Replica and even Adobe's own PostScript format. In those early years before the rise of the World Wide Web and HTML documents, PDF was popular mainly in desktop publishing workflows. 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 defined only by Adobe, such as Adobe XML Forms Architecture (XFA) and JavaScript extension for Acrobat, which are referenced by ISO 32000-1 as normative and indispensable for the application of the ISO 32000-1 specification. These proprietary technologies are not standardized and their specification is published only on Adobe’s website. Many of them are also not supported by popular third-party implementations of PDF. So when organizations publish PDFs which use these proprietary technologies, they present accessibility issues for some users.