Phase One H 5 - Manual (Page 46)

Curves
The next window in the Exposure
tab is the Curves control, again
this is a standard Curves control
that may look familiar to those of
other imaging programs.
The Curves control is extremely
powerful and can be used to
control every tone in the image.
An imaging curve is a graph that
represents the original data along
the bottom and the output or
developed data along the side.
The dark tones are to the left,
while the light colors are on the
right. The default curve is a
straight line, which means that the
image data is not changed by the curve. To use the curves, click
anywhere along the line to add a point and then drag the point up
or down to affect the tone in the image.
In the example a point has been added in the lower (darker) end of the
curve (called the three-quarter tone) and pulled down. This will make that
point darker in the developed image. A second point was added in the
quarter-tone (light end of the curve) and pushed up. This will make that
point lighter. In addition to darkening and lightening these two selected
points, because the entire curve was shifted between these points an
overall increase in contrast will occur from this “minor” change.
Curves are extremely powerful and should be used with caution and
discretion. Again, as with the Levels control, RGB channels can be
controlled individually, and settings saved and loaded.
To control the brightness and contrast of the image two standard tools
are available: Levels and Curves.
Levels
The first part of the Exposure Tab is the Levels control. This is a standard
levels box similar to that of Adobe Photoshop. To make an adjustment
drag the black or white slider left or right to either darken the shadows or
lighten the highlight. Alternativly, click on the black or white eyedropper
and select an area of the image to set as the shadow or highlight point.
Beneath the display are preview windows showing the “before and after”
of the changes.
At the top of the window
settings and tonal adjustments
can be loaded, or saved for
future use. The “Preserve
Balance” option ensures that
all three color channels are
adjusted simultaneously. If this
option is un-checked the three
color channels can be con-
trolled independently.
Editing and Selecting Images
13.10
Editing and Selecting Images
13.11