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Distiller and PDF Writer

Once you get used to the idea of reading on screen - and you'll have to if you want to get the best out of on-line options such as email and the World Wide Web - it begins to make sense to not print everything to paper. And these two options also offer another possibility that many businesses are exploring, namely distributing documents inexpensively to internal and external audiences.

Two utilities from Adobe can be used to create PDF files: PDF Writer and Acrobat Distiller. These are provided in the Acrobat Pro package that also includes software to manipulate PDF files after processing, and PostScript Printer Drivers (PPD) for non-Adobe applications like QuarkXPress. These PPDs make the task of producing PDF files even easier since they override the attached printer's page setup specifications and provide additional Acrobat options, such as screen sizes and screen values.

You can also use any of Adobe's own applications, such as Illustrator 6 and PageMaker 6, which have built-in functions to Save As... or export to PDF format.

Both Distiller and PDF Writer are capable of including (called embedding) fonts and compressing images and text. Yet the fundamental difference between these tools lies in the content they work with: Distiller uses PostScript and PDF Writer uses QuickDraw output.

Fonts and images

A PDF file can contain basic font data - such as whether the font is a serif or sans serif (Acrobat does not appear to recognise any other type form, for example scripts). This basic data ignores the subtle difference between the actual fonts, instead displaying in either a Times or Helvetica look-alike font (called Acrobat Multiple Masters) but displays the text precisely as it has been set. Embedding a font in a PDF file causes the font to be displayed (and printed) exactly as it would if the font existed on another computer. Should you embed fonts into a PDF file? That depends on how it will be used.

Obviously, including fonts will boost the file size, not very practical when for instance distributing documents via the Internet. The end purpose of a PDF file (is it to be printed? or viewed on screen?) will also help you to decide which fonts to use. Some fonts, like New Century Schoolbook set at 10 points, do not display as cleanly on screen as they do on paper, so the reader may be forced to increase the view scale of a document. The fonts that work best (and also take up the least amount of room in a PDF file) are sans serifs; my personal preference is Geneva set at10 points.

The most obvious way around the file size issue for embedded fonts is to use a limited number of fonts in a document (the old "one or two fonts to a page" rule for design), or to choose fonts that have small PostScript files. Of course, you can also choose to avoid the issue by not embedding fonts in a PDF file, but this means the Reader on a remote computer will use Multiple Master fonts to display the text. Ultimately, the decision to embed fonts in a PDF depends on the importance of the design of text.

Compression options include JPEG and LZW compression for colour images and additional CCITT compression options for monochrome images. Your choice of image compression will have an effect not only on the finished size of the file, but also on the colours displayed in the contents.

The differences

PDF Writer is recommended for printing from non-PostScript applications. Text-intensive documents, especially those created with TrueType fonts, are the main types of document to process with the PDF Writer. The PDF Writer driver is selected in the Chooser, just like any other driver option, and used to process the output from an application.

The advantage of PDF Writer lies in its speed of production. Documents are simply "printed" to the driver and appear as Acrobat Reader documents. PDF Writer offers similar options to Distiller, though these are divided between its Page setup... and Print dialogue boxes: including options for selecting particular page sizes, the inclusion of document information (which is harder to assign in Distiller) and a check box for ensuring file names comply with DOS constraints.

PDF Writer does have some drawbacks. Files tend to be larger than those created from PostScript output; especially when a file contains images. This is partly because a document is not processed as PostScript and thus some elements must be recreated from bitmapped screen versions. For instance, when an EPS image is imported into some documents, the original file is linked and a screen image is displayed on the page. When PDF Writer processes the document, it ignores the linked file and uses the screen version instead. If you want to display the crispest version of an image, PDF Writer does not provide the best solution.

Distiller is the better utility for creating PDF files that contain PostScript data, such as EPS artwork, blends or graduations and PostScript fonts. The process is as easy as selecting a PS file and letting Distiller do its thing. Processing times vary, but most of the large (15Mb) files I tested took only a few minutes.

Creating a PDF from PostScript

There is nothing new to learn to create a PDF file from an application. The major difference between the way you probably work now and the new way is that instead of printing to paper, the output will remain on your hard disk as a rather large file, which will shortly be much reduced in size when passed through Distiller.

Most applications have a "File" function in the print dialogue box. If a PostScript printer driver is selected in the Chooser, documents can be saved as PostScript to disk. You don't even need a printer connected to your system, since no information is transferred past the printer driver. The next step is to launch Distiller, open the PostScript output file, process it and create a file with the same name and the extension ".pdf". (If you rename a PDF file it should always contain this extension, otherwise it can cause problems for some applications - like Netscape - and non-Mac operating systems.)

Most of Adobe's products offer an almost seamless method for creating PDF files. Illustrator 6, for example, allows you to select the PDF file format in the Save As... dialogue box. (It is strange though that the PDF version is shown as 1.1, when the most recent release version is 2.1). Illustrator's advantage is that PDF files can be re-opened and individual pages manipulated as long as you have the correct fonts installed. PageMaker also offers powerful options for creating PDF files, including table of contents and indexing features, linked articles and attaching notes to pages. These are available in a dialogue box called "Create Adobe PDF" in the File menu.

Smart working is easy

Where PDF Writer is a single process utility - you run it for each file - Distiller offers alternatives for batch processing multiple files. Distiller can take a few moments to load and requires 8Mb of RAM to run. Unless you are swamped with RAM, it can be difficult to run other applications concurrently. For example, for one series of documents I used Adobe Illustrator, QuarkXPress and Adobe ScreenReady: applications that interact as a set but that require chunks of RAM.

Since Distiller is only required at the end of a series of "printouts" it was not necessary to have it running in the background. When all the PS files had been created, I quit two of the other applications, launched Distiller and went and made coffee! When I returned Distiller had finished the job. That's because you can set Distiller to watch a set of folders and automatically process the contents, deleting the PS files when they have been distilled.

Afterwards?

The PDF files created with PDF Writer or Distiller may not always contain all the elements you want in a file. For example, it is difficult to include QuickTime movies in the PS file processed by Distiller. It is also equally difficult to get Distiller to recognise a custom page size and the PDF file might easily have badly cropped pages.

Or you may decide to combine two or more PDF files into one, or swap pages between files.

While Illustrator allows you to include some of these options in individual pages, it is hardly the most useful solution. Instead, Adobe has produced a special application called Acrobat Exchange and in the next article, I will introduce some of the exciting possibilities for modifying PDF files.