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Three Ways to Isolate Color

(February 2009) posted on Fri Feb 20, 2009

Determining the best way to separate images in Photoshop can be a challenging decision. This month, Trimingham narrows the playing field with three useful approaches to color separation.

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By Thomas Trimingham

One of my favorite ways to make a quality selection using the Color Range tool is to pick a color from the image the way you normally would and then cancel the selection and double click on the color that you selected in the foreground on the toolbar. Take this Color Picker menu and adjust the color value upwards to the right and increase the saturation of the color so that the color you picked has a larger gamut than the one originally chosen in the image. What’s the point of this extra step? The idea is that if you start with a more saturated color, you will also extend both the top and bottom end of the range that the color you created adheres to—and it will pull a color that is more likely to work as a blended selection channel. In other words, when you push the saturation of the selected color up the gamut range goes up as well.

A second method that works well with the Color Range tool is to visualize the color of ink that you know you have and can reproduce. This takes some experience with the inks (or a good ink reference as a review source), but it’s effective because the color that you pick for the color range is then likely to emulate the final reproduction limitations that your inkset will have. Some artists have claimed that they scan the printed inks in and adjust to that, but I have found it easier and more reliable to use a visual approximation. The odds of scanning in an ink and having it work properly as a reference is unlikely without having a color scanner, monitor, and the related software in perfect calibration and probably more frustrating than just a visual comparison.


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