Understanding Unsharp Mask

Understanding Unsharp Mask

Sharpening is a critical part of a digital workflow aimed at producing the highest quality images possible. Having a good understanding of the use of Photoshop’s Unsharp Mask filter for sharpening your images will enable you to produce the best results possible.

SHARPENING FUNDAMENTALSThe most important thing to know about sharpening is that it doesn’t improve focus. If an image is out of focus, applying some sharpening to it can help improve the overall appearance, but it won’t make it a sharp image. If the image wasn’t sharp to begin with, the final print won’t be sharp. The sharpening tools available with image editing software don’t replace good photographic technique. You need to start with images that are in sharp focus.

Sharpening should be applied as the last step for your image before printing. That means not sharpening until all adjustments have been made to your image. To achieve optimal results, it is also best to sharpen your image after you have sized it for printing. My preference is to apply sharpening as part of the final printing workflow, after the master image has been saved and I’m preparing the file for printing. This sharpened print image may or may not be saved depending on how frequently I think I may print the image.

While sharpening can be a critical step in compensating for the loss of sharpness that occurs in the process of scanning film, recording a digital capture, or printing, it is important to know when sharpening is not only unnecessary, but potentially degrading to the quality of your image. If you don’t need to enhance detail in an image, and you want to be sure to avoid enhancing any grain or noise in the image, sharpening may best be avoided. For example, I have seen many photographs of sunsets where nothing has a crisp sharpness, and sharpening would only serve to enhance grain in the sky and potentially degrade the subtle gradations of tone and color. In such images, it is often wise to avoid sharpening. Just because sharpening is part of your normal workflow doesn’t mean it needs to be applied to every image.

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