Many people use the Shadow/Highlight adjustment in Photoshop simply to bring out detail in the shadows, leaving the highlights alone. There's certainly nothing wrong with that, especially since our eyes are not nearly as good at distinguishing highlight detail as they are with shadow detail, so the Shadow/Highlight command seems to get most of its "wow factor" from the shadows. However, the Highlights section of the Shadow/Highlight dialog box, which you'll find directly below the Shadows section, is designed specifically to bring out any hidden details in the highlights of an image, and the best part is, you already know how to use it!

The Highlights section contains the exact same three sliders - Amount, Tonal Width and Radius - that we just looked at in the Shadows section, and they work exactly the same way. The Amount slider determines the amount of darkening you want to apply to the highlights. The further you drag the Amount slider towards the right, the more highlight detail you'll bring out. The Tonal Width slider determines the range of tonal values that will be affected. The only difference here is that it sets the range for the highlights, not the shadows. At its lowest setting, only the brightest areas of the image will be affected by the adjustment. As you drag the Tonal Width slider towards the right, you'll expand the tonal range to include more of the midtones. The Radius slider determines how the adjusted highlight areas will blend in with the rest of the image. Just as with the Radius slider in the Shadows section, setting the Radius value too low will cause the image to look flat. Again, there are no specific values to use for these options since the correct settings will depend entirely on the image you're working on, so keep an eye on your image in the document window as you move the sliders.

Generally, it's best to avoid making any major changes to the highlights since it could reduce overall image contrast, but minor changes can often help. After adjusting and then fine-tuning my Highlights sliders, I've settled on an Amount value of 10%, a Tonal Width value of 62% and a Radius value of 80px. Of course, your settings with your image will most likely be different:

Here's my image after darkening some of the highlights. The difference is subtle, but the water reflections are not quite as bright as before, lessening their impact and bringing more attention to the duck. Also, some minor detail has been restored in the brighter areas of the duck's feathers:

If you find after you've finished adjusting the shadows and highlights that your image has lost some of its original color saturation, you can give the saturation a boost using the Color Correction slider found in the third section of the Shadow/Highlight dialog box, Adjustments. I'm not sure why Adobe chose to call it the Color Correction option since it really is nothing more than a saturation slider, but if you need to increase color saturation, simply drag the slider towards the right, or drag it towards the left to lower the saturation amount. The default value of +20 is usually good enough, but I'll increase mine to +30 to make the colors a little more intense. Finally, the Midtone Contrast slider can be used to increase contrast in the midtone brightness values, giving the image a bit more "pop" if needed. I'm going to increase my Midtone Contrast value to around +20:

And with that, we're done! Here is my original image once again for comparison:

And here, after bringing out the shadow details and toning down some of the highlights, is my final result using nothing more than the Shadow/Highlight adjustment in Photoshop:

And there we have it!