Selections and Gray Pixels

I’ve taken a number of digital photographs which show a forest of trees against a bald sky (no clouds – basically light blue to almost all white). I would like to use PS to replace the bald sky with another digital photograph of a deep blue sky containing an assortment of clouds. My preferred technique is to carefully make a selection of the bald sky, delete it and then place the new sky image as a layer underneath the original layer of the trees.

Here’s the problem: In any technique I’ve tried that uses a precise selection, I always seem to wind up with a small halo of gray pixels around the edges of the leaves and branches where the treetops meet the new sky. All my selections seem to be quite accurate yet the composite always has a small amount of gray pixels showing. I’ve tried the Matting>Defringe command but it doesn’t seem to help too much. (Just for the record, I have also used other techniques such as using a layer mask to bring in the new sky but I’ve found this to be too time consuming and the results are dependent on my ability to do a good job on "painting" away the bald sky).

I need some help with this Photoshop problem.

I’ve taken a number of digital photographs which show a forest of trees against a bald sky (no clouds – basically light blue to almost all white). I would like to use PS to replace the bald sky with another digital photograph of a deep blue sky containing an assortment of clouds. My preferred technique is to carefully make a selection of the bald sky, delete it and then place the new sky image as a layer underneath the original layer of the trees.

Here’s the problem: In any technique I’ve tried that uses a precise selection, I always seem to wind up with a small halo of gray pixels around the edges of the leaves and branches where the treetops meet the new sky. All my selections seem to be quite accurate yet the composite always has a small amount of gray pixels showing. I’ve tried the Matting>Defringe command but it doesn’t seem to help too much. (Just for the record, I have also used other techniques such as using a layer mask to bring in the new sky but I’ve found this to be too time consuming and the results are dependent on my ability to do a good job on "painting" away the bald sky).

I need something which gives me a result which looks natural and not obviously composited. Are there any tricks or alternate techniques which could produce the results I’m looking for? Any suggestions for helping me with this problem would be greatly appreciated. Thanks.

"JSB" wrote in message

I’ve taken a number of digital photographs which show a forest of trees against a bald sky (no clouds – basically light blue to almost all white). I would like to use PS to replace the bald sky with another digital photograph of a deep blue sky containing an assortment of clouds. My preferred technique is to carefully make a selection of the bald sky, delete it and then place the new sky image as a layer underneath the original layer of the trees.

Here’s the problem: In any technique I’ve tried that uses a precise selection, I always seem to wind up with a small halo of gray pixels around the edges of the leaves and branches where the treetops meet the new sky. All my selections seem to be quite accurate yet the composite always has a small amount of gray pixels showing. I’ve tried the Matting>Defringe command but it doesn’t seem to help too much. (Just for the record, I have also used other techniques such as using a layer mask to bring in the new sky but I’ve found this to be too time consuming and the results are dependent on my ability to do a good job on "painting" away the bald sky).

A layer mask does not require any painting. Make your selection as usual and use Layer>Add Layer Mask to convert the selection to a layer mask. Use Filter>Other>Maximum, Filter>Other>Maximum, and Filter>Blur>Gaussian Blur to fine-tune the mask.