PDF

< OperatingSystem | Knowledge Base | Pixel >

Acrobat Logo

PDF "Portable Document Format" is a file-format for text-type documents which preserves formatting, typography and other elements. Theoretically, a PDF file displays identically everywhere. PDF display software is available for nearly all graphical operating systems.

PDF was developed by Adobe, and is sometimes referred to as Adobe PDF. The PDF logo (left) is derived from the logo of the Adobe Acrobat software which is commonly used to view and create PDF files. It is not correct to call PDF files "Acrobat files".

PDF file should not be used on the World Wide Web nearly as often as they are. PDF files are "black blobs" the browser does not process natively but must hand them off to a plugin or a helper application, this disrupts the workflow of the user. Usability expert Jakob Nielson has written extensively about this.

The only time PDF files should be used on the Web is in documents intended primarily for printing, PDF files have many advantages for print use because, unlike the XHTML language used to define websites, PDF allow very precise control of kerning, typography, pagination, colors and other important matters which are not addressed by XHTML.

Rival formats to PDF have been developed over time, DWF was developed by CAD company Autodesk and is rarely used outside of Autodesk workflows. Of more promise is DjVu which was developed by the American Telephone and Telegraph Company, and which is now available in a free and open-source implementation called DjvuLibre. DjVu offers many advantages over PDF, such as file-size and superior data-compression. DjVu uses wavelet encoding to offer very high compression with very low artifacts.

The Vistua Hub uses PDF files to deliver documents intended for printing, since the process of starting a plug-in or helper application is lengthy and download times of PDF files are higher than download times of regular web-pages links to such files are marked with this icon: .

< OperatingSystem | K.B. Index | Pixel >