Choose Window > Channels to display the channels panel.
Click New Spot Channel from the pull down menu on the right
In the New Spot Channel dialog box, click the Color box. Then in the Color Picker, click Color Libraries to choose the PANTONE color. Please check our current list of ink colors for the equivalent Pantone color.
Enter a name for the spot channel (i.e. "Yellow")
Return to your layers and choose Select > All on one of the color layers.
Return to channels and paste the artwork onto the corresponding color channel.
Go to Image > Adjustments > Curves
Drag the top right point to become parallel with the darkest point to ensure the density of the color matches up.
Once you have your channels set up, you can delete any unused channels. The channel page should look something like this (one channel for each color):
Now that everything is in channels, go to Image > Trap to add trapping to the channels that may need it. We recommend at least 4 pixels of trap.
Go to File > Save As and save the file out as a Photoshop DCS 2.0 making sure "Spot Colors" is checked
Make sure the output matches this:
Create an InDesign or Illustrator document set up to the same size as your finished artwork
File > Place your Photoshop DCS 2.0 file into the InDesign or Illustrator file
Set bleed margins
Go to Window > Output > Separations Preview to view the spot color separations
Place or insert any text or vector images at this time
Alias the spot colors to make sure that you don't have duplicate spot colors or incorrect spot colors by going to Separations Preview > Ink Manager
Click on the spot color that is incorrect, pull down the Ink Alias menu and select the spot color that it should be