Aside with sliders.
check out the various hue ranges in the picture. You will
find four ranges in Tone Curve:
Highlights: The lightest colors of the
picture, areas close to white.
Lights: The light parts of the picture.
Darks: The dark parts of the picture.
Shadows: the shady areas, close to black.
If you click on the icon mentioned above and then on the
almost white sky, and then move the mouse up or down while
keeping the left button pressed, you can influence Highlights.
Move the mouse upwards to make these parts lighter, and
downwards to make them appear darker. Take a glance at Highlights
slider to check how its value changes accordingly.
Next find a light grey area, click on it and drag the mouse
pointer over the image with the button pressed. You are
now influencing the Lights slider, the
light areas. Finally repeat the action on a darker grey
(Darks) and a close to black area (Shadows)
as well. All the pixels will change in accordance with the
darkness of the area you clicked on, without having to interfere
with the sliders.
Histogram of Tone Curve window will be of help in this.
If you drag the mouse pointer over any point of the picture,
histogram will indicate whether it belongs
to Highlights, Lights, Darks or Shadows hue range, or in
other words, to which slider will be effected if you make
changes at that point.
You can carry this out at any point of the picture and later
fine-tune the lightness or darkness of the given range at
another point of the picture too.