Adobe photoshop elements 用户手册
CHAPTER 4
98
Making Color and Tonal Corrections
To use the Posterize command:
1
Do one of the following:
•
Choose Image > Adjustments > Posterize.
•
Create a new Posterize adjustment layer, or open
an existing Posterize adjustment layer. (See “Using
adjustment layers and fill layers” on page 181.)
adjustment layers and fill layers” on page 181.)
2
Enter the number of tonal levels you want, and
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.
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:
1
Do one of the following:
•
Choose Image > Adjustments > Gradient Map.
•
Create a new Gradient Map adjustment layer, or
open an existing Gradient Map adjustment layer.
(See “Using adjustment layers and fill layers” on
page 181.)
(See “Using adjustment layers and fill layers” on
page 181.)
2
Specify the gradient fill you want to use:
•
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 presets” on page 35 for information on
customizing the gradient fill list.)
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 presets” on page 35 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 151.)
Then modify the existing gradient fill or create a
new gradient fill. (See “Creating or editing
gradient fills” on page 151.)
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.
of the image are mapped respectively to the
starting (left) color, midpoint, and ending (right)
color of the gradient fill.
3
Select either, none, or both of the Gradient
Options:
•
Dither adds random noise to smooth the
appearance of the gradient fill and reduce banding
effects.
effects.
•
Reverse switches the direction of the gradient fill,
reversing the gradient map.
4
Click OK.
Sharpening images
Unsharp masking, or USM, is a traditional film
compositing technique used to sharpen edges in
an image. The Unsharp Mask filter corrects
blurring introduced during photographing,
scanning, resampling, or printing. It is useful for
images intended for both print and online
viewing.
compositing technique used to sharpen edges in
an image. The Unsharp Mask filter corrects
blurring introduced during photographing,
scanning, resampling, or printing. It is useful for
images intended for both print and online
viewing.