About flattening transparent artwork


    When printing or exporting an Illustrator file to a format that does not understand Illustrator's native transparency, Illustrator performs a process called flattening. During flattening, Illustrator looks for areas where transparent objects overlap other objects and isolates these areas by dividing the artwork into components. Illustrator then analyzes each component to determine if the artwork can be represented using vector data or if the artwork must be rasterized.

    As artwork becomes more complex (mixing images, vectors, type, spot colors, overprinting, and so on), so does the flattening and its results.

    You can access and specify flattening settings though the Transparency Flattener Presets dialog box, the Advanced options in the Print dialog box, and the Flattener Preview palette. Once specified, you can save and apply these settings as transparency flattener presets.

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

    Illustrator flattens a file when you do the following:

    • 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 (Acrobat 4 compatibility). For the Illustrator and Illustrator EPS formats, the Preserve Appearance option and/or the Preserve Appearance and Overprints option must be selected.
    • Export a file that contains transparency to a vector format that does not understand transparency (PICT, EMF, WMF).
    • Copy and paste transparent art from Illustrator into another application with both the AICB and the Preserve Appearance options checked (in the Files & Clipboard section of the Preferences dialog box).
    • Use the Flatten Transparency command.

    Note: This command and SWF (Flash) export can flatten artwork to color and alpha channels.

    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 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.

    Note: Adobe InDesign can place Illustrator's native and PDF 1.4 files with transparency intact and un\xdf attened. For best results retaining transparency without flattening using PDF with InDesign, save your files as PDF 1.4 rather than PDF 1.3 or PDF 1.5.

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

    File Format

    Extension

    Editable Transparency

    Flattened Data

    AI9 and later

    .ai

    checkmark

    AI9 EPS and later

    .eps

    checkmark and asterisk
    checkmark

    AI8 EPS

    .eps

    checkmark and degree symbol

    PDF 1.4 and PDF 1.5

    .pdf

    checkmark and dagger

    PDF 1.3

    .pdf

    checkmark and dagger
    checkmark and degree symbol

    asterisk Transparency is editable only when opened in Adobe Illustrator 9 and later. degree symbol Spot colors are not preserved when the file contains transparency and you choose Preserve Appearance. dagger Saved when Preserve Illustrator Editing Capabilities is selected.

    Tip iconFor 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.