5.8. Posterize

This tool is designed to intelligently weigh the pixel colors of the selection or active layer and reduce the number of colors while maintaining a semblance of the original image characteristics.

5.8.1. Activating the Tool

You can find this tool from the image-menu through: ToolsColor ToolsPosterize or ColorsPosterize,

or by clicking the icon in ToolBox, if Color Tools have been added to it.

5.8.2. Options

图 13.153. Posterize tool options

Posterize tool options

Posterize Levels

This slider and the input boxes with arrow-heads allow you to set the number of levels (2-256) in each RGB channel that the tool will use to describe the active layer. The total number of colors is the combination of these levels. A level to 3 will give 23 = 8 colors.

Preview

The Preview check-box makes all changes dynamically so that they can be viewed straight away.

5.8.3.  Example

图 13.154.  Example for the “Posterize” tool

Example for the Posterize tool

Image posterized in 4 levels. The histogram shows the 4 levels and 10 colors, counting black and white also.