PostScript Parts

I ve already discussed the fact the PDF files are based upon the document language called PostScript. PostScript is our preferred language because it is sophisticated and powerful enough to allow us to perform tasks such as scaling, stretching and rotating type, stroking and filling graphics, working with both pixel- and vector-based images, and performing sophisticated printing chores such as separating colors. PostScript, which was developed by Adobe, has become the graphics industry standard language for creating and outputting complex pages and is the foundation of a PDF file.

The PostScript Language

The PostScript language is the background code describing what is in the document, much like HTML code is the behind-the-scenes code that creates a web page. Below is a section of PostScript code ”Distiller converts this code into a viewable and editable PDF file.

 /Adieresis/Aring/Ccedilla/Eacute/Ntilde/Odieresis/Udieresis/aacute  /agrave/acircumflex/adieresis/atilde/aring/ccedilla/eacute/egrave  /ecircumflex/edieresis/iacute/igrave/icircumflex/idieresis/ntilde/oacute  /ograve/ocircumflex/odieresis/otilde/uacute/ugrave/ucircumflex/udieresis  /dagger/degree/cent/sterling/section/bullet/paragraph/germandbls  /registered/copyright/trademark/acute/dieresis/notequal/AE/Oslash  /infinity/plusminus/lessequal/greaterequal/yen/mu/partialdiff/summation  /product/pi/integral/ordfeminine/ordmasculine/Omega/ae/oslash  /questiondown/exclamdown/logicalnot/radical/florin/approxequal/Delta/  guillemotleft  /guillemotright/ellipsis/space/Agrave/Atilde/Otilde/OE/oe  /endash/emdash/quotedblleft/quotedblright/quoteleft/quoteright/divide/  lozenge  /ydieresis/Ydieresis/fraction/Euro/guilsinglleft/guilsinglright/fi/fl  /daggerdbl/periodcentered/quotesinglbase/quotedblbase/perthousand  /Acircumflex/Ecircumflex/Aacute/Edieresis/Egrave/Iacute/Icircumflex/  Idieresis/Igrave  /Oacute/Ocircumflex/apple/Ograve/Uacute/Ucircumflex/Ugrave/dotlessi/  circumflex/tilde  /macron/breve/dotaccent/ring/cedilla/hungarumlaut/ogonek/caron 

The PostScript File

The PostScript code is contained in a PostScript file. You create this PostScript file by printing (or saving) a file to disk rather than sending it directly to a printer. A PostScript file, although it is straight ASCII and can be edited within a plain-text editor, will typically have a .ps (Macintosh) or .prn (Windows) file extension.

The PostScript Printer Driver

A little known and understood but very important part of the PDF workflow is the printer driver used to output your document file. The printer driver ultimately determines the final code that is placed in the print/save to disk file. It is imperative that you begin your document construction process by choosing a PostScript printer driver rather than a non-PostScript printer driver before you start constructing your document. The reason for this is twofold:

• The printer driver will determine the code that leaves your document when you print or save a file to disk.

• Printer drivers work backward as well as forward ”that is, they feed document information such as page size and margins back into the document. If you wait until after your document is constructed to choose a PostScript printer driver, you may receive a rude awakening when your document is reformatted before your eyes and document elements such as text and graphic boxes are relocated on your page.

Note  

Windows users should pay special attention to this, because the default printer driver is a nonPostScript printer driver. I keep a Post-it note on my Windows monitor that reads Printer Driver! to remind me to select a PostScript printer driver prior to creating my documents.

Printer drivers are located in various places depending upon which computer operating system you are using. If you are working on Mac OS version 9.2 or earlier, you will find the printer drivers listed in the Chooser under the Apple menu. In Mac OS X you select the printer driver in the Printer utility, and in Windows XP you do so through the Printer And Faxes control panel. Some versions of operating systems also allow you to change printer drivers through the Page Setup and Print dialog boxes. Check to see which of these accesses work for you.

Figure 1.3 shows several versions of printer drivers that I have on one of my Macs (OS 9.2). Note that I have placed the version number labels on each icon. The reason for this is that some versions of printer drivers produce better PostScript code than other printer drivers. The version of PostScript created becomes increasingly important as the complexity of printing you intend to perform increases . When you are engaged in high-resolution, color -separated PostScript printing at a commercial print shop, the version of PostScript you use may make the difference between a job printing properly or not at all.

Figure 1.3: PostScript printer driver versions

Note  

Along with selecting the proper PostScript printer driver, you must also use the proper a PPD (PostScript Printer Description) file that matches your output device. For instance, even if the correct PostScript driver is selected (like AdobePS), if the PPD that is selected in the native program is a grayscale printer (like Laserwriter II), the resulting PDF may have most or all of the graphics rendered in grayscale.

You can download PostScript printer drivers for free from the Adobe website, www.adobe.com.

Note  

If you intend to send your PDF files to a commercial printer, get their recommendation as to which PostScript printer driver to use.