General Sharpening

^linost every digital image needs to be sharpened at some point, and the Unsharp Mask filter is a favorite tool. However, because it's a destructive process, Unsharp Mask is often applied as the final step before printing. There is a surprising nondestructive alternative that involves the Hard Mix blending mode used in conjunction with a low-radius Gaussian Blur. When I first encountered Hard Mix, its obvious use seemed to be to drastically transform an image. It reduces an image to just eight colors and this brutal behavior is still apparent even after reducing the opacity. However, if you apply a small amount of Gaussian Blur to the Hard Mix layer, then there is a noticeable sharpening effect. You can adjust the strength of the sharpening effect by experimenting with the Fill Opacity slider.

1 In the Layers palette, duplicate the original image by dragging the background layer onto the "Create a new layer" icon. Alternatively, just use the keyboard shortcut Ctrl/Cmd-J Name this layer "Hard Mix."

2 With the Hard Mix layer selected, choose Hard Mix from the blending mode pull-down menu

3 Apply a small amount of Gaussian Blur to the Hard Mix layer Somewhere between

3 and 4 seems to work best.

4 Experiment with the Fill Opacity slider until you achieve a satisfactory sharpening effect

Basic technique

Make a duplicate of the image layer Then if you want to see the effect of applying blur in real time, make the blend layer Hard Mix and reduce its opacity to ro% Next, apply a small amount of Gaussian Blur—I usually settle on something between 3 and ii. If you haven't already switched the layer to Hard Mix, do so now In either case, you will probably want to adjust the opacity again

Straight out of the camera, many digital images appear slightly soft.

Original image.

The dialog shows the blurred Hard Mix blend layer, but look at the image itself to see the sharpening effect resulting from small changes in blur amount.

At 8% fill opacity there is a distinct improvement in contrast and sharpness.

Gaussian Blur

Original image.


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