Nearly all digital images need sharpening to some degree, and I apply various techniques and amounts of sharpening throughout my workflow. The most important sharpening stage, so that the final image looks crisp and focused, is done as a final step to the image once it has been sized for its intended use. When images are downsized they lose sharpness, as detail along edges is lost in the reducing process. When images are enlarged, the lack of sharpness inherent in digital images is magnified. Using Photoshop’s digital sharpening filters makes it possible to increase contrast along fine edges to bring back lost image sharpness. There are many ways to do this, but I have recently developed a technique that I think does quite well. It is important to note that digital sharpening is not a substitute for lack of sharpness in the original image. Proper focus, shutter speed and technique is required at the point of capture to enable good digital sharpening.First, open an image in Photoshop. Then, flatten all layers (if any exist) and size the image for its intended use (print, email, screen saver, etc.). For help on how to size images you can refer to my articles on SIZING FOR PRINTING or SIZING FOR EMAIL. Once the image has been sized it is time to apply sharpening to make it look appropriately sharp. The technique I have developed makes two sharpening passes. The first pass uses the Unsharp Mask filter set to add a small degree of sharpening to larger edges and details to help with the overall crispness and “pop” in the image. The second pass uses the Smart Mask filter set to add a greater amount of contrast to the very finest edges and lines in the image for razor sharp fine detail. Versions of Photoshop prior to CS2 don’t include the Smart Sharpen filter, so the second pass can also be made with the Unsharp Mask filter with good results.

Make sure that you are viewing the image at 100%, or, if it is a larger sized print, 50%. To complete the first, large detail sharpening pass go to Filter>Sharpen>Unsharp Mask. Select a Threshold of 1, a radius of .7 to 1.0 for web images and 1.5 to 2.5 for prints, and an amount in the 50 to 75 % range. I find it helpful to check and uncheck the preview box to dial in the right amount of sharpening. Select OK when you are finished. Now to sharpen the fine edges and details, go to Filter>Sharpen>Smart Sharpen (or Unsharp Mask again if your version of PS is pre CS2). Set the Remove box to Lens Blur, the radius to 0.1 for screen and web size images or .2 to .4 for prints, depending on how large the print will be, and finally, adjust the amount to 100 to 140% or until the desired sharpness is achieved.

I find that this two-pass sharpening technique does a great job of targeting sharpening to both the larger and finer details separately, especially for images that will be displayed on a screen. As with any sharpening technique, knowing how far to go without going too far is the key and some experimentation is needed to determine the best combination of adjustments for each individual image. Below are samples of a screen sized image. The first is not sharpened, the second is sharpened appropriately using this technique and the final image is over sharpened in my opinion.

This entry was posted on Tuesday, November 27th, 2007 at 7:13 pm and is filed under Digital Image Editing Tips, Digital Photography Tips. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.