Preflighting, Correcting, and Printing PDF Files

As we discuss in Chapter 14, "Creating and Using PDF Files," many print service providers now accept and even prefer PDF files for print workflows. For a print service provider, outputting from PDF files can offer workflow advantages over application files. When receiving application files, here are some examples of common events that can interrupt the workflow:

• The application version that the print service provider uses doesn't match the customer's, which can cause confusion or output errors.

• The customer's job waits while the customer sends missing assets, like fonts or graphics, not included when the job was submitted (or if the customer initially sent the wrong assets).

• The print service provider's inexperienced staff sometimes doesn't understand the complexities of the application's print settings, causing the job to be re-run.

When properly created, a PDF file includes all the job assetsincluding fonts and graphicsin a single package. For a print service provider who has invested in creating an up-to-date workflow, printing from supplied PDF files creates a simpler process, bypassing many of the problems of receiving application files.

In this section, we describe some of the features of Acrobat 7.0 Professional that make this simpler process possible. We discuss how to preflight PDF files, how to correct many of the problems they may contain, and how to use some of Acrobat's advanced printing features.

Preflighting PDF Files

Acrobat 7.0 Professional includes a professional-level preflighting tool to check whether PDF files meet specific criteria that are required for the intended output and that work with your workflow. Typically, a print service provider uses this tool to check files coming from a customer, but anyone who uses the Creative Suite can use this tool. A creative professional could use it to check for transparency or RGB images in a PDF file, for example.

To open the Preflight tool, choose Tools > Print Production > Preflight, or click the Preflight icon on the Print Production toolbar that we discuss in the next section. The Preflight dialog box appears (Figure 16-33, left). Selecting a profile displays its purpose at the bottom of the dialog box. Many of the profiles have been created to reflect "best practices" for certain segments of the print industry.

Figure 16-33. Use the Preflight dialog box in Acrobat 7.0 Professional to select a profile to preflight a PDF file (left). The results indicate conditions which cause the preflight to fail (right).

To preflight a PDF file, select a profile in the Preflight dialog box, and click the Execute button. After a few moments, the Results panel appears (Figure 16-32, right). Conditions which cause the preflight to fail are marked with a red X. In the illustration, when a PDF/X-1a profile was run, the preflight failed because it contained colors other than CMYK and spot colors, and contained two instances of transparency. None of these is allowed by the PDF/X-1a standard. You can create a droplet (a mini-application) to preflight files (see "Droplets in Acrobat 7.0 Professional" in Chapter 15, "Automating Your Work").

To view or edit a profile, click the Edit button in the Preflight dialog box. The Preflight: Edit Profile dialog box appears. Since the profiles are locked by default, the best way to customize a profile is to click the Duplicate Profile button. You can then edit any of the conditions checked in the profile, and save the profile under a new name.

Previewing and Correcting PDF Files

In addition to preflighting, Acrobat 7.0 Professional includes a group of production-oriented tools for previewing and correcting PDF files so they will work in your print workflow. You can select tools individually by choosing Tools > Print Production, but the easiest way to use them is to open the Print Production toolbar (Figure 16-34). To do this, choose Tools > Print Production > Show Print Production Toolbar, or Control/right-click the Acrobat main toolbar to choose it from the context menu. We describe the primary PDF previewing and correction tools in this section. The PDF Optimizer tool is also found on this toolbar. We discuss this tool in the "Repurposing PDF Files" section of Chapter 14, "Creating and Using PDF Files."

Figure 16-34. Opening the Print Production toolbar in Acrobat makes its PDF correction tools quickly accessible.

Previewing Output

The Output Preview tool provides the same functions as the InDesign Separation Preview feature, but combines them with a soft preview, color warnings, access to an Ink Manager feature, and a color space preview. To use it, click the tool on the Print Production toolbar, or choose Tools > Print Production > Output Preview. In the Output Preview palette that appears, the Preview menu toggles between showing Separations Preview and Color Warnings.

Selecting Separations in the Preview menu (Figure 16-35, left), displays a Separations Preview feature similar to that in InDesign. Choose from these features:

• Use the cursor as a densitometer to view the color values underneath your cursor as you move it around the document window. It's analogous to using the Info palette to show color values when viewing a Photoshop image.

• Change color plate visibility by clicking plates on and off.

• Check the Total Ink Coverage option to show ink values similar to the InDesign Ink Limit display: Areas of the PDF document with ink values over the limit specified are shown in a highlight color.

• Soft proof a PDF document by selecting a Simulation Profile at the top of the palette. The Simulate Ink Black option previews the ink's dynamic range defined by the profile. The Simulate Paper White option previews the white of the paper described by the profile.

• Access the Ink Manager (described in the next section).

• Unique to Acrobat, you can choose a color space, such as RGB, from the Show menu. Only objects using that color space are displayed. You can use this to view any RGB images in your PDF file, for example. Choosing All from the Show menu displays all objects on the displayed pages.

Figure 16-35. The Output Preview dialog box in Acrobat 7.0 Professional, showing Separations Preview (left) and Color Warnings (right).

When you choose Color Warnings in the Preview menu (Figure 16-34, right), you see other choices in the Output Preview palette: Then you can check Show Overprinting to preview objects with the overprint attribute set, indicated in a highlight color. If you check Rich Black, areas will be highlighted where black is mixed with color inks. This is particularly useful for highlighting rich black text, which can cause problems on press.

Acrobat Ink Manager

Acrobat has an Ink Manager feature very similar to that in InDesign. To use it, click the Ink Manager tool in the Print Production toolbar, or click the Ink Manager button in Output Preview to display the Ink Manager dialog box (Figure 16-36). You can also access the Ink Manager from the Advanced Print Setup dialog box (described in the following section, "Advanced PDF Printing Features"). Use the dialog box to select which inks to output from the PDF file, convert all or individual spot colors to process, or alias spot-color inks. Using the Ink Manager doesn't change the PDF file, but causes it to be output using the inks selected in the Ink Manager dialog box.

Figure 16-36. The Ink Manager dialog box in Acrobat 7.0 Professional.

Converting Colors

If your PDF file will be output as high-resolution color separations, you may want to convert objects to CMYK or another color space. You might need to do this, for example, if you need to color-separate a PDF file created in a Microsoft Office application that supports only RGB color output, not CMYK. You can do this with the Convert Colors tool in Acrobat 7.0 Professional: Click the Convert Colors tool on the Print Production toolbar, or choose Tools > Print Production > Convert Colors. The Convert Colors dialog box (Figure 16-37) displays all the color spaces present in the PDF document. It shows the results of any colors already converted or mapped with the Ink Manager. Depending on the color space you select, you can use the Action menu to preserve, convert, or map color values. When converting colors, you choose a destination ICC profile for the conversion. You can convert colors on one page or all pages. Color conversion can be complex: Choose Help > Complete Acrobat 7.0 Help for details.

Figure 16-37. The Convert Colors dialog box in Acrobat 7.0 Professional. The effect of converting and mapping spot colors in the Ink Manager are displayed.

Tip: Convert PDF files to Grayscale

In addition to converting color spaces to CMYK (the most common use of the Convert Colors feature), you can also convert PDF files to grayscale. To do this, select Gray Gamma 1.8 or Gray Gamma 2.2 as your destination profile in the Profile menu. (The gamma value affects how light or dark an image appears. Mac OS systems normally use a gamma of 1.8, which makes images appear lighter than on Windows systems, with a gamma of 2.2.)

Fixing Hairlines

Hairlines that are too thin to reproduce present another potential printing problem. The Fix Hairlines tool on the Print Production toolbar searches for most thin hairlines in a PDF document and replaces them with a heavier line weight of your choice. You can do this for a particular page or the entire document.

Adding Printer's Marks and Enlarging Pages

Another important part of a PDF workflow is specifying the page boundary boxes of PDF files. This is a part of the PDF specification that allows printing workflow systems and printing devices to detect the boundaries of printed jobs: Crop, Trim, Bleed, and Art boxes define these boundaries. (A printing workflow system is an integrated management system, which typically organizes page processing, proofing, trapping, and computer-to-film and computer-to-plate output.)

If a PDF document has been created in InDesign or another page-layout application with trims and bleeds, then Acrobat 7.0 Professional can recognize that information. However, sometimes PDF files are created from applications that don't support proper printers' marks and boundary boxes. Acrobat 7.0 Professional provides two tools that help you correct problems. For details, refer to Help > Complete Acrobat 7.0 Help.

• The Add Printer Marks tool lets you add printer's marks (trim marks, bleed marks, and so on) to one or more pages of a PDF file. Choose the Add Printer Marks tool on the Print Production toolbar to open the Add Printer Marks dialog box.

• The Crop Pages tool opens the Crop Pages dialog box. This lets you define the margins for Crop, Trim, Bleed, and Art boxes in a PDF file. You can also use the Crop Pages dialog box to change the page size of a PDF file, either for one page or all pages. Note that the Crop Pages tool does not permanently delete a selection, and what was cropped can be restored.

Previewing and Flattening Transparency

Files created with Acrobat 5.0, 6.0, or 7.0 compatibility can contain transparency.

The files must be flattened before printing, exporting as PostScript or EPS files, or using the PDF Optimizer tool to save to Acrobat 4.0 compatibility.

Acrobat provides a Flattener Preview feature similar to those in InDesign and Illustrator (described in "Controlling Transparency Flattening" earlier in the chapter). To choose the feature in Acrobat 7.0 Professional, select the Transparency Flattening tool on the Print Production toolbar. A Flattener Preview palette similar to that in Illustrator appears (Figure 16-38). The transparency settings and their preview are similar to those in InDesign and Illustrator. You can use the palette to view the effects of selecting different flattening settings. However, unlike InDesign and Illustrator, you can also use this palette to immediately flatten the PDF file and remove transparency.

Figure 16-38. Flattener Preview palette in Acrobat 7.0 Professional.

Another difference from the Flattener Preview features in InDesign and Illustrator is that Acrobat doesn't provide a way of setting transparency flattener presets. Instead, you must choose Flattener Settings manually. For high-resolution output, the recommended settings are as follows:

• Raster/Vector Balance slider at 100 (moved all the way to the right).

• Line Art and Text Resolution: 1200 ppi

• Gradient and Mesh Resolution: 300 ppi.

• Turn off other options unless needed. For the nitty-gritty details of how to use these controls, refer to the Adobe InDesign CS2 Printing Guide for Prepress Service Providers, found in the Technical Info folder of the CS2 Std Content CD of your installation CDs.

Acrobat 7.0 Professional lets you flatten transparency in three places:

• In the Flattener Preview palette, make the Flattener settings as we describe above. Select a page range, and click the Apply button at the bottom of the dialog box. Flattening will take place immediately, removing all transparency from the PDF file. This operation cannot be undone; Acrobat will save the file under a different name.

• In the PDF Optimizer dialog box, choose the Transparency panel. Choose from the same settings as in the Flattener Preview palette, and click OK. Flattening will take place immediately.

• In the Advanced Print Setup dialog box, as described in the same-named section, you can flatten transparency at the time of printing the PDF file.

Participating in a JDF Workflow

A new print workflow is gathering steam. For several years now, a consortium of graphic arts vendors and creative professionals have been developing the concept of a digital job ticket to replace the mishmash of paper-based systems used for processing print jobs. The device-independent, vendor-neutral format developed by the CIP4 consortium is called Job Definition Format (JDF). (See the following sidebar, "The CIP4 Consortium and JDF.") Using a digital job ticket can enable both creative professionals who create files and print service providers who receive them to reduce errors and improve communication.

The first manifestation of this new standard and workflow in Acrobat 7.0 Professional is the JDF Job Definition dialog box (Figure 16-39). Choose the JDF Job Definitions tool on the Print Production toolbar to open the dialog box. You use this dialog box to create a JDF file. In a typical JDF workflow, a print service provider would supply a JDF template, based on conversations with a customer about the specifications for a job. It would include PDF presets to be used with the job, preflight profiles, and as much information about the job as is known. The customer would add other information, for example, contact information about the employees who will be working on the job.

Figure 16-39. JDF Job Definition dialog box.

When it's time to submit the job to the print service provider, the customer clicks the Submit button. The JDF Acrobat plug-in then checks the PDF files submitted with the JDF file for consistency with the job definition in the JDF file (for example, the number of pages and page size). If an inconsistency occurs (for example, a different number of pages in the PDF than is described in the JDF template), the customer is alerted. Then the plug-in preflights the files using the embedded preflight profile. As a last step, it turns the file into a MIME package so that it can be transmitted over the Internet (or passed by other means) to the print service provider for output.

The CIP4 Consortium and JDF

CIP4 is the International Cooperation for the Integration of Processes in Prepress, Press and Postpress. It's an international operating standards body located in Switzerland. The purpose of the association is to encourage computer-based integration of all processes that have to be considered in the graphic arts industry, in particular the specification of standards, such as the Job Definition Format.

For more information about JDF, download a white paper with more information from the Adobe web site: www.adobe.com/products/jdf/pdfs/jdf-wp.pdf

Advanced PDF Printing Features

In the first versions of Acrobat, printing was something of an afterthought, useful only for printing to your office printer. High-resolution printing of color separations had to be handled by expensive third-party Acrobat plug-ins. Beginning with Acrobat 6.0 Professional, printing has been considerably beefed up, and Acrobat 7.0 Professional continues that trend.

Acrobat 7.0 Professional Print Dialog Box

The initial Acrobat Print dialog box seems pretty Spartan but has some useful controls (Figure 16-40). As you'd expect, you can select the page range to print in this dialog box. What's not obvious is that you can print noncontiguous pages. To do this, before opening the Print dialog box, click the tab of the Pages panel to open it. Then Shift-click or Command/Ctrl-click the desired page thumbnails on the panel to select them. When you open the Print dialog box, the Selected pages option will be chosen.

Figure 16-40. Print dialog box in Acrobat 7.0 Professional, showing Page Scaling options. By default, Acrobat reduces a PDF page to printer margins.

The most important option to look at is Page Scaling, shown in the illustration above. Acrobat's default setting is Reduce To Printer Margins. This has been designed for office workers to ensure their documents fit on the printed page. This default has tripped up many a graphic artist who is left wondering how a page layout got reduced when printed. For high-resolution output, None would be a much better choice. Other useful options are Tile Large Pages and Tile All Pages. When you choose these options, additional choices become available for Tile Scale, Overlap, Cut Marks, and Labels. You can also select Multiple Pages Per Sheet, which lets you save paper and print page thumbnails. When the Multiple Pages Per Sheet option is chosen, you can also choose Pages Per Sheet, Page Order, Print Page Border, and Auto-Rotate Pages. The Comments And Forms menu lets you choose whether to print markups, stamps, and form fields; the preview window reflects your menu choices.

Tip: Print Part of a PDF Page

You can print a selected area within a PDF page. To do so, choose the Snapshot tool on the Acrobat toolbar, and drag a selection marquee of the area you want to print. Acrobat copies the selected area to the Clipboard and displays a message. Click OK. When you open the Print dialog box, the Selected graphic option will be chosen.

Advanced Print Setup Dialog Box

To get to the settings most useful for high-resolution printing, click the Advanced button at the bottom of the Print dialog box. This opens the Advanced Print Setup dialog box (Figure 16-41), which is organized much like the InDesign and Illustrator Print dialog boxes and contains four panels.

• The Output panel gives options for composite and separated output. When Composite is selected, the option to Simulate Overprinting is available. When Separations or In-RIP Separations is chosen, you can select plates to print. Screening choices reflect the options in the PPD file of the current printer. You can access the Ink Manager with a button.

• The Marks and Bleeds panel lets you add marks and bleeds at printing time (similar to the Add Printer Marks tool on the Print Production toolbar).

• The Transparency panel provides the same choices as the Flattener Preview palette to apply flattening settings at print time.

• The PostScript Options panel is a catch-all location to select which fonts and resources are included when printing.

Figure 16-41. Advanced Print Setup dialog box in Acrobat 7.0 Professional.