History and Evolution of PostScript
– PostScript language seeded in 1976 by John Gaffney at Evans & Sutherland
– Xerox PARC researchers developed the first laser printer and recognized the need for a standard means of defining page images
– Bob Sproull and William Newman developed the Press format, used in Xerox Star system
– John Gaffney and Martin Newell at Xerox PARC wrote J&M or JaM, which evolved into Interpress language
– Warnock, Geschke, Brotz, Taft, and Paxton created PostScript, visited by Steve Jobs who urged its use in laser printers
– First version of PostScript language released in 1984 (Level 1 qualifier added when Level 2 introduced)
– PostScript Level 2 introduced in 1991 with improved speed and reliability, support for in-Raster Image Processing (RIP) separations, image decompression, support for composite fonts, and caching reusable content using the form mechanism
– PostScript 3 released at the end of 1997, introducing better color handling, new filters, smooth shading operations with up to 4096 shades of grey, and DeviceN color space allowing addition of spot colors into composite color pages
– Font hinting introduced in PostScript to improve the appearance of fonts at low resolution
– Type 1 Font (PS1) was a simplified version of PostScript that included font hinting
– Type 3 Font (PS3) allowed for the sophistication of the PostScript language without standardized hinting
– Type 2 font format designed to reduce font file size and became the basis for OpenType fonts
– Third-party implementations of PostScript became common due to cost and lack of support from Adobe
– Microsoft licensed TrueImage to Apple, while Apple licensed TrueType to Microsoft
– TrueType became the standard outline font technology for both Windows and Macintosh
– Third-party PostScript-compatible interpreters widely used in printers and multifunction peripherals (MFPs)
– Display PostScript (DPS) developed by Steve Jobs for NeXT computers, used in NeXTStep system to provide an object-oriented graphics system
– PostScript revolutionized desktop publishing and printing industry
– Adobe and Microsoft collaborated to develop OpenType, a superset of Type 1 and TrueType formats
– Ghostscript, a free software version of PostScript interpreter, widely used
– PDF and PostScript share the same imaging model and are mutually convertible to each other
– PDF lacks the general-purpose programming language framework of PostScript
– PDF is a static data structure made for efficient access and interactive viewing
Use of PostScript in Printing
– Before PostScript, printers designed to print character output using physical glyphs
– Dot matrix printers introduced ability to print raster graphics with font table inside the printer
– Vector graphics printing left to plotters, limited use and expensive
– Laser printers combined features of printers and plotters, offered high-quality line art and text on the same page
– PostScript offered a single control language for any brand of printer, complete programming language, and device-independent rasterization
Use of PostScript as a Display System
– PostScript became successful with the introduction of graphical user interface (GUI)
– GUIs had less sophisticated graphics systems compared to PostScript
– PostScript evolved from a printing system to a graphics language used in the host computer
– Using PostScript as a display system eliminated differences between on-screen layout and printed output
– PostScript had features unsuitable for direct use in interactive display systems
– Display PostScript (DPS) developed by Steve Jobs for NeXT computers, used in NeXTStep system to provide an object-oriented graphics system
Technical Details of PostScript
– PostScript is a Turing-complete programming language
– PostScript belongs to the concatenative group of programming languages
– PostScript is an interpreted, stack-based language
– PostScript uses reverse Polish notation for unambiguous order of operations
– Most operators in PostScript take arguments from the stack and place results onto the stack
– PostScript uses the point as its unit of length, with 72 points equaling an inch
Additional Resources
– PostScript Language Reference Manual (PLR3) is the defining work on PostScript 3
– Supplement to the PostScript Language Reference Manual
– PostScript Language Reference Manual (PLR2) covers PostScript Level 2
– PostScript Language Reference Manual (PLR1) covers PostScript Level 1
– PostScript Language Tutorial and Cookbook (blue book) is an introductory text on PostScript
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PostScript (often abbreviated as PS) is a page description language and dynamically typed, stack-based programming language. It is most commonly used in the electronic publishing and desktop publishing realm, but as a Turing complete programming language, it can be used for many other purposes as well. PostScript was created at Adobe Systems by John Warnock, Charles Geschke, Doug Brotz, Ed Taft and Bill Paxton from 1982 to 1984. The most recent version, PostScript 3, was released in 1997.
 PostScript 3 logo | |
| Paradigm | Multi-paradigm: concatenative (stack-based), procedural |
|---|---|
| Designed by | John Warnock, Chuck Geschke, Doug Brotz, Ed Taft, Bill Paxton |
| Developer | Adobe Systems |
| First appeared | 1982 |
| Stable release | PostScript 3
/ 1997 |
| Typing discipline | Dynamic, weak |
| Major implementations | |
| Adobe PostScript, TrueImage, Ghostscript | |
| Influenced by | |
| Mesa, Interpress, Lisp | |
| Influenced | |
| Filename extension |
.ps |
|---|---|
| Internet media type |
application/postscript |
| Uniform Type Identifier (UTI) | com.adobe.postscript |
| Magic number | %! |
| Developed by | Adobe Systems |
| Type of format | printing file format |
| Extended to | Encapsulated PostScript |
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