Using the Clarity Slider in Lightroom
I believe that Jeff Schewe campaigned hard to get this particular feature included into Adobe Camera Raw, and here it is now in Adobe Lightroom 1.1. As Jeff himself will tell you, Clarity is a hybrid based on two separate contrast-enhancing techniques:
- A local contrast enhancement technique, devised by Thomas Knoll, using a low amount and high-radius setting in the Photoshop Unsharp Mask filter
- A midtone contrast enhancement Photoshop technique that was originally devised by Mac Holbert of Nash Editions
In my book Adobe Photoshop CS3 for Photographers: A Professional Image Editor's Guide to the Creative Use of Photoshop for the Macintosh and PC (Focal Press, 2007), you can read the steps Mac used in Photoshop to create this effect. The Photoshop instructions are admittedly quite complex. However, Clarity is now available as a simple one-shot slider control in the Basic panel of the Develop module in Lightroom 1.1.
Figure 1 shows a closeup 1:1 view of a photograph taken of some pumpkins. A few adjustments have been made to the basic tone controls, and sharpening has already been added via the Detail panel. You don't necessarily have to be viewing the image at 1:1 in order to evaluate the results, but it's usually the best way to work.
Figure 2 shows how the pumpkins look after adjusting the Clarity slider. In this example I've taken the slider to the maximum setting in order to show the most dramatic difference between the two. Normally, you would want to start around 10 and try not to overdo the effect. But as you can see, the Clarity adjustment adds a halo-edge effect to the midtones only (the shadows and highlights are protected). As you increase the amount, the halos get wider, strengthening the midtone contrast effect and making the midtone areas look sharper. You can see the halos forming as you drag the slider left and right.
The Clarity adjustment can be applied to many kinds of photographs. Mac Holbert originally devised this particular effect in order to boost the midtone contrast, and he found that it helped him to bring out crisper detail in his landscape prints. But I think most photographs can gain from adding a little bit of clarity.