Rainbow
Creates different rainbow gradients.

Beam | Linear | Radial
Curl | Twirl | Angle
Horizontal Bow | Vertical Bow |

Preview Cross | Right click on the preview to set the center of the effect. For the Linear effect you have to use the preview cross to change the angle and density of the linear rainbow gradient.
Angle Slider | Lets you rotate the rainbow color 360 degrees around.
Multiply Slider | Adjusts the density of the effect e.g. a value of four means that the effect consists of 4 rainbow gradients.
Brightness Slider | Lets you adjust the brightness of the effect.
Red / Green / Blue Sliders | If each of these three sliders has a value of 255, the rainbow effect uses the full color spectrum. Decreasing these slider values, will remove color components from the rainbow effect.
Blending Slider | Amount with which the effect is blended with the original image.
Negative / Positive Check Box | Blends the rainbow effect according to a negative or positive mode. Use the Brightness slider to control this effect. If both check boxes are activated, the blending effect will be more balanced.
Invert Check Box | Lets you invert the rainbow colors.