Optimal image sharpening is best done in three stages—capture (do it during RAW conversion), creative (do it in Photoshop) and output (automate it).
Capture sharpening benefits all images. It compensates for inherent deficiencies in optical and capture systems. All lenses and sensors have specific characteristics and deficiencies. They don’t all have the same characteristics or deficiencies.
To speed your workflow, default settings for a best starting point for capture sharpening can be determined for all images created with the same lens/chip combination and saved for subsequent use. To optimally sharpen an image, you’ll need to modify these settings to factor in additional considerations—variances in noise (ISO, exposure duration, temperature), noise-reduction settings and the frequencies of detail (low/smooth to high/fine texture) in an image.
Capture sharpening is determined visually. Perform capture sharpening while previewing an image on a monitor at 100%, the size that most precisely displays high-frequency detail such as texture and noise.
Capture sharpening is best done during RAW file conversion. (Do it after scanning for analog originals.) I recommend importing your RAW files into Photoshop as Smart Objects. If you do this, you quickly can access specific sharpening and noise-reduction settings simply by double-clicking the image layer. At the same time, you’ll also be able to take advantage of any updates in detail rendering (noise reduction and sharpening) with the click of a button.
Capture sharpening is typically done globally and uniformly to all areas of an image, but on-the-fly masking routines are recommended for reducing and removing sharpening effects, such as halos on contours and noise in low-frequency or smooth image areas.
When performing capture sharpening, err on the conservative side and avoid producing unwanted artifacts. Don’t fall prey to the temptation to fix unwanted sharpening artifacts you could produce at this first stage of sharpening in subsequent stages of image editing; you’ll get better results if you don’t produce unwanted sharpening artifacts at all. Additional sharpening enhancements can be performed locally with more precision in Photoshop during creative sharpening.
Set Clarity before sharpening. It produces a different but related contour contrast. If you change Clarity settings substantially, you need to double-check your sharpening settings.
Perform noise reduction before capture sharpening. You’ll use slightly more aggressive sharpening settings to compensate for the blurring noise reduction introduces. As with capture sharpening, produce as few artifacts as possible during noise reduction. If you need to perform more aggressive or localized noise reduction, do it in Photoshop. (See my noise-reduction series)
The Detail controls in Adobe Camera Raw and Lightroom are identical; only their appearance varies.
There are four Sharpening sliders:
1. Amount controls the contrast of the effect produced.
2. Radius controls the width of halos (light) and lines (dark) produced around contours.
3. Detail skews the effect toward a particular frequency of detail: high, medium or low.
4. Masking creates on-the-fly edge masks, removing the effect from smoother lower-contrast areas. (You can see the mask when you hold down the Option/Alt key and click on or slide the slider.)
Images with high-frequency detail benefit from using smaller Radius settings, and higher Amount and Detail settings (and lower noise-reduction settings). Images with low-frequency detail benefit from using higher Radius settings, and lower Amount and Detail settings (and higher noise-reduction settings). Images with a wider variety of frequencies, especially those that contain significant contours, benefit from higher Masking settings.
If you don’t know where to start, begin with an Amount of 100, a Radius of 1.0 and a Detail of 50. Look critically at the way the effect affects your image. There will be many times when you’ll want to readjust noise-reduction settings after determining sharpening settings. The two are intimately related.
Finding an optimum balance involves making trade-offs. Again, be conservative and avoid producing artifacts. This is perhaps the hardest part of capture sharpening, as the tools are powerful and the effects can be compelling, so the temptation to go too far is great. Resist. Remember, there’s a second stage of sharpening for localized effects: creative sharpening.
Double-processing RAW files with Photoshop allows you to apply different noise-reduction and sharpening settings to different areas of an image. In one version, you aggressively can sharpen high-frequency detail with little noise reduction, such as textured stone, and in a second version, you minimally can sharpen low-frequency detail with high noise reduction, such as a clear blue sky. When you do this, you can optimize sharpening settings for one frequency of detail and ignore the artifacts produced in another. With detail settings optimized for different frequencies on separate layers in Photoshop, you can mask the suboptimal areas in the overlying layer, and reveal the optimal detail in the layer below.
Here’s an easy way to do this. First, import the first version into Photoshop as a Smart Object. Second, go to Layer > Smart Objects > New Layer Via Copy. Third, double-click the new Smart Object to change the detail settings in the overlying layer. Note: If you simply duplicate a Smart Object instead, the settings will be reset in both layers. The way you make the Smart Object determines whether the duplicates share the same settings or have different settings.
John Paul Caponigro, author of Adobe Photoshop Master Class and the DVD series R/Evolution, is an internationally renowned fine artist, an authority on digital printing and a respected lecturer and workshop leader. Get over 100 Lessons with his free enews Insights at www.johnpaulcaponigro.com.