Operation Manual

Evaluating Tonality and Contrast
Although histogram graphs are good tools for evaluating an image’s exposure, you
shouldn’t interpret histograms for exposure information only, because the shape of the
histogram is also influenced by the tonality in the scene. You need to take the subject of
the image into account when evaluating its histogram. For example, images shot at night
are naturally going to have a majority of peaks in the darker side of the histogram.
Likewise, images of bright scenes, such as snow or light reflecting off the ocean, have a
majority of their peaks in the brighter side of the histogram.
Histograms can also depict contrast in an image. For example, this silhouette of the man
in the hammock in front of the sunset consists of a relatively even assortment of extreme
bright and dark tonal values with few midtones. In this case, the histogram is shaped like
a valley with peaks in both the dark and bright sides.
471Chapter 16 An Overview of Image Adjustments