Graphics Programs Reference
In-Depth Information
Curves
Curves is another editing tool providing the ability to af ect tone and contrast
correction within an image. Curves, however, is far more powerful. This is the
digital darkroom power tool. Just as a hand-held screwdriver and a power
operated drll can perform the same functionality, Levels and Curves, too,
accomplish the same tasks. Levels is to the hand-held driver with three points
of adjustment as Curves is to the power drill with 16 points of adjustment.
The concepts are the same as in the Levels dialog box; the method however,
is dif erent. The Curves box functions as a graph that plots the relationship
between input values along the bottom of the graph and the output values
plotted vertically along the side.
Curves gives you far more control of the corrections you apply, due to the
number of points that can be placed on the graph, but requires more skill in
its application.
Levels and Curves have many similar controls. There are shadow, highlight and
gray droppers that can be used to set white and black points, and a specii c
Curve adjustment can be saved and/or loaded.
As with any power tool, the best way to work in Curves is to make subtle
gentle movements and adjustments with smooth l owing curves. Too
aggressive or too many points haphazardly placed, and adjustments will be
out of the photographic digital darkroom and into the “way-out art” fast.
Experiment with the CS4 presets for medium contrast, linear contrast, strong
contrast, and lighter and darker image adjustments to get a feel for how to
apply these corrections with a free hand - subtle, gentle, and smooth.
Curves as viewed from
the Adjustment panel
The On-Image
Adjustment tool
This new feature is
available with three
adjustment tools: Hue/
Saturation, Black &
White, and Curves. The
On-Image Adjustment
tool allows you to
selectively modify tone,
colors and luminance
levels by dragging in an
image. There is no need
to isolate a tone, color or
hue range. Just drag!
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