Adobe PHOTOSHOP 5.0 User Manual page 239

USING CURVES FOR TONAL ADJUSTMENTS Curves lets you make precise adjustments to one area of the
tonal range while controlling the effect on the others. The first curve shown here is a common curve
adjustment used to boost contrast in a CMYK scan: the S-curve. The midpoint of the curve is anchored,
then the quartertones are decreased to lighten the highlights, and the three-quartertones are increased
to darken the shadows. The inverse of this curve could be used to correct an image with too much con-
trast. The final two curves demonstrate other typical tonal adjustments in CMYK mode. See "Using the
Curves command" on page 120.
Flat image
Midpoint fixed: 1/4 and 3/4 tones adjusted
in opposite directions to boost contrast
Light image
1/4 tone fixed: highlights, midtones, and
3/4 tones adjusted to darken image
Dark image
Entire curve dragged to lighten image
with emphasis in midtones
Original
Original
Original
Corrected
Corrected
Corrected
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