The ND or Neutral Density Gradient darkens only a portion of the image using a graduated transition between the darkened portion and the original image. It selectively adjusts brightness without affecting color balance. The most likely use for the ND Gradient would be to balance the difference between the sky and the ground.

Tints.

To select a preset, choose one from the Presets tab.

Select one of the ND Gradient presets from the pop-up list.

Darkens the image using F-Stops as the unit of measure.

Preserves the white areas of the image.

Grad is the transition area between the darkened portion and the original image. Its direction, corners and size can be adjusted. Go to the Grad section of Common Node Controls to see how the Grad controls work.