One of the things I really like about Aperture is being able to adjust my images while I’m sorting through them. Applying some quick modifications using the Adjustment HUD lets me make better decisions about which images to keep. One adjustment that can be particularly helpful is Highlight/Shadow. Using it can often reveal more detail in the darkest and lightest areas of the picture. Surprisingly quite a few Aperture users aren’t aware of, or using this powerful tool.
Highlight/Shadow is located in the Adjustment HUD right below Levels. By default there are two sliders - one for highlights and one for shadows. These are the Amount sliders and actually I find they often provide a good starting point. However for more control, click the Advanced expansion arrow. Additional sliders for Radius, Color Correction, High and Low Tonal width, and Mid Contrast appear.
Since Highlight/Shadow works by reducing contrast (it makes the darkest darks lighter, and the lightest lights darker) it’s best to apply it only where it’s really needed. So as a matter of habit, I use the minimum tonal width that I can, according to the needs of each image. I often increase the mid tone contrast slightly to compensate for the decrease in contrast at the extremes. The Color Correction slider will increase the saturation of the colors in the tonal values that you are lightening or darkening. I rarely find that I need to adjust the Radius slider, but if the results of the Highlight/Shadow adjustment don’t look natural, try adjusting the Radius slider.
The difference between the original version of this volcano image and the version with a Highlight/Shadow adjustment is pretty impressive. Without being able to see the detail revealed by the Highlight/Shadow adjustment, I probably would have deleted this file.
Original
After Highlight/Shadow Adjustment
Don’t use the Highlight/Shadow adjustment on every image - it’s not a replacement for setting the Exposure or Levels adjustments. But on certain images like this view of the volcano, it can make a huge difference. And the cool part is being able to apply the adjustment so quickly while you’re still sorting through your images.
Because I tend under expose many shots during a wedding shoot, I've found that these tools help recover highlights in areas. I use the shadow sparingly, however, becaue like you say it will decrease the contrast. And unlike with Lightroom, you don't have to click to Develop in order to get to and use the shadow recovery tool.
Now about the two above photos. I think the second is better. Has slightly more drama, but I do wish to see perhaps stronger contraast in the foreground clouds.
Photography truly is an art where personal taste plays a major role, doesn't it? I actually prefer a final version that was somewhere in between these two pictures, but pretty close to the "after" version. I chose to use this version here to emphasize how much detail might be lurking in the shadows.
Although I'm a big proponent of the power of layer masks, I find that by setting the tonal width carefully in Highlight/Shadow, along with the radius and other Advanced sliders, I can often achieve a natural looking result without needing to use an external editor such as Photoshop. However I sometimes follow the Highlight/Shadow adjustment with Levels quarter tone adjustments to adjust the midtone contrast further.
I too am a fan of these tools, but am I alone in preferring the 'before' picture to the 'after' one here? I think the original is more arresting.
I was using the shadow tool to bring out some of the detail on one of my photos earlier today and, while it did a splendid job of that, the result on the image overall was to make it flatter and less exciting.
This is where you really need to move to photoshop, perhaps, where layer masks will allow you to keep areas of greater contrast while still showing some of the revealed detail.