Brush mask
A brush mask lets you point out by hand exactly where an adjustment does or doesn't go, by painting over it. It's the freest form of masking: you control every stroke. Ideal for irregular shapes that don't follow a gradient or circle.
Set your adjustment first (more brightness, say) and then paint over the area you want to affect. Adjust brush size, feather and flow for soft or hard edges. In Lightroom you can turn on 'Auto Mask', which keeps your stroke neatly within contrast edges. Make a mistake and you simply erase back with the erase option. Combine with AI selections as a starting point and refine with the brush afterward.
Related terms
Prefer a look in one click?
The presets on this site set these adjustments up for you as a starting point, which you then fine-tune to taste.