Editing PostScript (section)

== History ==
The concepts of the PostScript language were seeded in 1976 by John Gaffney at [[Evans & Sutherland]],<ref name="reilly2003p206">{{cite book |last1=Reilly |first1=Edwin |url=https://archive.org/details/milestonesincomp0000reil/page/206 |title=Milestones in Computer Science and Information Technology |date=2003 |publisher=Greenwood Publishing Group |isbn=9781573565219 |page=206}}</ref><ref>{{cite book |last1=Peterson |first1=J.K |title=Fiber Optics Illustrated Dictionary |date=Jun 28, 2018 |publisher=Taylor & Francis Group |isbn=9781138455757}}</ref><ref>{{cite book |last1=Nguyen |first1=Binh |title=Linux Dictionary |date=2004 |publisher=Binh Nguyen |edition=0.16 |access-date=28 September 2019 |url=https://play.google.com/books/reader?id=vdZWBQAAQBAJ&hl=en&pg=GBS.PP1 |archive-date=24 February 2021 |archive-url=https://web.archive.org/web/20210224140917/https://play.google.com/books/reader?id=vdZWBQAAQBAJ&hl=en&pg=GBS.PP1 |url-status=live }}</ref> a [[computer graphics]] company. At that time, Gaffney and [[John Warnock]] were developing an interpreter for a large three-dimensional graphics database of [[New York Harbor]].

Concurrently, researchers at [[Xerox PARC]] had developed the first [[laser printer]] and had recognized the need for a standard means of defining page images. In 1975–76 [[Bob Sproull]] and [[William Newman (computer scientist)|William Newman]] developed the Press format, which was eventually used in the [[Xerox Star]] system to drive laser printers. But Press, a data format rather than a language, lacked flexibility, and PARC mounted the [[Interpress]] effort to create a successor.

In 1978, John Gaffney and [[Martin Newell (computer graphics)|Martin Newell]] then at Xerox PARC wrote J&nbsp;&amp;&nbsp;M or JaM<ref name="reilly2003p206" /><ref>{{Cite book|title=Masterminds of Programming|last1=Biancuzzi|first1=Federico|last2=Warden|first2=Shane|publisher=O'Reilly Media, Inc.|year=2009|isbn=9780596515171|chapter=Chapter 16. PostScript}}</ref> (for "John and Martin") which was used for [[Very-large-scale integration|VLSI]] design and the investigation of type and graphics printing. This work later evolved and expanded into the Interpress language.

Warnock left with [[Chuck Geschke]] and founded [[Adobe Systems]] in December 1982. They, together with Doug Brotz, Ed Taft and [[Bill Paxton (computer scientist)|Bill Paxton]] created a simpler language, similar to Interpress, called PostScript, which went on the market in 1984.

Meanwhile, in the spring of 1983, [[Steve Jobs]] came to visit Adobe and was dazzled by PostScript's potential, especially for the new [[Macintosh 128K|Macintosh]] computer he was developing at [[Apple Inc.|Apple]].<ref name="Pfiffner_Page_33">{{cite book |last1=Pfiffner |first1=Pamela |title=Inside the Publishing Revolution: The Adobe Story |date=2003 |publisher=Peachpit Press |location=Berkeley |isbn=0-321-11564-3 |page=33}}</ref> To [[John Sculley]]'s frustration, Jobs licensed the PostScript technology from Adobe by offering a $1.5 million advance against PostScript royalties, plus $2.5 million in exchange for 20 percent of Adobe shares.<ref name="Pfiffner_Page_34">{{cite book |last1=Pfiffner |first1=Pamela |title=Inside the Publishing Revolution: The Adobe Story |date=2003 |publisher=Peachpit Press |location=Berkeley |isbn=0-321-11564-3 |page=34}}</ref> During a series of meetings in 1983, Jobs also repeatedly offered for Apple to buy Adobe outright, but the founders kept turning him down.<ref name="Pfiffner_Page_34" /> In December 1983, the two companies finally signed off on the PostScript licensing deal, and Adobe had to shift focus immediately from high-end, high-resolution printing devices to the consumer-oriented Apple [[LaserWriter]] laser printer.<ref name="Pfiffner_Page_35">{{cite book |last1=Pfiffner |first1=Pamela |title=Inside the Publishing Revolution: The Adobe Story |date=2003 |publisher=Peachpit Press |location=Berkeley |isbn=0-321-11564-3 |page=35}}</ref>

At that time, the 300-dpi [[Canon Inc.|Canon]] laser printing engine to be used in LaserWriters was seen as good enough only for [[Prepress proofing|proof printing]] (i.e., for crude rough drafts of material whose final drafts would be sent to professional high-resolution devices), but Jobs presented Adobe with the challenge of making PostScript render high-quality output to such a low-resolution device (which for most consumers would be their only printing device).<ref name="Pfiffner_Page_36">{{cite book |last1=Pfiffner |first1=Pamela |title=Inside the Publishing Revolution: The Adobe Story |date=2003 |publisher=Peachpit Press |location=Berkeley |isbn=0-321-11564-3 |page=36}}</ref>  In response, Warnock and Brotz solved the so-called "appearance problem" of making the stem width of letters scale properly so that they look good at all resolutions.<ref name="Pfiffner_Page_37">{{cite book |last1=Pfiffner |first1=Pamela |title=Inside the Publishing Revolution: The Adobe Story |date=2003 |publisher=Peachpit Press |location=Berkeley |isbn=0-321-11564-3 |page=37}}</ref>  Their breakthrough was so important that Adobe has never patented the technology, in order to keep its details concealed as a [[trade secret]].<ref name="Pfiffner_Page_37" /> Paxton worked on several other related improvements, such as [[font hinting]].<ref name="Pfiffner_Page_37" /> Adobe was also responsible for porting PostScript to the Canon's [[Motorola 68000]] chip.<ref name="Pfiffner_Page_37" />

Apple and Adobe announced the LaserWriter at Apple's annual stockholder meeting on January 23, 1985.<ref name="Pfiffner_Page_47">{{cite book |last1=Pfiffner |first1=Pamela |title=Inside the Publishing Revolution: The Adobe Story |date=2003 |publisher=Peachpit Press |location=Berkeley |isbn=0-321-11564-3 |page=47}}</ref>  It was the first printer to ship with PostScript, sparking the [[desktop publishing]] (DTP) revolution in the mid-1980s.<ref name="Pfiffner_Page_48">{{cite book |last1=Pfiffner |first1=Pamela |title=Inside the Publishing Revolution: The Adobe Story |date=2003 |publisher=Peachpit Press |location=Berkeley |isbn=0-321-11564-3 |page=48}}</ref> The original PostScript royalty was five percent of the list price for each laser printer sold, which was $350 of the original LaserWriter list price of $6,995, and such royalties provided nearly all of Adobe's income during its early years.<ref name="Pfiffner_Page_69">{{cite book |last1=Pfiffner |first1=Pamela |title=Inside the Publishing Revolution: The Adobe Story |date=2003 |publisher=Peachpit Press |location=Berkeley |isbn=0-321-11564-3 |page=69}}</ref> (Apple later renegotiated the contract to pay a licensing fee based on volume of printers shipped.)<ref name="Pfiffner_Page_69" />  The combination of technical merits and widespread availability made PostScript the language of choice for graphical output for printing applications. An [[interpreter (computer software)|interpreter]] (sometimes referred to as a [[Raster Image Processor|RIP]] for Raster Image Processor) for the PostScript language was a common component of laser printers during the 1980s and 1990s.

However, the cost of implementation was high; computers output raw PS code that would be interpreted by the printer into a raster image at the printer's natural resolution. This required high-performance [[microprocessor]]s and ample [[computer memory|memory]]. The LaserWriter used a 12&nbsp;MHz [[Motorola 68000]], making it faster than any of the Macintosh computers to which it was attached.<ref name="Pfiffner_Page_53">{{cite book |last1=Pfiffner |first1=Pamela |title=Inside the Publishing Revolution: The Adobe Story |date=2003 |publisher=Peachpit Press |location=Berkeley |isbn=0-321-11564-3 |page=53}}</ref>  When the laser printer engines themselves cost over a thousand dollars, the added cost of PS was marginal. But, as printer mechanisms fell in price, the cost of implementing PS became too great a fraction of overall printer cost. In addition, with desktop computers becoming more powerful during the 1990s than their attached printers, it no longer made sense to offload the rasterization work onto the resource-constrained printer. By 2001, few low-end printer models came with onboard support for PostScript, largely due to growing competition from much cheaper non-PostScript inkjet printers, and new software-based methods to render PostScript images on computers, making them suitable for any printer. [[Portable Document Format|PDF]], a descendant of PostScript, provides one such method, and has largely replaced PostScript as the ''[[de facto]]'' standard for electronic document distribution.

On high-end printers, PostScript processors remain common, and their use can dramatically reduce the CPU work involved in printing documents, transferring the work of rendering PostScript images from the computer to the printer.

=== PostScript Level 1 ===
The first version of the PostScript language was released to the market in 1984. The qualifier ''Level 1'' was added when ''Level 2'' was introduced.<ref name=":0">{{Cite web |title=Differences Between Adobe PostScript Levels 1, 2, and 3 |url=https://www.thoughtco.com/difference-adobe-postscript-levels-1074580 |access-date=2025-03-04 |website=ThoughtCo |language=en}}</ref>

=== PostScript Level 2 ===
PostScript Level 2 was introduced in 1991, and included several improvements: improved speed and reliability, support for in-Raster Image Processing (RIP) separations, [[Image compression|image decompression]] (for example, [[JPEG]] images could be rendered by a PostScript program), support for composite [[Computer font|fonts]], and the form mechanism for caching reusable content.<ref name=":0" />

=== PostScript 3 ===
PostScript 3 (Adobe dropped the "level" terminology in favor of simple versioning) came at the end of 1997, and along with many new dictionary-based versions of older operators, introduced better color handling and new filters (which allow in-program compression/decompression, program chunking, and advanced error handling).

PostScript 3 was significant in terms of replacing the existing proprietary color electronic prepress systems, then widely used for magazine production, through the introduction of smooth shading operations with up to 4096 shades of grey (rather than the 256 available in PostScript Level 2), as well as DeviceN, a [[color space]] that allowed the addition of additional ink colors (called [[spot color]]s) into composite color pages.<ref name=":0" /><ref>{{Cite web |date=2002-06-04 |title=PostScript 3 General Information |url=https://pdfguru.com/ |archive-url=https://archive.today/20250304132704/https://web.archive.org/web/20030624050921/http://www.adobe.com/support/techdocs/210f6.htm |archive-date=2025-03-04 |access-date=2025-03-04 |website=Adobe}}</ref>