The clarity slider was introduced in Lightroom 1.1, and is also now in Camera Raw. A positive clarity value punches up an image, makes it look a little more three dimensional, by enhancing contrast along edges. The changes are concentrated in the midtones, and do little to highlights and shadows. Here is an example, a portion of an image with Clarity set to 0, and then set to 60.
60 may be a bit strong, but hopefully you see the difference. I find that almost all my images can use some clarity, at least 30. Note that it is not a substitute for sharpening, which does increase edge contrast, but along a much finer/narrower edge.
Now for the cool part: negative clarity, which as expected, decreases edge contrast. What are wrinkles, but edges?! So let’s soften some wrinkles and skin to get a little bit more of a healthy glow … my own face makes a great candidate. The first image shows no adjustment. In the second image, with the adjustment brush in LR (or CS4 Camera Raw) active, I set the Clarity slider to -100, and painted over my face, excluding the eyes and mouth.
Actually, since some of my wrinkles are deep enough to be dark shadows, clarity only improves them a little, but it does much to soften the blotchiness of my skin. If -100 was too much, I can dial it back after painting (can I ever look too young??) And it is so easy to do.
If you don’t know how to use the adjustment brush, watch my video HERE.