Adding spot colors (Photoshop)

Spot colors are special premixed inks used instead of, or in addition to, the process color (CMYK) inks. Each spot color requires its own plate on the press. (Because a varnish requires a separate plate, it is considered a spot color, too.) For information on printing spot color plates, see “Printing color separations” on page 483.

If you are planning to print an image with spot colors, you need to create spot channels to store the colors. To export spot channels, save the file in DCS 2.0 format or PDF. (See “Saving files in Photoshop EPS format (Photoshop)” on page 448.)

Note: ImageReady supports Photoshop spot color channels as alpha channels.

About spot colors

Note the following when working with spot colors:

•For spot color graphics that have crisp edges and knock out the underlying image, consider creating the additional artwork in a page-layout or illustration application.

•To apply spot color as a tint throughout an image, convert the image to Duotone mode and apply the spot color to one of the duotone plates. You can use up to four spot colors, one per plate. (See “Printing color separations” on page 483.)

•The names of the spot colors print on the separations.

•Spot colors are overprinted on top of the fully composited image. Each spot color is overprinted in the order it appears in the Channels palette.

•You cannot move spot colors above a default channel in the Channels palette except in Multichannel mode.

•Spot colors cannot be applied to individual layers.

•Printing an image with a spot color channel to a composite color printer will print the spot color at an opacity indicated by the solidity setting.

•You can merge spot channels with color channels, splitting the spot color into its color channel components.

Creating spot channels

You can create a new spot channel or convert an existing alpha channel to a spot channel.

To create a new spot channel:

1Choose Window > Channels to display the Channels palette.

2To fill a selected area with a spot color, make or load a selection.

3Do one of the following to create a channel:

•Ctrl-click (Windows) or Command-click (Mac OS) the New Channel button in the Channels palette.

•Choose New Spot Channel from the Channels palette menu.

If you made a selection, that area is filled with the currently specified spot color.

4 Click the color box, and choose a color. (See “Using the Adobe Color Picker” on page 261.)

If you select a custom color, your print service provider can more easily provide the proper ink to reproduce the image. For more information, see “Choosing custom colors (Photoshop)” on page 263.

5 For Solidity, enter a value between 0% and 100%.

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.

6 To enter a name for the spot channel, choose a custom color in step 4, and the channel automatically takes the name of that color.

Be sure to name spot colors so they’ll be recognized by other applications reading your file. Otherwise the file might not print.

To convert an alpha channel to a spot channel:

1 Do one of the following:

•Double-click the alpha channel thumbnail in the Channels palette.

•Select the alpha channel in the Channels palette, and choose Channel Options from the palette menu.

2If needed, rename the channel.

3Select Spot Color.

4Click the color box, choose a color in the Color Picker dialog box, and click OK. (See “Using the Adobe Color Picker” on page 261.)

5Click OK. The areas of the channel containing grayscale values are converted to spot color.

6Choose Image > Adjustments > Invert to apply the color to the selected area of the channel.

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)” on page 268.

To edit a spot channel:

1Select the spot channel in the Channels palette.

2Use 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.

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.