Quoting Florian Zieboll (f.zieb...@web.de): > I have a vague recollection, that there are printers and imagesetters, > that are able to render PDF directly (never was involved in such a > workflow myself) - but this is probably only true for equipment which > does PostScript, of which PDF is a direct successor.
'Successor' is not quite the right description, IMO. The key point is that PDF (which, to be sure, was developed later) is bidirectionally equivalent and semantically identical to PostScript. You can convert a .ps file to .pdf one and back, and not lose any substantive content in either direction. The primary physical difference is that the PDF version will be stored compressed, while the PS version will not. There is also a really important _legal_ difference. Adobe was quite aggressive in attempting to monetise PostScript for a long time, based on the firm's legal control via patent holdings. This is one reason why the groundbreaking Apple LaserWriter printers suffered a apricing premium, as did NeXT, Inc's lovely proprietary BSD variant NeXTStep, because instead of X11, it used a graphical subsystem constructed using Display PostScript. Both products were more expensive than they would have been without PostScript because patent royalties were owed to Adobe Systems for each unit sold. Predictably, Adobe's patent-based monopoly eroded as others invented alternatives, e.g., although Adobe's PostScript typefaces were the best in the world (in which category I include leading PS typefaces from other major foundries), increasingly the alternative TrueType technology (whose modern descendant is OpenType) choices were good enough and then competitive, along with some other advantages such as better-integrated on-screen rendering and lower RAM overhead. Adobe perceived that it had priced itself too high, and risked PS becoming 'really good, but too expensive hence irrelevant' like Apple's Firewire. Wishing to not miss the boat on a promising new subniche, print-like document formats, it made the _PDF_ variant of PS usable free of patent royalties in perpetuity, so as to increase the format's attractiveness for adopters. An ironic consequence of that market decision: When the now-late Steve Jobs returned to Apple, Inc. and arranged for his firm NeXT, Inc. to be 'acquired' by Apple (in form, albeit the substance was that NeXT, Inc. upper managers became Apple's new upper management, so one can say it was really more like NeXT acquiring Apple), the chief product problem to be solved was crafting a successor to legacy MacOS 9.x, which lacked both memory protection and a real multitasking model and basically needed to be junked and replaced. Jobs had been 'hired' (permitted to spearhaed a NeXT takeover of Apple) partly because NeXT still owned the rights to NeXTStep, which with a figurative paint-job and mild dusting was re-christened 'Macintosh OS X' (the 'X' not being pronounced 'ecks', but rather 'ten'). The crowning irony? Apple[/NeXT] solved its Adobe royalties headache through a small tweak: The NeXTStep Display PostScript graphics system was slightly updated (and dubbed 'Quartz' as a codename) to use Display PDF, which is pretty nearly exactly the same thing, instead of Display PostScript. There are to my knowledge no technical advantages, but they did this so that they would no longer (figuratively) need to cut a royalty cheque to Adobe for each and every copy. Without taking the time to investigate, my guesstimate is that Adobe's patents on PostScript (v.1 and possibly also v.2) have now expired and are no longer a burden. _______________________________________________ Dng mailing list Dng@lists.dyne.org https://mailinglists.dyne.org/cgi-bin/mailman/listinfo/dng
