Detail Panel Preview
When you're working with the Detail panel to sharpen a photo, it's often difficult to determine the exact effect of a particular slider. To see the effect in a new way, press Option (PC: Alt) and click-and-drag the sliders. This action will reveal a grayscale preview of the Amount, Radius, and Detail sliders to help you see exactly how the sharpening is working. In Figure 2, I dragged the Detail slider to view a grayscale version of the image. This view provided a helpful way to evaluate the amount of detail sharpening.
For the Masking slider, Option-clicking (PC: Alt-clicking) displays a white-and-black mask in which white reveals or allows sharpening, and black conceals or limits sharpening. At 0 the mask is completely white, meaning that the whole image is sharpened.