Apple Aperture 3.5 - Manual (Page 347)

Chapter 7 Make image adjustments 347
Likewise, histograms can depict a lack of contrast in an image. For example, an image of a
rainbow in the fog lacks contrast. Without directional lighting, there aren’t any highlights or
shadows in the image. In this case, the peaks of the histogram are concentrated in the center
and don’t come close to either the dark or bright side.
67% resize factor