A Quick Guide To Tone Curve Corrections; About The Tone Curve; Bringing Out Detail In The Shadows - Minolta Dimage Scan Elite II Instruction Manual

A QUICK GUIDE TO TONE CURVE CORRECTIONS

Image processing is a highly specialised and difficult field that takes years of practice to master.
This basic guide to using tone curves covers a few simple procedures to improve your pictures. For
more about digital-image processing, consult your local book dealer about self-help guides on this
subject.

ABOUT THE TONE CURVE

The tone curve is a graphic representation of the brightness
255
and colour levels of the image. The bottom axis is the 256 lev-
Highlights
els of the prescan image (input data) from black to white. The
vertical axis is the corrected prescan image (output data) with
the same scale from top to bottom.
The bottom left portion of the graph represents the dark
Mid-tones
colours 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
Shadows
curve can affect the brightness, contrast, and colour of the final 0 255
image.
INPUT

BRINGING OUT DETAIL IN THE SHADOWS

This is a simple technique to make a subject hidden in the shadows brighter. Unlike the brightness
level control (page 52), 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 centre of the curve. Click and
drag the curve up. Look at the prescan 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 subject
darker.
RGB
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