Combining 2 Images using a Mask

If you have taken 2 photos within seconds of eachother, you can combine them to get the best of each. Take for example these 2 photos (photos by Chris Orwig/Lynda.com). He is smiling in one, and she is smiling in the other:

Open up both files. Click onto one of them. Select All, Copy and then Paste it ontop of the other as a separate layer. Should look like this:

Now unlock the background layer by clicking on it. this "layer 0" window will appear. CLick OK, and the lock symbol goes away.

Now we need to align the layers since they are just slightly off. Highlight both layers (by shift clicking them) and then go to EDIT > AUTO ALIGN LAYERS. Choose the "Auto" option and hit OK. You may now need to crop the image a bit.

Next , click on the top layer. Then click the "add layer mask" button at the bottom. Invert the mask (command i).

Now, using a soft white brush, paint with white over the whole face that you want to reveal (in my case, his). Notice the white area I have painted on the mask:

By masking, we have gotten the best out of both photos!