Double exposure photography is an interesting technique, and there are several ways of achieving this look. You can do it the old-school way of running film through your camera twice or rewinding one negative and taking two exposures. Or you can take advantage of the double exposure feature in most modern DSLRs and mirrorless cameras. This will allow you to either choose which image you want to use as a base layer or it will show you how the double exposure overlay will look as you take the image.
Finally, the third option is to take two separate images and overlay the two in Photoshop. This can give you a lot more options, however, and there are a lot of tools available to create different looks. In this video, Blake Rudis from f64 Academy walks you through using the command Blend If in Photoshop to create these awesome double exposures.
By using the Blend If slider, you can decide if you want to protect either the highlights or the shadows. It will give you a lot more options for getting the image exactly how you wish.
From there, you can then either use layer masks to reveal the parts of the image you want to keep clean, or you can change blend modes.
Another great use for Blend If is to add a background texture easily. Once again, Blend If does a great job and saves you lots of time without having to draw selections and masks painstakingly. Of course, to refine it further, you can still use masks if you wish.
Multiple exposures can create interesting moods in photographs that you can’t easily create otherwise. It’s an awful lot of fun, have a look at the video and see what you can make!