Photoshop CS2's Smart Sharpen filter brings a new intelligence to an
Fade Amount: Adjusts the amount of sharpening in the highlights or shadows. A Fade value of 100 percent conceals the sharpening; lowering this value reveals it, incrementally, in effect increasing sharpness. Think of it as an opacity slider in reverse.
Tonal Width: Controls the range of specific tones that are modified by Smart Sharpening. Lower values restrict the adjustments to the darker areas for shadows and only the lighter regions for highlight correction. Lower settings produce more subtle results.
Radius: Controls the size of the area around each pixel that is used to determine whether a pixel is in the shadows or highlights. Just as with Radius in Basic Mode, moving the slider to the left specifies a smaller area, and moving it to the right specifies a larger area.
The true challenge in working with the Smart Sharpen filter is to find the right balance between the Amount and the Radius settings. For digital camera files or scans with minimal grain, use higher Amount settings, between 75 and 250, and lower Radius settings, between .3 and 1.5. This may look too "crispy" on your monitor, but such artifacts will be less visible in a print. For images with noticeable grain, use lower Amount settings of 15 to 30 and higher Radius settings of 10 to 20 in order to minimize texture.
In images with fine detail and a wide tonal scale, you can use the Smart Sharpen filter to adjust the actual contrast in addition to improving sharpness. In many of my full resolution digital camera files, especially of landscape subjects, I often apply a contrast sharpening to punch the image up. You can see the effect in the series of three images below. The process is very simple: Duplicate the Background layer, change the Layer Blending mode to Luminosity, and choose Filter > Sharpen > Smart Sharpen, setting an Amount of 20 and a Radius of 50. One thing hasn't changed in the shift from chemicals to pixels: Contrast and sharpness are intimately linked.
Artist and photo educator Katrin Eismann is the author of several books on digital imaging. Visit photoshopdiva.com.