Stamp

The Stamp effect makes an image appear as if it was created with a wood block stamp.

By default, this effect produces a monochrome (gray-scale) image.

Name	Specifies the operator's name.
Opacity	Sets the opacity of the effect over the input image. A value of 0 makes the effect completely transparent, while a value of 100 makes it completely opaque.
Use Alpha As Mask	Uses the input image's alpha channel as a mask for applying the effect. The effect is fully applied to areas of the image where the alpha channel is white, and not at all to areas where it is black.
Run Effect On	Enable the RGB and/or Alpha options to specify whether the effect is applied to the RGB channels, the Alpha channel, or both.
Light/Dark Balance	Set higher values to have more areas of the image take the foreground color (black by default), or set lower values to have more areas take on the background color (white by default).
Smoothness	Set higher values to make the overall image smoother, or to the left to make it less smooth.
Background Color	Sets the color for background regions of the effect. Set a color using the sliders.
Foreground Color	Sets the color for foreground regions of the effect. Set a color using the sliders.