Replace Sky

H

haunteddoc

Member
Ok, I am going nuts trying to replace the sky in a pic that has trees. Any good tips on how to make a good clean selection around tree leaves?
 
Usually, it's best to use a background eraser tool or try a contrast mask selection first, which most versions of Photoshop and Paint Shop have. ; Trees are never easy especially with lots of branches and light peeking through.

Here's what I do:

First, copy your desired sky photo as a new layer over your original photo. ; Then move that layer to the background.

Second, select the foreground layer (the ground & trees), and make a duplicate layer. ; Select the duplicate layer. ; Go to Saturation and reduce it 100% to make it B&W (don't do greyscale conversion as that may change the main layer, which you do not want). ; Then, go to the contrast adjustment tool...you want to boost contrast very high - 70% or so, then adjust the brightness as needed - the goal is to have the photo basically look like a inkblot test - the tree branches all pure black, the sky pure white. ; Adjust brightness and contrast until there are no grey in-betweens. ; This will give you a fairly accurate 'mask' from which to select all of the tree, including the myriad branches and leaves. ; Then using your selection wand, select the black portion of the photo. ; This should select all areas that are black. ; Then invert the selection area, which will highlight all white portions (hopefully, most of the sky). ; Then, click back on the original color ground & tree foreground layer so it is now the selected layer (you can hide the B&W layer to help you see what you're doing). ; Delete the selected area - and you'll see your newly desired sky show through. ; There may still be little bits of sky that didn't delete - usually outlines or halos around the branches. ; I then select the Background Eraser tool. ; Set it to sample only once, rather than continuously, so that when you click and drag to erase a desired portion of the photo, you are only erasing that specific point of color you clicked on. ; You can drag the eraser all over the layer, but it's only going to erase that one sampled color. ; Sometimes a little Soften tool around the edges of the branches can help transition the edges a little better.

It's no small task replacing a sky around lots of trees!
 
depending on what version of photoshop you have (i don't know PSP) it can easily be done using the channels pallet. ; let me know if you want an in-depth explanation on this (article?)
 
I think I know the channels way. ; Go to channels and find the channel that has the most contrast then use the levels adjustment and painting to make a black and white photo. ; Paint the edges with ether white or black with a blend mode of soft light to get the edges. ; Then load the load the channel as a selection? ; Is that the way you are talking about.

Not sure how to do it via LAB.
 
"mousefan" said:
I agree with Tim, easy way is through the channels pallet. ; I can give a pretty thorough tutorial if you'd like.
Click to expand...

if you want to give it a shot, it might make a great idea for a new TMIP article. ; i will give you first dibs on it if you like!
 
"haunteddoc" said:
I think I know the channels way. ; Go to channels and find the channel that has the most contrast then use the levels adjustment and painting to make a black and white photo. ; Paint the edges with ether white or black with a blend mode of soft light to get the edges. ; Then load the load the channel as a selection? ; Is that the way you are talking about.

Not sure how to do it via LAB.
Click to expand...

overcomplicated. ; you see what channel has the best contrast and duplicate it. ; then you use levels to get the best possible black and white and ctrl+click the channel name which selects all of the new white areas. ; then replace the sky with a gradient or photo or whatever. ; do it in layers and you can use a mask to fix whatever parts didn't quite look right.
 
"Tim" said:
overcomplicated. ; you see what channel has the best contrast and duplicate it. ; then you use levels to get the best possible black and white and ctrl+click the channel name which selects all of the new white areas. ; then replace the sky with a gradient or photo or whatever. ; do it in layers and you can use a mask to fix whatever parts didn't quite look right.
Click to expand...

Have you tried the method Scott Kelby explains in the 7-Point book (LAB/Blend If)? ; I'm curious as to which you prefer.
 
i haven't tried that method. ; i like the way i described and once i find a way to do something comfortably, i try to not stray from it. ; i might check out the 'blend if' method just for kicks.
 
I've tried the blend-if method and could never get it to work. ; I'm going to try the other methods posted here and let you know how it comes out. ; I think part of the problem is that there is not a lot of contrast between the leaves and sky as the day was hazy. ; BTW, I am using CS4.
 
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