The controls in the adjustment panels in the Develop module let you affect the color and tone of an entire photo. But sometimes you don’t want to make adjustments globally, to the entire photo. You want to make corrections to a specific area of a photo. For example, you may want to lighten a face to make it stand out in a portrait or enhance the blue sky in a landscape. To make local corrections in Lightroom, you can apply color and tonal adjustments using the Adjustment Brush tool and the Graduated Filter tool.
The Adjustment Brush tool lets you selectively apply Exposure, Clarity, Brightness, and other adjustments to photos by “painting” them onto the photo.
The Graduated Filter tool lets you apply Exposure, Clarity, and other tonal adjustments gradually across a region of a photo. You can make the region as wide or as narrow as you like.
As with all other adjustments applied in the Develop module in Lightroom, local adjustments are nondestructive and are not permanently applied to the photo.