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Transparency for Print Output in Adobe Creative Suite 3

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Table of Contents

  1. Introduction
  2. New transparency features in CS3
  3. The Adobe Print Engine
  4. New technology
  5. Creating transparency
  6. Transparency: live or flattened?
  7. Designers Guide to Transparency
  8. Creating and viewing transparency effects
  9. Best practices for working with transparency
  10. Transparency effects in Illustrator CS3
  11. Transparency effects in InDesign CS3
  12. Importing and placing files with transparency
  13. Building effects with transparency
  14. Saving and exporting files with transparency
  15. Printing files with transparency
  16. Delivering files with transparency to your print service provider
  17. Transparency-related resources
  18. Transparency: A Print Production Guide
  19. Best practices when flattening
  20. Flattening basics
  21. Advanced Flattener controls
  22. Flattening controls in Illustrator CS3
  23. Flattening controls in InDesign CS3
  24. Flattening controls in Acrobat 8 Professional
  25. Transparency and color
  26. Troubleshooting
  27. Glossary

Transparency: A Print Production Guide

Best practices when flattening

As a service provider, you often receive Adobe publishing software files without knowing exactly what they contain. To properly process these files, you need to determine if they contain any live transparency. In addition, you need to properly configure the Flattener settings before using it to flatten a file.

This topic covers:

If you think you may need to change artwork after flattening has occurred, be sure to save a copy of the unflattened artwork for future editing.

For information on what happens during flattening, see About the flattening process and Transparency and color.

See also

Overprint support

In some cases, when spot colors are involved in transparency, the Flattener relies on overprinting to render the proper result. Be sure to set your PDF viewers, composite proofers, and production RIPs to implement overprinting and not ignore it.

To properly view flattened transparency in a PDF file in Acrobat 8 Professional or Reader 8, as placed in an InDesign CS3 document, enable Overprint Preview.

Overprint Preview is available in Illustrator CS3, InDesign CS3, and Acrobat 7 and later to inspect overprinting objects. In Reader 7 and 8 users, preview overprinting objects in a PDF file by selecting the Overprint Preview preference (Edit > Preferences (Windows) or Reader > Preferences (Mac OS).

Simulating overprinting

Use the Simulate Overprint feature for creating proofs when your document contains spot colors that interact with transparency, and the software that you’ll use to view the flattened file, or the printer that will print it, doesn’t support overprinting. The Simulate Overprint feature creates the visual effect of overprinting. It renders transparency that interacts with spot colors, by converting all the spot colors to process colors, whether or not they are involved in transparency.

This feature is intended for creating proofs; it is generally not recommended for final production output. The converted image may appear the same as its spot-color counterpart, but will print as four-color CMYK rather than as spot color plates.

The Simulate Overprint option (Figure 30) is available in print and export dialog boxes in Illustrator, InDesign, and Acrobat 8 Professional. (Unique to Illustrator CS3, the Simulate Overprint option also appears in the Flattener Preview panel.) Choosing this option causes the Flattener to preprocess all of the overprint attributes and render them without reliance on overprinting—whether or not the file contains any live transparency—and to convert spot colors to process in any affected area. For this reason, be cautious using this method to flatten transparency in an Illustrator file.

The Simulate Overprint option in InDesign CS3. When selected, color separations are turned off when printing to a CMYK output device.

Figure 30. The Simulate Overprint option in InDesign CS3. When selected, color separations are turned off when printing to a CMYK output device.

Using the Flattener Preview to detect transparency

The Flattener Preview panel, available in InDesign CS3, Illustrator CS3, and Acrobat 8 Professional, is the best way to detect transparency in a file that was created with Adobe publishing software. Table 4 shows the Flattener Preview options and functions by CS3 components.

See Flattener Preview and sample settings.

See also

Table 4. CS3 component options for previewing flattening.

Flattener Preview Functions by Application
InDesign CS3 Illustrator CS3 Acrobat 8
Professional		 Flattener Preview function
• • • Affected Graphics shows all placed graphics that are involved with transparency.
  • • Affected Linked EPS Files shows all placed-linked EPS files that are involved in transparency.
• • • All Affected Objects shows all objects that interact with transparency.
• •   All Rasterized Regions shows all regions of the document that the Flattener would rasterize. These regions include complexity regions (previewed by the Rasterized Complex Regions preview option) and rasterized atomic regions. (To use this option in Illustrator, you must select Detailed Preview in the Flattener Preview panel menu.)
  • • Expanded Patterns shows all patterns that would be expanded because they are involved in transparency.
• • • Outlined Strokes shows all strokes that would convert to outlines because they are involved in transparency or because you selected Convert All Strokes to Outlines.
• •   Outlined Text shows all text that would be converted to outlines because it is involved in transparency or because you chose the Convert All Text to Outlines option.
•     Raster-fill Text and Strokes shows all text and strokes that the Flattener will outline to act as clipping masks for rasterized image data.
• • • Rasterized Complex Regions shows areas that will be rasterized as determined by the Raster/Vector Balance control.
• • • Transparent Objects shows objects that are sources of transparency, including those objects to which non-normal blending modes, styles, and raster effects are applied, as defined in Determining whether an object will be flattened. This option also highlights overprinting objects that interact with transparency.

Choosing a file format for your production workflow

When making decisions about the file types to use in your production workflow, try to choose a format that supports live transparency. Using a file format that supports live transparency is the best choice for prepress because you have complete control over the flattening process until the moment the file is printed or output.

See also

Illustrator native, InDesign native, and PDF file formats

Because they can contain live transparency, Illustrator CS3 native, InDesign CS3 native, and PDF 1.4, 1.5, or 1.6 file formats are the best choice for prepress.

Photoshop files

Photoshop files with transparent backgrounds correctly print and output when you place them into Illustrator or InDesign documents. Most applications that can accept file formats with transparency masks (such as TIFF and PDF 1.4 and 1.5) can use this transparency information.

Illustrator CS3 and InDesign CS3 both let you directly place native Photoshop files; however, all visible layers are effectively flattened—any remaining transparency is reduced to a single alpha channel. As a result, the blending modes of layers in a Photoshop file (PSD) do not remain live when placed into one of these applications.

File formats that do not support live transparency

If you must use a file format that doesn’t support live transparency (for example, PostScript, EPS, PDF 1.3, or PDF/X), consider the following:

  • Illustrator artwork that you save as EPS or PDF 1.3 from Illustrator 10, CS, CS2, or CS3, is flattened—allowing you to place the file in older layout applications—but it may be opened in an unflattened state in Illustrator at any time to inspect and correct any flattening problems. You can open the file in an unflattened state because these formats contain all of the live transparency information in an Illustrator-specific section of the file. You can open these files in Illustrator CS3, restore the live transparency objects for editing, and resave it with new flattener settings.
  • InDesign CS3 files saved as either EPS or PDF 1.3 are flattened, but they correctly retain overprinting and spot colors.

Flattening and printing performance trade-offs

Raster/Vector Balance settings trade off time and memory required to flatten a file versus the time to spool and print it.

Generally (when using resolution settings appropriate for high quality printing), if the Raster/Vector Balance in your Flattener setting is set to Vector (the far right position), the time and memory required to flatten a file may be greater if the file contains extensive transparency. The resulting flattened file, however, is usually smaller and takes less time for spooling because its rasterization is kept to a minimum. If the Raster/Vector Balance is set to Raster (the far left position), the time and memory required to flatten the same file can be substantially less. The resulting flattened file, however, may be much larger and take more time for spooling.

In either case, a flattened file may take longer to print than a file that doesn’t require flattening because of the memory demands a flattened file places on the RIP. These demands occur either because the Raster/Vector Balance setting has created an excessively large rasterized file or because the Raster/Vector Balance setting has created a file filled with a large number of small vector objects and clipping paths.

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