PostScript is a page description language, a protocol that is used to communicate between applications like Adobe InDesign or MS Word and output devices like laser printers or CtP systems, that are equipped with a PostScript interpreter. PostScript can also be used to exchange data between applications themselves and it forms the basis of the PDF file format.
The pages below go into more detail about PostScript:
- The purpose of PostScript
- The history of PostScript
- Postscript is a programming language
- Language specific details
- PostScript is an interpreted language
- Alternatives to PostScript
A description of what a page is supposed to look like is irrelevant if you can’t actually turn it into something physical, such as a printed sheet of paper or a printing plate. This article explains how PostScript is interpreted and output. The diagram below gives a basic overview: PostScript data are generated from a layout application when the operator wants to print a job. The data can be sent directly to a device with a built-in interpreter, such as an inkjet printer, or the data can be sent to a dedicated RIP that interprets the data for one or more devices such as a platesetter or an imposition proofer.
Links, products & stuff
Here are some other sites and resources that deal with PostScript (or graphic arts and prepress in general).
PostScript related sites
It seems logical that Adobe is the best place to look for information about PostScript. After all, they invented the stuff. The Adobe site is quite large so I picked just this little corner that has some PDF files about PostScript and PDF. The Adobe manual on PostScript, also known as the Red Book, is also available on-line.
The Inkguides PostScript page is another excellent pointer to other sources of information.
When problems occur, it is nice to get a second opinion. So it can be practical to have another RIP available in case of postscript errors: just send your problem file to the other RIP and if the problem reoccurs, at least your imagesetter RIP or printer is not to blame.
Adobe Acrobat is a must-have for every prepress professional. Acrobat Professional is a suite of programs that includes an application called Distiller. Distiller really is a RIP so you can send your troublesome page to Distiller and double-check whether it can handle your file. If this is the case, Distiller will convert the PostScript data into a PDF-file. This is still kind of a PostScript file but structured in a different, more robust format. This PDF can then be opened in Acrobat to preview the content on a screen. You can also make small corrections to the file and either print it or export it back to PostScript.
Ghostscript is a freeware PostScript RIP. It can RIP to screen, to a TIFF file or convert the file to another format like an EPS-file. It is available for Mac, PC, and Unix. I haven’t tried the Unix version, but the PC version is faster and more reliable than its Macintosh counterpart.
WYSIWYG PostScript editors
There are several programs on the market that allow you to view the content of a PostScript file on-screen and make modifications to it. Here are some of them:
Maybe you haven’t realized that you probably already own a WYSIWYG editor: Adobe Acrobat. Enhanced by some of the available plug-ins, it is a very powerful yet cost effective tool to manipulate PostScript files. Jump to the PDF section of my site to learn more about it.
OneVision, a German company, has a wide range of products for handling both PostScript and PDF files.
PostScript text editors
PostScript files are ASCII-files, meaning you can open them in an editor or word processor and have a look at the code. It is far beyond me to try and do major modifications in a PostScript. But for some problems it is useful to just take a look at the code and delete or add a bit. There are hundreds of editors on the market so I’ll just list my favorite two:
BBedit is a popular editor for Macintosh. There is a free version of it called TextWrangler which you can download from the same site.
Textpad is shareware, it is pretty cheap but don’t let this fool you. This is a great editor that runs on various flavors of Windows. I was pretty impressed by the speed as well when I started using its ‘find and replace’ option on a 280 MB PostScript file. Nowadays I have replaced this program by NotePad++, equally powerful but freeware.
Nowadays PostScript downloaders have largely become irrelevant. Most RIPs either have a manual upload mode in one of their menus or you can upload files by dropping them in a hotfolder. Back in the Mac OS 7/8/9 days my all time favorite PostScript downloader on Macintosh was LaserStatus. It is part of a series of utilities called ‘Mockpackage’.
There are no longer any newsletters dedicated to PostScript.
Newsgroups & forums
The newsgroup on PostScript is ideal if your PostScript error is not covered by my database. This list doesn’t delve too deep into PostScript programming itself.
Thinking in PostScript
This book gets mentioned first, not because it really stands out (although it is an excellent introduction to PostScript) but because you can download it for free (for Macintosh at least). Once this publication went out of print, its author Glenn Reid had the great idea to put it on the net as a PDF document.
PostScript Language Reference Manual
PDF is based on PostScript so it is impossible to ignore the famous Red Book. This huge volume contains everything you want to know about PostScript and more. It is written with the programmer in mind but can be useful for learning about PostScript or getting to know what the command that is causing that awful PostScript error actually does. A PDF version of this book can be downloaded from the Adobe website but you can still buy the printed version.
PostScript & Acrobat Bible
This excellent book by Thomas Merz is no longer available. If you’re a PostScript die-hard you may still be able to buy a second-hand version.