- Address the ghostly artifacts. One reason why using a tripod
is recommended when taking a series of HDR exposures is that
Photoshop needs to align the individual frames to fuse them.
The slightest movement in your scene from one frame to the
next will cause a shift and most likely create ghosting in your
combined image, meaning some movement or change between
frames creates a luminance aberration in the photograph. Even
in the case of our seemingly deserted barn, with no wind or
creature in sight, our scene is still subject to the rotation of the
earth. So the angle of sun moved slightly while I was capturing
my various exposures, thus creating an artifact along the raf-
ters in the upper-right corner, as you can see (zoomed to 200
percent) in Figure 9-40.
Turn on the Remove Ghosts check box at the top of the panel
(circled in Figure 9-41 on the facing page). You won’t notice
any immediate change to the problem area. You will, however,
see a green stroke around the leftmost frame in the filmstrip
at the bottom. This is Photoshop’s way of telling you that it is
using that lightest exposure as the source for determining how
to address the aberration, which doesn’t do us much good in
this case. Instead, click the fourth exposure from the left in
the filmstrip to move the green indicator stroke and set that
exposure as the source for fixing the problem area. You can
see improvement in the preview window on the facing page.- Click the OK button. We’re done with our HDR adjustments,
so click the OK button at the bottom of the Merge to HDR win-
dow. You’ll be treated to a parade of progress bars as Merge
to HDR cooks up a 16-bit image and ultimately hands off the
merged composite to Photoshop. Press Ctrl+Alt+S (�-Option-
S) and save the image as “Dark Interiors HDR.psd.”
Luminance “ghosts” left by
shifting light from the sunFigure 9-40.
332 Lesson 9: Pro Photography Tools