halos around masks

[rdtindsm]

A continual problem has been blending the edges of scenes where I've adjusted exposure in a specific area - e.g. sky vs foreground.

In my most recent attempt, I created a mask from the blue channel and used image->adjustments-.threshold to create a very nice mask of a scene that included trees.

I still get a halo at the edge. Not bad, but it's there. I've tried smoothing the edges of the mask a little and adding a few pixels of feathering to try to blend things. What is driving me bonkers is that the halo is lighter than either segment. If the halo were a continuous gradient, it would hardly be noticeable, but I get a discontinuity.

Using PS5

 

[Hoogle]

2 options really you could use a soft brush at 50% opacity and paint in black around the halo and gradually blend it in or use a gradient overlay of black to transparant and play with the blending options

 

[siodre]

for trees, as long as they're not too large and detailed in the foreground, i use a hard splatter brush and set it up to scatter. then zoom in, set the brush small and go over the white edge. the random pattern keeps it looking natural. if you need something more accurate use the pen tool to create your mask to begin with. sometimes, depending on the object and contrast, i may use blend if. but that can leave ragged edges and holes in the mask where i don't want them.