Tuesday, April 12, 2011
Creative Sharpening, Part I
When to sharpen in your workflow
Lightroom’s Print module with Output Sharpening
When performing creative sharpening, there are essentially no rules. Only the image source and the software you use to enhance it will determine the limits of how far you can go. If there are limits to how far you should go, those limits are only determined by consensus; in general, most viewers don’t want to be distracted unnecessarily by sharpening artifacts—unless they’re presented for a good reason. During creative sharpening, you can leverage any and all sharpening techniques. Creative sharpening can be as simple or as sophisticated as you choose or are able to choose. Increasing your skills will lead to enhancing your expression. The final determining factor during creative sharpening is that it creates a desired visual appearance.
Output sharpening benefits printed images. Images intended for display on monitors rarely need to be sharpened for output, unless they’re substantially resized. Output sharpening is intended to compensate for image softening due to characteristics of the output device, such as dot gain on inkjet printers, and varies with both the type of printer and substrate used and, in some cases, environmental factors such as humidity. Output sharpening typically also factors in the scale of the final product, which is used to determine an ideal viewing distance, though the actual viewing distance is usually variable.
Output sharpening is best done when viewing images at a screen magnification of 50%, the screen magnification that best displays medium-frequency detail such as contours. Previewing an image at 50% magnification is an imprecise, but practical way of compensating for the differences in between display (so many phosphors or diodes per inch) and printer (so many dots per inch, 2880 for Epson printers). Comparatively, low-resolution monitors can’t precisely preview what a print will look like on a high-resolution output device, much less precisely preview detail on many different output devices with varying resolutions and on varying substrates. Checking a file at 100% magnification for unwanted artifacts in high-frequency detail is recommended before committing to print.
As previewing output sharpening on monitors is imprecise, precise output sharpening must be confirmed with printed samples. The settings used to achieve optimum results in a representative image or selection of images then can be used for all images printed to the same output conditions. Output sharpening can be automated.
There are many competing solutions for output sharpening; automate it in Lightroom; automate it in Photoshop with plug-ins like Nik Software’s Sharpener Pro or Pixel Genius’ PhotoKit Sharpener; automate it with your own Actions in Photoshop. Using a preexisting solution reduces the testing necessary to create your own and brings to bear the expertise of experts in the field in your images. Though each solution requires a little testing before implementing, any one of them delivers better results than not performing output sharpening.
Output sharpening is one of the last things, if not the very last thing, you do to enhance an image file.
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