Working with Transparency

InDesign CS lets you import objects with transparent portions, as well as create transparent objects using the Color and Swatches panes. Using features such as the Drop Shadow and Feather options in the Object menu also might create transparency. But working with transparency can create unintended side effects in how overlapping objects actually appear when printed or viewed on-screen in a PDF file. To address that, InDesign offers the ability to both control transparency on selected objects and groups, as well as to control how transparency is handled during output.

To apply transparency to objects in InDesign, you use the Transparency pane (Window ‚ Transparency, or Shift+F10), as Chapter 25 explains. The more objects you have overlapping each other with transparency settings applied, the more complex the output calculations will be to print those effects. This can prevent a document from printing, as it overwhelms the printer or other output device. That's where transparency flattening comes into play. This feature breaks up the overlapping areas into distinct graphics during output ‚ creating a mosaic of pieces that will produce the intended effect.

QuarkXPress User ‚  

QuarkXPress has no equivalent to InDesign's transparency settings. QuarkXPress users instead must rely on such settings in Adobe Photoshop and Illustrator for imported pictures and do without them for objects created in QuarkXPress

InDesign comes with three transparency flattening settings ‚ [Low Resolution], [Medium Resolution], and [High Resolution] ‚ which you can edit in the Transparency Flattener Presets dialog box. To open this dialog box, shown in Figure 31-12, choose Edit ‚ Transparency Flattener Presets. The dialog box shows the settings for each preset as you select them. Use this dialog box to create, modify, delete, export (Save), and import (Load) presets. (You cannot modify or delete the three default presets.)

Figure 31-12: The Transparency Flattener Presets dialog box.

Figure 31-13 shows the Transparency Flattener Preset Options dialog box, which you get when you create or modify a preset. There's a lot of trial and error in developing transparency flattener presets, since the complexity of your documents and the capacity of your output devices will vary widely. But here are some guidelines:

• The most accurate transparency blends are achieved with a Raster/Vector Balance set to 100, which means use all vectors rather than convert blends to bitmap images. The [Low Resolution] preset is set at 75, which means that three- quarters of the blends are vectors and one-quarter is converted to bitmaps. The other options have higher vector proportions .

• Flattener resolution should be set to a value that corresponds with your output device's dpi. For Line Art and Text Resolution, 600 ppi or higher is fine, while 150 ppi is fine for gradients and meshes (overlapping transparencies ). But the higher the output resolution of your output device, the higher you would make these values.

• If you have applied transparency to objects that overprint or underprint text, you likely will check Convert All Text to Outlines; otherwise , InDesign may make the text that interacts with transparent objects thicker than text that doesn't.

• Convert Strokes to Outlines has the same effect on lines and strokes for InDesign objects that overlap or underlap objects with transparency.

• The Clip Complex Regions options apply only if the Raster/Vector Balance is less than 100. It corrects for a phenomenon called stitching, in which a transparent area has both vectors and bitmaps that create a blocky feel. This option isolates those areas and forces them to be all-vector.

  Note ‚  

  You can apply transparency settings directly to a spread by selecting a spread in the Pages pane (Window ‚ Pages, or F12), then choosing Spread Flattening ‚ Custom from the palette menu. You'll get a dialog box like the Transparency Flattener Presets dialog box (refer to Figure 31-12), except that any settings created here are applied only to the selected spread and are not saved as a preset for use elsewhere.

Figure 31-13: The Transparency Flattener Preset Options dialog box.

Once set up, you can apply transparency presets to your document via the Advanced pane of the Print dialog box, as described earlier in this chapter.

InDesign also lets you preview flattening settings, using the new Flattener Preview pane. Shown in Figure 31-14, this pane lets you preview transparent objects and their flattening. To open the pane, choose Window ‚ Output Preview ‚ Flattener.

Figure 31-14: The Flattener Preview pane.

New Feature ‚  

The Flattener Preview pane is new to InDesign CS.

In the pane, you can select what to preview via the Highlight pop-up menu. Your options are None, Rasterized Complex Regions, Transparent Objects, Affected Objects, Affected Graphics, Outlined Strokes, Outlined Text, Raster-Fill Text and Strokes, and All Rasterized Regions. (Note that the rasterized options display overlapping transparent objects that InDesign would need to convert to bitmaps during flattening ‚ not simply any bitmap images in your document.) Select the area you're concerned may not output at sufficient quality. If you check the Auto Refresh Highlight option, InDesign will update the preview if you change any settings; if not, you can update the preview by clicking the Refresh button.

You can also check the flattening of different presets ‚ just choose a preset from the Preset pop-up menu. Likewise, you can see what would happen to a spread that has a custom flattening applied if you were to override those custom settings ‚ just check the Ignore Spread Overrides option.

If you like how the flattening looks, you can pre-apply them to the Print dialog box by clicking the Apply Settings to Print button.