Viewing Overprints

You use overprints when printing files to commercial printing equipment and an offset press. When you assign an overprint in an authoring application such as Adobe Illustrator or Adobe InDesign, one color prints on top of another where the two colors overlap. Overprinting is desirable when, for example, you print black type over another color so the type prints without any visible gaps between the type color and the underlying color. However, assigning overprints to colors can also create printing problems by rendering illustrations and designs with different colors due to the blending of the overlapping colors.

Adobe Reader provides you with a means for checking overprints to ensure that files designed for commercial printing output correctly for overprints.

To see the results of overprints, use the file overprint.pdf at www.peachpit.com/adobereader7.

To check a document for appearances with overprints:

1.	Open a document that was designed with overprints assigned to image and/or object elements. Note that overprint previews only display overprint assignments in files where overprints are used.
2.	Examine the document in Adobe Reader. The view shown in the Document pane appears as the file is intended to printlike the document shown in Figure 6.15. Figure 6.15. Preview a document without viewing with the Overprint Preview.
3.	Press Ctrl/Command+K to open the Preferences dialog. Then click Page Display in the left pane and check the box for Overprint Preview (Figure 6.14). Figure 6.14. Check Overprint Preview in the Page Display preferences.
4.	Click OK in the Preferences dialog.
5.	Examine the file with Overprint Preview enabled (Figure 6.16). Compare the view between the document appearances when Overprint Preview is turned off (Figure 6.15) and when it's turned on. If overprints change the appearance of the document, as they do in Figure 6.16, then that indicates potential printing problems. Figure 6.16. When Overprint Preview is turned on, the improperly assigned overprints display problems when files are printed on commercial printing devices.