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PDF (Portable Document Format) is a digital format that enhances the production workflow. In prepress, PDF has many advantages over older formats such as PostScript.
A PDF file, like a PostScript file, contains data about included images and a description of their placement on the page. Because images (such as TIFFs or JPEGs) and fonts are embedded in the PDF file, the common problem of documents being sent to prepress without their associated files can be avoided.
A file that has been “distilled” into PDF has already been partially preflighted because any missing fonts or graphics have been identified during the process. However, saving a file as a PDF will not fix a poorly constructed page. The final PDF document can also be viewed on screen, presenting the opportunity to inspect for missing fonts or images and giving a good impression of how the page will look when it is output.
Another pre-processing benefit of PDF is its ability to clean-up PostScript files. When a PostScript file is converted to PDF, it is rewritten into a structure that optimizes the PostScript to output with greater page independence. While this does not guarantee that the PostScript will now RIP properly, it helps eliminate many processing surprises. Prepress houses and printers have found that distilling PostScript to PDF often eliminates some of the problems that cause files not to run.
PDF is the only format that allows pages to be processed independently of one another, allowing document pages to be recombined to create new products and facilitating easy movement of jobs among impositions and presses.
PDF files are also less troublesome to RIP, in part because a PDF packages the instructions and definitions needed to image within each page unit, not at the start of a long document as do PostScript files. Finally, PDF files are often smaller than PostScript files so they save on network processing and archiving resources.
Another plus of PDF within the offset printing workflow is that it is “device independent”; file creators do not need to designate any specific output device. A PDF file can be sent to multiple types of output devices: high-end proofers, imagesetters, or platesetters. Therefore, an archived file can be printed to a device other than that for which it was first intended, making the production of reprints easier, faster, and more economical.
Today PDF is RR Donnelley’s preferred format for one-, two-, and four-color jobs. Sophisticated color management, trapping, and color separating are fully compatible with the PDF workflow. Adobe’s Acrobat software is the primary tool for making PDF files, and Acrobat’s Distiller module can convert any standard PostScript file to PDF.
PDF’s uses also extend beyond print. When introduced in 1993, PDF was considered a non-print format primarily for screen display, allowing users of non-compatible systems or software to view each other’s documents. In today’s environment, this viewability feature enables PDF files to be utilized for CD-ROM or web site development. PDF evolution has seen the addition of keyword searchability, bookmarking, annotation, and forms capabilities, lending the potential for interactivity to the final PDF document.
PDFs are excellent candidates for digital file transfer because internal compression of the format reduces a file’s size. Plus, the critical font and art elements that make up the document can be embedded into a complete cross-platform package. PDF is also an excellent format in which to archive, as files can be converted back to PostScript for output on virtually any commercial device.
For additional information, RR Donnelley recommends the excellent guides to the creation of PDF files found on Adobe’s web site at: www.adobe.com  .
A book’s journey through digital production can vary depending on the format in which the files were submitted. At RR Donnelley, all files are converted to PDF, which is then interpreted by imposition software that assembles the pages for correct signature folding on press.
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To learn more about how we can help you with your Book Printing needs, contact us by phone at 1.800.742.4455.
About Book DSCs, Insite, Guidelines, PDF Setup Instructions, Contacts http://prepress.rrd.com
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