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"Select Sky" in Camera Raw and Photoshop produces excellent results, since it selectively adds alpha in tree silhouettes towards branch tips, etc. It's impressive when looking at the mask using "Show Overlay -> Black on White".

How can I create a mask with a similar quality between (e.g.) a foreground tree line and another background tree line ? "Select Sky" always selects the actual true sky line, or some other unintended result when there's a more complex horizon. Is there a "semi-automated, refine-the-users-rough-selection" mode that selectively adds alpha like the AI does ?

Quick Selection with a feather of constant width along the entire mask border doesn't cut it in many (most) cases.

edit: in the image below I'm trying to create a mask for the trees in the foreground which are too dark. enter image description here

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  • Hi. Welcome to GDSE. Do you have an example image which you are trying to work with? Can you share it? Different images may require different techniques depending on things like the complexity of the background or contrast between foreground an background. I very much doubt if there's a one size fits all solution. There is a refine mask function in Photoshop, but it's very much image dependent. It won't work for everything.
    – Billy Kerr
    Jan 13 at 22:27

2 Answers 2

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Thanks for the image update. Yes. It should be possible with that image.

Use the Quick Selection tool to make a rough selection of the trees in the foreground, like this

enter image description here

Then hit the Select and Mask button in the controls along the top

In the Select and Mask properties panel, choose the Onion Skin view from the dropdown, and set the transparency to something like 65%

enter image description here

Using the Refine Edge Brush, which you can adjust the size of using the square bracket keys, draw along the edge of the trees.

enter image description here

Apply this selection as your mask

Here's the result with the mask added

enter image description here

Here's a zoomed in close up showing the quality of the mask itself

enter image description here

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  • I can replicate the result using Select and Mask like you described. It does need some finesse though, and once the selection becomes a mask, I guess the Brush tool with Overlay mode needs to be used instead to make further changes.
    – patraulea
    Jan 14 at 0:10
  • @patraulea Yes that would work, also you can double click on the mask and continue to refine it in the Select and Mask workspace. Lot's of other possibilities too, like using a curves adjustment on the layer mask, etc.
    – Billy Kerr
    Jan 14 at 0:12
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Not much to add. But what to do with that mask? You may think you use it in a copy of your image layer and the copy gets some exposure or level adjustment. Or as well you put it to a curves adjustment layer and lift up the dark areas with it. Both of these ideas can give equivalent results- except adjustment layers can easily be readjusted.

An example:

enter image description here

Unfortunately making radical contrast adjustments change the color, too. The lifted bottom zone has wrong colors.

The color can be fixed by inserting to the top a new copy of the original. Let it have layer blending mode = Color:

enter image description here

Terminate the process by inserting a global contrast boost so that the whole brightness range of the RGB display is used. Insert a curves adjustment layer:

enter image description here

As said, adjustment layers are useful because they allow readjusting, so experimenting is possible. Here's an example. The dark foreground is a little more better visible:

enter image description here

The masked curves layer above Layer 1 is quite radical, it does more than the previously tried level adjustment. It makes the colors totally wrong, but the layer copy with blending mode color fixes it. The top layer maximizes the final global contrast.

You may wonder why I lifted the lightness of the foreground forest so little? Answer: Your JPG doesn't allow more without lifting up also the noise. If the original RAW image would be available instead of the JPG there probably would be much more room to lift the dark area.

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