Creating Spot Color Projects With Photoshop CS
This tutorial will start with very simple art to use for an example.
The first thing to do is be certain your image is in CMYK mode and not RGB. To check this choose Image > Mode from the menu. If your image is indeed in RGB mode, Choose Image > Mode > CMYK from the menu to convert the image to 4-color process.
Create a new spot channel. Open the channels palette by choosing Window > Channels from the menu. Click the flyout menu on the Channels palette and choose New Spot Channel.
A small dialog window will pop up. Click the small color box and the color picker will pop up. Choose the spot color you wish to use in the color picker, then click okay to dismiss the color picker, then okay to dismiss the spot color dialog.
Pantone Blue 072 was selected for this tutorial. When the new spot channel is created it will be empty. No apparent change to your image will take place.
To fill the spot channel, first select the area you wish to have in the spot color. In this case the blue. Use whatever method best works for you to select the blue portions of your image.
After you've made your selection, highlight the spot channel in the Channels Palette. Fill in this selection on the spot channel. Filling with 100% black will create 100% of your spot color. Shades of grey will translate to values within your spot color.
Repeat Step 1 and Step 2 for every unique spot color you wish to have in the document. You do not need to create spot channels for black, use the black channel for any black you may want. For the black channel, simply highlight the black channel and erase or delete anything you do not wish to appear in black.
Below you can see how the channels palette appears for this image. Note how the visibility is only on for the blue 072 channel and the document shows the areas of blue as a solid black.
To have a proper spot color file, the information on every other channel must be correct
Choose Edit > Select all.
Highlight the Cyan channel in the Channels palette by clicking it once in the Channels palette. Hit delete.
Highlight the Magenta channel in the Channels palette by clicking it once in the Channels palette. Hit delete.
Highlight the yellow channel in the Channels palette by clicking it once in the Channels palette. Hit delete.
Highlight the black channel. Using curves (or levels) be certain you've got 100% black where you want it. Sometimes black is not 100% due to CMYK mixing rich blacks for color profiles. With spot color you want 100% black rather than the mixed rich blacks.
Flatten your image by choosing "Flatten Image" from the flyout menu located on the Layers palette.
Turn on visibility for all channels and your spot channel by clicking the eye icon next to each channel in the Channels palette.
The file should look similar to the image below but the actual channel names may be different depending upon your color choices.
The MOST IMPORTANT step people often forget. . .
Highlight the black channel, hold down shift and highlight all the other spot channels in the file. From the image menu, choose "Trap . . . " Set the field to a value of 1 and hit okay.
Saving the file. Save the file in a DCS2.0 format, be certain the "Spot Colors" Option in the save dialog is checked.
When you click save a second dialog will pop up. Choose Single file, Color Composite for the second drop down in the DCS options dialog box. Leave all other options set to the default options. The 72ppi designation refers to the image used for a composite preview only, not the actual file resolution. Your image resolution will not be changed by this setting.
Check the include vector data if your file does indeed contain vector information such as shape layers or type.
This is the basic process I use for a good, solid, two color Photoshop file for Xpress. Leave the blank CMY channels in the file, don't delete them if you are using Xpress. For some reason QuarkXpress really likes to see those channels present. And leaving them may circumvent issue in RIP with the file.
When importing your DCS2 file into QuarkXpress, it is going to look much worse. This is just due to Xpress showing you the low resolution preview composite. Trust your view of the image in Photoshop and use the Xpress view for placement only.
This process is also possible with complex layers using styles or other values. Essentially your spot color channels act like a reverse mask. White = no color, black = 100% color and all values in between are achieved by grey on the spot channel.
You can use proxy setups, replacing data on the Cyan channel and indicating to a print provider that the Cyan channel should print Pantone XXX. However, if you aren't running the image-setter yourself or outputting the plate, there is a good possibility whatever color you specify for the C, M, or Y channel may get misinterpreted somewhere between print liaison - service bureau - sales rep - account manager - prepress - pressman. Safest bet is to build your files specific if you aren't directly working for the print provider. Not to mention if your files get passed off to another designer at a later time and they mis-specify the color at that time or forget to specify the color all together.
Duo-tones or multi-channel mode may work for some spot color work. It all depends upon the image itself. If you need different pixel data for each channel then the standard duo-tone mode won't work. It will work for photograph-like image where you want the entire image to have an overall color wash feel to it. If you're using QuarkXpress, then multi-channel can be problematic (it's not in Indesign).
And remember you cannot take a duo-tone, multi-channel or DCS file and import it into an Illustrator document, then import the Illustrator document into Xpress, or Indesign. It will not separate properly.Have a question?