Digital Darkroom

Output Options; Get Great Image Quality On The Web Page 2

Sharpening And Saving
Sharpening an image should be the last step performed before saving and will be different for each intended use. Sharpening an image is usually known as Unsharp Mask. It works by increasing the contrast along the edges of objects in the image. By emphasizing the contrast on the edges, the image appears to be sharper with more fine details.

In Elements, select Filter>Sharpen> Unsharp Mask. The three slider controls work together with Amount controlling how strongly the edge contrast is increased, Radius determines how wide the enhancement will be. Too much and the image will have obvious halos--obvious highlights around the edges of objects. Radius is the most important setting, so keep a close eye on the preview as you make adjustments. Threshold determines how much contrast there needs to be between objects to be considered an edge. Higher numbers require more contrast. There isn't one setting for Unsharp Mask that works for every image, but I find that web images are usually in the area of 100-150 percent Amount, .7-1.5 Radius, and 2-6 Threshold.

Sharpening should be the last step performed before saving your image to avoid over sharpening.

The final step is to save the image. Here, the goal is to keep file size to a minimum and the quality as high as possible. Normally, I save my web images with a JPEG setting of 7 or 70 (same setting, different scale). The Save For Web feature in Photoshop and Photoshop Elements is a great way to experiment with compression settings. Select File>Save For web, and make sure that JPEG is selected as the file type, and adjust the quality setting to an acceptable amount.

Save For Web is a great way to see what the effect of compression settings are. Using my normal quality setting of 70, I can detect no obvious difference in image quality, yet the file size shrinks from 731KB down to 75KB!

Conclusion
As always, I'm interested in your feedback and questions. If you have questions on this, or other digital output issues, send me an e-mail at editorial@edigitalphoto.com. I'll try to respond to all questions, and we'll answer some of the most common questions here in the column.

Jon Canfield is the co-author of "Photo Finish: The Digital Photographer's Guide To Printing, Showing, and Selling Images," published by Sybex. You can see Jon's work on his website, www.joncanfield.com.

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