GIT 341: Digital File Prep: Adobe Tutorial: How to Replace the Sky in a Photo

Step 1: Select all of the original photo (command + A) and copy it.
Step 2: Paste it into the replacement sky document window. The original photo is now on its own layer (layer 1) and will be blocking the replacement sky photo.
Step 3: Duplicate the original photo (command + J)
Step 4: Remove the visibility of the top layer (the duplicated original photo) by clicking on the visibility icon to the far left of the layer's preview thumbnail.
Step 5: Click on layer one to make it the active layer.
Step 6: Select the area of the original photo you want to protect by using one of the lasso tools or the quick selection tool.
Step 7: Once you have the area selected you want to protect, convert the selection to a layer mask by clicking on the layer mask icon at the bottom of the Layers Panel.
Step 8: Turn on the visibility of the top layer.
Step 9: Double click on the layer's preview thumbnail. This will open the Layer Style dialog box Blending Options. In the Advanced Blending section, change the Blend If option to Blue.
Step 10: On the This Layer slider bar, drag the right slider to the left. This will cause the sky in the original photo will to disappear, keep dragging until most of it is gone.
Step 11: Hold option (or alt for windows) on your key board and click on the slider and keep dragging toward the left. This will split the slider into two. Now you can adjust them independently of each other. Adjust the sliders until you are happy with the result, then click okay to complete the sky replacement.