GEM IN THE ROUGH: CHANGING THE MAGIC WAND'S SAMPLE SIZE Did you know you can change the way the Magic Wand calculates which pixels to select? Of course, you didn't; that's because the setting that controls the Magic Wand's selections appears only when you have the Eyedropper tool selected. (Makes perfect sense, doesn't it?) You can read about the Eyedropper tool on The Eyedropper Tool, but here's what you need to know about it to tweak the Magic Wand: Over in the Tools panel, select the Eyedropper tool (its icon, not surprisingly, looks like an eyedropper; it lives beneath the Crop tool). When you do that, a Sample Size pop-up menu containing a slew of settings appears in the Options bar. From the factory, the Sample Size menu is set to Point Sample, which makes the Magic Wand look only at the color of the pixel you clicked when determining its selection. However, the menu's other options cause it to look at the original pixel and average it with the colors of surrounding pixels. Depending on which option you choose, you can make the Magic Wand average the pixel you clicked plus the eight surrounding pixels (by choosing "3 by 3 Average") or as much as the surrounding 10,200 pixels (by choosing "101 by 101 Average"). The "3 by 3 Average" setting works well for most images. If you need to select a really big area, you can experiment with one of the higher settings like "31 by 31 Average". After you make your selection, simply activate the Magic Wand and then click somewhere in your image to see the effect of the new setting. It's that simple. Quoted from: Photoshop CS5: The Missing Manual [Book]
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