Hunter-Ch09.qxd
12:1:07
8-14 AM
Page 232
LIGHT—SCIENCE & MAGIC
9.4
A scene exposed normally
has some compression in both the shadows and the highlights, but the problems are not obvious.
wide range of highlights and shadows to study. Notice that individual stones are faintly visible in both the highlight and shadow areas of the wall. There is some compression in both those highlights and shadows. You cannot see the problems because we did not have bad CCD or ideal CCD to make comparison pictures. You will see these problems, however, in the next section, when they are exaggerated by exposure error. Overexposure Keep in mind that in an average scene with a normal exposure, compression occurs at both extremes of the density grayscale. Changing the general exposure decreases compression at one end of the grayscale, but it worsens the compression at the other extreme. Figure 9.5 shows the benefits and the sacrifices of overexposure.
232