Adobe PHOTOSHOP ELEMENTS 2 User Manual page 196

CHAPTER 10
188
Applying Filters, Effects, and Layer Styles
5 Reset the dialog box by pressing Alt (Windows)
or Option (Mac OS).
6 Click Cancel to close the Threshold dialog box
without applying changes to the image.
Using the Posterize command
The Posterize command lets you specify the
number of tonal levels (or brightness values) for
each channel in an image and then maps pixels to
the closest matching level. For example, choosing
two tonal levels in an RGB image gives six colors,
two for red, two for green, and two for blue.
This command is useful for creating special effects,
such as large, flat areas in a photograph. Its effects
are most evident when you reduce the number of
gray levels in a grayscale image. But it also
produces interesting effects in color images.
If you want a specific number of colors in your
image, convert the image to grayscale and
specify the number of levels you want. Then convert
the image back to the previous color mode, and
replace the various gray tones with the colors
you want.
To use the Posterize command:
Do one of the following:
1
Choose Image > Adjustments > Posterize.
•
Create a new Posterize adjustment layer, or open
•
an existing Posterize adjustment layer. (See "Using
adjustment and fill layers" on page 101.)
Enter the number of tonal levels you want, and
2
click OK.
Using the Gradient Map command
The Gradient Map command maps the equivalent
grayscale range of an image to the colors of a
specified gradient fill. If you specify a two-color
gradient fill, for example, shadows in the image
map to one of the endpoint colors of the gradient
fill, highlights map to the other endpoint color,
and midtones map to the gradations in between.
To use the Gradient Map command:
Do one of the following:
1
Choose Image > Adjustments > Gradient Map.
•
Create a new Gradient Map adjustment layer, or
•
open an existing Gradient Map adjustment layer.
(See "Using adjustment and fill layers" on
page 101.)
Specify the gradient fill you want to use:
2
To choose from a list of gradient fills, click the
•
triangle to the right of the gradient fill displayed in
the Gradient Map dialog box. Click to select the
desired gradient fill, and then click in a blank area
of the dialog box to dismiss the list. (See "Working
with preset options" on page 27 for information
on customizing the gradient fill list.)
To edit the gradient fill currently displayed in the
•
Gradient Map dialog box, click the gradient fill.
Then modify the existing gradient fill or create a
new gradient fill. (See "Creating or editing
gradient fills" on page 148.)
By default, the shadows, midtones, and highlights
of the image are mapped respectively to the
starting (left) color, midpoint, and ending (right)
color of the gradient fill.