In some print publishing workflows, documents are distributed in the format of the authoring application (called the native format). Once approved, the files are saved in PostScript or a proprietary format for prepress work and final printing. Because applications generate PostScript in many different ways, PostScript files can be arbitrarily large and complex. In addition, reliability problems such as missing fonts, corrupt files, missing graphic elements, and unsupported features can result at output time. In response, Adobe and its partners continue to create reliable, PDF-based publishing workflow solutions.
From InDesign, you can export your document to a composite PDF file called a digital master. These digital masters are compact, reliable files that you or your service provider can view, edit, organize, and proof. Then, at the appropriate time in the workflow, your service provider can either output the PDF directly, or process it using tools from various sources for post-processing tasks such as preflight checks, trapping, imposition, and color separation.
PDF files in the workflow
Many large publishers use PDFs to streamline their review and production cycles. For example, numerous magazines and newspapers have adopted PDF as the standard format for delivering advertisements to local publishing offices via satellite or ISDN lines. PDFs enable local publishers to instantly view an advertisement exactly as it was designed, make late-stage text edits, and reliably print from any computer.
PDF workflow technologies and requirements
Adobe is continually addressing the workflow needs of service providers, and recommends that you visit the Adobe website at www.adobe.com often for the latest developments. Currently, Adobe addresses publishing workflow needs by providing an integrated system of several technologies:
Adobe Acrobat 9, with its support for Adobe PDF version 1.7.
Adobe PostScript 3 printing technology, for device-independent support, Adobe In-RIP Trapping, in-RIP color separations, and smooth blends.
Adobe InDesign CS4, with its high-resolution page layout capabilities and direct PDF processing.
PDF/X, an ISO standard for graphic content exchange that eliminates many of the color, font, and trapping variables that lead to printing problems.
A high-resolution composite PDF workflow typically includes a PostScript 3 output device whose RIP supports in-RIP separations. Therefore, if your output device uses PostScript Level 2 or does not support in-RIP separations, use a preseparated PostScript printing workflow.
Before creating a PDF for a service provider, make sure that the InDesign document meets your service provider’s specifications. The following list offers some recommendations:
Use the InDesign Preflight feature to ensure that image resolution and color spaces are correct, that fonts are available and can be embedded, that graphics are up-to-date, and so on.
View your Adobe PDF export settings before exporting, and then adjust them as necessary. The Summary area includes a warning section that indicates when preset settings can’t be honored.
If your artwork contains transparency (including overprints and drop shadows) and you require high‑resolution output, it’s a good idea to preview the effects of flattening using the Flattener Preview panel before saving the file.
If your artwork contains transparency, ask your prepress service provider if they want to receive flattened or unflattened PDF files. Flattening is performed as late in the workflow as possible, preferably by the service provider. However, if your service provider wants you to flatten transparency, submit a PDF/X‑1a compliant file.
If your document is going to be separated, you can preview the separations and ink coverage limits using the Separations Preview panel.
Use only high-resolution images in your document.
For best results, use only CMYK images in a four-color-process job. Alternatively, you can choose to convert RGB images to CMYK in the Export Adobe PDF dialog box (Output category).
You can exclude hidden or nonprinting layers from the exported PDF document. (See Choose which layers are printed or exported to PDF.)
For detailed information about preparing InDesign documents for high-resolution PDF output, see the Adobe InDesign CS Printing Guide for Prepress Service Providers.
PDF Print Engine printer manufactures release new drivers based on Adobe PDFDriver SDK which have the capabilities of handling PDF in the pass-through mode. When such a printer is selected via InDesign, its PPD can indicate that it is a PDF printer (depends on the Printer manufacturer).
Since InDesign can generate a high-quality PDF via PDF export, printing to a PDF printer leverages that functionality, and this high quality PDF is passed on to the printer, rather than via intermediate postscript route.
In general, print quality from applications through PDF Driver is equivalent to (or better than) PostScript printing. PDF printing through the Adobe PDF printer also supports live transparency and ICC color management. At InDesign print dialog, options related to Color Management, Color Separation, and Graphics options are disabled because all the color management operations are done on the device for better quality printout.
Composite Leave Unchanged is selected by default and it can’t be changed.
A service provider can use Acrobat 7.0 Professional and later to perform preflight checks and color separations. Subsequent versions of Acrobat Professional contain more advanced preflight tools, including the ability to make certain corrections automatically. Various prepress applications and in-RIP technologies can also perform preflight checks, do trapping and imposition, and make the color separations of the pages in the digital master.
If you choose to leave out the images when creating the Adobe PDF file, make sure that the service provider has access to the original high-resolution images that are required for proper output. In addition, make sure that the service provider has Acrobat 7.0 or later for accurate viewing of text and color graphics. For best viewing, use Acrobat 8 Professional or later.
If you’re using a color-managed workflow, you can use the precision of color profiles to perform an onscreen preview (a soft proof). You can examine how your document’s colors look when reproduced on a particular output device.
Unless you are using a color management system (CMS) with accurately calibrated ICC profiles and are sure that you have properly calibrated your monitor, don’t rely on the on‑screen appearance of colors.