9 ms·

Inventing PostScript, the tech that took the pain out of printing (1988)

125 points by takiwatanga 4y ago

throw0101a 4y ago
PPD files can be very handy: * https://en.wikipedia.org/wiki/PostScript_Printer_Description https://en.wikipedia.org/wiki/PostScript_Printer_Description Sort of like 'OS-neutral printer drivers'.
svat 4y ago
(1988) > This article was first published as "‘PostScript’ prints anything: a case history." It appeared in the May 1988 issue of IEEE Spectrum. […] The diagrams and photographs appeared in the original print version. So the article is from 1988, except for the update at the bottom: > Update April 2022: While most home and office printers rely on other page description languages these days, PostScript remains the choice of graphics artists and commercial printers for its ability to accurately produce complex images. And the ubiquitous Portable Document Format (PDF) is based on PostScript.
vincent-manis 4y ago
I'm glad Warnock and Geschke didn't already have the ideas of the modern Adobe in their heads. If they had, the LaserWriter would have required a monthly cloud subscription, and if the customer cancelled, both the printer and everything they had already printed would vanish. I also think that Illustrator 88 was a great improvement on its successors.
- mistrial9 4y ago
  > was a great improvement on its successors was .. huh?
  - vincent-manis 4y ago
    I stole a line from C.A.R. Hoare: `[Algol 60 was] a language so far ahead of its time, that it was not only an improvement on its predecessors, but also on nearly all its successors.'
ivanviso 4y ago
That fixed the formatting. Next is fixing the printers. And then, the users. Ugh.
- kuschku 4y ago
  Printers are fixed and work fine – as long as you buy a laser printer (not HP though!) with postscript support
  - frosted-flakes 4y ago
    HP laser printers are fine.
    - User23 4y ago
      The Windows drivers are, to put it politely, absolute shit. They work well from MacOS and GNU/Linux though.
      - smackeyacky 4y ago
        To be a little fairer to HP, windows printing is an abomination. I have two HP printers that I did nothing to enable printing on the linux installations, they appear automatically and work out of the box. The windows machines? Expect to have to reinstall or reconfigure 6 monthly, and not just for HP.
  - dotancohen 4y ago
    HP had been my go-to printers for the time I was still printing, maybe for a decade and a half starting around 2000. They "just work" on Linux systems with no driver downloads or other nonsense, including advanced non-printing features such as scanning. I'll admit that the build quality went down with every printer purchased, but that was an acceptable tradeoff for just plugging it in and getting to work. Not to mention that HP aftermarket ink is readily available and relatively affordable, especially if you simply refill the cartridges yourself (literally three minute job).
deleted 4y ago
[deleted]
fortran77 4y ago
I worked at Adobe in the early days; my first job was embedding PostScript into various manufacturer's printers. I love the PostScript language and still play with the PostScript interpreter every now and then. Often if I need to plot something, it's fun to try to write the code in raw PostScript. It's a shame "nobody" cares about printing anymore. In the late 80s as soon as I was able to afford a 300 dpi laser printer, I ran down to the store and plunked down $2500 or so for an HP LaserWriter. I used it with TeX (this was before Adobe) and thought I was witnessing a revolution! A real, powerful, printing press in my home! I'm old enough to have leaned how to set letterpress type in high school shop class....
- trop 4y ago
  My high school had a computer lab with a networked LaserWriter (this might have been 1987). It outclassed any screen in the room, so far as display resolution. And with its 68000 processor and PostScript interpreter, it was the fastest and most capable graphics machine I'd ever seen. Indeed, a 300dpi laser printer driven by PostScript was a wonder. I ordered the Addison Wesley documentation. I figured out that sending a text file to the printer which started with "%!PS" would make the rest be processed as PostScript. Suddenly I could code vector graphics programs and send them to the LaserWriter and get beautiful prints. I was reading Douglas Hofstadter's Metamagical Themas, and my memory is that there were some great ideas for graphics in that. The good news: I got a chance to program in a well thought-out interpreted language (a wonder, coming from the world of BASIC, Fortran, C or even Pascal). I got to produce wonderful and intricate graphics output. Reading the IEEE article makes me grateful that the Adobe designers "put functionality over speed". The bad news: The most interesting output could still take minutes (or more) to run. Of course, this was confusing (or annoying) if someone else in the lab wanted, say, to print their term paper then run off to class. I'd like to think that I learned to run my print jobs at odd hours, and in the worst case, to power cycle the printer and lose my print, to make the device available to the room.
- pstuart 4y ago
  > thought I was witnessing a revolution! You were. They were heady times indeed. My girlfriend at the time was a typesetter and did a lot of freelance using Ventura Publisher (on a 286 w/ 4MB!) Quark XPress, Pagemaker, FrameMaker, Ventura... ahh the good old days ;-).
throwpdfloop 4y ago
But PDF (or maybe PDF/X) is just as good nowadays?
- wombatpm 4y ago
  PDF/X is just a PDF with interactivity/JavaScript/forms removed and the layout instructions rationalized and colorspace for RIP fir commercial printers
  - throwpdfloop 4y ago
    Does "layout instructions" refer to the paper/trim dimensions?
- mkl 4y ago
  PDF is just as good in the sense of being able to represent the documents people want to (arguably better, if only for transparency, compression (including JPEG), and (usually!) the ability to search for and select text). PDF does have many other additional features that people disagree on the value of, many of which are not supported by most PDF viewers. Being a full programming language, PostScript is technically much more powerful in many ways, but it turns out that's no longer very useful for most purposes (computers are much more powerful*, storage is cheap, networks are fast, most documents are viewed on screen, etc.). * I've heard of people writing programs in PostScript to take advantage of printers' fast vector processors instead of running them on (at the time) comparatively slower PC CPUs, a bit like the early days of GPGPU.
  - anthk 4y ago
    You can search into PS files too. On viewing then in a computer, GV+GhostScript will do perfectly fine. Oh, and you can run Zmachine V3 games on an interpreter written in PostScript.
  - throwpdfloop 4y ago
    Are there common cases in which a printshop with up-to-date equipment would prefer PostScript to PDF?
euske 4y ago
Hate to be negative, but this new site design of IEEE Spectrum is just abhorrent. It's ad-ridden and there's an infinite scrolling thing. I use reader mode, but I miss the old design. Sigh
- dredmorbius 4y ago
  https://archive.ph/RjtDd https://archive.ph/RjtDd
- tux1968 4y ago
  Firefox "Reader View" works nicely on that site. I assume there is something similar for Chrome if that's what you're using.
- spicybright 4y ago
  They literally have paragraphs repeated randomly in the article to. Does no one even bother proofing either?
TYPE_FASTER 4y ago
Watching a LaserWriter print from a Mac for the first time after being used to dot matrix printers was mind blowing. Such a huge leap forward in print quality and speed.
deleted 4y ago
[deleted]
transfire 4y ago
I think it’s sad that Postscript fell out of use instead of evolving into a better language.
taviso 4y ago
Funny, I think I might be one of the worlds foremost experts on PostScript security :) I spent a lot of time researching PostScript interpreter security, and ended up finding a bunch of really interesting bugs. There are of course the regular memory corruption, type confusion, etc, bugs, but PostScript has it's own security model that's intended to stop documents you're printing from interfering with the runtime environment or using internal operators. Those bugs can be fascinating! The TL;DR summary is that PostScript functions are basically just arrays, so to stop documents you're printing from peeking inside and altering system routines, there is a security boundary called "executeonly". The intention is to allow documents to to call routines that might do something powerful on their behalf - e.g. open a printer specification, or run `lpr` or whatever - but not let them open any file or run any command they want. If you could interfere with them, you can break that expectation and get access to root-equivalent operators that let you do whatever you want. Turns out, that's really hard to get right - often you can trick them into faulting and then crawl through the error state to find references to their internals you're not supposed to have! Exploiting these bugs requires some really weird PostScript, here are fun examples: https://www.openwall.com/lists/oss-security/2019/01/23/5 https://www.openwall.com/lists/oss-security/2019/01/23/5 https://bugs.chromium.org/p/project-zero/issues/detail?id=1682 https://bugs.chromium.org/p/project-zero/issues/detail?id=16... I found about a dozen bugs like these while working on it, fun times.
- chunkyks 4y ago
  I worked on postscript drivers for a few years. Escaping the sandbox was a feature! You could usually exitserver with a default password, then set global state to do annoying things. Imagine every print job being rotated five degrees, or having a weird dead spot somewhere on the page. I really enjoyed writing postscript. Fun language
- rileyphone 4y ago
  Proof of the object capabilities model, at least why it’s needed for highly interpreted languages. Maybe E does it better? http://wiki.erights.org/wiki/Walnut/Complete http://wiki.erights.org/wiki/Walnut/Complete
sytelus 4y ago
I am still confused why one needs to produce a document as "program" as opposed to set of pixel to be printed. If we know the page size in advance (which we do while pressing the print button), I would expect document program rasterizes it and so "print anything" can be achieved pretty simply. Why they needed to invent a new programming language called postscript?
- hamburglar 4y ago
  Part of the point was that it was device independent, and simple rasterization wasn’t practical for printing on both low end office printers and the highest end commercial printing imagesetters.
- danachow 4y ago
  Because in the good old days you expected to share an expensive page printer with many, and it made sense to put a powerful embedded computer (for the time) to do rasterizing within it. It could save on bandwidth, RAM, and storage. The RAM requirements for rasterizing a page would be quite costly at the time.
- mongol 4y ago
  I regularily have to print some specific pdf files that fail to print on my Epson printer. The workaround I found was to rasterize them with ImageMagick, because then they print. But so slow.... It is not an efficient approach.
- pfortuny 4y ago
  Plotters were much more common those days, also.
- andybak 4y ago
  Rasterize for what? A plotter doesn't need rasterization. If you're printing colour offset then the halftone grid would probably use a different rasterization to the one that you want to use for an inkjet or dot-matrix. "Rasterization" if needed at all probably needs intimate knowledge of the printing hardware.
- simonh 4y ago
wly_cdgr 4y ago
"took the pain out of printing" that's a good laugh
bluenose69 4y ago
I remember clearly how postscript changed things for scientific work. Of course, it improved upon the daisy printers that we used for text. But the same language could also draw graphs, so it was a sort of all-in-one solution. A limitation on the graph side of things was the requirement that any so-called "path" (to be drawn as a line or filled as a polygon) could hold at most 1500 elements. This limit was exceeded in a lot of work. If the task was just to draw the line, the solution was simple: chop the path up into subpaths and draw each. (The transition point would be ugly due to line-ending issues, but the problem would be difficult to see on visual inspection). This chopping method wasn't useful for polygons, though. So I came up with a scheme in which I examined each point with respect to it's two neighbours. If the point was within some distance of a line segment connecting the neighbours, then I omitted it. If the first pass got the number of points under 1500, I'd render them. Otherwise, I repeated the procedure, with wider tolerances. This was done in C, so it was not really too time-consuming. And it worked. The software is still in use today, many decades later.
coldcode 4y ago
I wrote a postscript library in late 1988 for our application. Learning Postscript enough to support everything our app could generate (charts) involved boxes and boxes of paper, since the only way to debug anything was to print debugging info on paper. Sometimes the bugs made nothing print, which was hard to figure out! Still it was a fun language, and I could learn a lot by looking at Illustrator's file format (which was basically Postscript, and I think eventually became PDF). I was even able to export everything we drew into Illustrator format, which was a popular feature. Postscript is probably the most unusual language I ever worked with (APL comes close) but I enjoyed working with it.

125 points by takiwatanga 4y ago

PPD files can be very handy: * https://en.wikipedia.org/wiki/PostScript_Printer_Description https://en.wikipedia.org/wiki/PostScript_Printer_Description Sort of like 'OS-neutral printer drivers'.

svat 4y ago

(1988) > This article was first published as "‘PostScript’ prints anything: a case history." It appeared in the May 1988 issue of IEEE Spectrum. […] The diagrams and photographs appeared in the original print version. So the article is from 1988, except for the update at the bottom: > Update April 2022: While most home and office printers rely on other page description languages these days, PostScript remains the choice of graphics artists and commercial printers for its ability to accurately produce complex images. And the ubiquitous Portable Document Format (PDF) is based on PostScript.

vincent-manis 4y ago

I'm glad Warnock and Geschke didn't already have the ideas of the modern Adobe in their heads. If they had, the LaserWriter would have required a monthly cloud subscription, and if the customer cancelled, both the printer and everything they had already printed would vanish. I also think that Illustrator 88 was a great improvement on its successors.

mistrial9 4y ago
> was a great improvement on its successors was .. huh?
- vincent-manis 4y ago
  I stole a line from C.A.R. Hoare: `[Algol 60 was] a language so far ahead of its time, that it was not only an improvement on its predecessors, but also on nearly all its successors.'

ivanviso 4y ago

That fixed the formatting. Next is fixing the printers. And then, the users. Ugh.

kuschku 4y ago
Printers are fixed and work fine – as long as you buy a laser printer (not HP though!) with postscript support
- frosted-flakes 4y ago
  HP laser printers are fine.
  - User23 4y ago
    The Windows drivers are, to put it politely, absolute shit. They work well from MacOS and GNU/Linux though.
    - smackeyacky 4y ago
      To be a little fairer to HP, windows printing is an abomination. I have two HP printers that I did nothing to enable printing on the linux installations, they appear automatically and work out of the box. The windows machines? Expect to have to reinstall or reconfigure 6 monthly, and not just for HP.
- dotancohen 4y ago
  HP had been my go-to printers for the time I was still printing, maybe for a decade and a half starting around 2000. They "just work" on Linux systems with no driver downloads or other nonsense, including advanced non-printing features such as scanning. I'll admit that the build quality went down with every printer purchased, but that was an acceptable tradeoff for just plugging it in and getting to work. Not to mention that HP aftermarket ink is readily available and relatively affordable, especially if you simply refill the cartridges yourself (literally three minute job).

deleted 4y ago

[deleted]

fortran77 4y ago

I worked at Adobe in the early days; my first job was embedding PostScript into various manufacturer's printers. I love the PostScript language and still play with the PostScript interpreter every now and then. Often if I need to plot something, it's fun to try to write the code in raw PostScript. It's a shame "nobody" cares about printing anymore. In the late 80s as soon as I was able to afford a 300 dpi laser printer, I ran down to the store and plunked down $2500 or so for an HP LaserWriter. I used it with TeX (this was before Adobe) and thought I was witnessing a revolution! A real, powerful, printing press in my home! I'm old enough to have leaned how to set letterpress type in high school shop class....

trop 4y ago
My high school had a computer lab with a networked LaserWriter (this might have been 1987). It outclassed any screen in the room, so far as display resolution. And with its 68000 processor and PostScript interpreter, it was the fastest and most capable graphics machine I'd ever seen. Indeed, a 300dpi laser printer driven by PostScript was a wonder. I ordered the Addison Wesley documentation. I figured out that sending a text file to the printer which started with "%!PS" would make the rest be processed as PostScript. Suddenly I could code vector graphics programs and send them to the LaserWriter and get beautiful prints. I was reading Douglas Hofstadter's Metamagical Themas, and my memory is that there were some great ideas for graphics in that. The good news: I got a chance to program in a well thought-out interpreted language (a wonder, coming from the world of BASIC, Fortran, C or even Pascal). I got to produce wonderful and intricate graphics output. Reading the IEEE article makes me grateful that the Adobe designers "put functionality over speed". The bad news: The most interesting output could still take minutes (or more) to run. Of course, this was confusing (or annoying) if someone else in the lab wanted, say, to print their term paper then run off to class. I'd like to think that I learned to run my print jobs at odd hours, and in the worst case, to power cycle the printer and lose my print, to make the device available to the room.
pstuart 4y ago
> thought I was witnessing a revolution! You were. They were heady times indeed. My girlfriend at the time was a typesetter and did a lot of freelance using Ventura Publisher (on a 286 w/ 4MB!) Quark XPress, Pagemaker, FrameMaker, Ventura... ahh the good old days ;-).

throwpdfloop 4y ago

But PDF (or maybe PDF/X) is just as good nowadays?

wombatpm 4y ago
PDF/X is just a PDF with interactivity/JavaScript/forms removed and the layout instructions rationalized and colorspace for RIP fir commercial printers
- throwpdfloop 4y ago
  Does "layout instructions" refer to the paper/trim dimensions?
mkl 4y ago
PDF is just as good in the sense of being able to represent the documents people want to (arguably better, if only for transparency, compression (including JPEG), and (usually!) the ability to search for and select text). PDF does have many other additional features that people disagree on the value of, many of which are not supported by most PDF viewers. Being a full programming language, PostScript is technically much more powerful in many ways, but it turns out that's no longer very useful for most purposes (computers are much more powerful*, storage is cheap, networks are fast, most documents are viewed on screen, etc.). * I've heard of people writing programs in PostScript to take advantage of printers' fast vector processors instead of running them on (at the time) comparatively slower PC CPUs, a bit like the early days of GPGPU.
- anthk 4y ago
  You can search into PS files too. On viewing then in a computer, GV+GhostScript will do perfectly fine. Oh, and you can run Zmachine V3 games on an interpreter written in PostScript.
- throwpdfloop 4y ago
  Are there common cases in which a printshop with up-to-date equipment would prefer PostScript to PDF?

euske 4y ago

Hate to be negative, but this new site design of IEEE Spectrum is just abhorrent. It's ad-ridden and there's an infinite scrolling thing. I use reader mode, but I miss the old design. Sigh

dredmorbius 4y ago
https://archive.ph/RjtDd https://archive.ph/RjtDd
tux1968 4y ago
Firefox "Reader View" works nicely on that site. I assume there is something similar for Chrome if that's what you're using.
spicybright 4y ago
They literally have paragraphs repeated randomly in the article to. Does no one even bother proofing either?

TYPE_FASTER 4y ago

Watching a LaserWriter print from a Mac for the first time after being used to dot matrix printers was mind blowing. Such a huge leap forward in print quality and speed.

deleted 4y ago

[deleted]

transfire 4y ago

I think it’s sad that Postscript fell out of use instead of evolving into a better language.

taviso 4y ago

Funny, I think I might be one of the worlds foremost experts on PostScript security :) I spent a lot of time researching PostScript interpreter security, and ended up finding a bunch of really interesting bugs. There are of course the regular memory corruption, type confusion, etc, bugs, but PostScript has it's own security model that's intended to stop documents you're printing from interfering with the runtime environment or using internal operators. Those bugs can be fascinating! The TL;DR summary is that PostScript functions are basically just arrays, so to stop documents you're printing from peeking inside and altering system routines, there is a security boundary called "executeonly". The intention is to allow documents to to call routines that might do something powerful on their behalf - e.g. open a printer specification, or run `lpr` or whatever - but not let them open any file or run any command they want. If you could interfere with them, you can break that expectation and get access to root-equivalent operators that let you do whatever you want. Turns out, that's really hard to get right - often you can trick them into faulting and then crawl through the error state to find references to their internals you're not supposed to have! Exploiting these bugs requires some really weird PostScript, here are fun examples: https://www.openwall.com/lists/oss-security/2019/01/23/5 https://www.openwall.com/lists/oss-security/2019/01/23/5 https://bugs.chromium.org/p/project-zero/issues/detail?id=1682 https://bugs.chromium.org/p/project-zero/issues/detail?id=16... I found about a dozen bugs like these while working on it, fun times.

chunkyks 4y ago
I worked on postscript drivers for a few years. Escaping the sandbox was a feature! You could usually exitserver with a default password, then set global state to do annoying things. Imagine every print job being rotated five degrees, or having a weird dead spot somewhere on the page. I really enjoyed writing postscript. Fun language
rileyphone 4y ago
Proof of the object capabilities model, at least why it’s needed for highly interpreted languages. Maybe E does it better? http://wiki.erights.org/wiki/Walnut/Complete http://wiki.erights.org/wiki/Walnut/Complete

sytelus 4y ago

I am still confused why one needs to produce a document as "program" as opposed to set of pixel to be printed. If we know the page size in advance (which we do while pressing the print button), I would expect document program rasterizes it and so "print anything" can be achieved pretty simply. Why they needed to invent a new programming language called postscript?

hamburglar 4y ago
Part of the point was that it was device independent, and simple rasterization wasn’t practical for printing on both low end office printers and the highest end commercial printing imagesetters.
danachow 4y ago
Because in the good old days you expected to share an expensive page printer with many, and it made sense to put a powerful embedded computer (for the time) to do rasterizing within it. It could save on bandwidth, RAM, and storage. The RAM requirements for rasterizing a page would be quite costly at the time.
mongol 4y ago
I regularily have to print some specific pdf files that fail to print on my Epson printer. The workaround I found was to rasterize them with ImageMagick, because then they print. But so slow.... It is not an efficient approach.
pfortuny 4y ago
Plotters were much more common those days, also.
andybak 4y ago
Rasterize for what? A plotter doesn't need rasterization. If you're printing colour offset then the halftone grid would probably use a different rasterization to the one that you want to use for an inkjet or dot-matrix. "Rasterization" if needed at all probably needs intimate knowledge of the printing hardware.
simonh 4y ago

wly_cdgr 4y ago

"took the pain out of printing" that's a good laugh

bluenose69 4y ago

I remember clearly how postscript changed things for scientific work. Of course, it improved upon the daisy printers that we used for text. But the same language could also draw graphs, so it was a sort of all-in-one solution. A limitation on the graph side of things was the requirement that any so-called "path" (to be drawn as a line or filled as a polygon) could hold at most 1500 elements. This limit was exceeded in a lot of work. If the task was just to draw the line, the solution was simple: chop the path up into subpaths and draw each. (The transition point would be ugly due to line-ending issues, but the problem would be difficult to see on visual inspection). This chopping method wasn't useful for polygons, though. So I came up with a scheme in which I examined each point with respect to it's two neighbours. If the point was within some distance of a line segment connecting the neighbours, then I omitted it. If the first pass got the number of points under 1500, I'd render them. Otherwise, I repeated the procedure, with wider tolerances. This was done in C, so it was not really too time-consuming. And it worked. The software is still in use today, many decades later.

coldcode 4y ago

I wrote a postscript library in late 1988 for our application. Learning Postscript enough to support everything our app could generate (charts) involved boxes and boxes of paper, since the only way to debug anything was to print debugging info on paper. Sometimes the bugs made nothing print, which was hard to figure out! Still it was a fun language, and I could learn a lot by looking at Illustrator's file format (which was basically Postscript, and I think eventually became PDF). I was even able to export everything we drew into Illustrator format, which was a popular feature. Postscript is probably the most unusual language I ever worked with (APL comes close) but I enjoyed working with it.