Apply a vignetting effect to the image.

Vignetting is a modification of the brightness and saturation at the borders of the image in a specified shape. Many of the parameters listed below can also be modified with a graphical control that overlays the image when the module has focus, showing the shape and extent of the effect.

Note: This module is known to provoke banding artifacts under certain conditions. You should consider activating the dithering module to alleviate this.

Also note: This module can produce unnatural-looking results and should be used with care. Instead, use the exposure module with an elliptical mask with a large transition area and, if necessary, use the color balance rgb module with the same mask to reduce saturation at the edges.

module controls

The radius of the vignetting area.
fall-off strength
The progressiveness of the fall-off. Lower values cause a steeper transition.
The intensity of brightening (positive values) or darkening (negative values).
Control how strong colors become when desaturated/saturated in the darkened/brightened vignetting area.
horizontal/vertical center
Shift the center of the vignetting area horizontally/vertically.
The shape of the vignetting effect. The default value of 1 creates a circular or elliptical area. Smaller values shift the shape to being more square; higher values turn it into a cross-like shape.
automatic ratio
Automatically adjust the width/height ratio of the vignetting area to match the aspect ratio of the underlying image. This typically causes the vignetting area to become elliptical.
width/height ratio
Manually adjust the width/height ratio of the vignetting area.
Activate random noise dithering to alleviate banding artifacts caused by vignette gradients. Select “8-bit output” to prevent banding on monitor display and for JPEGs. When set to “16-bit output”, only a small amount of dithering is applied, just strong enough to compensate for banding on the fine grained 16-bit level. It is now recommended that you instead use the dithering module to alleviate banding artifacts.