Portable Document Format, or simply PDF, is a type of file format that is universally used for sharing and distributing files. A single PDF file may contain any type of multimedia elements like pictures, text, or sound. Yet, despite the complexities of PDF, one must keep in mind that it is only a subset of a computer language called Postscript.
Postscript, as earlier described, is a computer language ? or more accurately, a page description language -- optimized for printing graphics and text and run in an interpreter. Because Postscript is geared towards image production, it is the primary programming language used in the electronic and publishing areas.
The concept of postscript was first conceived by John Warnock, one of the pioneers in Adobe Systems, the principal developer of PDF. First used in March 1985 with Apple?s LaserWriter, it was Postscript that sparked the desktop publishing revolution in the mid-1980s. Postscript became a ubiquitous component of laser printers, especially since it combined both technical merits and widespread accessibility.
Postscript in Printing
Postscript made the greatest impact on printing. Before postscript, characters were pressed into printer keys, metal bands, or optical plates, thus making it difficult to change texts.
The DotMatrix was created to address this issue but only to a certain extent since it could only produce some poor-quality graphics that were not ideal for widespread distribution. A device called plotter was then designed specifically for printing ?real? graphics but this too was limited as it can do nothing else but print graphics.
By combining the best features of printers and plotters, postscript was thus able to break through the barriers in traditional printing. Postscript was nicknamed ?device-independent? by experts in the field since the ?postscript?-ed documents remain the same whether they are being viewed on screen or printed out as hard copies.
Postscript in other Implementations
Perhaps the best way to describe the complexity of postscript is through its font handling. Postscript?s font system is rich with graphics which could draw line art and could be viewed at any screen resolution.
To avoid typographic issues which are sure to emerge when dealing with fonts, Adobe included hints along with font outlines in its postscript printers which they then called Type 1 Font. Hints in postscript help prevent scale problems and troubles with character sizes.
Postscript only used to run on the Adobe-manufactured RIP (Raster Image Processor) but by the mid-1980s a lot of third-party RIPs were introduced. One enduring example of a RIP is the Ghostscript, a free postscript-interpreter that can view and print postscript documents on non-postscript printers.
About the Author: Will Mathison is a freelance writer who writes articles for http://www.pdfconverter.com