PDF Research Adobe Acrobat Components...
|
|
|
|
|
|
|
Distiller...
Distiller is the most complete way to create a PDF file. It retains virtually all of the features of the original Postscript document, offers a range of options for compressing it, allows control over font embedding, and is simple to use. Distilling involves the following steps:
- Creating Postscript Files
- Setting Up a Watched Folder
- Setting Job Options
- Setting Advanced Prepress Job Options
- Dynamically Creating PDF files
In comparison to using PDF Writer, Distiller is used for documents that:
- contain Encapsulated PostScript (EPS) graphics
- contain bitmap images for which you need to choose specific resampling and compression methods
- were produced from desktop publishing applications,such as QuarkXPress, Adobe PageMaker, and Adobe FrameMaker, that have been optimized to print to PostScript.
Below are the recommended procedures for distilling files to work as highly compressed files ideal for emailing and publishing to the web. These are the settings used for virtually all of the PDF files found on this site, for example.
For a complete AGFA tutorial on the subject of distilling files for pre-press applications, see Michael Jahn's (AGFA PDF Evangelist) .pdf document on How to Distill.
1. Creating Postscript Files
The first step in Distilling is to save documents into the Postscript page description language. Usually this is accomplished by using the Print command and specifying Postscript instead of a printer. It is critical to realize that the print driver that you use to create your postscript file will determine its color and size characteristics. The safest procedure is to use PSPrinter or AdobePS as the print driver and Acrobat Distiller as the Printer Type. It is a good idea to include registration marks (in Quark Xpress for example) because these can be used to accurately crop your final PDF pages in Exchange later.
Adobe has released a plug-in for AdobePS Printer 8.5.1 (PDF Printer Driver Plug-in) that automates the Distilling procedure by adding PDF options to your print dialog boxes.
When presented with the dialog box options, be sure to specify Binary. Specifying will slow down the process by creating a larger file. One might select ASCII if they wanted to open and examine a PDF file in a text editor such as MacSink or BBEdit.
In general, always choose Font Inclusion ALL. This will insure that you will have the most options for font embedding into the PDF file - important for editing text in PDF files later.
2. Setting Up a Watched Folder (Optional)
Once the Postscript file has been made, open Distiller.
A powerful option is to have Distiller work in the
background. The user can set up Watched Folders in the
Distiller Menu. The program will periodically check any of
up to 100 folders on a server for distilling purposes and
separate settings can be designated for different PDF types
("Low Res" vs. "High Res" for example). When it finds a file
its hasn't converted, it will automatically process them and
move them to an Out Folder.
There is a technique for distilling multiple postscript files into a single PDF file. Look in Distiller Help for information on the RunFile procedure utilizing Rundirex.txt. This is a Distiller Xtra (packaged with Distiller).
3. Setting Job Options
General
In Acrobat Distiller's Job Options "General" tab, select the "Acrobat 3.0" option from the pop-up menu for Compatibility.
Again, do not select the box for "ASCII Format".
In the Device Settings section, enter the resolution (dpi) of the PDF file's final output device in the Default Resolution text box. This will affect only vector EPS files which might contain device resolution dependent elements, such as gradients or blends.
You can ignore the Default Page Size option. Distiller only uses the values you enter in these text boxes when a PostScript file doesn't include a paper size.
Compression
In Distiller's Compression Tab are the controls which affect file size and image quality. Leave Compress Text And Line Art option selected (vector EPS graphics); this compression is lossless and has no effect on quality.
For creating files small enough to use as a compressed, portable digital graphic for use on web sites and transferrable via email we recommend using a minimum setting of 72dpi ro compressing all images. If you need lossless compression at a higher resolution, then by all means increase the units. Because all compression choices for Monochrome images are lossless, we also recommend selecting CCITT Group 4. This usually results in the smallest file sizes.
Font Embedding
Distiller never embeds the Base 13 fonts (the Helvetica, Times, Courier, and Symbol font families) because these fonts are included in all PostScript devices. Select the Embed All Fonts so that Distiller includes all fonts used in the document in the PDF file.
The Subset Fonts below affects the editability of the file in Exchange. If you think that the end user (who may be yourself) will someday want to edit the file without having to go through the distilling process again, you should make sure that the entire character set for each embedded font is included in the file. Accomplish this by simply not checking the Subset Fonts below box (as shown).
On the other hand, if you are positive that the end user will never have to edit your file, subsetting fonts will reduce the size of the file. It will embed only those characters that are used in the font of the file. To accomplish this, it is customary to specify 99% and check the box. This means that even if 99% of each of the embedded fonts' characters are used in the document, only those characters used will be included.
4. Setting Advanced Prepress Job Options
For the latest information on emerging PDF Workflows for pre-press, check out Adobe's PDF Workflows reference site. Currently (10/98) this site contains four references:
- PDF for Prepress Workflow and Document Delivery White Paper (64K, 8 pages)
- Creating High Resolution PDF Files for Macintosh (2.1Mb, 26 pages)
- Creating High Resolution PDF Files for Windows (2.4 Mb, 25 pages)
- Creating High Resolution PDF Files for Prepress Production (185K, 12 pages)
Distilling files for maximum compression generally means that you will not need to set Advanced options, except perhaps to confirm that all CMYK images will be converted to RGB. The rest of the settings of this dialog box have to do with the needs of Service Bureaus and users who are sending PDF files to RIPs for color separation or pre-press output. For these advanced cases, we refer you to Michael Jahn's website and his description of steps to use to distilled advanced PDF files.
Now you are ready to OK distilling the file. Proceed to Exchange.
5. Dynamically Creating PDF files
It is possible to create PDF files dynamically using C routines. This is terrific for the web because is allows the web designer to devise interfaces that allows the user to dynamically generate PDF documents the same way that HTML pages can be generated using CGI scripts.
There is a library of C routines (PDFlib) already written contained on a CD-ROM disk that accompanies Tom Merz' book Web Publishing with Acrobat/PDF (Springer-Verlag 1997). A description of PDFlib as described by the author:
"PDFlib features
The PDFlib API offers the following major features:
- PDF documents of arbitrary length and page formats
- text output in different fonts
- the ability to embed PostScript font descriptions
- common vector graphics primitives ­ lines, curves, arcs, rectangles, etc.
- read PostScript font metrics from AFM files
- process common graphics file formats, e.g. TIFF, GIF, JPEG
- generate hypertext elements such as bookmarks
- features supported in PDF but not accessible in Acrobat software, e.g., page transition effects like shades and mosaic.
All of these may be achieved by using a simple API without the application programmer being directly involved with PDF objects or operators.
New: as of version 0.6, PDFlib can also be used from Perl, Tcl, and Python scripts (with a little help from SWIG).
What can I use PDFlib for?
PDFlib's primary target is creating dynamic PDF on the World Wide Web. Similar to HTML pages dynamically generated with a CGI script on the Web server, you may use a PDFlib program for dynamically generating PDF reflecting user input or some other dynamic data, e.g. data retrieved from the Web server's database. The PDFlib approach offers several advantages as opposed to creating PDF from PostScript files with Acrobat Distiller:
- The PDFlib "driver" can be integrated directly in the application generating (or otherwise handling) the data, eliminating the convoluted creation path application­PostScript­Acrobat Distiller­PDF.
- As an implication of this straightforward process, PDFlib is by far the fastest PDF-generating method, making it perfectly suited for the Web.
- PDFs need not be created ahead of time and stored on the server, but can be generated if needed. This is a big win not only if you want to deal with dynamic data which do not exist prior to the Web interaction, but also if large amounts of data have to be handled which make it impractical to pre-generate all the necessary PDF.
However, PDFlib is not restricted to dynamic PDF on the Web. Equally important are all kinds of converters from X to PDF, where X represents any text or graphics file format. Again, this replaces the sequence X­PostScript­PDF with simply X­PDF, which offers many advantages for some common graphics file formats like GIF or JPEG. Using such a PDF converter, batch converting lots of text or graphics files is much easier than using the Adobe Acrobat suite of programs. Several converters of this kind are supplied with the library."
|
a production of Performance Graphics ©1998 The Miller De Wulf Corporation |