Today’s Question: I’ve been exploring the addition of a vignette effect to photos, and so far I’m happy with the results. However, no matter what setting I use for the Highlights slider I’m not seeing an effect. What is this slider supposed to do?
Tim’s Quick Answer: The Highlights slider for the vignette adjustment in Lightroom Classic, Lightroom, and Camera Raw, enables you to have bright highlights (such as the sun in the frame) overpower the vignette effect rather than being darkened down unnaturally.
More Detail: The vignette effect adjustment in Lightroom Classic, Lightroom, and Camera Raw enables you to more or less mimic the behavior of a natural lens vignette, along with other creative possibilities. The Highlights adjustment enables you to make the vignette effect more realistic in this context.
When a lens creates a vignette effect it is the result of light falloff around the edges of the frame, causing those areas to appear darker than the central area of the image. However, if there is a very bright light source, such as the sun, near the edge of the frame, that will overpower the vignette effect so that the area appears bright, with little or no visible vignette. The Highlights slider enables you to mimic this effect.
The Highlights slider is only available when you have selected either “Highlight Priority” or “Color Priority” for the style option, not with “Paint Overlay”. The Highlights slider is also only available when you have used a negative value for the vignette effect, resulting in a darkening rather than lightening of the perimeter of the photo.
In addition, the Highlights slider will only have an obvious effect if you have very bright areas (such as bright lights or the sun) in the area of the image that is being darkened by the vignette effect. In that case, increasing the value for Highlights will cause bright areas to overpower the vignette effect, so they are not darkened (or not darkened as much) as areas that are not as bright. This can create a more natural vignette effect in photos that have bright areas toward the perimeter.
