Unsharp Mask vs. Smart Sharpening Revisited in Photoshop

Now to clearly illustrate when using the Smart Sharpen tool will provide a definite advantage, let’s compare applying Unsharp Mask and Smart Sharpen to the same image.

1. Open your image that has a wide range of grayscale values: some obvious lighter leaves suspended in ice, which comprises a dark background. We would like to apply a large amount of sharpening to really emphasize the edges of the leaves suspended in the hard transparent ice.
2. To help make my point we will place a Color Sampler point along the edge of one of the leaf edges in order to monitor its RGB values during sharpening. Select the Color Sampler tool (the second Eyedropper tool). Also activate the Info panel (Window --> Info or F8) and place it where you can monitor it at all times. Also activate the Layers panel (Window --> Layers or F7).
3. Zoom in on the left edge of the lightest colored/middle leaf. Click with the Color Sampler Tool to place a Color Sampler point on the edge of the leaf. This will be labeled with a #1 both on the Color Sampler point and in the Info Panel. Note the initial RGB values recorded in the Info Panel (233, 235, 220) These are all printable values.
4. Make a duplicate of the background layer and name it USM 200_1.5_0.
5. Choose Filter --> Sharpen --> Unsharp Mask to activate its dialog.
6. Apply the following values: Amount = 200, Radius = 1.5, Threshold = 0.
7. Now view the RGB values of the Color Sampler point (Figure 9.18). They now measure 255, 255, 255. All three values have been blown out and are not printable. And the only way to reduce these values is to reduce the Amount and/or radius of sharpening applied.
8. Now create another duplicate of the background layer and name it SS 200_1.5.
9. Choose Filter --> Sharpen --> Smart Sharpen to activate its dialog.
10. Click the Advanced button and click the Sharpen tab. Apply the following values: Amount = 200, Radius = 1.5 (Figure 9.19).
11. Click the Highlight tab. In the Fade field type in 15%. Also type in 15% in the Tonal Range field. Leave the Radius = 1. While you type in these values, monitor the RGB values of the Color Sampler point. Note the resulting RGB values have now been reduced from (255,255,255) to (246,247,237), far more acceptable and printable values. We have used the Highlight tab values to rescue the impact of the sharpening along the edge of the leaves, which were previously blowing out, without having to reduce the  overall sharpening values of Amount = 200, Radius = 1.5.

Limit the sharpening effect along a very narrow tonal range, the light pixels along the edge of the leaves. So we used a combination of small values (there are a range of Fade and Tonal Range values that could work here). Here is an overview of the three value fields.
Fade Percentage of reduction, or fade, which will occur from the values created by the Amount and Radius settings applied in the Basic dialog.
Tonal Range The range of tonal values that will be affected by the Fade percentage.
Radius The width, in pixels, of the number of pixels that will be evaluated and affected. I typically set this close to the Radius value set in the Basic dialog. This field is limited to whole pixel values, so I would choose either 1 or 2 here because the Basic field Radius = 1.5. I use the lower value here because my intent was to limit the distribution of the amount of Fade. If you want to remember the values you used, update the name of this layer to include your values.
12. Alternately, activate your Unsharp Mask and Smart Sharpen layers and view the RGB vales of the Color Sampler point. Experiment with several layers with different sets of field values to see the impact of various value sets. You will likely find you will fine tune the combination of Fade and Tonal Range to achieve the result you like. You can see why many have abandoned Unsharp Mask in favor of Smart Sharpen. But you can also see that using the Smart Sharpen method is a bit more complicated. So if you  have an image that only requires a global set of sharpening vales, Unsharp Mask is still a useful production tool. Now, keep this Leaf in Ice image open. In our final section on sharpening tools and techniques we will explore how to use selections, masks, and filters to control the distribution of sharpening in an image.