Adjusts the intensity of an image. This value corresponds to the master contrast, it varies the amount of incoming white. The default value is 256 and it has no effect. This value corresponds to the secondary contrast (inverse whiteness), it varies the amount of incoming black into the image. The default value is 256 and it has no effect. contrast about black contrast about white produces a grid like the incoming grid but with different constrast. resulting values outside 0-255 are automatically clipped.