In Camera Raw, I saw the "Auto Mask" option at the bottam of all the slides of Adjustment Brush, what is this option for?
When you halt your mouse in this option, it prompts that it is for adjusting the sensitivity of brush's edge, but I don't understand what does it mean exactly.
Auto mask acts to limit brush strokes to areas of similar color. Suppose you had an image with a red flower on a green and brown background, and you want to use the adjustment brush to lighten the red flower but not lighten any of the background. Check auto mask and keep the center of the cursor within the red as you stroke the brush. The mask should be constrained to the red area. With auto mask off, brush strokes near the edge of the red could be feathered into the adjacent background area.
Is there a way to control the halos around the edges?
Might as well go into Photoshop and spend 30 minutes doing my own mask if the excessive haloing can't be improved.
Many of us were hoping Adobe would invest in improving the auto-masking technology for Lr4, but didn't happen. Fingers crossed for Lr5...
As is, it's only marginally useful...