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[ 53 ]is set to RGB, because we only want
to work with tones, and not individ-
ual color channels.
You’ll find the main controls for
Levels below the histogram: three in-
put levels sliders directly below the
graph, and two output levels sliders
below the gradient strip. The input
levels sliders are blacks, grays (mid-
tones), and whites; and the output
levels sliders are blacks and whites.
Both sets of sliders range from
0–255 levels.
Let’s start with the three-slider
group. The sliders on the outer edges
(blacks on the left and whites on the
right) control the cutoff points of
the image values. Observe the his-
togram (the actual histogram in the
Histogram panel) after you drag the
blacks slider closer to the middle. It
shows that anything to the left of this
slider is now cut off (or set to 0 levels,
which is pure black), and the whole
range will be extended to accommo-
date the space created by the cutoff.
Similarly, if you move the slider
that controls the whites, it cuts off
anything to its right by making ev-
erything to the right of it pure white
(level 255).
If you move the middle slider
(grays) to the right, it will darken the
image by compressing the shadows
and expanding the highlights; if you
move it to the left, it will brighten the
image by compressing the highlights
and expanding the shadows.
The output levels sliders below
the gradient strip control the nega-
tive starting point. As you move
either of them, it creates a gap on
the sides of the histogram, based on
the position of the slider. This way
you can tell Photoshop to make the
darkest values lighter and the light-
est values darker. [For more on Lev-
els, turn to page 88 .—Ed.]LEVELS
Levels is an extremely powerful tool. With it, you can adjust the tonal values and
color balance of an image; however, in this article, we’re only going to talk about its
basic tonal applications, but even that’s a lot in itself.
Create a new Levels adjustment layer by going to Layer >New Adjustment
Layer>Levels. This automatically opens the Properties panel, where you’ll see a
big histogram in the middle. This is what you’re going to work with visually. Before
you do anything, make sure that the Channels drop-down in the Properties panel