6.9. Vignette

6.9. Vignette
	6. Lys- og skyggefiltra

6.9.1. Oversyn

In photography, vignetting is a reduction of the image brightness toward periphery. It is often an undesired effect due to camera settings or lens limitations. But it is also deliberately used to draw attention to the center of the image. «Vignette» can produce this effect.

Figur 17.128. Original images used for examples

Original

Filter applied with default options

GIMP-2.10.20 comes with on-canvas controls (default): two limits with white handles that turn to orange, and become active, when mouse pointer hovers over them. The black (default) area is the vignette. The outer limit is the limit of the vignette. The inner limit is the limit of the soft area, the unchanged area. Between the outer and the inner limits is the fade area, where the vignette is fading progressively, with a dotted line that is the midpoint line.

Vignette with default options and on-canvas controls

Click-and-drag action is different on lines and on handles:

Click-and-drag a limit line to move the limit and the midpoint (Radius and Softness).
Click-and-drag a handle to move both limits (Radius and Squeeze).
Click-and-drag the midpoint line to move it.
In the three cases, pressing Shift only changes Radius.

6.9.2. Aktivering

You can find this filter in the image menu menu through Filters → Light and Shadow → Vignette….

6.9.3. Innstillingar

Figur 17.129. «Vignette» filter options

Presets, Preview, Split view, Blending options

	Notat
	These options are described in Del 2, «Common Features».

Vignette shape

Circle
Square
Diamond
Horizontal, Vertical: limits and line are horizontal or vertical.

The shape of the vignette (ellipse or circle for example) depends on Proportion setting.

Radius

Vignette size: how far out vignetting goes as part of half image diagonal.

Radius = 0.700

Softness

Soft (unchanged) area size.

Softness = 0.100

Gamma

Falloff linearity controls the curve of the falloff from the center to periphery: set how fast is brightness reduced towards edges of the vignette(fading area size).

Gamma = 1.00

Proportion

Proportion is particular: with the default value (maxi) 1.00, the vignette is a circle in a square image and an ellipse in a rectangular image. Reducing Proportion, this ellipse tends to a circle.

Squeeze

Aspect ratio to use:

0.0 = 1:1
0.5 = 2:1

Diamond shape, proportion = 0.0 and squeeze = 0.5
1.0 = completely squeezed vertically
-0.5 = 1:2
-1.0 = completely squeezed horizontally

	Notat
	To directly use squeeze factor as proportion, set Proportion to 0.0.

Center X, Center Y

Coordinates of vignette center. Origin is the upper left corner of the image. 1.00 is the right border of the image. The center can be placed outside of the image.

Rotasjon

Rotation of the vignette. The vignette keeps its shape.

You can also click-and-drag outside the outer limit to rotate the vignette.

On-canvas controls

Uncheck this option to remove on-canvas controls.