If you’ve ever applied adjustments in Lightroom using the Adjustment Brush, you may have experienced some frustration trying to get them precisely where you want them. Even if you use the Auto Mask feature of the tool, Lightroom may still have a hard time selecting precisely what you want.
In this video, I am showing you a trick that helps you create highly precise masks nevertheless. The idea is to take a 2-stage approach by first creating a mask that extends beyond the edges of the area you’re trying to select. At the second stage, we’re going to use the Eraser brush with the Auto Mask feature to get rid of the excess mask areas.
You should apply this trick whenever the pixels outside the area you’re trying to select are more homogeneous than those inside the area. If, for example, you’re trying to select a clear blue sky against a mountain crest, it’s better to use the Auto Mask directly while you’re brushing on the sky (the standard way).