A vignette post-processing effect is a visual technique used in computer graphics and image processing to darken or fade the corners or edges of an image, creating a subtle or dramatic framing effect. The vignette effect draws the viewer's attention towards the center of the image and adds a sense of depth, focus, or mood to the composition.
How the original image and the effect are blended together, in most cases it does not make sense to deviate from the default value.
The Vignette darkness.
The Vignette offset.
The Vignette technique.