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ADOBE PHOTOSHOP CS2
User Guide
Customizing indexed color tables
The Color Table command lets you make changes to the color table of an indexed-color image. These customization
features are particularly useful with
pseudocolor images
—images displaying variations in gray levels with color rather
than shades of gray, often used in scientific and medical applications. However, customizing the color table can also
produce special effects with indexed-color images that have a limited number of colors.
Note:
To shift colors simply in a pseudocolor image, choose Image > Adjustments, and use the color adjustment
commands in the submenu.
To edit colors and assign transparency with a color table
You can edit colors in the color table to produce special effects, or assign transparency in the image to a single color
in the table.
1
Open the indexed-color image.
2
Choose Image > Mode > Indexed Color.
3
In the Indexed Color dialog box, choose Custom from the Palette menu.
4
In the Color Table dialog box, click or drag in the table to choose the color or range of colors you want to change.
5
Choose a color and click OK.
If you are changing a range of colors, Photoshop creates a gradient in the color table between the starting and ending
colors. The first color you choose in the Color Picker is the beginning color for the range. When you click OK, the
Color Picker reappears so that you can choose the last color in the range.
The colors you selected in the Color Picker are placed in the range you selected in the Color Table dialog box.
6
Click OK in the Color Table dialog box to apply the new colors to the indexed-color image.
7
Click OK in the Indexed Color dialog box.
To assign transparency to a single color
1
Open the indexed-color image.
2
Choose Image > Mode > Indexed Color.
3
In the Indexed Color dialog box, choose Custom from the Palette menu. This opens the Color Table dialog box.
4
In the Color Table dialog box, select the Eyedropper tool
, and click the desired color in the table or in the
image. The sampled color is replaced with transparency in the image.
Predefined color tables
Your indexed color table can be modeled after the following predefined color tables:
Custom
Creates a palette you specify.
Black Body
Displays a palette based on the different colors a black body radiator emits as it is heated—from black
to red, orange, yellow, and white.
Grayscale
Displays a palette based on 256 levels of gray—from black to white.
Spectrum
Displays a palette based on the colors produced as white light passes through a prism—from violet, blue,
and green to yellow, orange, and red.
