Noise Functions
 

The Noise functions are very useful to make the textures look less clean and artificial. They add for example aging effects, erosion, spots and scratches.

 

Here is a list of the Noise modificators:

Erosion Erosion simulating function to make your textures look aged.
Pixel Simple monochrome pixel noise.
Randomize Variate the shades of isolated areas.
Scratch Add directional scratches.
Spots Fractal, colored spots.
Structure Apply a multifractal pattern to the texture.
Tears Fractal, bright and dark tears.
Variate Variate the shades with a coherent noise.