When you save an Illustrator file in certain formats, the native transparency information is retained. For example, when you save a file in Illustrator CS (or later) EPS format, the file contains both native Illustrator data and EPS data. When you reopen the file in Illustrator, the native (unflattened) data is read. When you place the file into another application, the EPS (flattened) data is read.

About flattening

If your document or artwork contains transparency, to be output it usually needs to undergo a process called flattening. Flattening divides transparent artwork into vector-based areas and rasterized areas. As artwork becomes more complex (mixing images, vectors, type, spot colors, overprinting, and so on), so does the flattening and its results.

Flattening may be necessary when you print or when you save or export to other formats that don’t support transparency. To retain transparency without flattening when you create PDF files, save your file as Adobe PDF 1.4 (Acrobat 5.0) or later.

You can specify flattening settings and then save and apply them as transparency flattener presets. Transparent objects are flattened according to the settings in the selected flattener preset.

Note:

Transparency flattening cannot be undone after the file is saved.

Overlapping art that is divided when flattened
Overlapping art is divided when flattened.

Note:

For more information on transparency output issues, see the Print Service Provider Resources page of the Adobe Solutions Network (ASN) (English only), available on the Adobe website.

File formats that retain transparency

When you save an Illustrator file in certain formats, the native transparency information is retained. For example, when you save a file in Illustrator CS (or later) EPS format, the file contains both native Illustrator data and EPS data. When you reopen the file in Illustrator, the native (unflattened) data is read. When you place the file into another application, the EPS (flattened) data is read.

When possible, keep your file in a format in which native transparency data is retained, allowing you to make edits as necessary.

Native transparency data is retained when you save to the following formats:

  • AI9 and later

  • AI9 EPS and later

  • PDF 1.4 and later (when Preserve Illustrator Editing Capabilities option is selected)

Illustrator flattens artwork when you perform any of the following actions:

  • Print a file that contains transparency.

  • Save a file that contains transparency in a legacy format such as native Illustrator 8 and earlier, Illustrator 8 EPS and earlier, or PDF 1.3 format. (For the Illustrator and Illustrator EPS formats, you can choose to discard transparency rather than flatten it.)

  • Export a file that contains transparency to a vector format that does not understand transparency (such as EMF or WMF).

  • Copy and paste transparent art from Illustrator into another application with both the AICB and the Preserve Appearance options checked (in the File Handling & Clipboard section of the Preferences dialog box).

  • Export in SWF (Flash) or use the Flatten Transparency command with the Preserve Alpha Transparency option selected. This command lets you preview how artwork will look when exported in SWF.

Note:

For more information on creating and printing transparency, see the Transparency white paper in the Adobe Technical Info/White Papers folder on the Illustrator CD. You can also find more information on printing and flattening files with transparency in the Adobe Illustrator User to User forum. This is a public forum that offers a wealth of tips and answers to frequently asked questions, and can be found at www.adobe.com/support/forums.

Set transparency flattening options for printing

  1. Choose File > Print.
  2. Select Advanced on the left side of the Print dialog box.
  3. Select a flattening preset from the Preset menu, or click Custom to set specific flattening options.
  4. If the artwork contains overprinted objects that interact with transparent objects, select an option from the Overprints menu. You can preserve, simulate, or discard overprints.

    Note:

    If the artwork does not contain transparency, the document will not be flattened and the flattening settings are not relevant. Use the Flattener Preview panel to determine which areas of the artwork contain transparency.

Transparency Flattener options

You can set Transparency Flattener options when creating, editing, or previewing flattener presets in Illustrator, InDesign, or Acrobat.

Highlight (preview) options

None (Color Preview)

Disables previewing.

Rasterized Complex Regions

Highlights the areas that will be rasterized for performance reasons (as determined by the Rasters/Vectors slider). Keep in mind that the boundary of the highlight area has a higher probability of producing stitching problems (depending on the print-driver settings and the rasterization resolution). To minimize stitching problems, select Clip Complex Regions.

Transparent Objects

Highlights the objects that are sources of transparency, such as objects with partial opacity (including images with alpha channels), objects with blending modes, and objects with opacity masks. In addition, note that styles and effects may contain transparency, and overprinted objects may be treated as sources of transparency if they are involved in transparency or if the overprint needs to be flattened.

All Affected Objects

Highlights all objects that are involved in transparency, including transparent objects and objects that are overlapped by transparent objects. The highlighted objects will be affected by the flattening process—their strokes or patterns will be expanded, portions of them may get rasterized, and so on.

Affected Linked EPS Files (Illustrator only)

Highlights all linked EPS files that are affected by transparency.

Affected Graphics (InDesign only)

Highlights all placed content affected by transparency or transparency effects. This option is useful for service providers who need to see graphics that require attention to print properly.

Expanded Patterns (Illustrator and Acrobat)

Highlights all patterns that will be expanded if involved in transparency.

Outlined Strokes

Highlights all strokes that will be outlined if involved in transparency or because Convert All Strokes To Outlines is selected.

Outlined Text (Illustrator and InDesign)

Highlights all text that will be outlined if involved in transparency or because Convert All Text To Outlines is selected.

note: In the final output, outlined strokes and text may appear slightly different from native ones, especially very thin strokes and very small text. However, the Flattener Preview doesn’t highlight this altered appearance.

Raster-Fill Text And Strokes (InDesign only)

Highlights text and strokes that have rasterized fills as a result of flattening.

All Rasterized Regions (Illustrator and InDesign)

Highlights objects and intersections of objects that will be rasterized because there is no other way of representing them in PostScript or because they are more complex than the threshold specified by the Rasters/Vectors slider. For example, the intersection of two transparent gradients will always be rasterized, even if the Rasters/Vectors value is 100. The All Rasterized Regions option also shows raster graphics (such as Photoshop files) involved in transparency, and raster effects such as drop shadows and feathers. Note that this option takes longer to process than the others.

Transparency Flattener Preset options

Name/Preset

Specifies the name of the preset. Depending on the dialog box, you can type a name in the Name text box or accept the default. You can enter the name of an existing preset to edit that preset. However, you can’t edit the default presets.

Raster/Vector balance

Specifies the amount of vector information that will be preserved. Higher settings preserve more vector objects, while lower settings rasterize more vector objects; intermediate settings preserve simple areas in vector form and rasterize complex ones. Select the lowest setting to rasterize all the artwork.

Note: The amount of rasterization that occurs depends on the complexity of the page and the types of overlapping objects.

Line Art And Text Resolution

Rasterizes all objects, including images, vector artwork, text, and gradients, to the specified resolution. Acrobat and InDesign allow a maximum of 9600 pixels per inch (ppi) for line art, and 1200 ppi for gradient mesh. Illustrator allows a maximum of 9600 ppi for both line art and gradient mesh. The resolution affects the precision of intersections when flattened. Line Art and Text Resolution should generally be set to 600‑1200 to provide high-quality rasterization, especially on serif or small point sized type.

Gradient And Mesh Resolution

Specifies the resolution for gradients and Illustrator mesh objects rasterized as a result of flattening, from 72 to 2400 ppi. The resolution affects the precision of intersections when flattened. Gradient and mesh resolution should generally be set between 150 and 300 ppi, because the quality of the gradients, drop shadows, and feathers do not improve with higher resolutions, but printing time and file size increase.

Convert All Text To Outlines

Converts all type objects (point type, area type, and path type) to outlines and discards all type glyph information on pages containing transparency. This option ensures that the width of text stays consistent during flattening. Note that enabling this option will cause small fonts to appear slightly thicker when viewed in Acrobat or printed on low-resolution desktop printers. It doesn’t affect the quality of the type printed on high-resolution printers or imagesetters.

Convert All Strokes To Outlines

Converts all strokes to simple filled paths on pages containing transparency. This option ensures that the width of strokes stays consistent during flattening. Note that enabling this option causes thin strokes to appear slightly thicker and may degrade flattening performance.

Clip Complex Regions

Ensures that the boundaries between vector artwork and rasterized artwork fall along object paths. This option reduces stitching artifacts that result when part of an object is rasterized while another part of the object remains in vector form. However, selecting this option may result in paths that are too complex for the printer to handle.

note: Some print drivers process raster and vector art differently, sometimes resulting in color stitching. You may be able to minimize stitching problems by disabling some print-driver specific color-management settings. These settings vary with each printer, so see the documentation that came with your printer for details.

Stitching, where rasters and vectors meet
Stitching, where rasters and vectors meet.

(Illustrator only) Select Preserve Alpha Transparency (Flatten Transparency dialog box only)

Preserves the overall opacity of flattened objects. With this option, blending modes and overprints are lost, but their appearance is retained within the processed artwork, along with the level of alpha transparency (as when you rasterize artwork using a transparent background). Preserve Alpha Transparency can be useful if you are exporting to SWF or SVG, since both of these formats support alpha transparency.

(Illustrator only) Select Preserve Spot Colors And Overprints (Flatten Transparency dialog box only)

Generally preserves spot colors. It also preserves overprinting for objects that aren’t involved in transparency. Select this option when printing separations if the document contains spot colors and overprinted objects. Deselect this option when saving files for use in page-layout applications. With this option selected, overprinted areas that interact with transparency are flattened, while overprinting in other areas is preserved. The results are unpredictable when the file is output from a page-layout application.

Preserve Overprint (Acrobat only)

Blends the color of transparent artwork with the background color to create an overprint effect.

Preview which areas of artwork will be flattened

Use the preview options in the Flattener Preview to highlight areas that are affected by flattening. You can use this color-coded information to adjust flattening options.

Note:

The Flattener Preview is not intended for precise previewing of spot colors, overprints, and blending modes. Instead, use Overprint Preview mode for those purposes.

  1. Display the Flattener Preview panel (or dialog box):
    • In Illustrator, choose Window > Flattener Preview.

    • In Acrobat, choose Tools > Print Production > Flattener Preview.

    • In InDesign, choose Window > Output > Flattener Preview.

  2. From the Highlight menu, choose the kind of areas you want to highlight. The availability of options depends on the content of the artwork.
  3. Select the flattening settings you want to use: Either choose a preset or, if available, set specific options.

    Note:

    (Illustrator) If the flattening settings aren’t visible, select Show Options from the panel menu to display them.

  4. If the artwork contains overprinted objects that interact with transparent objects, in Illustrator, select an option from the Overprints menu. You can preserve, simulate, or discard overprints. In Acrobat, choose Preserve Overprint to blend the color of transparent artwork with the background color to create an overprint effect.
  5. At any time, click Refresh to display a fresh preview version based on your settings. Depending on the complexity of the artwork, you may need to wait a few seconds for the preview image to appear. In InDesign, you can also choose Auto Refresh Highlight.

    Note:

    In Illustrator and Acrobat, to magnify the preview, click in the preview area. To zoom out, Alt-click/Option-click in the preview area. To pan the preview, hold down the spacebar and drag in the preview area.

Flattener Preview panel overview

You use the preview options in the Flattener Preview panel to highlight the areas affected by flattening artwork. You can use this information to adjust the flattening options, and even use the panel to save flattener presets. To display the Flattener Preview panel, choose Window > Flattener Preview.

Flattener Preview panel
Flattener Preview panel

A. Panel menu B. Refresh button C. Highlight menu D. Overprint menu E. Transparency flattening settings F. Preview area 

You can control the speed and quality of the preview image by selecting an option from the panel menu. Select Quick Preview to compute the quickest preview; select Detailed Preview to add the option All Rasterized Regions to the Highlight pop‑up menu (this option is more performance-intensive to compute).

Note:

Keep in mind that the Flattener Preview panel is not intended for precise previewing of spot colors, overprints, blending modes, and image resolution. Use Overprint Preview mode in Illustrator to preview spot colors, overprints, and blending modes as they will appear when output.

About transparency flattener presets

If you regularly print or export documents that contain transparency, you can automate the flattening process by saving flattening settings in a transparency flattener preset. You can then apply these settings for print output as well as for saving and exporting files to PDF 1.3 (Acrobat 4.0) and EPS and PostScript formats. In addition, in Illustrator you can apply them when saving files to earlier versions of Illustrator or when copying to the clipboard; in Acrobat, you can also apply them when optimizing PDFs.

These settings also control how flattening occurs when you export to formats that don’t support transparency.

You can choose a flattener preset in the Advanced panel of the Print dialog box or of the format-specific dialog box that appears after the initial Export or Save As dialog box. You can create your own flattener presets or choose from the default options provided with the software. The settings of each of these defaults are designed to match the quality and speed of the flattening with an appropriate resolution for rasterized transparent areas, depending on the document’s intended use:

High Resolution

is for final press output and for high-quality proofs, such as separations-based color proofs.

Medium Resolution

is for desktop proofs and print-on-demand documents that will be printed on PostScript color printers.

Low Resolution

is for quick proofs that will be printed on black-and-white desktop printers and for documents that will be published on the web or exported to SVG.

Create or edit a transparency flattener preset

You can save transparency flattener presets in a separate file, making it easy to back them up or to make them available to your service providers, clients, or others in your workgroup. In InDesign, transparency flattener preset files have an .flst extension.

  1. Choose Edit > Transparency Flattener Presets.
  2. Do one of the following:
    • To create a new preset, click New.

    • To base a preset on a predefined preset, select one in the list and click New.

    • To edit an existing preset, select the preset and click Edit.

    Note:

    You can’t edit the default flattener presets.

  3. Set flattening options.
  4. Click OK to return to the Transparency Flattener Presets dialog box, and click OK again.

Export and import a custom transparency flattener preset

You can export and import transparency flattener presets in order to share them with your service providers, your clients, or others in your workgroup.

  1. Choose Edit > Transparency Flattener Presets.
  2. Select a preset in the list.
  3. Do one of the following:
    • To export a preset to a separate file, click Save (InDesign) or Export (Illustrator), specify a name and location, and then click Save.

      Consider saving the preset outside of the application’s preferences folder. That way, it won’t be lost if you delete your preferences.

    • To import presets from a file, click Load (InDesign) or Import (Illustrator). Locate and select the file containing the preset you want to load, and then click Open.

Rename or delete a custom transparency flattener preset

  1. Choose Edit > Transparency Flattener Presets.
  2. Select a preset in the list.
  3. Do one of the following:
    • To rename an existing preset, click Edit, type a new name, and then click OK.

    • To delete a preset, click Delete, and then click OK to confirm the deletion.

      note: You cannot delete the default presets.

Flatten transparency for individual objects

The Flatten Transparency command lets you see what your artwork will look like when flattened. For instance, you might use this command before saving the file in SWF (Flash) format or if you are having problems printing legacy art where transparency may be the culprit.

  1. Select the object.
  2. Choose Object > Flatten Transparency.
  3. Select the flattening settings you want to use, either by choosing a preset or setting specific options.
  4. Click OK.

    Note:

    To save the flattening settings for use with other objects and documents in the current session, click Save Preset. If you want to create a permanent preset, choose Edit > Transparency Flattener Presets instead.

Rasterize all artwork during printing

When you print to a low-resolution or non-PostScript printer, such as a desktop inkjet printer, you can choose to rasterize all artwork during printing. This option is useful when printing documents that contain complex objects (such as objects with smooth shading or gradients) because it reduces the possibility of errors.

  1. Choose File > Print.
  2. Select Advanced on the left side of the Print dialog box.
  3. Select Print As Bitmap.

    This option is only available if the printer driver for the selected printer supports bitmap printing.

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License  Twitter™ and Facebook posts are not covered under the terms of Creative Commons.

Legal Notices   |   Online Privacy Policy