Sharpening without an Aura

This is a method of sharpening designed to avoid the annoying "auras" that invariably will surround a photo using any of the sharpening techniques reccomended in other tips. There are three files used for demo purposes, all basically the same picture. I don't think this good-lookin' fella will give anybody much guff over putting his image online...seeing as how they're all me.

The first is the original blurred image. The second is an image sharpened using unsharp mask (I pushed it too far to prove a point by making the aura really visible). And the third, also pushed a bit too far is sharpened using my technique.

When sharpening an entire image, the most common technique is to simply use the Unsharp Mask Filter. This works OK, except that in order to sharpen, Photoshop must increase the contrast between pixels, making the dark parts darker, and the light parts lighter...it's those light parts that are much more visible, and usually cause the aura.

Look at a blurry photograph, not too blurry, though. This may be a good technique, but a miracle worker it does not you make. The image should be adjusted as necessary (levels, curves, hue/saturation), and cropped to size before really beginning. While doing the adjustments, incidentally, it may well be worth your time to switch to 16-bit mode while making the adjustments, then switching back to 8-bit mode when finished. This prevents any loss of quality in the histogram.

Once all of this is done, flatten your image, then duplicate the bottommost layer (usually the background, unless you merged instead of flattening. Either way, the bottommost frame must be then duplicated...this is where the sharpening is going to take place.

I'm going to assume you are working with an image with dark regions maintaining the subject,rather than the lighter regions. On the duplicate layer, apply Filter>Other> High Pass. This needs to be adjusted to choice, but the best starting point is approximately one two-hundreth the image's resolution (i.e. 150 ppi, 1.5 pixel radius).

This makes the light edges become very ligt, and he dark become very dark. It takes everything that was not an edge and makes it 50% gray.

Now, applied properly, those auras would still show up and ruin the edges of the image. So the light regions need to be removed, my best reccomendation is to apply the Gaussian Blur filter, setting it for at least three times the radius setting used with the High Pass filter. Since this destroys all of the detail, something must be done about it. Go to the edit menu, and select "Fade Gaussian Blur."

When the dialog comes up, change the blending mode to 'darken,' and the opacity setting to something lower than 100%. I reccomend something between 65-85%...I usually use 70%, which brings back some of the highlighting, just not so much as to leave an aura afterwards. Now, change the blending mode on that layer to "Hard Light" and reduce the opacity until the effect doesn't appear so obvious what the photo looks faked...again, 70-75% seems to work just fine. Flatten the image, you're done.

If you have a tutorial relevant to photo restoration, retouching, or manipulation, please email me with details and we'll either publish it here or link to it.

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