Mastering the Photoshop Smart Sharpen Filter

In this article we look at mastering the Photoshop Smart Sharpen filter, answering questions like:

• Why use the Smart Sharpen filter?
• What do all the sharpening controls do?
• Where in my workflow does Smart Sharpening fit?

If you’ve tried to use Smart Sharpening with limited success or even given up with frustration, don’t worry. It’s not as difficult as it appears at first glance. By the end of this tutorial, you’ll be using the Photoshop Smart Sharpen filter like a professional. I’m using Adobe Photoshop CC for the screenshots but if you’re using an older Photoshop version, the controls will be similar.

Why Use Photoshop Smart Sharpen

Let’s be honest, the Photoshop Unsharp Mask filter is a lot simpler and easier to use than Smart Sharpen. It also does a pretty good job of sharpening images so why not use it? Well, if you’re happy with the results from the Unsharp Mask there’s no reason not to. It’s a great tool. But, if you’re wondering if you can achieve better results, and especially if you’re a Landscape Photographer, then consider using the Smart Sharpen filter instead.

Ultimately the reason to use Smart Sharpening comes down to control. When you use the Smart Sharpen filter you have more controls than in the Unsharp Mask filter. You can use these to fine tune your sharpening whilst minimising sharpening problems. But before I can explain how, you need to understand how image sharpening works. If you don’t or you’re not entirely sure, take a moment to read this article I published (opens in a new window).

Let’s now examine the Smart Sharpen controls to understand what they do.

The Smart Sharpen Dialog

Below you can see a screenshot of the Photoshop Smart Sharpen dialog.

Before we look at the controls here are some important things to be aware of:

• You can resize the dialog by clicking and dragging the edges and corners. When you resize the dialog it also makes the image preview area larger. This can help you better monitor the impact of your sharpening adjustments.
• You can pick a preview area for the dialog using your mouse. Just more your mouse pointer over an area of the image and click. This sets the preview point, but you can also reposition it by clicking on it and dragging as well as zooming in and out.
• To zoom the preview area, you can use the + and – magnifying glass icons to the bottom of the preview window. This also shows the level of magnification in the preview.
• When you’re sharpening an image, it’s also a good idea to zoom the main image window to 100%. You can then scroll around the main image by positioning the mouse pointer over the image and holding down the space bar. You’ll then see the mouse pointer change to a hand icon, then you can then click and drag. You can use this technique to monitor one area of the image on the screen and another in the Smart Sharpen dialog preview.
• At the top right of the Smart Sharpen dialog is the Preview option. Click this to toggle the sharpening of the main image off and on. Watch out though for it being slow to update with large images. The Preview option is useful for comparing the sharpened and unsharpened image so you can check to results.
• Below the Preview option, there’s a dropdown list of Presets which you can use to save your sharpening settings. If you want to apply the same settings to another image just select the Preset from the dropdown list. When you’re starting a new image, it’s often best to select the Default Preset from the list as a first step.

Smart Sharpen Controls

The main controls for sharpening with the Photoshop Smart Sharpen filter are in the top part of the dialog.

Here we have the Amount slider controlling how strong the sharpening is. Sharpening works by enhancing the contrast along edges. This means dark pixels along an edge become darker and light pixels become lighter. The higher you push the Amount slider the greater this contrast enhancement is. You need the enhancement to be strong enough to notice sharpening but not so strong that you can see the edge it creates. This contrast edge is usually better known as the sharpening halo.

The other sharpening control we have is the Radius slider. This controls how wide the sharpening effect along the edge is in pixels. As we make the Radius wider the halo becomes wider making it easier to see. This can make the sharpening effect appear stronger but if it becomes too wide the halo becomes obvious and looks ugly.

Use the Amount and Radius sliders together to produce the best sharpening effect for your image. It needs to be strong enough to notice but not so strong that the sharpening halos become obvious when viewed at 100% magnification. Whilst some people claim certain settings work best for all images, I disagree. The best approach is to refine the settings to match the image content and the type of sharpening you need to apply.

The third control we can see is Reduce Noise. When sharpening an image, you can also end up sharpening noise rather than detail. A good example of this is the sky in a landscape photo. When you increase the Reduce Noise slider it applies noise reduction and possibly threshold detection to reduce this problem. Take care not to use too high a Noise Reduction setting as it can remove fine details and damage the image. If you try setting a very high value, you will see it makes the image appear smeared.

Sharpening Options

Further down the controls, we have the Remove dropdown. The default setting is “Lens Blur” but there are two other options “Gaussian Blur” and “Motion”. Motion Blur is to help when sharpening images that have either moving objects or camera movement you want to minimise. We’re not covering the Motion Blur option in this tutorial as it really needs a full tutorial of its own.

The “Gaussian Blur” option applies the same type of sharpening used to match the Unsharp Mask filter. You will probably find this slightly stronger than the “Lens Blur” option. The benefit of applying it in the Smart Sharpen filter rather than the Unsharp Mask filter is the additional controls in Smart Sharpen.

For sharpening landscape photography and other images where you want to draw out the finest detail, use the “Lens Blur” option. This option’s optimised to emphasise detail whilst minimising halos and avoiding unnecessary sharpening of noise. This is the real secret of the Photoshop Smart Sharpen filter. 

Shadows / Highlights

The Shadows and Highlights sections of the Smart Sharpen dialog helps you to suppress sharpening halo problems. Earlier we said sharpening works by enhancing the contrast along edges and that this can cause problems at higher Amount settings. That’s because the contrast enhancement becomes so strong it can produce black and white edges in shadow and highlight areas.

The controls in the Shadow and Highlight section help you to fade the sharpening in those areas, reducing the halo effect. The default setting for the dialog turns these off by setting the Fade Amount slider to 0%. As you increase the fade amount it reduces the sharpening in these tones, restricting it instead to the image mid-tones.

The Tone Width slider controls how wide a tonal range the fading takes place across. If you want to fade the sharpening from a wide range of tones set a high slider value. Set it to a low value if you only want to fade the sharpening from only the lightest and darkest tones.

The Radius control sets how wide an area Photoshop checks to determine if it’s applying the sharpening’s in the shadows or highlights. Very low and very high radius settings are likely to produce poor results, but you should though judge each image individually.

Sharpening Workflow

Now you understand how the Photoshop Smart Sharpen controls, let’s look at when to use it. The best way to answer this is with the three-stage sharpening model:

1. Capture Sharpening applied during RAW conversion removes the softening effect of digital capture.
2. Creative Sharpening selectively enhances detail in the image.
3. Output Sharpening optimises the image for display or printing.

The Photoshop Smart Sharpen filter is best suited to the second and third stages of sharpening mentioned above. Even then, I would suggest it’s better to use a tool like Nik Sharpener Pro for Output Sharpening if you’re printing your image. It’s a complex area and Nik Sharpener Pro’s optimised for the many variables like viewing distance, print size, paper type etc.

When it comes to Creative Sharpening, apply this towards the end of your workflow. Typically, all your image adjustments are complete, and you’re working on a copy of your master image. Be sure to resize your image to its finished dimensions before sharpening. Resizing can often exaggerate or reduce the sharpening effect.

One final tip is that the Photoshop Smart Sharpen filter is a destructive edit. This means you can’t reopen the filter to tweak adjustments if you find problems. It’s therefore safest to create a new duplicate layer to apply your sharpening to. You should also convert this layer to a Smart Object so that when you do apply Smart Sharpening you can reopen and adjust settings. 

Watch the Smart Sharpen Video

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Summary

I’m sure you appreciate the Photoshop Smart Sharpen filter provides a high degree of control over your sharpening that’s not possible in the Unsharp Mask filter. As well as minimising noise and optimise fine detail, you have additional controls to supress problems with halos. Combine these features with Photoshop masks and layers and you can produce excellent results for any image.