Preserved Topic: post scripts

people, as you can imagine i am newbee. I want to know what is a post script (i imagine that is the lenguage for programming in photshop, isn´t it?), what can you dou with it, what lenguage use, etc..
Thanks.



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Welcome jorgito,

Post script is a language developed by Adobe for describing pages and graphics. It is basically a page layout language, but, its grapics abilities are so strong it can be used for description and creation of graphics.

Postscript is the language used by most Apple printers. There are other printers such as HP and Lexmark that understand a limited subset of Postscript, but are not truly post script printers.

Most people use programs such as Illustrator or Freehand to create Postscript files. While it is possible to create a postscript file by hand, it is such a tedious job that most people don't do it. It is not a general purpose programming language and is harder to program in than most languages such as C or Pascal.

<edit> I forgot to answer you question about programming Photoshop with PostScript. I assume you are talking about creating Plug-Ins. That is done in C or C++. If you are talking about creating actions, that is done in Photoshops own internal langauage. I don't know of a way to program PhotoShop with PostScript. The closest PhotoShop comes to PostScript is that it can read and create Encapsulated PostScript files which are not really PostScript at all but a kludge added to PostScript to make it possible for it to handle raster files
</edit>


[This message has been edited by hyperbole (edited 03-24-2001).]

hyperbole left out a huge category of output devices that rely on postscript: imagesetters. Any document intended for offset printing - catalogs, data sheets, corporate newsletters, newspapers ....... all pass through a RIP which converts the data which describes the page (including text and images) into the postscript language that tells the imagesetter where to place the halftone dot, and how big to make it.

I've read articles about programming directly in postscript, but unless you seriously intend to write software for laser printers or imagesetters I'd bag that idea early on! That is some daunting code to look at.

goooood!! Thanks. The reason because i post this topic is that i ´m working with Arc View GIS (Geographic Information System), and some people told me that if i get my datas in postscript format i will have better results printing them... so i´m going to try it. Thanks, and only one more question, steve: Can you explain me what is exactly the RIP you mention in your response? maybe i must use it to convert my maps datas...

Todos los caminos llevan a Roma

>>if i get my datas in postscript format i will have better results printing them<<

Okay - that makes more sense. You don't want to program postscript, you want to print USING postscript. That's a printing issue.
- First: Photoshop is not a postscript environment, so unless you are using Photoshop to create or manipulte photographic images, don't worry about Photoshop at all. (I know - Photoshop 6 is changing that a bit, but for the sake of real world discussion here let's overlook that.)

- Drawing software (the two most popular are Macromedia Freehand and Adobe Illustratr) ARE postscript based. They are vector based, meaning they describe shapes with mathematics insted of pixels. Many type faces are postscript also (again, describing the shapes of the letter forms with math). TrueType fonts are a variant of this. IF you create your artwork with Illustrator or Freehand, and IF you use postscript of truetype type, and IF you print using a postscript device (a postscipt enabled laser printer or image setter), you will have clean, sharp output at virtually any size you want, from a post card to a poster. Vector artwork and type scales up and down perfetly, with no edge artifacts because the shapes and outlines are not described by pixels.

SO - what is the data you want to output? Alpha/numeric characters? Most any word processor I know of should handle that fine if you have good quality type and a decent printer. If it is charts, maps or graphs, then you do want to create these in a drawing program such as I mentioned above if you want the highest quality output. If these maps are already supplied to you, and if they were created in a bitmap software such as Photoshop, then I think yu may just have to live with the quality you get. There will probably be a point of enlargement where the quality becomes unacceptable, and you will have to stay within that.

>>Can you explain me what is exactly the RIP you mention in your response? maybe i must use it to convert my maps datas<<

RIP stands for "Raster Image Processor", and it's typically a software processor either built into a printer or as a stand-alone unit at the front end of an imagesetter. As I said above, the beauty of vector based type and artwork is that it is described as lines and curves, permitting it to be scaled up and down perfectly with no loss of quality. BUT .... At some point all that beautiful vector data in an illustration or a page of text has to get printed, at which point its dimensions get fixed. It might become a 4x6 inch mailer, or a 4x6 foot banner, but it moves out of the abstract into the concrete at this point. And the printer doesn't work with curves and lines, it works with spots of toner or dots of density on the halftone plate. The RIP is the workhorse that translates the abstract vector data from the digital file to the physical world of dots and spots. It transforms the data from vector to raster. Needless to say, this is a very processor-intensive operation for something like a catalog.

So - a free-standing RIP is not something an individual buys. It's an invisible part of the printing process. Tell us a little more about the sorts of data you need to work with: how is it generated? How is it supplied to you? What is the output?

Let's see if we can come up with something to make your work easier.

Isn't it possible nowadays to use PDF instead of postscript? I work for a printing company and as far as I know we have something called a PDF-flow for the process fo making the printing plates from the digital file. And I imagine creating a PDF is something more people are familiar with, so that could be an easier alternative.

I am not all sure exactly how the system work though, as I myself only work with webdesign and image retouching...

Steve, Thanks for elucidating my answer. I had forgotten about imagesetters and commercial printing. I just kind of lumped them all together with the word printer. And I think you did a better job of stating the difficulty of programming directly in PostScript than I did.


ZOX,

A PDF file is a PostScript file that has been run through Adobe's Acrobat program. PDF files are really good for transporting documents back a forth from one location to another because they are very small and will create the exact same image from machine to machine.

One of the advantages of a PDF is that you can include the Fonts used in your document in the PDF. Whereas with PostScript you have to depend on the same fonts being available on the source machine as well as the target machine.

To print a PDF, the file still needs to be translated back into a PostScript file so the printer can understand the information. I don't know of any print devices that understand PDF format. Do you Steve?

I confess I'm a bit hazy on PDF myself, but it's taking the printing world by story. PDF stands for "Portable Digital File", and if I understnad correctly, the files is sort of pre-RIPped - it's in a postscript state. It can be viewed with freely available viewers, but can't be edited without the Acrobat app.

Advantage: you don't need anything but the viewer to see the file: dedsigner can use any crazy font they want, and any flavor of software - Quark, Pagemaker, InDesign, Illustrator - anything, on any platform. The person viewing the file only needs the acrobat viewer for their particular OS. This makes for a very good situation when publishing papers or forms on the net for instance. Printers like it, because most flaws in a file that would croak a RIP will stump Acrobat too, so if it saves to PDF okay it should print fine too; also avoids the issue of designers forgetting to supply type with their file.

Disadvantage: can't easily edit, copy, paste, whatever. Also, it requires a bit of sophistication on the part of the creator. Especially images - it's easy to place low res versions by accident. Also, some type designers are unwilling to allow their proprietary font shapes, hinting etc. to be accessible (intellectual property issues), so Acrobat can't access them. Heard a few stories regarding this gotcha.

But it's a good technology, getting better. Love it when you need that last minute IRS tax form, or college admission paperwork, and can snag it off the 'net, print it out and it looks EXACTLY like what you'd get at the office! That's a powerful technology. Art directors routinely email me layouts as PDF files, and it doesn't matter whether I have the latest version or Quark or whatever. Beats the hell out of squinting at a crummy fax!