Problem Solving Using the Histogram

Problem Solving Using the Histogram

As you’ve no doubt noticed, the Levels histogram does not
update as you make adjustments. After Effects lacks a panel
equivalent to Photoshop’s Histogram palette, but you can,
of course, apply a Levels effect just for the histogram, if only
for the purposes of learning (as was done in Figure 5.11).
The histogram reveals a couple of new wrinkles in the
backlit shot from Figure 5.5, now adjusted with Levels to
bring out foreground highlights (Figure 5.12). At the top
end of the histogram the levels peak into a spike. This may
indicate clipping and a loss of image detail.
At the other end of the scale is the common result of a
Gamma adjustment: a series of spikes rising out of the
lower values like protruding hash marks, even though
a 16 bpc project prevents quantization. Raising Gamma
stretches the levels below the midpoint, causing them to
clump up at regular intervals. As with crushing blacks and

blowing out highlights—the net effect is a loss of detail,
although in this case, the spikes are not a worry because
they occur among a healthy amount of surrounding
data. In more extreme cases, in which there is no data in
between the spikes whatsoever, you may see a prime symptom
of overadjustment, banding .


Banding is typically the result of limitations of 8-bit color,
and 16-bit color mode was added to After Effects 5.0 specifi
cally to address that problem. You can switch to 16 bpc
by Alt-clicking (Option-clicking) on the bit-depth identifi
er along the bottom of the Project panel (Figure 5.14)
or by changing it in File > Project Settings. Chapter 11
explains more.