Perlin noise generates pixels with values that vary between the foreground and background colours, resulting in a cloud pattern. Sometimes known as Clouds or Difference Clouds. It can be used to create realistic looking scaleable textures, including cloud, smoke, and rock or earth-like effects, and is a great way of adding realism to textured areas.
This filter can be found in the Filters menu, in the Noise category.
When the filter is applied, the clouds are generated using the currently selected foreground and background colours. The image data on the active layer is replaced.
The following settings can be adjusted in the filter dialog: