Mixed visibility effect

Start by opening an image of a waterfall.

Open another image you want to mix the visibility with above waterfall image.
Drag the file to the main file.
Using lasso tool make selection of the girl.

Press Ctrl+J to copy the selection in a new layer. Hide the main girl image.
Change the color mode to linear dodge.
Enable visibility of the main girl image and make the selection of the cloth.

 

Press Ctrl+Alt+D to feather the edges. We use 2 pixels for feather. Now press Ctrl+J to copy the cloth selection in new layer. Hide the main girl image.
Change the cloth layer mode to screen.
Heres the result with an intresting mixed visibility effect.