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Wednesday, August 1, 2007

Sharpening Techniques


A strong use of Radius in Unsharp Mask may help your nature images


Smart Sharpen in Photoshop uses totally new algorithms for sharpening compared to USM. Still, its controls work similarly to USM, allowing you to set Amount and Radius, but it has better compensation for halos and other artifacts.

Unfortunately, Smart Sharpen has no Threshold setting. That’s a severe limitation to me and keeps me from using it as my main sharpening tool. Without a Threshold setting, Smart Sharpen often increases the appearance of noise in a photo, and for that reason, I use it on a restricted basis.

I like Nik Software Sharpener Pro for printing. This is a Photoshop plug-in (though it works in other programs, including Photoshop Elements). Sharpener Pro does some nicely automated sharpening for specific printer types, print sizes and viewing distances. You don’t have to know anything about USM settings because it doesn’t use them. It uses terms like Size and Viewing Distance that are more intuitive. It also uses some advanced sharpening algorithms.

But the biggest benefit comes from the Advanced settings in Sharpener Pro. There you can tell the program how much to sharpen areas based on their colors and tones. This allows you, for example, to not sharpen a color or tone that has a lot of noise (noise is most common in specific colors or tones). The program smartly finds these areas and sharpens only what and how much you tell it to sharpen. It does a nice job with tiny highlights, too, bringing out image brilliance as well.

You should sharpen a photo based on its printed size. Size has a big effect on what details show up in a photo and how the image should be sharpened. This is especially true with Radius choices, so a photo should be sized before sharpening. In addition, there are good reasons for sharpening a photo late in the image-processing workflow. Many adjustments to an image can affect detail rendition and noise, both of which affect sharpness. Sharpening too early can result in less than optimum sharpening for a subject, plus it can result in sharpening artifacts that are intensified from the work on an image.

Editor Rob Sheppard will be leading a digital workshop and tour to Costa Rica in December. For more information, see the Holbrook Travel website, www.holbrooktravel.com (click on Nature Travel).



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