Step 2: Select overprint options for overlapping colors


    If you have not changed the transparency of your artwork with the Transparency palette, the fills and strokes in the artwork will appear opaque because the top color knocks out, or cuts out, the area underneath. You can prevent knockout by using the Overprint option in the Attributes palette to make the topmost overlapping printing ink appear transparent in relation to the underlying ink.

    Note: The degree of transparency in printing depends on the ink, paper, and printing method used. Consult your print shop to determine how these variables will affect your final artwork.

    The Filter > Colors > Overprint Black command allows you to set black fill or black stroked lines to overprint (or, alternatively, to remove overprinting commands from black fill or black stroked lines).

    After you have set your overprinting options, you should use the Overprint Preview mode to see an approximation of how the overprinting colors will print. However, it is important that you carefully check overprinted colors on separated artwork using integral proofs (where each separation is shown in register on a single piece of paper) or overlay proofs (where the separations are shown in register on separate plastic sheets stacked on top of each other). (See Previewing how artwork will print.)

    Colors knocked out by default and with the Overprint option in the Attributes palette selected
    Colors knocked out by default and with the Overprint option in the Attributes palette selected

    You may want to overprint in the following situations:

    • Overprint 100% black lines against a color background when the illustration style allows, to aid in registration.
    • Overprint when the artwork does not share common ink colors and you want to create a trap or overlaid ink effects. When overprinting process color mixes or custom colors that do not share common ink colors, the overprint color is added to the background color. For example, if you print a fill of 100% magenta over a fill of 100% cyan, the overlapping fills appear violet, not magenta.

To set overprinting on objects:

  1. Select the object or objects that you want to overprint.
  2. Result of selecting and overprinting front circle (yellow) compared to middle circle (magenta)
    Result of selecting and overprinting front circle (yellow) compared to middle circle (magenta)
  3. Choose Window > Attributes.
  4. Select Overprint Fill.
  5. If you use the Overprint option on a 100% black stroke or fill, the black ink may not be opaque enough to prevent the underlying ink colors from showing through. To eliminate the show-through problem, use a four-color (rich) black instead of a 100% black. Consult with your print shop about the exact percentages of color to add to the black.

    Appearance of artwork on monitor (without Overprint preview) compared to printed artwork
    Appearance of artwork on monitor (without Overprint preview) compared to printed artwork

To set or remove overprinting from black lines:

  1. Select the objects on which to have overprinting applied or removed. You can set overprinting for custom colors whose process equivalents contain specific percentages of black or for process colors that include black.
  2. Choose Filter > Colors > Overprint Black.
  3. In the dialog box, choose Add Black from the menu to add overprinting or Remove Black to remove overprinting.
  4. Enter the percentage of black to indicate which objects have overprinting added or removed. For example, enter 80% to select only objects containing 80% black.
  5. Choose any of the following options and click OK:
    • Fill, Stroke, or both options to apply overprinting to filled paths, stroked paths, or both types of paths.
    • Include Blacks with CMY to apply overprinting to paths painted with cyan, magenta, or yellow if the path also contains black at the specified percentage.
    • Include Spot Blacks to apply overprinting to custom colors whose process equivalents include black at the specified percentage.

    Note: If you are overprinting a spot color that contains process colors as well as the specified percentage of black, it is necessary to choose both the Include Blacks with CMY option and the Include Spot Blacks option.