The Variate bump function can be used to quickly add structure to the texture (e.g. bevel). It shades the texture by slightly brightening the illuminated sides of the texture and darkening the other pixels.

The illumination is dependent upon the position of the light source, which is simulated on a sphere at the Direction panel. Setting the light source radius to its maximum works best for this function.

The Variate function is optimally used with the Mask as Heightmap. Image2 was created with the Shadow Fill preset, which added the bark structure to the texture.

Regulate the intensity of the function with the Amplify value.