Portable Document Format .pdf
Adobe Portable Document Format pdf
Invented by Adobe Systems and perfected over 15 years, Adobe Portable Document Format (PDF) lets you capture and view robust information—from any application, on any computer system—and share it with anyone around the world. Individuals, businesses, and government agencies everywhere trust and rely on Adobe® PDF to communicate their ideas and vision.
When the PDF first came out in the early 1990s, its general adoption was slow. At that time, the PDF-creation tools (Acrobat) and the viewing and printing software had to be bought. Early versions of PDF had no support for external hyperlinks, reducing its usefulness on the World Wide 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.
The PDF file format has changed several times, as new versions of Adobe Acrobat have been released. There have been eight versions of PDF: 1.0 (1993), pdf 1.1 (1994), pdf 1.2 (1996), pdf 1.3 (1999), pdf 1.4 (2001), pdf 1.5 (2003), pdf 1.6 (2005), and pdf 1.7 (2006), corresponding to Acrobat releases 1.0 to 8.0.
pdf Technical Foundations
Anyone may create applications that read and write PDF files without having to pay royalties to Adobe Systems; Adobe holds patents to PDF, but licenses them for royalty-free use in developing software complying with its PDF specification.
The PDF combines three technologies:
A sub-set of the PostScript page description programming language, for generating the layout and graphics.
A font-embedding/replacement system to allow fonts to travel with the documents.
A structured storage system to bundle these elements and any associated content into a single file, with data compression where appropriate.