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Modifying spot channels


    You can edit a spot channel to add or remove color in it, change a spot channel's color or on-screen color solidity, and merge a spot channel with the image's color channels.

    For information on rearranging, duplicating, or deleting spot channels, see Managing channels (Photoshop).

To edit a spot channel:

  1. Select the spot channel in the Channels palette.
  2. Use a painting or editing tool to paint in the image. Paint with black to add more spot color at 100% opacity; paint with gray to add spot color with lower opacity.
  3. Note: Unlike the Solidity option in the Spot Channel Options dialog box, the Opacity option in the painting or editing tool's options determines the actual density of ink used in the printed output.

To change a spot channel's options:

  1. Do one of the following:
    • Double-click the spot channel thumbnail in the Channels palette.
    • Select the spot channel in the Channels palette, and choose Channel Options from the palette menu.
  2. Click the color box, and choose a color. (See Using the Adobe Color Picker.)
  3. By selecting a custom color, your print service can more easily provide the proper ink to reproduce the image. For more information, see Choosing custom colors (Photoshop).

  4. For Solidity, enter a value between 0% and 100%.
  5. This option lets you simulate on-screen the solidity of the printed spot color. A value of 100% simulates an ink that completely covers the inks beneath (such as a metallic ink); 0% simulates a transparent ink that completely reveals the inks beneath (such as a clear varnish). You can also use this option to see where an otherwise transparent spot color (such as a varnish) will appear.

    Note: The Solidity and color choice options affect only the on-screen preview and the composite print. They have no effect on the printed separations.

To merge spot channels:

  1. Select the spot channel in the Channels palette.
  2. Choose Merge Spot Channel from the palette menu.
  3. The spot color is converted to and merged with the color channels. The spot channel is deleted from the palette.

    Merging spot channels flattens layered images. The merged composite reflects the preview spot color information, including the Solidity settings. For example, a spot channel with a solidity of 50% will produce different merged results than the same channel with a solidity of 100%.

    In addition, the resulting merged spot channels usually don't reproduce the same colors as the original spot channels, because CMYK inks can't represent the range of colors available from spot color inks.