EDIT: WOA! Woke up today to find I had gotten my first DD. A lovely surprise. For those that are wondering how I did this, this isn't photoshopped. This is a double exposure done with a film camera. (Canon AE-1) The background is a piece of checkered material tacked to the wall of my bathroom (LOL) and the mask I ended up making myself specifically for this photoshoot. The model is one of my oldest friends, Brittany. She was awesome to work with. Thanks again for the DD.
"This isn't photoshopped".... WHOA. That's amazing. I didn't think creating stuff like this was possible without computerized edits. You proved me wrong.
It is possible albeit a bit unpredictable but sometimes you get amazing shots. It takes a little practice to position things where you want them compared to your last exposure but definitely not impossible and really fun.
Good luck! Some of it is easier than others (as you probably know). I remember some of my friends struggling with personality theory more than anything.