Image sharpness is a pretty critical thing. Photographers spend hours and days and years honing their craft in order to make sharper pictures. They spend thousands of dollars on the sharpest lenses, and then they—hopefully—apply the appropriate sharpening prior to output of a finished digital image file. There are lots of different tools for going about that last bit, and one of the most popular in Photoshop is the Smart Sharpen filter. But there’s another filter that can be a powerful ally in the quest for sharpness, and that’s the Unsharp Mask filter. Named for a traditional film process that creates the illusion of sharpness in a finished print, Unsharp Mask helps digital photographers in much the same way by enhancing contours and edges to increase the appearance of sharpness. John Paul Caponigro, master of digital imaging and, maybe even more valuable, master of explaining how to apply high-tech digital tools in an easy to comprehend manner, recently delved into Unsharp Mask on his blog, and it’s a must read for anyone looking to add another powerful tool to their sharpening repertoire.