The Shadow/Highlight adjustment is an excellent way to reveal subtle detail in the shadow and/or highlight areas of your images. Although you could theoretically produce similar results with sophisticated use of Curves, the Shadow/Highlight adjustment is far easier to use when you need to recover detail that has been lost in shadow or highlight areas because of excessive contrast. It’s similar to the Fill Light and Recovery sliders in ACR, but it has additional controls so you can fine-tune the results.

Note: Some photographers are tempted to try to use Shadow/Highlight to fix all their exposure problems. We don’t recommend that because the Shadow/Highlight adjustment works by reducing contrast. That’s fine for small tonal ranges, but it’s not usually a good idea to do throughout the entire image. We find it’s far more effective to limit the Shadow/Highlight tool to recovering detail in the deep shadows and recovering highlights in very light areas.

Although you can’t apply the Shadow/Highlight adjustment as an adjustment layer, in CS4 you can use it as a Smart Filter. A filter that’s applied as a Smart Filter behaves similarly to an adjustment layer. The advantage of using it as a Smart Filter is that you can tweak the settings as needed, and you can add a layer mask to it to target the effects to certain areas of your image. For example, perhaps you have a portrait of a dark animal against a dark background. You may want to reveal details in the shadows of the animal but not in the background.

1. If your background layer is not already a Smart Object, you’ll need to convert it to one by choosing Filter > Convert for Smart Filters. That way, you can use Shadow/Highlight as a Smart Filter.
2. Choose Image > Adjustments > Shadow/Highlight. Shadow/Highlight will automatically be opened as a Smart Filter, as shown below.

Photoshop CS4 enables you to use the Shadow/Highlight adjustment as a Smart Filter.

The default dialog box for Shadow/Highlight in Photoshop includes only the Amount sliders for Shadows and Highlights. You should never use it in this abbreviated form; instead check the option for More Options. This enlarges the dialog box to include many additional controls for fine-tuning the adjustment (see below) and unlocks the real power of the Shadow/Highlight tool.

When you select the Show More Options check box, the Shadow/Highlight dialog box expands to include more controls.

The controls are divided into three sections. The Shadows and Highlights sections provide similar controls for adjusting areas of your image based on tonal value; the Adjustments section provides additional controls for improving specific aspects of the image. Using the basic Shadow/Highlight control is a simple matter of adjusting the sliders to extract the desired level of detail in the image. As you make these adjustments, use care not to overcorrect, which can create an image that is excessively flat or that has an artificial appearance.

The controls in both the Shadows and Highlights sections are the same, although they obviously target different areas of the image based on tonal value:

Amount The Amount slider affects the strength of the adjustment you’re making to the area. Think of the Amount slider for Shadows as allowing you to decide how much to lighten the darkest areas of your image. The Amount slider for Highlights provides a similar ability to darken the brightest areas. Your first reaction may be that doing so simply reduces contrast and produces a muddy image. However, keep in mind that this adjustment is designed for situations where contrast is too high or when you want to extract more detail from the darkest and brightest areas of your image. When used with modest settings, the result is an effective increase in detail without a problematic loss of contrast.

Tonal Width To adjust the range of tonal values that will be affected by this adjustment, use the Tonal Width slider. A low value causes only a limited range of tonal values within the image to be affected, whereas a high value allows the adjustment to apply to a wider range. In other words, you expand or contract the area to be adjusted by defining a tonal range. Try to limit the tonal width to as narrow a range as possible to give you the desired results.

Radius The Radius slider determines how far outward from pixels that fit within the defined tonal range the adjustment will spread. This provides the ability to blend the adjustment to produce a more realistic effect.

Note: You’ll find the best settings with experimentation. Usually you’ll want the Tonal Width setting to be as limited as possible and still affect the desired tonal range. Often we find effective radius settings around the 25–40 range and again at the very high range of the scale. Don’t hesitate to drag the sliders and experiment.

After you’ve adjusted the controls in the Shadows and Highlights sections, use the Adjustments section to fine-tune the final result. The Color Correction slider is really a saturation adjustment that affects the darkest areas of your image. This control allows you to compensate for shadow areas that often have reduced saturation compared to other areas of the image because there isn’t adequate light to enhance the colors. After you’ve brightened up shadow areas, you’ll likely want to increase the saturation slightly so those areas match the rest of the image.

Similarly, brightening shadows and darkening highlights helps extract more detail but results in an overall reduction in contrast. The Midtone Contrast slider allows you to apply some compensation by adjusting contrast for just the midtone values within the image, leaving the shadow and highlight areas you’ve already adjusted relatively unchanged.

The Black Clip and White Clip settings allow you to specify how much detail can be sacrificed in the image when making adjustments by using Shadow/Highlight. We recommend leaving these values to their default of 0.01% to minimize the loss of detail.

Note: Don’t let the Save As Defaults button lull you into thinking you can establish one set of adjustments for Shadow/Highlight that will be appropriate for all images. Each image deserves its own custom settings.

Once you’ve established the optimal settings in the Shadow/Highlight dialog box, click OK to apply the adjustment to your image, as you can see below.

The Shadow/Highlight adjustment allows you to extract detail in your image with relative ease. Photo by Ellen Anon