Format: Acrobat and PDF tips
These are extracts from the FORMAT NEWSLETTER
INS AND OUTS OF PDF
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If you are responsible for creating PDFs for publishing or printing, or for specifying how such files should be produced, you will find <http://www.direct2.time.com/> valuable reading. It covers to the creation and submission of files for use in Time Inc. titles. Many printers have problems with the files that are sent to them to be printed. Time has established strict requirements to eliminate many of the potential pitfalls in digital file preparation. While they focus attention on exchanging digital advertisements readers can learn a lot about electronic of files.
Time endorses and uses the DDAP specification. The DDAP Association, <http://www.digitaldocumentspanel.com> is working towards enabling a universal system for the exchange of digital ads. Time also allows you access to procedure manuals showing the new printing workflow.
Time used to insist on TIFF/IT format, an extension of the TIFF specification which adds a vector specification to the TIFF raster format (in other words, it is, in old terms, a combined line and tone specification. The programs and plugins to work with TIFF/IT are expensive, but then Time's advertisers are at the top end of the market, and so are their agents. Last month, Time told its printers that June 1st was the target for delivering all content in PDF/X-1a.
What Is PDF/X-1a?
It is a subset of Adobe's Portable Document Format (PDF). PDF/X1a stands for PDF eXchange 1a. The "1" means that it is a blind exchange document -- all fonts and images are embedded and "a" is the variant that was ISO accredited to standard ISO15930-1 :2001.
PDF/X1a meets the following specifications:
- All fonts and images are embedded.
- All elements are encoded as CMYK, spot or Device N.
- They may not be encoded as three-art color spaces such as RGB or CIELab.
- The MediaBox and TrimBox or ArtBox are defined. - Trap must be indicated as on or off, alerting the printer to the condition of the document. The printing condition characterized (such as SWOP) through the use of an Output intents operator.
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"AutoPilot" is the way long time print system suppliers Callas are planning PDF workflow -- from creating PDF files, preflighting, modifying, trapping, to proofing and printing, but in an open format so that the user can decide what steps to implement. A list on AutoPilot compliant products as well as the White Paper on automating PDF workflows is on the Callas website: <http://www.callas.de/>. It is in the upper price range -- US$2000 per server -- with individual parts available separately, priced upwards from a free usable demo version of pdfInspektor2.
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Another of those solutions without logic: The latest Acrobat Reader under Mac OSX may not allow you to double click to open a second file after the first has been read. You need to use the Open dialog box. The answer? Select any PDF file, and in the Finder select "Show Info". From the pop-up menu select "Open with application" and in the list of applications you should see two entries for Acrobat Reader. Select Acrobat Reader 5.0 (5.0) NOT Acrobat Reader 5.0 (5.0.5) and then click the "Change all" button. Ignore all dialogs prompting you to set Acrobat Reader 5.0 (5.0.5) as you default PDF "open with" application. It seems OS X thinks two versions of Acrobat Reader are installed even though you have only one, and then you need to select the one which you don't have installed.
KEEP A WATCH ON NESTED PDF FILES
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Some good advice from Olav Kvern of Adobe in a recent posting to the Blueworld InDesign mailing list
<http://www.listsearch.com/indesigntalk.lasso?manage>: Remember how you shouldn't "nest" an EPS inside an EPS inside an EPS, because you'll run into PostScript limitcheck errors? The same is true for PDF--only more so--I've found that you exceed the PostScript language implementation limit of 15 save levels (see page 739 of the PostScript Language Reference Manual, 3rd Edition) *very* quickly when using nested PDF. It only takes about 4 "generations" of PDF encapsulation before you hit it.
In other words, PDF export from InDesign does not "flatten" the PDF save level, as creating a file by running it through the Distiller will. If you're at risk of exceeding the implementation limits on a page, export the page as a prepress file, then create a PDF using the Distiller--this will flatten the page contents back to a single save level (or thereabouts). If you have already exceeded the implementation limit, the Distiller, like any other PostScript RIP, will generate an error.
In short: placing PDF good, nesting PDFs bad.
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There is a small arrow in the upper right-hand corner of Acrobat 5 Reader which when clicked on will show you a short drop-down list that includes "fonts". Selecting fonts will show you what's embedded (or not) and the type of font.
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Callas Software have launched a beta version of "pdfInspektor2", a preflight tool that now includes a wider analysis of PDF files. As well as running as a plugin for Acrobat 4.05 or 5, it can be integrated in the Callas suite of production tools and can run as part of a fully automated production workflow. It ranges in price from US$149 upwards for 3 versions. Windows version available now, Mac version soon. Details at <http://www.callas.de/>
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PLACING MULTI-PAGE PDF FILES
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Placing multiple-page PDFs seem to cause heartaches for many in publishing. In recent days we've seen reports of a problem with the QuarkXPress PDF filter that if you update links, the links may update to the first page of the PDF rather than to the chosen page. It was an error found by others but not reproducible by all.
In PageMaker the PDF filter can't be scripted, so if you have a lot of reproductions from multiple page PDFs, it may be easier to export as EPS files from Acrobat. This will create a separate EPS for each page, with a consistent naming format that should enable the placing process to be scripted.
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In response to a question about how to tell if graphics in an ad supplied as a PDF are RGB or CMYK, and what resolution, we pointed Nick Morenos of Fruit Tree Media to <http://www.PDFzone.com> as a source for many PDF plugins. We suggested he look at CheckUp from Enfocus. He replied: "Thanks for your quick reply to my question. I went to the pdfzone and discovered a little gem of a freebee from Enfocus called EyeDropper which 'is an Adobe Acrobat plug-in that provides a tool to accurately measure the color of a point on a page. Enfocus EyeDropper uses the color information specified within the PDF page description, not the on-screen RGB color.'
"This little plug in gets me one step closer to identifying if a PDF is ready for print or not -- if it's RGB it's No ... Good. Top Stuff, and it would have saved me a major headache only a couple of days ago - if only I had it then...
"Many thanks. If you think this little bit of info will be of value to anyone else I'd be more than happy if you passed it on."
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An Acrobat hint from the PDF list run by PDFzone.com <http://www.pdfzone.com>: You can create different watched folders for each printer setup and assign them the desired distiller job option. Then, all you have to do is save the PS file to the correct folder. Distiller will know what kind of PDF (screen, press-optmized, etc.) to make from PS files dropped in that folder, based on the job option assigned to it.
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One more reason for always sending a clearly marked fax or hard copy of an ad even in this electronic age: A designer reports sending a PDF of an ad cropped right on the outer box of the ad using Acrobat's crop function, but which was printed reduced in size so that the whole uncropped area was used -- giving a large white border. Some layout programs give an option on PDF import to select either the whole area or the copy, and it seems likely the person bringing it into the page made the wrong selection. It is easy to do.
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You can also use Acrobat's crop function to create tiles for printing a large page to a small printer.
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