User Guide

Canvas 12 User Guide
Indexed image mode
Indexed color mode uses a palette of 256 colors for images. Since this mode stores fewer colors, it
requires significantly less memory than RGB and CMYK color modes, both of which support millions
of colors. Smaller memory requirements make Indexed mode especially useful for images used on
Web pages.
An Indexed image includes a color table, or palette, of colors used in the image. When you convert an
existing image to Indexed mode, you can specify the number of colors from the image to include in
the color table.
Most image filters, effects, and opacity controls aren’t available to be applied to Indexed images,
except the Offset and De-Interlace filters, as well as some third-party plug-in filters.
To convert an existing image to Indexed mode:
1. Select the paint objects and choose Indexed from the Image Mode menu.
2. In the Indexed Color dialog box, choose an option in the Indexed Color dialog box for the
color table.
Depending on which method you select, the Colors area in the dialog box displays
information about how the color table is computed.
Exact Creates a color table from the colors in the image, if the image
contains 256 colors or less; otherwise, this option isn’t available.
The Colors area displays the number of colors in the selected
image.
Uniform/
System
Creates a color table based on the operating system’s palette of 256
colors (System), or a subset of these colors (Uniform). The Colors
area displays the number of colors in the operating system’s
palette; if you choose Uniform, a pop-up menu that lets you select
8, 27, 64, 125, 216, or 256 colors appears.
Adaptive Creates a color table from the most frequently used colors in the
image. The Colors area displays a text box that lets you enter a
number of colors from 2 to 256
Custom Lets you create a color table, load, and save color table files. The
Colors area displays “Custom colors”.
Previous Applies the last color table used in the Indexed Color dialog box
during the current Canvas session. The Colors area displays the
number of colors in the last color table created by the Indexed Color
dialog box during the current Canvas session.
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