Adobe Photoshop CS4 Studio Techniques

Histograms and Automatic Adjustments

When you work with images that contain large areas of white/black (like ones with fancy borders, as in Figure 5.52), the Histogram panel can be less than useful, because the histogram indicates that the image contains the full range of brightness levels (Figure 5.53)—even though the image itself (minus the border) might be rather low-contrast. To get around this problem, you’ll need to take steps to limit what the histogram examines when analyzing the image. You need to optimize the contrast of the important areas of the image, without having to look at spikes at the ends of the histogram that reflect the large areas of black or white in the border area. You can also use this technique when you want to enhance ...