Every few months I see in person or read about in online forums someone who, through some weird accident, wound up creating a two- or three-color image in Photoshop using a dozen or more channels. In the document’s Channels panel, he has multiple channels (plates) for each of the two or three spot colors. Why is this a disaster? Because each of those channels will be treated as a separate plate, turning a 2- or 3-color job into a 10- or 12-color job; the price of printing goes through the roof, as does the poor pressman who has to run the thing. The worst I ever saw personally was a two-color PSD with 14 channels for a single spot and 11 more for the second color. As near as I could figure, the designer, whom we’ll call Jane, had mistakenly used channels like layers, creating a new channel for every new object or section of color while she painted.
When these types of Photoshop images pop up, there isn’t a great deal that can be done to fix them within Photoshop. Sometimes cutting all image data off the extraneous channels one at a time and pasting onto a single target channel works, sometimes it doesn’t. Splitting the image into two, one to hold each color, merging the channels down into a single channel each, and then reconsolidating the images also works once in a while. Converting the image to grayscale and then back to duotone in Photoshop consolidates the channels easily but destroys the original color separations and usually requires copious recoloring work.
InDesign’s Ink Manager has provided the solution to Jane’s problem via ink aliases. If you find yourself dealing with such a Photoshop document, place it into InDesign and output from there.
Select one instance of each doppelganger ink as the primary, and, using the Ink Manager, alias all the others to their primary. Upon output, you’ll have just one plate for each color. Often images such as those previously described are set in multichannel color mode, and InDesign does not support placing PSD images in multichannel. InDesign only handles images in the CMYK, RGB, and Lab color spaces.
To get around the limitation:
1. Re-open the image in Photoshop.
2. On the Channels panel, create four empty new channels, and drag them to the top of the channels list.
3. Convert the document color mode to CMYK via Image >Mode >CMYK Color. The conversion will automatically turn the four empty channels into empty Cyan, Magenta, Yellow, and Black channels. Spot channels—the ones containing all the image data in this case—will be preserved, and upon save from Photoshop, InDesign will now be able to import the image.
Note: If the image will be the only content of the InDesign document, you’ll wind up outputting blank
C, M, Y, and K plates. When it’s time to output, disable printing of the cyan, magenta, yellow, and black inks in the Print dialog Output pane.
Often when channel disaster images are made, they contain several identically named channels (e.g., PANTONE 462 C). Photoshop doesn’t care that these are the names of spot colors, only that they’re the name of channels, which is what leads to this problem in the first place. InDesign, however, does care about taking in two or more spots with the same name, and it will complain, preventing you from importing the image. If you get this, just go back to Photoshop’s Channels panel and rename the duplicate channels to something like PANTONE 462 C copy 1, PANTONE 462 C copy 2, and so on. This will also make it easier to identify the target and aliased colors in InDesign.
Once correctly aliased, the extra inks will disappear off the Separations Preview panel, leaving only one of each ink.
