A Short Guide To Tone-Curve Corrections - Minolta DIMAGE S404 - SOFTWARE Instruction Manual

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DVANCED IMAGE PROCESSING

A short guide to tone-curve corrections

Highlights
Mid-tones
Shadows
Input
This is a simple technique to make a subject hidden in the shadows
brighter. Unlike the brightness level control (page 22), this method
of correction will not lose details in the highlight areas of the image.
With the RGB channel selected, place the smooth-curve cursor on
the center of the curve. Click and drag the curve up. Look at the
displayed image to judge the result. The adjustment can be very
small and still have a significant impact on the image. Moving the
tone curve down will make the image darker.
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The tone curve is a graphic representation of the brightness and color
levels of the image. The bottom axis is the 256 levels of the original
image (input data) from black to white. The vertical axis is the correct-
ed image (output data) with the same scale from top to bottom.
The bottom left portion of the graph represents the dark colors and
shadow areas of the image. The middle section represents the mid-
tones: skin, grass, blue sky. The top right section is the highlights:
clouds, lights. Changing the tone curve can affect the brightness, con-
trast, and color of the image.