Background generator
The Background Generator effect can be used to create horizontal, vertical or four corner color gradients. These gradients are then applied to the current image.
You may choose any color you like as well as the opacity and then have them change with time by creating FX Stack keyframes. Here are four examples of gradients used in Colorize, Add, Tint or Subtract mode:
Source image Gradient in Color mode Gradient applied in Colorize mode
Source image Gradient in Color mode Gradient applied in Add mode
Source image Gradient in Color mode Gradient applied in Tint mode
Source image Gradient in Color mode Gradient applied in Subtract mode