The Posterize adjustment creates a simpler image by reducing the number of lightness levels in each color channel. Watch our video tutorial to learn more about the Posterize adjustment.
Select Image -> Adjustment -> Posterize... to make the adjustment parameters appear in the Settings Panel.
You can also use a Posterize adjustment layer (Layers -> New -> Adjustment Layer -> Posterize...) which will affect all underlying layers without changing their content.
Levels (1-255). The parameter determines the degree of posterization of the image. At higher values of this parameter, fewer colors are used, and the image becomes more uniform and flat.
Simplicity (0-8). The parameter removes fine details. The boundaries become more uniform.
Fixed Preview Area check-box. If the check-box is enabled, all changes will be displayed in a small area indicated by the dotted line. If the check-box is disabled, the changes will be applied to the area visible in the Image Window.
Click on Default to restore the default values.
Click on OK to apply all changes and close the dialog box.
Click on Cancel to close the dialog box without applying any changes.