Graphics Programs Reference
In-Depth Information
shadow input slider to the right until it reaches the graph (a value
of 31 in this case). Drag the highlight input slider to the left until it
reaches the graph (a value of 222 in this case). The image now has
much more contrast. Drag the gamma slider to the right so that more
of the pixels in the graph are on the left of the slider, thereby darken-
ing the image (see Figure 11.3). Click OK.
O
Keep in mind that
8-bit images such
as the example have
2
8
, or 256, possible
values of luminosity
from black up to
white.
Shadow
input
Gamma
Highlight
input
FIGURe 11.3
Remapping the tones to take advantage
of the full range available in the image
5.
Click the yellow warning triangle icon in the Histogram panel to
recalculate the graph. The recalculated graph is shown in Figure 11.4.
The pixels are now distributed across the full tonal range. The gaps
represent missing data; every adjustment partially destroys some of
the original tone data in the mathematical transformations. You'll
learn later in this chapter how to work nondestructively with smart
filters and adjustment layers.
FIGURe 11.4
Histogram
after the Levels adjustment
