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Index Color: The Fastest Proof-to-Print System?

(February 2008) posted on Wed Feb 06, 2008

Index separations are often avoided by those who fear being stuck with too many colors to print. This month, Trimingham debunks some myths about index color and explains how to use it as an effective tool in prepress.

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By Thomas Trimingham

Remember that an image must be the best it can be before you attempt to crunch colors or separate it. The final separations and print on the shirt will never be any better than the detail and information that can be properly reproduced from the original source. Once I adjusted and prepared the wolf, I created several layers that were painted with bright colors on top of the original layers. These painted layers are used for visual reference to see where I would create selections to simplify the final color palette in the image. This method has worked well for me in the past to show how the selections balance against one another. It accommodates a level of subtlety that is difficult to get with a hardedge selection tool like the Magic Wand.

The wolf had several areas in which I wanted to average the color gamut into browns, tans, or grays. This method allowed me to do that to a duplicate of the image in a very short time (Figure 2). When the layers were all finished I just created a selection of a specific layer by holding down the Control key (Cmd on the Mac) and clicking the layer. The next step was to select the original image copy layer that could then be adjusted by using the Hue/Saturation dialog box and its Colorize button. I carefully adjusted the hue on the selection to get the proper color tone so that it knocked out most of the extra colors. On the gray areas I used the Hue/Saturation dialog to take out most of the color by lowering the saturation value. These steps vastly improved the image and dramatically reduced the colors needed so that I could go ahead and finalize the design.


Setting up an image for a good index separation


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