If you need to clean up the edges of your masks in Effects we are adding the Blur and Chisel Mask tools. The Chisel Tool is perfect for removing halos that may remain along the edges of your mask. It will remove just a small amount of pixels from the edge. The Blur Tool is perfect for only blurring or feathering the edge of your mask. Softening the edges of your mask will allow for a more natural transition when blending photos together.
Beginner Legacy Layers Develop Effects Masking Local Dan Harlacher ON1 Photo RAW 2018