The expanded version of the Shadow/Highlight dialog box may appear a little intimidating at first, especially since the simplified version of the dialog box contained only two sliders. If you look closely though, you'll see that it's divided into three sections, and two of the three sections are exactly the same. At the top is the Shadows section containing three sliders to help us bring out shadow detail in the image. Directly below it is the Highlights section which contains the exact same three sliders. These sliders allow us to bring out detail in the highlights and they function exactly the same as the sliders in the Shadows section, so once you understand how the Shadows section works, you'll already know how the Highlights section works! Below the Highlights section is the Adjustments section which contains a few additional options for adjusting the image. We'll look at the Adjustments sections a bit later. First, let's look at the three sliders that make up the Shadows section.

The first slider, Amount, is straightforward stuff. It controls the amount of brightening that you want to apply to the shadows. The further you drag the slider towards the right, the more shadow detail you'll recover. If you drag it too far, you'll brighten the shadows too much, but there's no need to worry about it since you can go back and fine-tune it later. Every photo is different, which means there is no specific value to use here, so keep an eye on your image in the document window as you drag the Amount slider and set it to whatever looks good for now. I'm going to set mine to around 40% to start with. The amount you decide on may be completely different depending on your image:

Simply by increasing the Amount value, I've brought out lots of detail in the shadow areas of the image. The photo is already looking much better:

Below the Amount setting is the Tonal Width slider, which determines the range of tonal values that will be affected by the adjustment. At its lowest setting, only the darkest areas of the image will be affected. As you drag the Tonal Width slider towards the right, you'll expand the range of affected tonal values to include more of the midtones. Again, there is no specific value to use, so you'll need to look at your image as you drag the Tonal Width slider to determine which setting works best for the photo you're working on. For me, a Tonal Width value of around 60% looks good:

Finally, the Radius slider determines how the adjusted areas of the image will blend in with the rest of the photo. If you set the Radius value too low, the image will appear flat and dull and you could also see harsh transition areas between the adjusted and unadjusted areas of the image. Generally, a higher Radius value works best, although again it depends on the photo so you'll want to look at the image while dragging the Radius slider to judge the correct setting. I'm going to drag my Radius slider to a value of around 70px:

Once you've set the Radius value, you'll most likely want to go back and fine-tune the Amount and Tonal Width settings until you determine the values that work best. It's not uncommon to go back and forth several times with the settings before you get them just right. I'm going to bump my Amount value up even further to around 60%. My original Tonal Width setting of 60% still works well:

I've settled on an Amount value of 60%, a Tonal Width value also of 60% and a Radius value of 70%. I think my photo now looks greatly improved with much brighter, more detailed and natural looking shadow areas:

We'll look at how to bring out detail in the highlights, as well as some additional options, next!