Highest Quality Capture: Workflow Phase I - Black and White in Photoshop CS4 and Photoshop Lightroom - page 58

Example 11. Highlight Preference
This image and exposure histogram indicate preserved highlight information
in the bright curtain with some data loss in the shadow information. As the
detail in the highlights was my main concern with this image, I scrutinized the
data on the right.
If the image were not exposed to preserve the highlight information and were
overexposed, as the histogram to the left indicates, we would see a slam of
information on the right side of the chart.
Once again, if we notice a histogram indicating loss of highlight information
with an image such as the tent (below) or the woman by the window (right),
we would want to reshoot, stopping down or speeding up the shutter speed
to achieve an exposure that maintains highlight information.
Preserved highlights
Overexposed highlights